8 .ds RF FORMFEED[Page %]
17 Network Working Group P. Riikonen
19 draft-riikonen-silc-spec-01.txt 6 October 2000
25 Secure Internet Live Conferencing (SILC),
26 Protocol Specification
27 <draft-riikonen-silc-spec-01.txt>
32 This document is an Internet-Draft and is in full conformance with
33 all provisions of Section 10 of RFC 2026. Internet-Drafts are
34 working documents of the Internet Engineering Task Force (IETF), its
35 areas, and its working groups. Note that other groups may also
36 distribute working documents as Internet-Drafts.
38 Internet-Drafts are draft documents valid for a maximum of six months
39 and may be updated, replaced, or obsoleted by other documents at any
40 time. It is inappropriate to use Internet-Drafts as reference
41 material or to cite them other than as "work in progress."
43 The list of current Internet-Drafts can be accessed at
44 http://www.ietf.org/ietf/1id-abstracts.txt
46 The list of Internet-Draft Shadow Directories can be accessed at
47 http://www.ietf.org/shadow.html
49 The distribution of this memo is unlimited.
55 This memo describes a Secure Internet Live Conferencing (SILC)
56 protocol which provides secure conferencing services over insecure
57 network channel. SILC is IRC [IRC] like protocol, however, it is
58 not equivalent to IRC and does not support IRC. Strong cryptographic
59 methods are used to protect SILC packets inside SILC network. Two
60 other Internet Drafts relates very closely to this memo; SILC Packet
61 Protocol [SILC2] and SILC Key Exchange and Authentication Protocols
75 1 Introduction .................................................. 3
76 2 SILC Concepts ................................................. 3
77 2.1 SILC Network Topology ..................................... 4
78 2.2 Communication Inside a Cell ............................... 5
79 2.3 Communication in the Network .............................. 6
80 2.4 Channel Communication ..................................... 7
81 2.5 Router Connections ........................................ 7
82 3 SILC Specification ............................................ 8
83 3.1 Client .................................................... 8
84 3.1.1 Client ID ........................................... 9
85 3.2 Server .................................................... 10
86 3.2.1 Server's Local ID List .............................. 10
87 3.2.2 Server ID ........................................... 11
88 3.2.3 SILC Server Ports ................................... 11
89 3.3 Router .................................................... 12
90 3.3.1 Router's Local ID List .............................. 12
91 3.3.2 Router's Global ID List ............................. 13
92 3.3.3 Router's Server ID .................................. 13
93 3.4 Channels .................................................. 14
94 3.4.1 Channel ID .......................................... 15
95 3.5 Operators ................................................. 15
96 3.6 SILC Commands ............................................. 15
97 3.7 SILC Packets .............................................. 16
98 3.8 Packet Encryption ......................................... 16
99 3.8.1 Determination of the Source and the Destination ..... 17
100 3.8.2 Client To Client .................................... 17
101 3.8.3 Client To Channel ................................... 19
102 3.8.4 Server To Server .................................... 19
103 3.9 Key Exchange And Authentication ........................... 20
104 3.10 Algorithms ............................................... 20
105 3.10.1 Ciphers ............................................ 20
106 3.10.2 Public Key Algorithms .............................. 21
107 3.10.3 Hash Functions ..................................... XXX
108 3.10.4 MAC Algorithms ..................................... XXX
109 3.10.5 Compression Algorithms ............................. XXX
110 3.11 SILC Public Key .......................................... 22
111 3.12 SILC Version Detection ................................... 24
112 4 SILC Procedures ............................................... 25
113 4.1 Creating Client Connection ................................ 25
114 4.2 Creating Server Connection ................................ 26
115 4.3 Joining to a Channel ...................................... 27
116 4.4 Channel Key Generation .................................... 28
117 4.5 Private Message Sending and Reception ..................... 29
118 4.6 Private Message Key Generation ............................ 29
119 4.7 Channel Message Sending and Reception ..................... 30
120 4.8 Session Key Regeneration .................................. 30
121 4.9 Command Sending and Reception ............................. 30
122 5 SILC Commands ................................................. 31
123 5.1 SILC Commands Syntax ...................................... 31
124 5.2 SILC Commands List ........................................ 33
125 5.3 SILC Command Status Types ................................. 56
126 5.3.1 SILC Command Status Payload ......................... 56
127 5.3.2 SILC Command Status List ............................ 57
128 6 Security Considerations ....................................... 61
129 7 References .................................................... 61
130 8 Author's Address .............................................. 62
137 Figure 1: SILC Network Topology
138 Figure 2: Communication Inside cell
139 Figure 3: Communication Between Cells
140 Figure 4: Router Connections
141 Figure 5: SILC Public Key
142 Figure 6: SILC Command Status Payload
148 This document describes a Secure Internet Live Conferencing (SILC)
149 protocol which provides secure conferencing services over insecure
150 network channel. SILC is IRC [IRC] like protocol, however, it is
151 not equivalent to IRC and does not support IRC.
153 Strong cryptographic methods are used to protect SILC packets inside
154 SILC network. Two other Internet Drafts relates very closely to this
155 memo; SILC Packet Protocol [SILC2] and SILC Key Exchange and
156 Authentication Protocols [SILC3].
158 The protocol uses extensively packets as conferencing protocol
159 requires message and command sending. The SILC Packet Protocol is
160 described in [SILC2] and should be read to fully comprehend this
161 document and protocol. [SILC2] also describes the packet encryption
162 and decryption in detail.
164 The security of SILC protocol and for any security protocol for that
165 matter is based on strong and secure key exchange protocol. The SILC
166 Key Exchange protocol is described in [SILC3] along with connection
167 authentication protocol and should be read to fully comprehend this
168 document and protocol.
170 The SILC protocol has been developed to work on TCP/IP network
171 protocol, although it could be made to work on other network protocols
172 with only minor changes. However, it is recommended that TCP/IP
173 protocol is used under SILC protocol. Typical implementation would
174 be made in client-server model.
180 This section describes various SILC protocol concepts that forms the
181 actual protocol, and in the end, the actual SILC network. The mission
182 of the protocol is to deliver messages from clients to other clients
183 through routers and servers in secure manner. The messages may also
184 be delivered from one client to many clients forming a group, also
187 This section does not focus to security issues, instead basic network
188 concepts are introduced to make the topology of the SILC network
193 2.1 SILC Network Topology
195 SILC network is a cellular network as opposed to tree style network
196 topology. The rationale for this is to have servers that can perform
197 specific kind of tasks what other servers cannot perform. This leads
198 to two kinds of servers; normal SILC servers and SILC routers.
200 A difference between normal server and router server is that routers
201 knows everything about everything in the network. They also do the
202 actual routing of the messages to the correct receiver. Normal servers
203 knows only about local information and nothing about global information.
204 This makes the network faster as there are less servers that needs to
205 keep global information up to date at all time.
207 This, on the other hand, leads to cellular like network, where routers
208 are in the center of the cell and servers are connected to the router.
210 Following diagram represents SILC network topology.
230 ---- ---- ---- ---- ---- ----
231 | S8 | S5 | S4 | | S7 | S5 | S6 |
232 ----- ---- ----- ----- ---- -----
233 | S7 | S/R1 | S2 | --- | S8 | S/R2 | S4 |
234 ---- ------ ---- ---- ------ ----
235 | S6 | S3 | S1 | | S1 | S3 | S2 | ---- ----
236 ---- ---- ---- ---- ---- ---- | S3 | S1 |
237 Cell 1. \\ Cell 2. | \\____ ----- -----
239 ---- ---- ---- ---- ---- ---- ---- ------
240 | S7 | S4 | S2 | | S1 | S3 | S2 | | S2 | S5 |
241 ----- ---- ----- ----- ---- ----- ---- ----
242 | S6 | S/R3 | S1 | --- | S4 | S/R5 | S5 | ____/ Cell 4.
243 ---- ------ ---- ---- ------ ----
244 | S8 | S5 | S3 | | S6 | S7 | S8 | ... etc ...
245 ---- ---- ---- ---- ---- ----
250 Figure 1: SILC Network Topology
253 A cell is formed when a server or servers connect to one router. In
254 SILC network normal server cannot directly connect to other normal
255 server. Normal server may only connect to SILC router which then
256 routes the messages to the other servers in the cell. Router servers
257 on the other hand may connect to other routers to form the actual SILC
258 network, as seen in above figure. However, router is also normal SILC
259 server; clients may connect to it the same way as to normal SILC
260 servers. Normal server also cannot have active connections to more
261 than one router. Normal server cannot be connected to two different
262 cells. Router servers, on the other hand, may have as many router to
263 router connections as needed.
265 There are many issues in this network topology that needs to be careful
266 about. Issues like the size of the cells, the number of the routers in
267 the SILC network and the capacity requirements of the routers. These
268 issues should be discussed in the Internet Community and additional
269 documents on the issue will be written.
273 2.2 Communication Inside a Cell
275 It is always guaranteed that inside a cell message is delivered to the
276 recipient with at most two server hops. Client who is connected to
277 server in the cell and is talking on channel to other client connected
278 to other server in the same cell, will have its messages delivered from
279 its local server first to the router of the cell, and from the router
280 to the other server in the cell.
282 Following diagram represents this scenario:
296 Figure 2: Communication Inside cell
299 Example: Client 1. connected to Server 1. message sent to
300 Client 4. connected to Server 2. travels from Server 1.
301 first to Router which routes the message to Server 2.
302 which then sends it to the Client 4. All the other
303 servers in the cell will not see the routed message.
306 If client is connected directly to the router, as router is also normal
307 SILC server, the messages inside the cell are always delivered only with
308 one server hop. If clients communicating with each other are connected
309 to the same server, no router interaction is needed. This is the optimal
310 situation of message delivery in the SILC network.
314 2.3 Communication in the Network
316 If the message is destined to server that does not belong to local cell
317 the message is routed to the router server to which the destination
318 server belongs, if the local router is connected to destination router.
319 If there is no direct connection to the destination router, the local
320 router routes the message to its primary route. Following diagram
321 represents message sending between cells.
326 1 --- S1 S4 --- 5 S2 --- 1
327 S/R - - - - - - - - S/R
337 Figure 3: Communication Between Cells
340 Example: Client 5. connected to Server 4. in Cell 1. message sent
341 to Client 2. connected to Server 1. in Cell 2. travels
342 from Server 4. to Router which routes the message to
343 Router in Cell 2, which then routes the message to
344 Server 1. All the other servers and routers in the
345 network will not see the routed message.
348 The optimal case of message delivery from client point of view is
349 when clients are connected directly to the routers and the messages
350 are delivered from one router to the other router.
354 2.4 Channel Communication
356 Messages may be sent to group of clients as well. Sending messages to
357 many clients works the same way as sending messages point to point, from
358 message delivery point of view. Security issues are another matter
359 which are not discussed in this section.
361 Router server handles the message routing to multiple recipients. If
362 any recipient is not in the same cell as the sender the messages are
365 Server distributes the channel message to its local clients who are
366 joined to the channel. Also, router distributes the message to its
367 local clients on the channel.
371 2.5 Router Connections
373 Router connections play very important role in making the SILC like
374 network topology to work. For example, sending broadcast packets in
375 SILC network require special connections between routers; routers must
376 be connected in specific way.
378 Every router has their primary route which is a connection to another
379 router in the network. Unless there is only two routers in the network
380 must not routers use each other as their primary routes. The router
381 connections in the network must form a circular.
383 Example with three routers in the network:
393 S/R1 - > - > - > - > - > - > - S/R2
396 \\ - < - < - S/R3 - < - < - /
401 Figure 4: Router Connections
404 Example: Network with three routers. Router 1. uses Router 2. as its
405 primary router. Router 2. uses Router 3. as its primary router,
406 and Router 3. uses Router 1. as its primary router. There may
407 be other direct connections between the routers but they must
408 not be used as primary routes.
410 The above example is applicable to any amount of routers in the network
411 except for two routers. If there are only two routers in the network both
412 routers must be able to handle situation where they use each other as their
415 The issue of router connections are very important especially with SILC
416 broadcast packets. Usually all router wide information in the network is
417 distributed by SILC broadcast packets.
421 3. SILC Specification
423 This section describes the SILC protocol. However, [SILC2] and
424 [SILC3] describes other important protocols that are part of this SILC
425 specification and must be read.
431 A client is a piece of software connecting to SILC server. SILC client
432 cannot be SILC server. Purpose of clients is to provide the user
433 interface of the SILC services for end user. Clients are distinguished
434 from other clients by unique Client ID. Client ID is a 128 bit ID that
435 is used in the communication in the SILC network. The client ID is
436 based on the nickname selected by the user. User uses logical nicknames
437 in communication which are then mapped to the corresponding Client ID.
438 Client ID's are low level identifications and must not be seen by the
441 Clients provide other information about the end user as well. Information
442 such as the nickname of the user, username and the hostname of the end
443 user and user's real name. See section 3.2 Server for information of
444 the requirements of keeping this information.
446 The nickname selected by the user is not unique in the SILC network.
447 There can be 2^8 same nicknames for one IP address. As for comparison
448 to IRC [IRC] where nicknames are unique this is a fundamental difference
449 between SILC and IRC. This causes the server names to be used along
450 with the nicknames to identify specific users when sending messages.
451 This feature of SILC makes IRC style nickname-wars obsolete as no one
452 owns their nickname; there can always be someone else with the same
453 nickname. The maximum length of nickname is 128 characters.
459 Client ID is used to identify users in the SILC network. The Client ID
460 is unique to the extent that there can be 2^128 different Client ID's,
461 and ID's based on IPv6 addresses extends this to 2^224 different Client
462 ID's. Collisions are not expected to happen. The Client ID is defined
466 128 bit Client ID based on IPv4 addresses:
468 32 bit Server ID IP address (bits 1-32)
469 8 bit Random number or counter
470 88 bit Truncated MD5 hash value of the nickname
472 224 bit Client ID based on IPv6 addresses:
474 128 bit Server ID IP address (bits 1-128)
475 8 bit Random number or counter
476 88 bit Truncated MD5 hash value of the nickname
478 o Server ID IP address - Indicates the server where this
479 client is coming from. The IP address hence equals the
480 server IP address where to the client has connected.
482 o Random number or counter - Random number to further
483 randomize the Client ID. Another choice is to use
484 a counter starting from the zero (0). This makes it
485 possible to have 2^8 same nicknames from the same
488 o MD5 hash - MD5 hash value of the nickname is truncated
489 taking 88 bits from the start of the hash value. This
490 hash value is used to search the user's Client ID from
494 Collisions could occur when more than 2^8 clients using same nickname
495 from the same server IP address is connected to the SILC network.
496 Server must be able to handle this situation by refusing to accept
497 anymore of that nickname.
499 Another possible collision may happen with the truncated hash value of
500 the nickname. It could be possible to have same truncated hash value for
501 two different nicknames. However, this is not expected to happen nor
502 cause any problems if it would occur. Nicknames are usually logical and
503 it is unlikely to have two distinct logical nicknames produce same
504 truncated hash value.
510 Servers are the most important parts of the SILC network. They form the
511 basis of the SILC, providing a point to which clients may connect to.
512 There are two kinds of servers in SILC; normal servers and router servers.
513 This section focus on the normal server and router server is described
514 in the section 3.3 Router.
516 Normal servers may not directly connect to other normal server. Normal
517 servers may only directly connect to router server. If the message sent
518 by the client is destined outside the local server it is always sent to
519 the router server for further routing. Server may only have one active
520 connection to router on same port. Normal server may not connect to other
521 cell's router except in situations where its cell's router is unavailable.
523 Servers and routers in the SILC network are considered to be trusted.
524 With out a doubt, servers that are set to work on ports above 1023 are
525 not considered to be trusted. Also, the service provider acts important
526 role in the server's trustworthy.
530 3.2.1 Server's Local ID List
532 Normal server keeps various information about the clients and their end
533 users connected to it. Every normal server must keep list of all locally
534 connected clients, Client ID's, nicknames, usernames and hostnames and
535 user's real name. Normal servers only keeps local information and it
536 does not keep any global information. Hence, normal servers knows only
537 about their locally connected clients. This makes servers efficient as
538 they don't have to worry about global clients. Server is also responsible
539 of creating the Client ID's for their clients.
541 Normal server also keeps information about locally created channels and
545 Hence, local list for normal server includes:
548 server list - Router connection
559 client list - All clients in server
567 channel list - All channels in server
570 o Client ID's on channel
571 o Client ID modes on channel
580 Servers are distinguished from other servers by unique 64 bit Server ID
581 (for IPv4) or 160 bit Server ID (for IPv6). The Server ID is used in
582 the SILC to route messages to correct servers. Server ID's also provide
583 information for Client ID's, see section 3.1.1 Client ID. Server ID is
587 64 bit Server ID based on IPv4 addresses:
589 32 bit IP address of the server
593 160 bit Server ID based on IPv6 addresses:
595 128 bit IP address of the server
599 o IP address of the server - This is the real IP address of
602 o Port - This is the port the server is bound to.
604 o Random number - This is used to further randomize the Server ID.
607 Collisions are not expected to happen in any conditions. The Server ID
608 is always created by the server itself and server is responsible of
609 distributing it to the router.
613 3.2.3 SILC Server Ports
615 Following ports has been assigned by IANA for the SILC protocol:
622 If there are needs to create new SILC networks in the future the port
623 numbers must be officially assigned by the IANA.
625 Server on network above privileged ports (>1023) should not be trusted
626 as they could have been set up by untrusted party.
632 Router server in SILC network is responsible for keeping the cell together
633 and routing messages to other servers and to other routers. Router server
634 is also a normal server thus clients may connect to it as it would be
635 just normal SILC server.
637 However, router servers has a lot of important tasks that normal servers
638 do not have. Router server knows everything about everything in the SILC.
639 They know all clients currently on SILC, all servers and routers and all
640 channels in SILC. Routers are the only servers in SILC that care about
641 global information and keeping them up to date at all time. And, this
642 is what they must do.
646 3.3.1 Router's Local ID List
648 Router server as well must keep local list of connected clients and
649 locally created channels. However, this list is extended to include all
650 the informations of the entire cell, not just the server itself as for
653 However, on router this list is a lot smaller since routers do not keep
654 information about user's nickname, username and hostname and real name
655 since these are not needed by the router. Router keeps only information
659 Hence, local list for router includes:
662 server list - All servers in the cell
669 client list - All clients in the cell
673 channel list - All channels in the cell
675 o Client ID's on channel
676 o Client ID modes on channel
681 Note that locally connected clients and other information include all the
682 same information as defined in section section 3.2.1 Server's Local ID
687 3.3.2 Router's Global ID List
689 Router server must also keep global list. Normal servers do not have
690 global list as they know only about local information. Global list
691 includes all the clients on SILC, their Client ID's, all created channels
692 and their Channel ID's and all servers and routers on SILC and their
693 Server ID's. That is said, global list is for global information and the
694 list must not include the local information already on the router's local
697 Note that the global list does not include information like nicknames,
698 usernames and hostnames or user's real names. Router does not keep
699 these informations as they are not needed by the router. This
700 information is available from the client's server which maybe queried
703 Hence, global list includes:
706 server list - All servers in SILC
712 client list - All clients in SILC
715 channel list - All channels in SILC
717 o Client ID's on channel
718 o Client ID modes on channel
723 3.3.3 Router's Server ID
725 Router's Server ID's are equivalent to normal Server ID's. As routers
726 are normal servers as well same types of ID's applies for routers as well.
727 Thus, see section 3.2.2 Server ID. Server ID's for routers are always
728 created by the remote router where the router is connected to.
734 A channel is a named group of one or more clients which will all receive
735 messages addressed to that channel. The channel is created when first
736 client requests JOIN command to the channel, and the channel ceases to
737 exist when the last client has left it. When channel exists, any client
738 can reference it using the name of the channel.
740 Channel names are unique although the real uniqueness comes from 64 bit
741 Channel ID that unifies each channel. However, channel names are still
742 unique and no two global channels with same name may exist. The Channel
743 name is a string of maximum length of 256 characters. Channel names may
744 not contain any spaces (` '), any non-printable ASCII characters,
745 commas (`,') and wildcard characters.
747 Channels can have operators that can administrate the channel and
748 operate all of its modes. Following operators on channel exist on SILC
752 o Channel founder - When channel is created the joining client becomes
753 channel founder. Channel founder is channel operator with some more
754 privileges. Basically, channel founder can fully operate the channel
755 and all of its modes. The privileges are limited only to the particular
756 channel. There can be only one channel founder per channel. Channel
757 founder supersedes channel operator's privileges.
759 Channel founder privileges cannot be removed by any other operator on
760 channel. When channel founder leaves the channel there is no channel
761 founder on the channel. Channel founder also cannot be removed by
762 force from the channel.
764 o Channel operator - When client joins to channel that has not existed
765 previously it will become automatically channel operator (and channel
766 founder discussed above). Channel operator is able administrate the
767 channel, set some modes on channel, remove a badly behaving client from
768 the channel and promote other clients to become channel operator.
769 The privileges are limited only to the particular channel.
771 Normal channel user may be promoted (opped) to channel operator
772 gaining channel operator privileges. Channel founder or other channel
773 operator may also demote (deop) channel operator to normal channel
781 Channels are distinguished from other channels by unique Channel ID.
782 The Channel ID is a 64 bit ID (for IPv4) or 160 bit ID (for IPv6), and
783 collisions are not expected to happen in any conditions. Channel names
784 are just for logical use of channels. The Channel ID is created by the
785 server where the channel is created. The Channel ID is defined as
789 64 bit Channel ID based on IPv4 addresses:
791 32 bit Router's Server ID IP address (bits 1-32)
792 16 bit Router's Server ID port (bits 33-48)
795 160 bit Channel ID based on IPv6 addresses:
797 128 bit Router's Server ID IP address (bits 1-128)
798 16 bit Router's Server ID port (bits 129-144)
801 o Router's Server ID IP address - Indicates the IP address of
802 the router of the cell where this channel is created. This is
803 taken from the router's Server ID. This way SILC router knows
804 where this channel resides in the SILC network.
806 o Router's Server ID port - Indicates the port of the channel on
807 the server. This is taken from the router's Server ID.
809 o Random number - To further randomize the Channel ID. This makes
810 sure that there are no collisions. This also means that
811 in a cell there can be 2^16 channels.
818 Operators are normal users with extra privileges to their server or
819 router. Usually these people are SILC server and router administrators
820 that take care of their own server and clients on them. The purpose of
821 operators is to administrate the SILC server or router. However, even
822 an operator with highest privileges is not able to enter invite-only
823 channel, to gain access to the contents of a encrypted and authenticated
824 packets traveling in the SILC network or to gain channel operator
825 privileges on public channels without being promoted. They have the
826 same privileges as everyone else except they are able to administrate
827 their server or router.
833 Commands are very important part on SILC network especially for client
834 which uses commands to operate on the SILC network. Commands are used
835 to set nickname, join to channel, change modes and many other things.
837 Client usually sends the commands and server replies by sending a reply
838 packet to the command. Server may also send commands usually to serve
839 the original client's request. However, server may not send command
840 to client and there are some commands that server must not send.
842 Note that the command reply is usually sent only after client has sent
843 the command request but server is allowed to send command reply packet
844 to client even if client has not requested the command. Client may,
845 however, choose ignore the command reply, but should not.
847 It is expected that some of the commands may be miss-used by clients
848 resulting various problems on the server side. Every implementation
849 should assure that commands may not be executed more than once, say,
850 in two (2) seconds. However, to keep response rate up, allowing for
851 example five (5) commands before limiting is allowed. It is recommended
852 that commands such as SILC_COMMAND_NICK, SILC_COMMAND_JOIN and
853 SILC_COMMAND_LEAVE should be limited in all cases as they require
854 heavy operations. This should be sufficient to prevent the miss-use of
857 SILC commands are described in section 5 SILC Commands.
863 Packets are naturally the most important part of the protocol and the
864 packets are what actually makes the protocol. Packets in SILC network
865 are always encrypted using, usually, the shared secret session key
866 or some other key, for example, channel key, when encrypting channel
867 messages. The SILC Packet Protocol is a wide protocol and is described
868 in [SILC2]. This document does not define or describe details of
874 3.8 Packet Encryption
876 All packets passed in SILC network must be encrypted. This section
877 defines how packets must be encrypted in the SILC network. The detailed
878 description of the actual encryption process of the packets are
879 described in [SILC2].
881 Client and its server shares secret symmetric session key which is
882 established by the SILC Key Exchange Protocol, described in [SILC3].
883 Every packet sent from client to server, with exception of packets for
884 channels, are encrypted with this session key.
886 Channels has their own key that are shared by every client on the channel.
887 However, the channel keys are cell specific thus one cell does not know
888 the channel key of the other cell, even if that key is for same channel.
889 Channel key is also known by the routers and all servers that has clients
890 on the channel. However, channels may have channel private keys that
891 are entirely local setting for client. All clients on the channel must
892 know the channel private key before hand to be able to talk on the
893 channel. In this case, no server or router knows the key for channel.
895 Server shares secret symmetric session key with router which is
896 established by the SILC Key Exchange Protocol. Every packet passed from
897 server to router, with exception of packets for channels, are encrypted
898 with the shared session key. Same way, router server shares secret
899 symmetric key with its primary route. However, every packet passed
900 from router to other router, including packets for channels, are
901 encrypted with the shared session key. Every router connection has
902 their own session keys.
906 3.8.1 Determination of the Source and the Destination
908 The source and the destination of the packet needs to be determined
909 to be able to route the packets to correct receiver. This information
910 is available in the SILC Packet Header which is included in all packets
911 sent in SILC network. The SILC Packet Header is described in [SILC2].
913 The header is always encrypted with the session key who is next receiver
914 of the packet along the route. The receiver of the packet, for example
915 a router along the route, is able to determine the sender and the
916 destination of the packet by decrypting the SILC Packet Header and
917 checking the ID's attached to the header. The ID's in the header will
918 tell to where the packet needs to be sent and where it is coming from.
920 The header in the packet does not change during the routing of the
921 packet. The original sender, for example client, assembles the packet
922 and the packet header and server or router between the sender and the
923 receiver must not change the packet header.
925 Note that the packet and the packet header may be encrypted with
926 different keys. For example, packets to channels are encrypted with
927 the channel key, however, the header is encrypted with the session key
928 as described above. However, the header and the packet may be encrypted
929 with same key. This is case, for example, with command packets.
933 3.8.2 Client To Client
935 Process of message delivery and encryption from client to another
936 client is as follows.
938 Example: Private message from client to another client on different
939 servers. Clients do not share private message delivery
940 keys; normal session keys are used.
942 o Client 1. sends encrypted packet to its server. The packet is
943 encrypted with the session key shared between client and its
946 o Server determines the destination of the packet and decrypts
947 the packet. Server encrypts the packet with session key shared
948 between the server and its router, and sends the packet to the
951 o Router determines the destination of the packet and decrypts
952 the packet. Router encrypts the packet with session key
953 shared between the router and the destination server, and sends
954 the packet to the server.
956 o Server determines the client to which the packet is destined
957 to and decrypts the packet. Server encrypts the packet with
958 session key shared between the server and the destination client,
959 and sends the packet to the client.
961 o Client 2. decrypts the packet.
964 Example: Private message from client to another client on different
965 servers. Clients has established secret shared private
966 message delivery key with each other and that is used in
967 the message encryption.
969 o Client 1. sends encrypted packet to its server. The packet is
970 encrypted with the private message delivery key shared between
973 o Server determines the destination of the packet and sends the
974 packet to the router.
976 o Router determines the destination of the packet and sends the
977 packet to the server.
979 o Server determines the client to which the packet is destined
980 to and sends the packet to the client.
982 o Client 2. decrypts the packet with the secret shared key.
985 If clients share secret key with each other the private message
986 delivery is much simpler since servers and routers between the
987 clients do not need to decrypt and re-encrypt the packet.
989 The process for clients on same server is much simpler as there are
990 no need to send the packet to the router. The process for clients
991 on different cells is same as above except that the packet is routed
992 outside the cell. The router of the destination cell routes the
993 packet to the destination same way as described above.
997 3.8.3 Client To Channel
999 Process of message delivery from client on channel to all the clients
1002 Example: Channel of four users; two on same server, other two on
1003 different cells. Client sends message to the channel.
1005 o Client 1. encrypts the packet with channel key and sends the
1006 packet to its server.
1008 o Server determines local clients on the channel and sends the
1009 packet to the Client on the same server. Server then sends
1010 the packet to its router for further routing.
1012 o Router determines local clients on the channel, if found
1013 sends packet to the local clients. Router determines global
1014 clients on the channel and sends the packet to its primary
1015 router or fastest route.
1017 o (Other router(s) do the same thing and sends the packet to
1020 o Server determines local clients on the channel and sends the
1021 packet to the client.
1023 o All clients receiving the packet decrypts the packet.
1027 3.8.4 Server To Server
1029 Server to server packet delivery and encryption is described in above
1030 examples. Router to router packet delivery is analogous to server to
1031 server. However, some packets, such as channel packets, are processed
1032 differently. These cases are described later in this document and
1033 more in detail in [SILC2].
1037 3.9 Key Exchange And Authentication
1039 Key exchange is done always when for example client connects to server
1040 but also when server and router and router and router connects to each
1041 other. The purpose of key exchange protocol is to provide secure key
1042 material to be used in the communication. The key material is used to
1043 derive various security parameters used to secure SILC packets. The
1044 SILC Key Exchange protocol is described in detail in [SILC3].
1046 Authentication is done after key exchange protocol has been successfully
1047 completed. The purpose of authentication is to authenticate for example
1048 client connecting to the server. However, Usually clients are accepted
1049 to connect to server without explicit authentication. Servers are
1050 required use authentication protocol when connecting. The authentication
1051 may be based on passphrase (pre-shared-secret) or public key. The
1052 connection authentication protocol is described in detail in [SILC3].
1056 3.9.1 Authentication Payload
1058 Authentication payload is used separately from the SKE and the Connection
1059 authentication protocol. It is used during the session to authenticate
1060 with the remote. For example, the client can authenticate itself to the
1061 server to be server operator. In this case, Authentication Payload is
1064 The format of the Authentication Payload is as follows:
1070 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1071 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1072 | Payload Length | Authentication Method |
1073 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1074 | Public Data Length | |
1075 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1079 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1080 | Authentication Data Length | |
1081 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1083 ~ Authentication Data ~
1085 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+|
1089 Figure 5: Authentication Payload
1093 o Payload Length (2 bytes) - Length of the entire payload.
1095 o Authentication Type (2) - The method of the authentication.
1096 The authentication methods are defined in [SILC2] in the
1097 Connection Auth Request Payload. The NONE authentication
1098 method is not recommended.
1100 o Public Data Length (2 bytes) - Indicates the length of
1101 the Public Data field.
1103 o Public Data (variable length) - This is defined only if
1104 the authentication method is public key. If it is any other
1105 this field does not exist and the Public Data Length field
1108 When the authentication method is public key this includes
1109 128 to 4096 bytes of non-zero random data that is used in
1110 the signature process, described subsequently.
1112 o Authentication Data Length (2 bytes) - Indicates the
1113 length of the Authentication Data field.
1115 o Authentication Data (variable length) - Authentication
1116 method dependent authentication data.
1120 If the authentication method is password based, the Authentication
1121 Data field includes the plaintext password. It is safe to send
1122 plaintext password since the entire payload is encrypted. In this
1123 case the Public Data Lenght is set to zero (0).
1125 If the authentication method is public key based (or certificate)
1126 the Authentication Data is computed as follows:
1128 HASH = hash(random bytes | ID | public key (or certificate));
1129 Authentication Data = sign(HASH);
1131 The hash() and the sign() are the hash funtion and the public key
1132 cryptography function selected in the SKE protocol. The public key
1133 is SILC style public key unless certificates are used. The ID is the
1134 entity's ID (Client or Server ID) who is authenticating itself. The ID
1135 is raw ID data. The random bytes are non-zero random bytes of length
1136 between 128 and 4096 bytes, and will be included into the Public Data
1139 The receiver will compute the signature using the random data received
1140 in the payload, the ID associated to the connection and the public key
1141 (or certificate) received in the SKE protocol. After computing the
1142 receiver must verify the signature. In this case also, the entire
1143 payload is encrypted.
1149 This section defines all the allowed algorithms that can be used in
1150 the SILC protocol. This includes mandatory cipher, mandatory public
1151 key algorithm and MAC algorithms.
1157 Cipher is the encryption algorithm that is used to protect the data
1158 in the SILC packets. See [SILC2] of the actual encryption process and
1159 definition of how it must be done. SILC has a mandatory algorithm that
1160 must be supported in order to be compliant with this protocol.
1162 Following ciphers are defined in SILC protocol:
1165 aes-256-cbc AES in CBC mode, 256 bit key (mandatory)
1166 aes-192-cbc AES in CBC mode, 192 bit key (optional)
1167 aes-128-cbc AES in CBC mode, 128 bit key (optional)
1168 twofish-256-cbc Twofish in CBC mode, 256 bit key (optional)
1169 twofish-192-cbc Twofish in CBC mode, 192 bit key (optional)
1170 twofish-128-cbc Twofish in CBC mode, 128 bit key (optional)
1171 blowfish-128-cbc Blowfish in CBC mode, 128 bit key (optional)
1172 cast-256-cbc CAST-256 in CBC mode, 256 bit key (optional)
1173 cast-192-cbc CAST-256 in CBC mode, 192 bit key (optional)
1174 cast-128-cbc CAST-256 in CBC mode, 128 bit key (optional)
1175 rc6-256-cbc RC6 in CBC mode, 256 bit key (optional)
1176 rc6-192-cbc RC6 in CBC mode, 192 bit key (optional)
1177 rc6-128-cbc RC6 in CBC mode, 128 bit key (optional)
1178 mars-256-cbc Mars in CBC mode, 256 bit key (optional)
1179 mars-192-cbc Mars in CBC mode, 192 bit key (optional)
1180 mars-128-cbc Mars in CBC mode, 128 bit key (optional)
1181 none No encryption (optional)
1185 Algorithm none does not perform any encryption process at all and
1186 thus is not recommended to be used. It is recommended that no client
1187 or server implementation would accept none algorithms except in special
1190 Additional ciphers may be defined to be used in SILC by using the
1191 same name format as above.
1195 3.10.2 Public Key Algorithms
1197 Public keys are used in SILC to authenticate entities in SILC network
1198 and to perform other tasks related to public key cryptography. The
1199 public keys are also used in the SILC Key Exchange protocol [SILC3].
1201 Following public key algorithms are defined in SILC protocol:
1208 DSS is described in [Menezes]. The RSA must be implemented according
1209 PKCS #1 [PKCS1]. The mandatory PKCS #1 implementation in SILC must be
1210 compliant to either PKCS #1 version 1.5 or newer with the following
1211 notes: The signature encoding is always in same format as the encryption
1212 encoding regardles of the PKCS #1 version. The signature with appendix
1213 (with hash algorithm OID in the data) must not be used in the SILC. The
1214 rationale for this is that there is no binding between the PKCS #1 OIDs
1215 and the hash algorithms used in the SILC protocol. Hence, the encoding
1216 is always in PKCS #1 version 1.5 format.
1218 Additional public key algorithms may be defined to be used in SILC.
1222 3.10.3 Hash Functions
1224 Hash functions are used as part of MAC algorithms defined in the next
1225 section. They are also used in the SILC Key Exchange protocol defined
1228 Following Hash algorithm are defined in SILC protocol:
1230 sha1 SHA-1, length = 20 (mandatory)
1231 md5 MD5, length = 16 (optional)
1235 3.10.4 MAC Algorithms
1237 Data integrity is protected by computing a message authentication code
1238 (MAC) of the packet data. See [SILC2] for details how to compute the
1241 Following MAC algorithms are defined in SILC protocol:
1244 hmac-sha1-96 HMAC-SHA1, length = 12 (mandatory)
1245 hmac-md5-96 HMAC-MD5, length = 12 (optional)
1246 hmac-sha1 HMAC-SHA1, length = 20 (optional)
1247 hmac-md5 HMAC-MD5, length = 16 (optional)
1248 none No MAC (optional)
1251 The none MAC is not recommended to be used as the packet is not
1252 authenticated when MAC is not computed. It is recommended that no
1253 client or server would accept none MAC except in special debugging
1256 The HMAC algorithm is described in [HMAC] and hash algorithms that
1257 are used as part of the HMACs are described in [Scheneir] and in
1260 Additional MAC algorithms may be defined to be used in SILC.
1264 3.10.5 Compression Algorithms
1266 SILC protocol supports compression that may be applied to unencrypted
1267 data. It is recommended to use compression on slow links as it may
1268 significantly speed up the data transmission. By default, SILC does not
1269 use compression which is the mode that must be supported by all SILC
1272 Following compression algorithms are defined:
1275 none No compression (mandatory)
1276 zlib GNU ZLIB (LZ77) compression (optional)
1279 Additional compression algorithms may be defined to be used in SILC.
1283 3.11 SILC Public Key
1285 This section defines the type and format of the SILC public key. All
1286 implementations must support this public key type. See [SILC3] for
1287 other optional public key and certificate types allowed in SILC
1288 protocol. Public keys in SILC may be used to authenticate entities
1289 and to perform other tasks related to public key cryptography.
1291 The format of the SILC Public Key is as follows:
1297 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1298 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1299 | Public Key Length |
1300 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1301 | Algorithm Name Length | |
1302 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1306 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1307 | Identifier Length | |
1308 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1312 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1316 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1320 Figure 5: SILC Public Key
1324 o Public Key Length (4 bytes) - Indicates the full length
1325 of the public key, not including this field.
1327 o Algorithm Name Length (2 bytes) - Indicates the length
1328 of the Algorithm Length field, not including this field.
1330 o Algorithm name (variable length) - Indicates the name
1331 of the public key algorithm that the key is. See the
1332 section 3.10.2 Public Key Algorithms for defined names.
1334 o Identifier Length (2 bytes) - Indicates the length of
1335 the Identifier field, not including this field.
1337 o Identifier (variable length) - Indicates the identifier
1338 of the public key. This data can be used to identify
1339 the owner of the key. The identifier is of following
1343 HN Host name or IP address
1350 Examples of an identifier:
1352 `UN=priikone, HN=poseidon.pspt.fi, E=priikone@poseidon.pspt.fi'
1354 `UN=sam, HN=dummy.fi, RN=Sammy Sam, O=Company XYZ, C=Finland'
1356 At least user name (UN) and host name (HN) must be provided as
1357 identifier. The fields are separated by commas (`,'). If
1358 comma is in the identifier string it must be written as `\\,',
1359 for example, `O=Company XYZ\\, Inc.'.
1361 o Public Data (variable length) - Includes the actual
1362 public data of the public key.
1364 The format of this field for RSA algorithm is
1373 The format of this field for DSS algorithm is
1385 The variable length fields are multiple precession
1386 integers encoded as strings in both examples.
1388 Other algorithms must define their own type of this
1389 field if they are used.
1392 All fields in the public key are in MSB (most significant byte first)
1397 3.12 SILC Version Detection
1399 The version detection of both client and server is performed at the
1400 connection phase while executing the SILC Key Exchange protocol. The
1401 version identifier is exchanged between initiator and responder. The
1402 version identifier is of following format:
1405 SILC-<protocol version>-<software version>
1408 The version strings are of following format:
1411 protocol version = <major>.<minor>
1412 software version = <major>[.<minor>[.<build>]]
1415 Protocol version may provide both major and minor version. Currently
1416 implementations must set the protocol version and accept the protocol
1417 version as SILC-1.0-<sotware version>.
1419 Software version may provide major, minor and build version. The
1420 software version may be freely set and accepted.
1423 Thus, the version string could be, for example:
1433 This section describes various SILC procedures such as how the
1434 connections are created and registered, how channels are created and
1435 so on. The section describes the procedures only generally as details
1436 are described in [SILC2] and [SILC3].
1440 4.1 Creating Client Connection
1442 This section describes the procedure when client connects to SILC server.
1443 When client connects to server the server must perform IP address lookup
1444 and reverse IP address lookup to assure that the origin host really is
1445 who it claims to be. Client, host, connecting to server must have
1446 both valid IP address and fully qualified domain name (FQDN).
1448 After that the client and server performs SILC Key Exchange protocol
1449 which will provide the key material used later in the communication.
1450 The key exchange protocol must be completed successfully before the
1451 connection registration may continue. The SILC Key Exchange protocol
1452 is described in [SILC3].
1454 Typical server implementation would keep a list of connections that it
1455 allows to connect to the server. The implementation would check, for
1456 example, the connecting client's IP address from the connection list
1457 before the SILC Key Exchange protocol has been started. Reason for
1458 this is that if the host is not allowed to connect to the server there
1459 is no reason to perform a key exchange protocol.
1461 After successful key exchange protocol the client and server performs
1462 connection authentication protocol. The purpose of the protocol is to
1463 authenticate the client connecting to the server. Flexible
1464 implementation could also accept the client to connect to the server
1465 without explicit authentication. However, if authentication is
1466 desired for a specific client it may be based on passphrase or
1467 public key authentication. If authentication fails the connection
1468 must be terminated. The connection authentication protocol is described
1471 After successful key exchange and authentication protocol the client
1472 registers itself by sending SILC_PACKET_NEW_CLIENT packet to the
1473 server. This packet includes various information about the client
1474 that the server uses to create the client. Server creates the client
1475 and sends SILC_PACKET_NEW_ID to the client which includes the created
1476 Client ID that the client must start using after that. After that
1477 all SILC packets from the client must have the Client ID as the
1478 Source ID in the SILC Packet Header, described in [SILC2].
1480 Client must also get the server's Server ID that is to be used as
1481 Destination ID in the SILC Packet Header when communicating with
1482 the server (for example when sending commands to the server). The
1483 ID may be resolved in two ways. Client can take the ID from an
1484 previously received packet from server that must include the ID,
1485 or to send SILC_COMMAND_INFO command and receive the Server ID as
1488 Server may choose not to use the information received in the
1489 SILC_PACKET_NEW_CLIENT packet. For example, if public key or
1490 certificate were used in the authentication, server may use those
1491 informations rather than what it received from client. This is suitable
1492 way to get the true information about client if it is available.
1494 The nickname of client is initially set to the username sent in the
1495 SILC_PACKET_NEW_CLIENT packet. User should set the nickname to more
1496 suitable by sending SILC_COMMAND_NICK command. However, this is not
1497 required as part of registration process.
1499 Server must also distribute the information about newly registered
1500 client to its router (or if the server is router, to all routers in
1501 the SILC network). More information about this in [SILC2].
1505 4.2 Creating Server Connection
1507 This section descibres the procedure when server connects to its
1508 router (or when router connects to other router, the cases are
1509 equivalent). The procedure is very much alike when client connects
1510 to the server thus it is not repeated here.
1512 One difference is that server must perform connection authentication
1513 protocol with proper authentication. Proper authentication is based
1514 on passphrase or public key authentication.
1516 After server and router has successfully performed the key exchange
1517 and connection authentication protocol, the server register itself
1518 to the router by sending SILC_PACKET_NEW_SERVER packet. This packet
1519 includes the server's Server ID that it has created by itself and
1520 other relevant information about the server.
1522 After router has received the SILC_PACKET_NEW_SERVER packet it
1523 distributes the information about newly registered server to all routers
1524 in the SILC network. More information about this in [SILC2].
1526 As client needed to resolve the destination ID this must be done by the
1527 server that connected to the router, as well. The way to resolve it is
1528 to get the ID from previously received packet. Server must also start
1529 using its own Server ID as Source ID in SILC Packet Header and the
1530 router's Server ID as Destination when communicating with the router.
1532 If the server has already connected clients and locally created
1533 channels the server must distribute these informations to the router.
1534 The distribution is done by sending packet SILC_PACKET_NEW_CHANNEL.
1535 See [SILC2] for more information on this.
1539 4.3 Joining to a Channel
1541 This section describes the procedure when client joins to a channel.
1542 Client may join to channel by sending command SILC_COMMAND_JOIN to the
1543 server. If the receiver receiving join command is normal server the
1544 server must check its local list whether this channel already exists
1545 locally. This would indicate that some client connected to the server
1546 has already joined to the channel. If this is case the client is
1547 joined to the client, new channel key is created and information about
1548 newly joined channel is sent to the router. The router is informed
1549 by sending SILC_NOTIFY_TYPE_JOIN notify type. The notify type must
1550 also be sent to the local clients on the channel. The new channel key
1551 is also sent to the router and to local clients on the channel.
1553 If the channel does not exist in the local list the client's command
1554 must be sent to the router which will then perform the actual joining
1555 procedure. When server receives the reply to the command from the
1556 router it must be sent to the client who sent the command originally.
1557 Server will also receive the channel key from the server that it must
1558 send to the client who originally requested the join command. The server
1559 must also save the channel key.
1561 If the receiver of the join command is router it must first check its
1562 local list whether anyone in the cell has already joined to the channel.
1563 If this is the case the client is joined to the channel and reply is
1564 sent to the client. If the command was sent by server the command reply
1565 is sent to the server who sent it. Then the router must also create
1566 new channel key and distribute it to all clients on the channel and
1567 all servers that has clients on the channel. Router must also send
1568 the SILC_NOTIFY_TYPE_JOIN notify type to local clients on the channel
1569 and to local servers that has clients on the channel.
1571 If the channel does not exist on the router's local list it must
1572 check the global list whether the channel exists at all. If it does
1573 the client is joined to the channel as described previously. If
1574 the channel does not exist the channel is created and the client
1575 is joined to the channel. The channel key is also created and
1576 distributed as previously described. The client joining to the created
1577 channel is made automatically channel founder and both channel founder
1578 and channel operator privileges is set for the client.
1580 If the router created the channel in the process, information about the
1581 new channel must be broadcasted to all routers. This is done by
1582 broadcasting SILC_PACKET_NEW_CHANNEL packet to the router's primary
1583 route. When the router joins the client to the channel it must also
1584 send information about newly joined client to all routers in the SILC
1585 network. This is done by broadcasting the SILC_NOTIFY_TYPE_JOIN notify
1586 type to the router's primary route.
1588 It is important to note that new channel key is created always when
1589 new client joins to channel, whether the channel has existed previously
1590 or not. This way the new client on the channel is not able to decrypt
1591 any of the old traffic on the channel. Client who receives the reply to
1592 the join command must start using the received Channel ID in the channel
1593 message communication thereafter. Client also receives the key for the
1594 channel in the command reply.
1598 4.4 Channel Key Generation
1600 Channel keys are created by router who creates the channel by taking
1601 enough randomness from cryptographically strong random number generator.
1602 The key is generated always when channel is created, when new client
1603 joins a channel and after the key has expired. Key could expire for
1606 The key must also be re-generated whenever some client leaves a channel.
1607 In this case the key is created from scratch by taking enough randomness
1608 from the random number generator. After that the key is distributed to
1609 all clients on the channel. However, channel keys are cell specific thus
1610 the key is created only on the cell where the client, who left the
1611 channel, exists. While the server or router is creating the new channel
1612 key, no other client may join to the channel. Messages that are sent
1613 while creating the new key are still processed with the old key. After
1614 server has sent the SILC_PACKET_CHANNEL_KEY packet must client start
1615 using the new key. If server creates the new key the server must also
1616 send the new key to its router. See [SILC2] on more information about
1617 how channel messages must be encrypted and decrypted when router is
1620 When client receives the SILC_PACKET_CHANNEL_KEY packet with the
1621 Channel Key Payload it must process the key data to create encryption
1622 and decryption key, and to create the HMAC key that is used to compute
1623 the MACs of the channel messages. The processing is as follows:
1625 channel_key = raw key data
1626 HMAC key = hash(raw key data)
1628 The raw key data is the key data received in the Channel Key Payload.
1629 The hash() function is the hash function used in the HMAC of the channel.
1633 4.5 Private Message Sending and Reception
1635 Private messages are sent point to point. Client explicitly destines
1636 a private message to specific client that is delivered to only to that
1637 client. No other client may receive the private message. The receiver
1638 of the private message is destined in the SILC Packet Header as any
1639 other packet as well.
1641 If the sender of a private message does not know the receiver's Client
1642 ID, it must resolve it from server. There are two ways to resolve the
1643 client ID from server; it is recommended that client implementations
1644 send SILC_COMMAND_IDENTIFY command to receive the Client ID. Client
1645 may also send SILC_COMMAND_WHOIS command to receive the Client ID.
1646 If the sender has received earlier a private message from the receiver
1647 it should have cached the Client ID from the SILC Packet Header.
1649 Receiver of a private message should not explicitly trust the nickname
1650 that it receives in the Private Message Payload, described in [SILC2].
1651 Implementations could resolve the nickname from server, as described
1652 previously, and compare the received Client ID and the SILC Packet
1653 Header's Client ID. The nickname in the payload is merely provided
1654 to be displayed for end user.
1656 See [SILC2] for description of private message encryption and decryption
1661 4.6 Private Message Key Generation
1663 Private message may be protected by key generated by client. The key
1664 may be generated and sent to the other client by sending packet
1665 SILC_PACKET_PRIVATE_MESSAGE_KEY which travels through the network
1666 and is secured by session keys. After that the private message key
1667 is used in the private message communication between those clients.
1669 Other choice is to entirely use keys that are not sent through
1670 the SILC network at all. This significantly adds security. This key
1671 would be pre-shared-key that is known by both of the clients. Both
1672 agree about using the key and starts sending packets that indicate
1673 that the private message is secured using private message key.
1675 The key material used as private message key is implementation issue.
1676 However, SILC_PACKET_KEY_AGREEMENT packet may be used to negotiate
1677 the key material. If the key is normal pre-shared-key or randomly
1678 generated key, and the SILC_PACKET_KEY_AGREEMENT was not used, then
1679 the key material should be processed as defined in the [SILC3]. In
1680 the processing, however, the HASH, as defined in [SILC3] must be
1681 ignored. After processing the key material it is employed as defined
1682 in [SILC3], however, the HMAC key material must be discarded.
1684 If the key is pre-shared-key or randomly generated the implementations
1685 should use the SILC protocol's mandatory cipher as the cipher. If the
1686 SKE was used to negotiate key material the cipher was negotiated as well.
1689 4.7 Channel Message Sending and Reception
1691 Channel messages are delivered to group of users. The group forms a
1692 channel and all clients on the channel receives messages sent to the
1695 Channel messages are destined to channel by specifying the Channel ID
1696 as Destination ID in the SILC Packet Header. The server must then
1697 distribute the message to all clients on the channel by sending the
1698 channel message destined explicitly to a client on the channel.
1700 See [SILC2] for description of channel message encryption and decryption
1705 4.8 Session Key Regeneration
1707 Session keys should be regenerated periodically, say, once in an hour.
1708 The re-key process is started by sending SILC_PACKET_REKEY packet to
1709 other end, to indicate that re-key must be performed.
1711 If perfect forward secrecy (PFS) flag was selected in the SILC Key
1712 Exchange protocol [SILC3] the re-key must cause new key exchange with
1713 SKE protocol. In this case the protocol is secured with the old key
1714 and the protocol results to new key material. See [SILC3] for more
1715 information. After the SILC_PACKET_REKEY packet is sent the sender
1716 will perform the SKE protocol.
1718 If PFS flag was not set, which is the default case, then re-key is done
1719 without executing SKE protocol. In this case, the new key is created by
1720 hashing the old key with hash function selected earlier in the SKE
1721 protocol. If the digest length of the hash function is too short for the
1722 key, then the key is distributed as described in section Processing the
1723 Key Material in [SILC3]. After both parties has regenerated the session
1724 key, both send SILC_PACKET_REKEY_DONE packet to each other. These packets
1725 are still secured with the old key. After these packets, following
1726 packets must be protected with the new key.
1730 4.9 Command Sending and Reception
1732 Client usually sends the commands in the SILC network. In this case
1733 the client simply sends the command packet to server and the server
1734 processes it and replies with command reply packet.
1736 However, if the server is not able to process the command, it is sent
1737 to the server's router. This is case for example with commands such
1738 as, SILC_COMMAND_JOIN and SILC_COMMAND_WHOIS commands. However, there
1739 are other commands as well. For example, if client sends the WHOIS
1740 command requesting specific information about some client the server must
1741 send the WHOIS command to router so that all clients in SILC network
1742 are searched. The router, on the other hand, sends the WHOIS command
1743 further to receive the exact information about the requested client.
1744 The WHOIS command travels all the way to the server who owns the client
1745 and it replies with command reply packet. Finally, the server who
1746 sent the command receives the command reply and it must be able to
1747 determine which client sent the original command. The server then
1748 sends command reply to the client. Implementations should have some
1749 kind of cache to handle, for example, WHOIS information. Servers
1750 and routers along the route could all cache the information for faster
1751 referencing in the future.
1753 The commands sent by server may be sent hop by hop until someone is able
1754 to process the command. However, it is preferred to destine the command
1755 as precisely as it is possible. In this case, other routers en route
1756 must route the command packet by checking the true sender and true
1757 destination of the packet. However, servers and routers must not route
1758 command reply packets to clients coming from other server. Client
1759 must not accept command reply packet originated from anyone else but
1760 from its own server.
1767 5.1 SILC Commands Syntax
1769 This section briefly describes the syntax of the command notions
1770 in this document. Every field in command is separated from each
1771 other by whitespaces (` ') indicating that each field is independent
1772 argument and each argument must have own Command Argument Payload.
1773 The number of maximum arguments are defined with each command
1774 separately. The Command Argument Payload is described in [SILC2].
1776 Every command defines specific number for each argument. Currently,
1777 they are defined in ascending order; first argument has number one
1778 (1), second has number two (2) and so on. This number is set into the
1779 Argument Type field in the Command Argument Payload. This makes it
1780 possible to send the arguments in free order as the number must be
1781 used to identify the type of the argument. This makes is it also
1782 possible to have multiple optional arguments in commands and in
1783 command replies. The number of argument is marked in parentheses
1784 before the actual argument.
1789 Example: Arguments: (1) <nickname> (2) <username@host>
1793 Every command replies with Status Payload. This payload tells the
1794 sender of the command whether the command was completed successfully or
1795 whether there was an error. If error occured the payload includes the
1796 error type. In the next section the Status Payload is not described
1797 as it is common to all commands and has been described here. Commands
1798 may reply with other arguments as well. These arguments are command
1799 specific and are described in the next section.
1808 Arguments: (1) <nickname>[@<server>] (2) <message>
1811 The command has maximum of 3 arguments. However, only first
1812 and second arguments are mandatory.
1814 First argument <nickname> is mandatory but may have optional
1815 <nickname@server> format as well. Second argument is mandatory
1816 <message> argument. Third argument is optional <count> argument.
1818 The numbers in parentheses are the argument specific numbers
1819 that specify the type of the argument in Command Argument Payload.
1820 The receiver always knows that, say, argument number two (2) is
1821 <message> argument, regardless of the ordering of the arguments in
1822 the Command Payload.
1824 Reply messages to the command:
1827 Arguments: (1) <Status Payload> (2) [<channel list>]
1828 (3) <idle time> (4) [<away message>]
1830 This command may reply with maximum of 4 arguments. However,
1831 only the first and third arguments are mandatory. The numbers
1832 in the parentheses have the same meaning as in the upper
1833 command sending specification.
1835 Every command reply with <Status Payload>, it is mandatory
1836 argument for all command replies and for this reason it is not
1837 described in the command reply descriptions.
1844 SILC_STATUS_ERR_TOO_MANY_TARGETS
1845 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
1846 SILC_STATUS_ERR_NO_SUCH_NICK
1848 Every command reply also defines set of status message that it
1849 may return inside the <Status Payload>. All status messages
1850 are defined in the section 5.3 SILC Command Status Types.
1853 Every command that has some kind of ID as argument (for example
1854 <Client ID>) are actually ID Payloads, defined in [SILC2] that includes
1855 the type of the ID, length of the ID and the actual ID data. This
1856 way variable length ID's can be sent as arguments.
1860 5.2 SILC Commands List
1862 This section lists all SILC commands, however, it is expected that a
1863 implementation and especially client implementation has many more
1864 commands that has only local affect. These commands are official
1865 SILC commands that has both client and server sides and cannot be
1866 characterized as local commands.
1868 List of all defined commands in SILC follows.
1873 None. This is reserved command and must not be sent.
1876 1 SILC_COMMAND_WHOIS
1879 Arguments: (1) [<nickname>[@<server>]] (2) [<count>]
1880 (3) [<Client ID>] (n) [...]
1882 Whois command is used to query various information about specific
1883 user. The user maybe requested by their nickname and server name.
1884 The query may find multiple matching users as there are no unique
1885 nicknames in the SILC. The <count> option maybe given to narrow
1886 down the number of accepted results. If this is not defined there
1887 are no limit of accepted results. The query may also be narrowed
1888 down by defining the server name of the nickname.
1890 It is also possible to search the user by Client ID. If <Client ID>
1891 is provided server must use it as the search value instead of
1892 the <nickname>. One of the arguments must be given. It is also
1893 possible to define multiple Client ID's to search multiple users
1894 sending only one WHOIS command. In this case the Client ID's are
1895 appended as normal arguments. The server replies in this case
1896 with only one reply message for all requested users.
1898 To prevent miss-use of this service wildcards in the nickname
1899 or in the servername are not permitted. It is not allowed
1900 to request all users on some server. The WHOIS requests must
1901 be based on specific nickname request.
1903 The WHOIS request must be always sent to the router by server
1904 so that all users are searched. However, the server still must
1905 search its locally connected clients. The router must send
1906 this command to the server who owns the requested client. That
1907 server must reply to the command. Server should not send whois
1908 replies to the client until it has received the reply from its
1911 Reply messages to the command:
1914 Arguments: (1) <Status Payload> (2) <Client ID>
1915 (3) <nickname>[@<server>] (4) <username@host>
1916 (5) <real name> (6) [<channel list>]
1919 This command may reply with several command reply messages to
1920 form a list of results. In this case the status payload will
1921 include STATUS_LIST_START status in the first reply and
1922 STATUS_LIST_END in the last reply to indicate the end of the
1923 list. If there are only one reply the status is set to normal
1926 The command replies include the Client ID of the nickname,
1927 nickname and servername, username and hostname and users real
1928 name. Client should process these replies only after the last
1929 reply has been received with the STATUS_LIST_END status. If the
1930 <count> option were defined in the query there will be only
1931 <count> many replies from the server.
1936 SILC_STATUS_LIST_START
1937 SILC_STATUS_LIST_END
1938 SILC_STATUS_ERR_NO_SUCH_NICK
1939 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
1940 SILC_STATUS_ERR_WILDCARDS
1941 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
1942 SILC_STATUS_ERR_TOO_MANY_PARAMS
1947 2 SILC_COMMAND_WHOWAS
1950 Arguments: (1) <nickname>[@<server>] (2) [<count>]
1952 Whowas. This command is used to query history information about
1953 specific user. The user maybe requested by their nickname and
1954 server name. The query may find multiple matching users as there
1955 are no unique nicknames in the SILC. The <count> option maybe
1956 given to narrow down the number of accepted results. If this
1957 is not defined there are no limit of accepted results. The query
1958 may also be narrowed down by defining the server name of the
1961 To prevent miss-use of this service wildcards in the nickname
1962 or in the servername are not permitted. The WHOWAS requests must
1963 be based on specific nickname request.
1965 The WHOWAS request must be always sent to the router by server
1966 so that all users are searched. However, the server still must
1967 search its locally connected clients.
1969 Reply messages to the command:
1972 Arguments: (1) <Status Payload> (2) <Client ID>
1973 (3) <nickname>[@<server>] (4) <username@host>
1976 This command may reply with several command reply messages to form
1977 a list of results. In this case the status payload will include
1978 STATUS_LIST_START status in the first reply and STATUS_LIST_END in
1979 the last reply to indicate the end of the list. If there are only
1980 one reply the status is set to normal STATUS_OK.
1982 The command replies with nickname and username and hostname.
1983 Every server must keep history for some period of time of its
1984 locally connected clients.
1989 SILC_STATUS_LIST_START
1990 SILC_STATUS_LIST_END
1991 SILC_STATUS_ERR_NO_SUCH_NICK
1992 SILC_STATUS_ERR_WILDCARDS
1993 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
1994 SILC_STATUS_ERR_TOO_MANY_PARAMS
1997 3 SILC_COMMAND_IDENTIFY
2000 Arguments: (1) [<nickname>[@<server>]] (2) [<count>]
2001 (3) [<Client ID>] (n) [...]
2003 Identify. Identify command is almost analogous to WHOIS command,
2004 except that it does not return as much information. Only relevant
2005 information such as Client ID is returned. This is usually used
2006 to get the Client ID of a client used in the communication with
2009 The query may find multiple matching users as there are no unique
2010 nicknames in the SILC. The <count> option maybe given to narrow
2011 down the number of accepted results. If this is not defined there
2012 are no limit of accepted results. The query may also be narrowed
2013 down by defining the server name of the nickname.
2015 It is also possible to search the user by Client ID. If <Client ID>
2016 is provided server must use it as the search value instead of
2017 the <nickname>. One of the arguments must be given. It is also
2018 possible to define multiple Client ID's to search multiple users
2019 sending only one IDENTIFY command. In this case the Client ID's are
2020 appended as normal arguments. The server replies in this case
2021 with only one reply message for all requested users.
2023 To prevent miss-use of this service wildcards in the nickname
2024 or in the servername are not permitted. It is not allowed
2025 to request all users on some server. The IDENTIFY requests must
2026 be based on specific nickname request.
2028 Implementations may not want to give interface access to this
2029 command as it is hardly a command that would be used by an end user.
2030 However, it must be implemented as it is used with private message
2033 The IDENTIFY must be always sent to the router by server so that
2034 all users are searched. However, server must still search its
2035 locally connected clients.
2037 Reply messages to the command:
2040 Arguments: (1) <Status Payload> (2) <Client ID>
2041 (3) [<nickname>[@<server>]] (4) [<username@host>]
2043 This command may reply with several command reply messages to form
2044 a list of results. In this case the status payload will include
2045 STATUS_LIST_START status in the first reply and STATUS_LIST_END in
2046 the last reply to indicate the end of the list. If there are only
2047 one reply the status is set to normal STATUS_OK.
2049 The command replies with Client ID of the nickname and if more
2050 information is available it may reply with nickname and username
2051 and hostname. If the <count> option were defined in the query
2052 there will be only <count> many replies from the server.
2057 SILC_STATUS_LIST_START
2058 SILC_STATUS_LIST_END
2059 SILC_STATUS_ERR_NO_SUCH_NICK
2060 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2061 SILC_STATUS_ERR_WILDCARDS
2062 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2063 SILC_STATUS_ERR_TOO_MANY_PARAMS
2069 Arguments: (1) <nickname>
2071 Set/change nickname. This command is used to set nickname for
2072 user. There is no limit of the length of the nickname in SILC.
2073 Nickname must not include any spaces (` '), non-printable
2074 characters, commas (`,') and any wildcard characters. Note:
2075 nicknames in SILC are case-sensitive which must be taken into
2076 account when searching clients by nickname.
2078 When nickname is changed new Client ID is generated. Server must
2079 distribute SILC_NOTIFY_TYPE_NICK_CHANGE to local clients on the
2080 channels (if any) the client is joined on. Then it must send
2081 SILC_PACKET_REPLACE_ID to its primary route to replace the old
2082 Client ID with the new one.
2084 Reply messages to the command:
2087 Arguments: (1) <Status Payload> (2) <New ID Payload>
2089 This command is replied always with New ID Payload that is
2090 generated by the server every time user changes their nickname.
2091 Client receiving this payload must start using the received
2092 Client ID as its current valid Client ID. The New ID Payload
2093 is described in [SILC2].
2098 SILC_STATUS_ERR_WILDCARDS
2099 SILC_STATUS_ERR_NICKNAME_IN_USE
2100 SILC_STATUS_ERR_BAD_NICKNAME
2101 SILC_STATUS_ERR_NOT_REGISTERED
2102 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2103 SILC_STATUS_ERR_TOO_MANY_PARAMS
2109 Arguments: (1) [<Channel ID>] [<server>]
2111 The list command is used to list channels and their topics on
2112 current server. If the <Channel ID> parameter is used, only the
2113 status of that channel is displayed. Secret channels are not
2114 listed at all. Private channels are listed with status indicating
2115 that the channel is private.
2117 If the <server> argument is specified the specified server's
2118 channels are listed. In this case the command must be sent to
2119 the server who owns the channel that was requested.
2121 Reply messages to the command:
2124 Arguments: (1) <Status Payload> (2) <Channel ID>
2125 (3) <channel> (4) <topic>
2127 This command may reply with several command reply messages to form
2128 a list of results. In this case the status payload will include
2129 STATUS_LIST_START status in the first reply and STATUS_LIST_END in
2130 the last reply to indicate the end of the list. If there are only
2131 one reply the status is set to normal STATUS_OK.
2133 This command replies with Channel ID, name and the topic of the
2134 channel. If the channel is private channel the <topic> includes
2140 SILC_STATUS_LIST_START
2141 SILC_STATUS_LIST_END
2142 SILC_STATUS_ERR_WILDCARDS
2143 SILC_STATUS_ERR_NOT_REGISTERED
2144 SILC_STATUS_ERR_TOO_MANY_PARAMS
2145 SILC_STATUS_ERR_NO_SUCH_CHANNEL
2146 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2147 SILC_STATUS_ERR_NO_SUCH_SERVER
2150 6 SILC_COMMAND_TOPIC
2153 Arguments: (1) <Channel ID> (2) [<topic>]]
2155 This command is used to change or view the topic of a channel.
2156 The topic for channel <Channel ID> is returned if there is no
2157 <topic> given. If the <topic> parameter is present, the topic
2158 for that channel will be changed, if the channel modes permit
2161 Reply messages to the command:
2164 Arguments: (1) <Status Payload> (2) <Channel ID>
2167 The command may reply with the topic of the channel if it is
2173 SILC_STATUS_ERR_NOT_ON_CHANNEL
2174 SILC_STATUS_ERR_WILDCARDS
2175 SILC_STATUS_ERR_NOT_REGISTERED
2176 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2177 SILC_STATUS_ERR_NO_SUCH_CHANNEL
2178 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2179 SILC_STATUS_ERR_NO_CHANNEL_ID
2180 SILC_STATUS_ERR_BAD_CHANNEL_ID
2181 SILC_STATUS_ERR_TOO_MANY_PARAMS
2182 SILC_STATUS_ERR_NO_CHANNEL_PRIV
2185 7 SILC_COMMAND_INVITE
2188 Arguments: (1) <Client ID> (2) <Channel ID>
2190 This command is used to invite other clients to join to the
2191 channel. The <Client ID> argument is the target client's ID that
2192 is being invited. The <Channel ID> is the Channel ID of the
2193 requested channel. The sender of this command must be on the
2194 channel. This command must fail if the requested channel does
2195 not exist, the requested client is already on the channel or if
2196 the channel is invite only channel and the caller of this command
2197 does not have at least channel operator privileges.
2199 Reply messages to the command:
2202 Arguments: (1) <Status Payload>
2204 This command replies only with Status Payload.
2209 SILC_STATUS_ERR_NOT_REGISTERED
2210 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2211 SILC_STATUS_ERR_TOO_MANY_PARAMS
2212 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2213 SILC_STATUS_ERR_NO_CLIENT_ID
2214 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2215 SILC_STATUS_ERR_NO_CHANNEL_ID
2216 SILC_STATUS_ERR_NOT_ON_CHANNEL
2217 SILC_STATUS_ERR_USER_ON_CHANNEL
2223 Arguments: (1) [<quit message>]
2225 This command is used by client to end SILC session. The server
2226 must close the connection to a client which sends this command.
2227 if <quit message> is given it will be sent to other clients on
2228 channel if the client is on channel when quitting.
2230 Reply messages to the command:
2232 This command does not reply anything.
2238 Arguments: (1) <Client ID> (2) [<comment>]
2240 This command is used by SILC operators to remove a client from
2241 SILC network. The removing has temporary effects and client may
2242 reconnect to SILC network. The <Client ID> is the client to be
2243 removed from SILC. The <comment> argument may be provided to
2244 give to the removed client some information why it was removed
2247 Reply messages to the command:
2250 Arguments: (1) <Status Payload>
2252 This command replies only with Status Payload.
2257 SILC_STATUS_ERR_WILDCARDS
2258 SILC_STATUS_ERR_NOT_REGISTERED
2259 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2260 SILC_STATUS_ERR_TOO_MANY_PARAMS
2261 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2262 SILC_STATUS_ERR_NO_CLIENT_ID
2263 SILC_STATUS_ERR_NO_ROUTER_PRIV
2266 10 SILC_COMMAND_INFO
2269 Arguments: (1) [<server>]
2271 This command is used to fetch various information about a server.
2272 If <server> argument is specified the command must be sent to
2273 the requested server.
2275 Reply messages to the command:
2278 Arguments: (1) <Status Payload> (2) <Server ID>
2281 This command replies with the Server ID of the server and a
2282 string which tells the information about the server.
2287 SILC_STATUS_ERR_WILDCARDS
2288 SILC_STATUS_ERR_NOT_REGISTERED
2289 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2290 SILC_STATUS_ERR_TOO_MANY_PARAMS
2291 SILC_STATUS_ERR_NO_SUCH_SERVER
2294 11 SILC_COMMAND_CONNECT
2297 Arguments: (1) <remote server/router> (2) [<port>]
2299 This command is used by operators to force a server to try to
2300 establish a new connection to remote server or router. The
2301 Operator must specify the server/router to be connected by
2302 setting <remote server> argument. The port is 32 bit MSB value.
2304 Reply messages to the command:
2307 Arguments: (1) <Status Payload>
2309 This command replies only with Status Payload.
2316 SILC_STATUS_ERR_WILDCARDS
2317 SILC_STATUS_ERR_NOT_REGISTERED
2318 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2319 SILC_STATUS_ERR_TOO_MANY_PARAMS
2320 SILC_STATUS_ERR_NO_SERVER_PRIV
2321 SILC_STATUS_ERR_NO_ROUTER_PRIV
2324 12 SILC_COMMAND_PING
2327 Arguments: (1) <Server ID>
2329 This command is used by client and server to test the communication
2330 channel to its server if one suspects that the communication is not
2331 working correctly. The <Server ID> is the ID of the server the
2332 sender is connected to.
2334 Reply messages to the command:
2337 Arguments: (1) <Status Payload>
2339 This command replies only with Status Payload. Server returns
2340 SILC_STATUS_OK in Status Payload if pinging was successful.
2347 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2348 SILC_STATUS_ERR_TOO_MANY_PARAMS
2349 SILC_STATUS_ERR_NO_SERVER_ID
2350 SILC_STATUS_ERR_NO_SUCH_SERVER
2351 SILC_STATUS_ERR_NOT_REGISTERED
2354 13 SILC_COMMAND_OPER
2357 Arguments: (1) <username> (2) <authentication data>
2359 This command is used by normal client to obtain server operator
2360 privileges on some server or router. Note that router operator
2361 has router privileges that supersedes the server operator
2362 privileges and this does not obtain those privileges. Client
2363 must use SILCOPER command to obtain router level privileges.
2365 The <username> is the username set in the server configurations
2366 as operator. The <authentication data> is the data that the
2367 client is authenticated against. It may be passphrase prompted
2368 for user on client's screen or it may be public key
2369 authentication data (data signed with private key), or
2372 Reply messages to the command:
2375 Arguments: (1) <Status Payload>
2377 This command replies only with Status Payload.
2382 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2383 SILC_STATUS_ERR_TOO_MANY_PARAMS
2384 SILC_STATUS_ERR_NOT_REGISTERED
2385 SILC_STATUS_ERR_BAD_PASSWORD
2386 SILC_STATUS_ERR_AUTH_FAILED
2389 14 SILC_COMMAND_JOIN
2392 Arguments: (1) <channel> (2) <Client ID>
2393 (3) [<passphrase>] (4) [<cipher>]
2396 Join to channel/create new channel. This command is used to
2397 join to a channel. If the channel does not exist the channel is
2398 created. If server is normal server this command must be sent
2399 to router who will create the channel. The channel may be
2400 protected with passphrase. If this is the case the passphrase
2401 must be sent along the join command.
2403 The name of the <channel> must not include any spaces (` '),
2404 non-printable characters, commas (`,') or any wildcard characters.
2406 The second argument <Client ID> is the Client ID of the client who
2407 is joining to the client. When client sends this command to the
2408 server the <Client ID> must be the client's own ID.
2410 Cipher to be used to secure the traffic on the channel may be
2411 requested by sending the name of the requested <cipher>. This
2412 is used only if the channel does not exist and is created. If
2413 the channel already exists the cipher set previously for the
2414 channel will be used to secure the traffic. The computed MACs
2415 of the channel message are produced by the default HMAC or by
2416 the <hmac> provided for the command.
2418 The server must check whether the user is allowed to join to
2419 the requested channel. Various modes set to the channel affect
2420 the ability of the user to join the channel. These conditions
2423 o The user must be invited to the channel if the channel
2424 is invite-only channel.
2426 o The Client ID/nickname/username/hostname must not match
2429 o The correct passphrase must be provided if passphrase
2430 is set to the channel.
2432 o The user count limit, if set, must not be reached.
2434 Reply messages to the command:
2437 Arguments: (1) <Status Payload> (2) <channel>
2438 (3) <Channel ID> (4) <Client ID>
2439 (5) <channel mode mask> (6) <created>
2440 (7) <Channel Key Payload> (8) [<ban mask>]
2441 (9) [<invite list>] (10) [<topic>]
2442 (11) [<hmac>] (12) <list count>
2443 (13) <Client ID list> (14) <client mode list>
2445 This command replies with the channel name requested by the
2446 client, channel ID of the channel and topic of the channel
2447 if it exists. The <Client ID> is the Client ID which was joined
2448 to the channel. It also replies with the channel mode mask
2449 which tells all the modes set on the channel. If the
2450 channel is created the mode mask is zero (0). If ban mask
2451 and/or invite list is set they are sent as well.
2453 The <list count>, <Client ID list> and <client mode list> are
2454 the clients curerntly on the channel and their modes on the
2457 Client receives the channel key in the reply message as well
2458 inside <Channel Key Payload>.
2463 SILC_STATUS_ERR_WILDCARDS
2464 SILC_STATUS_ERR_NOT_REGISTERED
2465 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2466 SILC_STATUS_ERR_TOO_MANY_PARAMS
2467 SILC_STATUS_ERR_BAD_PASSWORD
2468 SILC_STATUS_ERR_CHANNEL_IS_FULL
2469 SILC_STATUS_ERR_NOT_INVITED
2470 SILC_STATUS_ERR_BANNED_FROM_CHANNEL
2471 SILC_STATUS_ERR_BAD_CHANNEL
2472 SILC_STATUS_ERR_USER_ON_CHANNEL
2475 15 SILC_COMMAND_MOTD
2478 Arguments: (1) <server>
2480 This command is used to query the Message of the Day of the server.
2482 Reply messages to the command:
2485 Arguments: (1) <Status Payload> (2) [<motd>]
2487 This command replies with the motd message if it exists.
2492 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2493 SILC_STATUS_ERR_TOO_MANY_PARAMS
2494 SILC_STATUS_ERR_NOT_REGISTERED
2495 SILC_STATUS_ERR_NO_SUCH_SERVER
2498 16 SILC_COMMAND_UMODE
2501 Arguments: (1) <Client ID> (2) <client mode mask>
2503 This command is used by client to set/unset modes for itself.
2504 However, there are some modes that the client may not set itself,
2505 but they will be set by server. However, client may unset any
2506 mode. Modes may be masked together ORing them thus having
2507 several modes set. Client must keep its client mode mask
2508 locally so that the mode setting/unsetting would work without
2509 problems. Client may change only its own modes.
2511 Following client modes are defined:
2513 0x0000 SILC_UMODE_NONE
2515 No specific mode for client. This is the initial
2516 setting when new client is created. The client is
2520 0x0001 SILC_UMODE_SERVER_OPERATOR
2522 Marks the user as server operator. Client cannot
2523 set this mode itself. Server sets this mode to the
2524 client when client attains the server operator
2525 privileges by SILC_COMMAND_OPER command. Client
2526 may unset the mode itself.
2529 0x0002 SILC_UMODE_ROUTER_OPERATOR
2531 Marks the user as router (SILC) operator. Client
2532 cannot this mode itself. Router sets this mode to
2533 the client when client attains the router operator
2534 privileges by SILC_COMMAND_SILCOPER command. Client
2535 may unset the mode itself.
2537 Reply messages to the command:
2540 Arguments: (1) <Status Payload> (2) <client mode mask>
2542 This command replies with the changed client mode mask that
2543 the client is required to keep locally.
2549 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2550 SILC_STATUS_ERR_TOO_MANY_PARAMS
2551 SILC_STATUS_ERR_NOT_REGISTERED
2552 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2553 SILC_STATUS_ERR_BAD_CLIENT_ID
2554 SILC_STATUS_ERR_NOT_YOU
2555 SILC_STATUS_ERR_UNKNOWN_MODE
2556 SILC_STATUS_ERR_NO_RECIPIENT
2557 SILC_STATUS_ERR_NO_CLIENT_ID
2560 17 SILC_COMMAND_CMODE
2563 Arguments: (1) <Channel ID> (2) <channel mode mask>
2564 (3) [<user limit>] (4) [<passphrase>]
2565 (5) [<ban mask>] (6) [<invite list>]
2566 (7) [<cipher>] (8) [<hmac>]
2568 This command is used by client to set or change channel flags on
2569 a channel. Channel has several modes that set various properties
2570 of a channel. Modes may be masked together by ORing them thus
2571 having several modes set. The <Channel ID> is the ID of the
2572 target channel. The client changing channel mode must be on
2573 the same channel and poses sufficient privileges to be able to
2576 When the mode is changed SILC_NOTIFY_TYPE_CMODE_CHANGE notify
2577 type is distributed to the channel.
2579 Following channel modes are defined:
2581 0x0000 SILC_CMODE_NONE
2583 No specific mode on channel. This is the default when
2584 channel is created. This means that channel is just plain
2588 0x0001 SILC_CMODE_PRIVATE
2590 Channel is private channel. Private channels are shown
2591 in the channel list listed with SILC_COMMAND_LIST command
2592 with indication that the channel is private. Also,
2593 client on private channel will no be detected to be on
2594 the channel as the channel is not shown in the client's
2595 currently joined channel list. Channel founder and
2596 channel operator may set/unset this mode.
2598 Typical implementation would use [+|-]p on user interface
2599 to set/unset this mode.
2602 0x0002 SILC_CMODE_SECRET
2604 Channel is secret channel. Secret channels are not shown
2605 in the list listed with SILC_COMMAND_LIST command. Secret
2606 channels can be considered to be invisible channels.
2607 Channel founder and channel operator may set/unset this
2610 Typical implementation would use [+|-]s on user interface
2611 to set/unset this mode.
2614 0x0004 SILC_CMODE_PRIVKEY
2616 Channel uses private channel key to protect the traffic
2617 on the channel. When this mode is set the client will be
2618 responsible to set the key it wants to use to encrypt and
2619 decrypt the traffic on channel. Server generated channel
2620 keys are not used at all. This mode provides additional
2621 security as clients on channel may agree to use private
2622 channel key that even servers do not know. Naturally,
2623 this requires that every client on the channel knows
2624 the key before hand (it is considered to be pre-shared-
2625 key). This specification does not define how the private
2626 channel key is set as it is entirely local setting on
2629 As it is local setting it is possible to have several
2630 private channel keys on one channel. In this case several
2631 clients can talk on same channel but only those clients
2632 that share the key with the message sender will be able
2633 to hear the talking. Client should not display those
2634 message for the end user that it is not able to decrypt
2635 when this mode is set.
2637 Only channel founder may set/unset this mode. If this
2638 mode is unset the server will distribute new channel
2639 key to all clients on the channel which will be used
2642 Typical implementation would use [+|-]k on user interface
2643 to set/unset this mode.
2646 0x0008 SILC_CMODE_INVITE
2648 Channel is invite only channel. Client may join to this
2649 channel only if it is invited to the channel. Channel
2650 founder and channel operator may set/unset this mode.
2652 Typical implementation would use [+|-]i on user interface
2653 to set/unset this mode.
2656 0x0010 SILC_CMODE_TOPIC
2658 The topic of the channel may only be set by client that
2659 is channel founder or channel operator. Normal clients
2660 on channel will not be able to set topic when this mode
2661 is set. Channel founder and channel operator may set/
2664 Typical implementation would use [+|-]t on user interface
2665 to set/unset this mode.
2668 0x0020 SILC_CMODE_ULIMIT
2670 User limit has been set to the channel. New clients
2671 may not join to the channel when the limit set is
2672 reached. Channel founder and channel operator may set/
2673 unset the limit. The <user limit> argument is the
2674 number of limited users.
2676 Typical implementation would use [+|-]l on user interface
2677 to set/unset this mode.
2680 0x0040 SILC_CMODE_PASSPHRASE
2682 Passphrase has been set to the channel. Client may
2683 join to the channel only if it is able to provide the
2684 correct passphrase. Setting passphrases to channel
2685 is entirely safe as all commands are protected in the
2686 SILC network. Only channel founder may set/unset
2687 the passphrase. The <passphrase> argument is the
2690 Typical implementation would use [+|-]a on user interface
2691 to set/unset this mode.
2694 0x0080 SILC_CMODE_BAN
2696 Ban mask has been set to the channel. The ban mask
2697 may be used to ban specific clients to join the channel.
2698 The <ban mask> argument is the set ban mask. When
2699 unsetting a ban mask the mask must be provided as
2700 argument. Channel founder and channel operator may
2701 set/unset this mode. Channel founder may not be
2702 added to the ban list. <ban mask> is an comma (`,')
2703 separated list of banned clients in the following format:
2705 [<nickname>[@<server>]!][<username>]@[<hostname>]
2707 Wildcards maybe used when banning clients.
2709 Typical implementation would use [+|-]b on user interface
2710 to set/unset this mode.
2713 0x0100 SILC_CMODE_INVITE_LIST
2715 Invite list has been set to the channel. The invite list
2716 can be used to mark the clients that is able to join
2717 channel without being invited when the channel is set to
2718 be invite-only channel. The <invite list> argument is the
2719 set invite mask. When unsetting entry from the invite list
2720 the entry must be provided as argument. Channel founder and
2721 channel operator may set/unset this mode. The <invite list>
2722 is command (`,') separated list of invited clients in the
2725 [<nickname>[@<server>]!][<username>]@[<hostname>]
2727 Wildcards maybe used when setting the invite list.
2729 Typical implementation would use [+|-]I on user interface
2730 to set/unset this mode.
2733 0x0200 SILC_CMODE_CIPHER
2735 Sets specific cipher to be used to protect channel
2736 traffic. The <cipher> argument is the requested cipher.
2737 When set or unset the server must re-generate new
2738 channel key. Only channel founder may set the cipher of
2739 the channel. When unset the new key is generated using
2740 default cipher for the channel.
2742 Typical implementation would use [+|-]c on user interface
2743 to set/unset this mode.
2746 0x0400 SILC_CMODE_HMAC
2748 Sets specific hmac to be used to compute the MACs of the
2749 channel message. The <hmac> argument is the requested hmac.
2750 Only channel founder may set the hmac of the channel.
2752 Typical implementation would use [+|-]h on user interface
2753 to set/unset this mode.
2756 To make the mode system work, client must keep the channel mode
2757 mask locally so that the mode setting and unsetting would work
2758 without problems. The client receives the initial channel mode
2759 mask when it joins to the channel. When the mode changes on
2760 channel the servers distributes the changed channel mode mask to
2761 all clients on the channel by sending SILC_NOTIFY_TYPE_CMODE_CHANGE
2765 Reply messages to the command:
2768 Arguments: (1) <Status Payload> (2) <channel mode mask>
2770 This command replies with the changed channel mode mask that
2771 client is required to keep locally.
2776 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2777 SILC_STATUS_ERR_TOO_MANY_PARAMS
2778 SILC_STATUS_ERR_NOT_REGISTERED
2779 SILC_STATUS_ERR_NOT_ON_CHANNEL
2780 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2781 SILC_STATUS_ERR_BAD_CHANNEL_ID
2782 SILC_STATUS_ERR_NO_CHANNEL_ID
2783 SILC_STATUS_ERR_NO_CHANNEL_PRIV
2784 SILC_STATUS_ERR_UNKNOWN_MODE
2785 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2788 19 SILC_COMMAND_CUMODE
2791 Arguments: (1) <Channel ID> (2) <mode mask>
2794 This command is used by client to change channel user modes on
2795 channel. Users on channel may have some special modes and this
2796 command is used by channel operators to set or change these modes.
2797 The <Channel ID> is the ID of the target channel. The <mode mask>
2798 is OR'ed mask of modes. The <Client ID> is the target client.
2799 The client changing channel user modes must be on the same channel
2800 as the target client and poses sufficient privileges to be able to
2803 When the mode is changed SILC_NOTIFY_TYPE_CUMODE_CHANGE notify
2804 type is distributed to the channel.
2806 Following channel modes are defined:
2808 0x0000 SILC_CUMODE_NONE
2810 No specific mode. This is the normal situation for client.
2811 Also, this is the mode set when removing all modes from client.
2814 0x0001 SILC_CUMODE_FOUNDER
2816 The client is channel founder of the channel. This mode
2817 cannot be set by other client, it is set by the server when
2818 the channel was founded (created). The mode is provided
2819 because client may remove the founder rights from itself.
2822 0x0002 SILC_CUMODE_OPERATOR
2824 Sets channel operator privileges on the channel for a
2825 client on the channel. Channel founder and channel operator
2826 may set/unset (promote/demote) this mode.
2829 Reply messages to the command:
2832 Arguments: (1) <Status Payload> (2) <channel user mode mask>
2835 This command replies with the changed channel user mode mask that
2836 client is required to keep locally. The <Client ID> is the target
2842 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2843 SILC_STATUS_ERR_TOO_MANY_PARAMS
2844 SILC_STATUS_ERR_NOT_REGISTERED
2845 SILC_STATUS_ERR_NOT_ON_CHANNEL
2846 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2847 SILC_STATUS_ERR_BAD_CHANNEL_ID
2848 SILC_STATUS_ERR_NO_CHANNEL_ID
2849 SILC_STATUS_ERR_NO_CHANNEL_PRIV
2850 SILC_STATUS_ERR_UNKNOWN_MODE
2851 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2854 19 SILC_COMMAND_KICK
2857 Arguments: (1) <Channel ID> (2) <Client ID>
2860 This command is used by channel operators to remove a client from
2861 channel. The <channel> argument is the channel the client to be
2862 removed is on currently. Note that the "kicker" must be on the same
2863 channel. If <comment> is provided it will be sent to the removed
2866 Reply messages to the command:
2869 Arguments: (1) <Status Payload>
2871 This command replies only with Status Payload.
2876 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2877 SILC_STATUS_ERR_TOO_MANY_PARAMS
2878 SILC_STATUS_ERR_NOT_REGISTERED
2879 SILC_STATUS_ERR_NO_SUCH_CHANNEL
2880 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2881 SILC_STATUS_ERR_NO_CHANNEL_PRIV
2882 SILC_STATUS_ERR_NO_CLIENT_ID
2885 20 SILC_COMMAND_RESTART
2890 This command may only be used by server operator to force a
2891 server to restart itself.
2893 Reply messages to the command:
2896 Arguments: (1) <Status Payload>
2898 This command replies only with Status Payload.
2903 SILC_STATUS_ERR_NOT_REGISTERED
2904 SILC_STATUS_ERR_NO_SERVER_PRIV
2910 21 SILC_COMMAND_CLOSE
2913 Arguments: (1) <remote server/router> (2) [<port>]
2915 This command is used only by operator to close connection to a
2918 Reply messages to the command:
2921 Arguments: (1) <Status Payload>
2923 This command replies only with Status Payload.
2928 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2929 SILC_STATUS_ERR_TOO_MANY_PARAMS
2930 SILC_STATUS_ERR_NOT_REGISTERED
2931 SILC_STATUS_ERR_NO_SUCH_SERVER
2932 SILC_STATUS_ERR_NO_SERVER_PRIV
2933 SILC_STATUS_ERR_NO_SUCH_SERVER_ID
2936 22 SILC_COMMAND_SHUTDOWN
2941 This command is used only by operator to shutdown the server.
2942 All connections to the server will be closed and the server is
2945 Reply messages to the command:
2950 Arguments: (1) <Status Payload>
2952 This command replies only with Status Payload.
2957 SILC_STATUS_ERR_NOT_REGISTERED
2958 SILC_STATUS_ERR_NO_SERVER_PRIV
2961 23 SILC_COMMAND_SILCOPER
2964 Arguments: (1) <username> (2) <authentication data>
2966 This command is used by normal client to obtain router operator
2967 privileges (also known as SILC operator) on some router. Note
2968 that router operator has router privileges that supersedes the
2969 server operator privileges.
2971 The <username> is the username set in the server configurations
2972 as operator. The <authentication data> is the data that the
2973 client is authenticated against. It may be passphrase prompted
2974 for user on client's screen or it may be public key
2975 authentication data (data signed with private key), or
2978 Difference between router operator and server operator is that
2979 router operator is able to handle cell level properties while
2980 server operator (even on router server) is able to handle only
2981 local properties, such as, local connections and normal server
2984 Reply messages to the command:
2987 Arguments: (1) <Status Payload>
2989 This command replies only with Status Payload.
2994 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2995 SILC_STATUS_ERR_TOO_MANY_PARAMS
2996 SILC_STATUS_ERR_NOT_REGISTERED
2997 SILC_STATUS_ERR_BAD_PASSWORD
2998 SILC_STATUS_ERR_AUTH_FAILED
3001 24 SILC_COMMAND_LEAVE
3004 Arguments: (1) <Channel ID>
3006 This command is used by client to leave a channel the client is
3007 joined to. After a client has leaved the channel the server
3008 must create new key for the channel and distribute to all clients
3009 still currently on the channel.
3011 Reply messages to the command:
3014 Arguments: (1) <Status Payload>
3016 This command replies only with Status Payload.
3021 SILC_STATUS_ERR_NOT_REGISTERED
3022 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
3023 SILC_STATUS_ERR_TOO_MANY_PARAMS
3024 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
3025 SILC_STATUS_ERR_BAD_CHANNEL_ID
3026 SILC_STATUS_ERR_NO_CHANNEL_ID
3029 25 SILC_COMMAND_USERS
3032 Arguments: (1) <Channel ID>
3034 This command is used to list user names currently on the requested
3035 channel; argument <Channel ID>. The server must resolve the
3036 user names and send a comma (`,') separated list of user names
3037 on the channel. Server or router may resolve the names by sending
3038 SILC_COMMAND_WHOIS commands.
3040 If the requested channel is a private or secret channel, this
3041 command must not send the list of users, as private and secret
3042 channels cannot be seen by outside. In this case the returned
3043 name list may include a indication that the server could not
3044 resolve the names of the users on the channel. Also, in this case
3045 Client ID's or client modes are not sent either.
3047 Reply messages to the command:
3050 Arguments: (1) <Status Payload> (2) <Channel ID>
3051 (3) <list count> (4) <Client ID list>
3052 (5) <client mode list>
3054 This command replies with the Channel ID of the requested channel
3055 Client ID list of the users on the channel and list of their modes.
3056 The Client ID list has Client ID's of all users in the list. The
3057 <Client ID list> is formed by adding Client ID's one after another.
3058 The <client mode list> is formed by adding client's user modes on
3059 the channel one after another (4 bytes (32 bits) each). The <list
3060 count> of length of 4 bytes (32 bits), tells the number of entries
3061 in the lists. Both lists must have equal number of entries.
3066 SILC_STATUS_ERR_NOT_REGISTERED
3067 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
3068 SILC_STATUS_ERR_TOO_MANY_PARAMS
3069 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
3070 SILC_STATUS_ERR_BAD_CHANNEL_ID
3071 SILC_STATUS_ERR_NO_CHANNEL_ID
3072 SILC_STATUS_ERR_NOT_ON_CHANNEL
3077 Currently undefined commands.
3082 These commands are reserved for private use and will not be defined
3086 255 SILC_COMMAND_MAX
3088 Reserved command. This must not be sent.
3093 5.3 SILC Command Status Types
3096 5.3.1 SILC Command Status Payload
3098 Command Status Payload is sent in command reply messages to indicate
3099 the status of the command. The payload is one of argument in the
3100 command thus this is the data area in Command Argument Payload described
3101 in [SILC2]. The payload is only 2 bytes of length. Following diagram
3102 represents the Command Status Payload (field is always in MSB order).
3111 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
3112 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3114 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3118 Figure 6: SILC Command Status Payload
3122 o Status Message (2 bytes) - Indicates the status message.
3123 All Status messages are described in the next section.
3128 5.3.2 SILC Command Status List
3130 Command Status messages are returned in the command reply messages
3131 to indicate whether the command were executed without errors. If error
3132 has occured the status tells which error occured. Status payload only
3133 sends numeric reply about the status. Receiver of the payload must
3134 convert the numeric values into human readable error messages. The
3135 list of status messages below has an example human readable error
3136 messages that client may display for the user.
3138 List of all defined command status messages following.
3141 Generic status messages:
3145 Ok status. Everything went Ok. The status payload maybe
3146 safely ignored in this case.
3148 1 SILC_STATUS_LIST_START
3150 Start of the list. There will be several command replies and
3151 this reply is the start of the list.
3153 2 SILC_STATUS_LIST_ITEM
3155 Item in the list. This is one of the item in the list but not the
3158 3 SILC_STATUS_LIST_END
3160 End of the list. There were several command replies and this
3161 reply is the last of the list. There won't be other replies
3162 belonging to this list after this one.
3166 Currently undefined and has been reserved for the future.
3169 Error status message:
3171 10 SILC_STATUS_ERR_NO_SUCH_NICK
3173 "No such nickname". Requested nickname does not exist.
3175 11 SILC_STATUS_ERR_NO_SUCH_CHANNEL
3177 "No such channel". Requested channel name does not exist.
3179 12 SILC_STATUS_ERR_NO_SUCH_SERVER
3181 "No such server". Requested server name does not exist.
3183 13 SILC_STATUS_ERR_TOO_MANY_TARGETS
3185 "Duplicate recipients. No message delivered". Message were
3186 tried to be sent to recipient which has several occurrences in
3189 14 SILC_STATUS_ERR_NO_RECIPIENT
3191 "No recipient given". Command required recipient which was
3194 15 SILC_STATUS_ERR_UNKNOWN_COMMAND
3196 "Unknown command". Command sent to server is unknown by the
3199 16 SILC_STATUS_ERR_WILDCARDS
3201 "Wildcards cannot be used". Wildcards were provided but they
3204 17 SILC_STATUS_ERR_NO_CLIENT_ID
3206 "No Client ID given". Client ID were expected as command
3207 parameter but were not found.
3209 18 SILC_STATUS_ERR_NO_CHANNEL_ID
3211 "No Channel ID given". Channel ID were expected as command
3212 parameter but were not found.
3214 19 SILC_STATUS_ERR_NO_SERVER_ID
3216 "No Serve ID given". Server ID were expected as command
3217 parameter but were not found.
3219 20 SILC_STATUS_ERR_BAD_CLIENT_ID
3221 "Bad Client ID". Client ID provided were erroneous.
3223 21 SILC_STATUS_ERR_BAD_CHANNEL_ID
3225 "Bad Channel ID". Channel ID provided were erroneous.
3227 22 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
3229 "No such Client ID". Client ID provided does not exist.
3231 23 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
3233 "No such Channel ID". Channel ID provided does not exist.
3235 24 SILC_STATUS_ERR_NICKNAME_IN_USE
3237 "Nickname already exists". Nickname created could not be
3238 registered because number of same nicknames were already set to
3239 maximum. This is not expected to happen in real life but is
3242 25 SILC_STATUS_ERR_NOT_ON_CHANNEL
3244 "You are not on that channel". The command were specified for
3245 channel user is not currently on.
3247 26 SILC_STATUS_ERR_USER_NOT_ON_CHANNEL
3249 "They are not on channel". The requested target client is not
3250 on requested channel.
3252 27 SILC_STATUS_ERR_USER_ON_CHANNEL
3254 "User already on channel". User were invited on channel they
3257 28 SILC_STATUS_ERR_NOT_REGISTERED
3259 "You have not registered". User executed command that requires
3260 the client to be registered on the server before it may be
3263 29 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
3265 "Not enough parameters". Command requires more parameters
3268 30 SILC_STATUS_ERR_TOO_MANY_PARAMS
3270 "Too many parameters". Too many parameters were provided
3273 31 SILC_STATUS_ERR_PERM_DENIED
3275 "Your host is not among the privileged". The client tried to
3276 register on server that does not allow this host to connect.
3278 32 SILC_STATUS_ERR_BANNED_FROM_SERVER
3280 "You are banned from this server". The client tried to register
3281 on server that has explicitly denied this host to connect.
3283 33 SILC_STATUS_ERR_BAD_PASSWORD
3285 "Cannot join channel. Incorrect password". Password provided for
3286 channel were not accepted.
3288 34 SILC_STATUS_ERR_CHANNEL_IS_FULL
3290 "Cannot join channel. Channel is full". The channel is full
3291 and client cannot be joined to it.
3293 35 SILC_STATUS_ERR_NOT_INVITED
3295 "Cannot join channel. You have not been invited". The channel
3296 is invite only channel and client has not been invited.
3298 36 SILC_STATUS_ERR_BANNED_FROM_CHANNEL
3300 "Cannot join channel. You have been banned". The client has
3301 been banned from the channel.
3303 37 SILC_STATUS_ERR_UNKNOWN_MODE
3305 "Unknown mode". Mode provided by the client were unknown to
3308 38 SILC_STATUS_ERR_NOT_YOU
3310 "Cannot change mode for other users". User tried to change
3311 someone else's mode.
3313 39 SILC_STATUS_ERR_NO_CHANNEL_PRIV
3315 "Permission denied. You are not channel operator". Command may
3316 be executed only by channel operator.
3318 40 SILC_STATUS_ERR_NO_CHANNEL_FOPRIV
3320 "Permission denied. You are not channel founder". Command may
3321 be executed only by channel operator.
3323 41 SILC_STATUS_ERR_NO_SERVER_PRIV
3325 "Permission denied. You are not server operator". Command may
3326 be executed only by server operator.
3328 42 SILC_STATUS_ERR_NO_ROUTER_PRIV
3330 "Permission denied. You are not SILC operator". Command may be
3331 executed only by router (SILC) operator.
3333 43 SILC_STATUS_ERR_BAD_NICKNAME
3335 "Bad nickname". Nickname requested contained illegal characters
3338 44 SILC_STATUS_ERR_BAD_CHANNEL
3340 "Bad channel name". Channel requested contained illegal characters
3343 45 SILC_STATUS_ERR_AUTH_FAILED
3345 "Authentication failed". The authentication data sent as
3346 argument were wrong and thus authentication failed.
3348 46 SILC_STATUS_ERR_UNKOWN_ALGORITHM
3350 "The algorithm was not supported." The server does not support the
3351 requested algorithm.
3356 6 Security Considerations
3358 Security is central to the design of this protocol, and these security
3359 considerations permeate the specification. Common security considerations
3360 such as keeping private keys truly private and using adequate lengths for
3361 symmetric and asymmetric keys must be followed in order to maintain the
3362 security of this protocol.
3368 [SILC2] Riikonen, P., "SILC Packet Protocol", Internet Draft,
3371 [SILC3] Riikonen, P., "SILC Key Exchange and Authentication
3372 Protocols", Internet Draft, June 2000.
3374 [IRC] Oikarinen, J., and Reed D., "Internet Relay Chat Protocol",
3377 [IRC-ARCH] Kalt, C., "Internet Relay Chat: Architecture", RFC 2810,
3380 [IRC-CHAN] Kalt, C., "Internet Relay Chat: Channel Management", RFC
3383 [IRC-CLIENT] Kalt, C., "Internet Relay Chat: Client Protocol", RFC
3386 [IRC-SERVER] Kalt, C., "Internet Relay Chat: Server Protocol", RFC
3389 [SSH-TRANS] Ylonen, T., et al, "SSH Transport Layer Protocol",
3392 [PGP] Callas, J., et al, "OpenPGP Message Format", RFC 2440,
3395 [SPKI] Ellison C., et al, "SPKI Certificate Theory", RFC 2693,
3398 [PKIX-Part1] Housley, R., et al, "Internet X.509 Public Key
3399 Infrastructure, Certificate and CRL Profile", RFC 2459,
3402 [Schneier] Schneier, B., "Applied Cryptography Second Edition",
3403 John Wiley & Sons, New York, NY, 1996.
3405 [Menezes] Menezes, A., et al, "Handbook of Applied Cryptography",
3408 [OAKLEY] Orman, H., "The OAKLEY Key Determination Protocol",
3409 RFC 2412, November 1998.
3411 [ISAKMP] Maughan D., et al, "Internet Security Association and
3412 Key Management Protocol (ISAKMP)", RFC 2408, November
3415 [IKE] Harkins D., and Carrel D., "The Internet Key Exchange
3416 (IKE)", RFC 2409, November 1998.
3418 [HMAC] Krawczyk, H., "HMAC: Keyed-Hashing for Message
3419 Authentication", RFC 2104, February 1997.
3421 [PKCS1] Kalinski, B., and Staddon, J., "PKCS #1 RSA Cryptography
3422 Specifications, Version 2.0", RFC 2437, October 1998.
3434 EMail: priikone@poseidon.pspt.fi
3436 This Internet-Draft expires 6 Jun 2001