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. This should be sufficient to prevent the miss-use
853 SILC commands are described in section 5 SILC Commands.
859 Packets are naturally the most important part of the protocol and the
860 packets are what actually makes the protocol. Packets in SILC network
861 are always encrypted using, usually, the shared secret session key
862 or some other key, for example, channel key, when encrypting channel
863 messages. The SILC Packet Protocol is a wide protocol and is described
864 in [SILC2]. This document does not define or describe details of
870 3.8 Packet Encryption
872 All packets passed in SILC network must be encrypted. This section
873 defines how packets must be encrypted in the SILC network. The detailed
874 description of the actual encryption process of the packets are
875 described in [SILC2].
877 Client and its server shares secret symmetric session key which is
878 established by the SILC Key Exchange Protocol, described in [SILC3].
879 Every packet sent from client to server, with exception of packets for
880 channels, are encrypted with this session key.
882 Channels has their own key that are shared by every client on the channel.
883 However, the channel keys are cell specific thus one cell does not know
884 the channel key of the other cell, even if that key is for same channel.
885 Channel key is also known by the routers and all servers that has clients
886 on the channel. However, channels may have channel private keys that
887 are entirely local setting for client. All clients on the channel must
888 know the channel private key before hand to be able to talk on the
889 channel. In this case, no server or router knows the key for channel.
891 Server shares secret symmetric session key with router which is
892 established by the SILC Key Exchange Protocol. Every packet passed from
893 server to router, with exception of packets for channels, are encrypted
894 with the shared session key. Same way, router server shares secret
895 symmetric key with its primary route. However, every packet passed
896 from router to other router, including packets for channels, are
897 encrypted with the shared session key. Every router connection has
898 their own session keys.
902 3.8.1 Determination of the Source and the Destination
904 The source and the destination of the packet needs to be determined
905 to be able to route the packets to correct receiver. This information
906 is available in the SILC Packet Header which is included in all packets
907 sent in SILC network. The SILC Packet Header is described in [SILC2].
909 The header is always encrypted with the session key who is next receiver
910 of the packet along the route. The receiver of the packet, for example
911 a router along the route, is able to determine the sender and the
912 destination of the packet by decrypting the SILC Packet Header and
913 checking the ID's attached to the header. The ID's in the header will
914 tell to where the packet needs to be sent and where it is coming from.
916 The header in the packet does not change during the routing of the
917 packet. The original sender, for example client, assembles the packet
918 and the packet header and server or router between the sender and the
919 receiver must not change the packet header.
921 Note that the packet and the packet header may be encrypted with
922 different keys. For example, packets to channels are encrypted with
923 the channel key, however, the header is encrypted with the session key
924 as described above. However, the header and the packet may be encrypted
925 with same key. This is case, for example, with command packets.
929 3.8.2 Client To Client
931 Process of message delivery and encryption from client to another
932 client is as follows.
934 Example: Private message from client to another client on different
935 servers. Clients do not share private message delivery
936 keys; normal session keys are used.
938 o Client 1. sends encrypted packet to its server. The packet is
939 encrypted with the session key shared between client and its
942 o Server determines the destination of the packet and decrypts
943 the packet. Server encrypts the packet with session key shared
944 between the server and its router, and sends the packet to the
947 o Router determines the destination of the packet and decrypts
948 the packet. Router encrypts the packet with session key
949 shared between the router and the destination server, and sends
950 the packet to the server.
952 o Server determines the client to which the packet is destined
953 to and decrypts the packet. Server encrypts the packet with
954 session key shared between the server and the destination client,
955 and sends the packet to the client.
957 o Client 2. decrypts the packet.
960 Example: Private message from client to another client on different
961 servers. Clients has established secret shared private
962 message delivery key with each other and that is used in
963 the message encryption.
965 o Client 1. sends encrypted packet to its server. The packet is
966 encrypted with the private message delivery key shared between
969 o Server determines the destination of the packet and sends the
970 packet to the router.
972 o Router determines the destination of the packet and sends the
973 packet to the server.
975 o Server determines the client to which the packet is destined
976 to and sends the packet to the client.
978 o Client 2. decrypts the packet with the secret shared key.
981 If clients share secret key with each other the private message
982 delivery is much simpler since servers and routers between the
983 clients do not need to decrypt and re-encrypt the packet.
985 The process for clients on same server is much simpler as there are
986 no need to send the packet to the router. The process for clients
987 on different cells is same as above except that the packet is routed
988 outside the cell. The router of the destination cell routes the
989 packet to the destination same way as described above.
993 3.8.3 Client To Channel
995 Process of message delivery from client on channel to all the clients
998 Example: Channel of four users; two on same server, other two on
999 different cells. Client sends message to the channel.
1001 o Client 1. encrypts the packet with channel key and sends the
1002 packet to its server.
1004 o Server determines local clients on the channel and sends the
1005 packet to the Client on the same server. Server then sends
1006 the packet to its router for further routing.
1008 o Router determines local clients on the channel, if found
1009 sends packet to the local clients. Router determines global
1010 clients on the channel and sends the packet to its primary
1011 router or fastest route.
1013 o (Other router(s) do the same thing and sends the packet to
1016 o Server determines local clients on the channel and sends the
1017 packet to the client.
1019 o All clients receiving the packet decrypts the packet.
1023 3.8.4 Server To Server
1025 Server to server packet delivery and encryption is described in above
1026 examples. Router to router packet delivery is analogous to server to
1027 server. However, some packets, such as channel packets, are processed
1028 differently. These cases are described later in this document and
1029 more in detail in [SILC2].
1033 3.9 Key Exchange And Authentication
1035 Key exchange is done always when for example client connects to server
1036 but also when server and router and router and router connects to each
1037 other. The purpose of key exchange protocol is to provide secure key
1038 material to be used in the communication. The key material is used to
1039 derive various security parameters used to secure SILC packets. The
1040 SILC Key Exchange protocol is described in detail in [SILC3].
1042 Authentication is done after key exchange protocol has been successfully
1043 completed. The purpose of authentication is to authenticate for example
1044 client connecting to the server. However, Usually clients are accepted
1045 to connect to server without explicit authentication. Servers are
1046 required use authentication protocol when connecting. The authentication
1047 may be based on passphrase (pre-shared-secret) or public key. The
1048 connection authentication protocol is described in detail in [SILC3].
1052 3.9.1 Authentication Payload
1054 Authentication payload is used separately from the SKE and the Connection
1055 authentication protocol. It is used during the session to authenticate
1056 with the remote. For example, the client can authenticate itself to the
1057 server to be server operator. In this case, Authentication Payload is
1060 The format of the Authentication Payload is as follows:
1066 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
1067 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1068 | Payload Length | Authentication Method |
1069 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1070 | Public Data Length | |
1071 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1075 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1076 | Authentication Data Length | |
1077 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1079 ~ Authentication Data ~
1081 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+|
1085 Figure 5: Authentication Payload
1089 o Payload Length (2 bytes) - Length of the entire payload.
1091 o Authentication Type (2) - The method of the authentication.
1092 The authentication methods are defined in [SILC2] in the
1093 Connection Auth Request Payload. The NONE authentication
1094 method is not recommended.
1096 o Public Data Length (2 bytes) - Indicates the length of
1097 the Public Data field.
1099 o Public Data (variable length) - This is defined only if
1100 the authentication method is public key. If it is any other
1101 this field does not exist and the Public Data Length field
1104 When the authentication method is public key this includes
1105 128 to 4096 bytes of non-zero random data that is used in
1106 the signature process, described subsequently.
1108 o Authentication Data Length (2 bytes) - Indicates the
1109 length of the Authentication Data field.
1111 o Authentication Data (variable length) - Authentication
1112 method dependent authentication data.
1116 If the authentication method is password based, the Authentication
1117 Data field includes the plaintext password. It is safe to send
1118 plaintext password since the entire payload is encrypted.
1120 If the authentication method is public key based (or certificate)
1121 the Authentication Data is computed as follows:
1123 HASH = hash(random bytes | ID | public key (or certificate));
1124 Authentication Data = sign(HASH);
1126 The hash() and the sign() are the hash funtion and the public key
1127 cryptography function selected in the SKE protocol. The public key
1128 is SILC style public key unless certificates are used. The ID is the
1129 entity's ID (Client or Server ID) who is authenticating itself. The ID
1130 is raw ID data. The random bytes are non-zero random bytes of length
1131 between 128 and 4096 bytes, and will be included into the Public Data
1134 The receiver will compute the signature using the random data received
1135 in the payload, the ID associated to the connection and the public key
1136 (or certificate) received in the SKE protocol. After computing the
1137 receiver must verify the signature. In this case also, the entire
1138 payload is encrypted.
1144 This section defines all the allowed algorithms that can be used in
1145 the SILC protocol. This includes mandatory cipher, mandatory public
1146 key algorithm and MAC algorithms.
1152 Cipher is the encryption algorithm that is used to protect the data
1153 in the SILC packets. See [SILC2] of the actual encryption process and
1154 definition of how it must be done. SILC has a mandatory algorithm that
1155 must be supported in order to be compliant with this protocol.
1157 Following ciphers are defined in SILC protocol:
1160 aes-256-cbc AES in CBC mode, 256 bit key (mandatory)
1161 aes-192-cbc AES in CBC mode, 192 bit key (optional)
1162 aes-128-cbc AES in CBC mode, 128 bit key (optional)
1163 twofish-256-cbc Twofish in CBC mode, 256 bit key (optional)
1164 twofish-192-cbc Twofish in CBC mode, 192 bit key (optional)
1165 twofish-128-cbc Twofish in CBC mode, 128 bit key (optional)
1166 blowfish-128-cbc Blowfish in CBC mode, 128 bit key (optional)
1167 cast-256-cbc CAST-256 in CBC mode, 256 bit key (optional)
1168 cast-192-cbc CAST-256 in CBC mode, 192 bit key (optional)
1169 cast-128-cbc CAST-256 in CBC mode, 128 bit key (optional)
1170 rc6-256-cbc RC6 in CBC mode, 256 bit key (optional)
1171 rc6-192-cbc RC6 in CBC mode, 192 bit key (optional)
1172 rc6-128-cbc RC6 in CBC mode, 128 bit key (optional)
1173 mars-256-cbc Mars in CBC mode, 256 bit key (optional)
1174 mars-192-cbc Mars in CBC mode, 192 bit key (optional)
1175 mars-128-cbc Mars in CBC mode, 128 bit key (optional)
1176 none No encryption (optional)
1180 Algorithm none does not perform any encryption process at all and
1181 thus is not recommended to be used. It is recommended that no client
1182 or server implementation would accept none algorithms except in special
1185 Additional ciphers may be defined to be used in SILC by using the
1186 same name format as above.
1190 3.10.2 Public Key Algorithms
1192 Public keys are used in SILC to authenticate entities in SILC network
1193 and to perform other tasks related to public key cryptography. The
1194 public keys are also used in the SILC Key Exchange protocol [SILC3].
1196 Following public key algorithms are defined in SILC protocol:
1203 DSS is described in [Menezes]. The RSA must be implemented according
1204 PKCS #1 [PKCS1]. The mandatory PKCS #1 implementation in SILC must be
1205 compliant to either PKCS #1 version 1.5 or newer with the following
1206 notes: The signature encoding is always in same format as the encryption
1207 encoding regardles of the PKCS #1 version. The signature with appendix
1208 (with hash algorithm OID in the data) must not be used in the SILC. The
1209 rationale for this is that there is no binding between the PKCS #1 OIDs
1210 and the hash algorithms used in the SILC protocol. Hence, the encoding
1211 is always in PKCS #1 version 1.5 format.
1213 Additional public key algorithms may be defined to be used in SILC.
1217 3.10.3 Hash Functions
1219 Hash functions are used as part of MAC algorithms defined in the next
1220 section. They are also used in the SILC Key Exchange protocol defined
1223 Following Hash algorithm are defined in SILC protocol:
1225 sha1 SHA-1, length = 20 (mandatory)
1226 md5 MD5, length = 16 (optional)
1230 3.10.4 MAC Algorithms
1232 Data integrity is protected by computing a message authentication code
1233 (MAC) of the packet data. See [SILC2] for details how to compute the
1236 Following MAC algorithms are defined in SILC protocol:
1239 hmac-sha1-96 HMAC-SHA1, length = 12 (mandatory)
1240 hmac-md5-96 HMAC-MD5, length = 12 (optional)
1241 hmac-sha1 HMAC-SHA1, length = 20 (optional)
1242 hmac-md5 HMAC-MD5, length = 16 (optional)
1243 none No MAC (optional)
1246 The none MAC is not recommended to be used as the packet is not
1247 authenticated when MAC is not computed. It is recommended that no
1248 client or server would accept none MAC except in special debugging
1251 The HMAC algorithm is described in [HMAC] and hash algorithms that
1252 are used as part of the HMACs are described in [Scheneir] and in
1255 Additional MAC algorithms may be defined to be used in SILC.
1259 3.10.5 Compression Algorithms
1261 SILC protocol supports compression that may be applied to unencrypted
1262 data. It is recommended to use compression on slow links as it may
1263 significantly speed up the data transmission. By default, SILC does not
1264 use compression which is the mode that must be supported by all SILC
1267 Following compression algorithms are defined:
1270 none No compression (mandatory)
1271 zlib GNU ZLIB (LZ77) compression (optional)
1274 Additional compression algorithms may be defined to be used in SILC.
1278 3.11 SILC Public Key
1280 This section defines the type and format of the SILC public key. All
1281 implementations must support this public key type. See [SILC3] for
1282 other optional public key and certificate types allowed in SILC
1283 protocol. Public keys in SILC may be used to authenticate entities
1284 and to perform other tasks related to public key cryptography.
1286 The format of the SILC Public Key is as follows:
1292 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
1293 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1294 | Public Key Length |
1295 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1296 | Algorithm Name Length | |
1297 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1301 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1302 | Identifier Length | |
1303 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1307 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1311 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1315 Figure 5: SILC Public Key
1319 o Public Key Length (4 bytes) - Indicates the full length
1320 of the public key, not including this field.
1322 o Algorithm Name Length (2 bytes) - Indicates the length
1323 of the Algorithm Length field, not including this field.
1325 o Algorithm name (variable length) - Indicates the name
1326 of the public key algorithm that the key is. See the
1327 section 3.10.2 Public Key Algorithms for defined names.
1329 o Identifier Length (2 bytes) - Indicates the length of
1330 the Identifier field, not including this field.
1332 o Identifier (variable length) - Indicates the identifier
1333 of the public key. This data can be used to identify
1334 the owner of the key. The identifier is of following
1338 HN Host name or IP address
1345 Examples of an identifier:
1347 `UN=priikone, HN=poseidon.pspt.fi, E=priikone@poseidon.pspt.fi'
1349 `UN=sam, HN=dummy.fi, RN=Sammy Sam, O=Company XYZ, C=Finland'
1351 At least user name (UN) and host name (HN) must be provided as
1352 identifier. The fields are separated by commas (`,'). If
1353 comma is in the identifier string it must be written as `\\,',
1354 for example, `O=Company XYZ\\, Inc.'.
1356 o Public Data (variable length) - Includes the actual
1357 public data of the public key.
1359 The format of this field for RSA algorithm is
1368 The format of this field for DSS algorithm is
1380 The variable length fields are multiple precession
1381 integers encoded as strings in both examples.
1383 Other algorithms must define their own type of this
1384 field if they are used.
1387 All fields in the public key are in MSB (most significant byte first)
1392 3.12 SILC Version Detection
1394 The version detection of both client and server is performed at the
1395 connection phase while executing the SILC Key Exchange protocol. The
1396 version identifier is exchanged between initiator and responder. The
1397 version identifier is of following format:
1400 SILC-<protocol version>-<software version>
1403 The version strings are of following format:
1406 protocol version = <major>.<minor>
1407 software version = <major>[.<minor>[.<build>]]
1410 Protocol version may provide both major and minor version. Currently
1411 implementations must set the protocol version and accept the protocol
1412 version as SILC-1.0-<sotware version>.
1414 Software version may provide major, minor and build version. The
1415 software version may be freely set and accepted.
1418 Thus, the version string could be, for example:
1428 This section describes various SILC procedures such as how the
1429 connections are created and registered, how channels are created and
1430 so on. The section describes the procedures only generally as details
1431 are described in [SILC2] and [SILC3].
1435 4.1 Creating Client Connection
1437 This section describes the procedure when client connects to SILC server.
1438 When client connects to server the server must perform IP address lookup
1439 and reverse IP address lookup to assure that the origin host really is
1440 who it claims to be. Client, host, connecting to server must have
1441 both valid IP address and fully qualified domain name (FQDN).
1443 After that the client and server performs SILC Key Exchange protocol
1444 which will provide the key material used later in the communication.
1445 The key exchange protocol must be completed successfully before the
1446 connection registration may continue. The SILC Key Exchange protocol
1447 is described in [SILC3].
1449 Typical server implementation would keep a list of connections that it
1450 allows to connect to the server. The implementation would check, for
1451 example, the connecting client's IP address from the connection list
1452 before the SILC Key Exchange protocol has been started. Reason for
1453 this is that if the host is not allowed to connect to the server there
1454 is no reason to perform a key exchange protocol.
1456 After successful key exchange protocol the client and server performs
1457 connection authentication protocol. The purpose of the protocol is to
1458 authenticate the client connecting to the server. Flexible
1459 implementation could also accept the client to connect to the server
1460 without explicit authentication. However, if authentication is
1461 desired for a specific client it may be based on passphrase or
1462 public key authentication. If authentication fails the connection
1463 must be terminated. The connection authentication protocol is described
1466 After successful key exchange and authentication protocol the client
1467 registers itself by sending SILC_PACKET_NEW_CLIENT packet to the
1468 server. This packet includes various information about the client
1469 that the server uses to create the client. Server creates the client
1470 and sends SILC_PACKET_NEW_ID to the client which includes the created
1471 Client ID that the client must start using after that. After that
1472 all SILC packets from the client must have the Client ID as the
1473 Source ID in the SILC Packet Header, described in [SILC2].
1475 Client must also get the server's Server ID that is to be used as
1476 Destination ID in the SILC Packet Header when communicating with
1477 the server (for example when sending commands to the server). The
1478 ID may be resolved in two ways. Client can take the ID from an
1479 previously received packet from server that must include the ID,
1480 or to send SILC_COMMAND_INFO command and receive the Server ID as
1483 Server may choose not to use the information received in the
1484 SILC_PACKET_NEW_CLIENT packet. For example, if public key or
1485 certificate were used in the authentication, server may use those
1486 informations rather than what it received from client. This is suitable
1487 way to get the true information about client if it is available.
1489 The nickname of client is initially set to the username sent in the
1490 SILC_PACKET_NEW_CLIENT packet. User should set the nickname to more
1491 suitable by sending SILC_COMMAND_NICK command. However, this is not
1492 required as part of registration process.
1494 Server must also distribute the information about newly registered
1495 client to its router (or if the server is router, to all routers in
1496 the SILC network). More information about this in [SILC2].
1500 4.2 Creating Server Connection
1502 This section descibres the procedure when server connects to its
1503 router (or when router connects to other router, the cases are
1504 equivalent). The procedure is very much alike when client connects
1505 to the server thus it is not repeated here.
1507 One difference is that server must perform connection authentication
1508 protocol with proper authentication. Proper authentication is based
1509 on passphrase or public key authentication.
1511 After server and router has successfully performed the key exchange
1512 and connection authentication protocol, the server register itself
1513 to the router by sending SILC_PACKET_NEW_SERVER packet. This packet
1514 includes the server's Server ID that it has created by itself and
1515 other relevant information about the server.
1517 After router has received the SILC_PACKET_NEW_SERVER packet it
1518 distributes the information about newly registered server to all routers
1519 in the SILC network. More information about this in [SILC2].
1521 As client needed to resolve the destination ID this must be done by the
1522 server that connected to the router, as well. The way to resolve it is
1523 to get the ID from previously received packet. Server must also start
1524 using its own Server ID as Source ID in SILC Packet Header and the
1525 router's Server ID as Destination when communicating with the router.
1527 If the server has already connected clients and locally created
1528 channels the server must distribute these informations to the router.
1529 The distribution is done by sending packet SILC_PACKET_NEW_CHANNEL.
1530 See [SILC2] for more information on this.
1534 4.3 Joining to a Channel
1536 This section describes the procedure when client joins to a channel.
1537 Client may join to channel by sending command SILC_COMMAND_JOIN to the
1538 server. If the receiver receiving join command is normal server the
1539 server must check its local list whether this channel already exists
1540 locally. This would indicate that some client connected to the server
1541 has already joined to the channel. If this is case the client is
1542 joined to the client, new channel key is created and information about
1543 newly joined channel is sent to the router. The router is informed
1544 by sending SILC_NOTIFY_TYPE_JOIN notify type. The notify type must
1545 also be sent to the local clients on the channel. The new channel key
1546 is also sent to the router and to local clients on the channel.
1548 If the channel does not exist in the local list the client's command
1549 must be sent to the router which will then perform the actual joining
1550 procedure. When server receives the reply to the command from the
1551 router it must be sent to the client who sent the command originally.
1552 Server will also receive the channel key from the server that it must
1553 send to the client who originally requested the join command. The server
1554 must also save the channel key.
1556 If the receiver of the join command is router it must first check its
1557 local list whether anyone in the cell has already joined to the channel.
1558 If this is the case the client is joined to the channel and reply is
1559 sent to the client. If the command was sent by server the command reply
1560 is sent to the server who sent it. Then the router must also create
1561 new channel key and distribute it to all clients on the channel and
1562 all servers that has clients on the channel. Router must also send
1563 the SILC_NOTIFY_TYPE_JOIN notify type to local clients on the channel
1564 and to local servers that has clients on the channel.
1566 If the channel does not exist on the router's local list it must
1567 check the global list whether the channel exists at all. If it does
1568 the client is joined to the channel as described previously. If
1569 the channel does not exist the channel is created and the client
1570 is joined to the channel. The channel key is also created and
1571 distributed as previously described. The client joining to the created
1572 channel is made automatically channel founder and both channel founder
1573 and channel operator privileges is set for the client.
1575 If the router created the channel in the process, information about the
1576 new channel must be broadcasted to all routers. This is done by
1577 broadcasting SILC_PACKET_NEW_CHANNEL packet to the router's primary
1578 route. When the router joins the client to the channel it must also
1579 send information about newly joined client to all routers in the SILC
1580 network. This is done by broadcasting the SILC_NOTIFY_TYPE_JOIN notify
1581 type to the router's primary route.
1583 It is important to note that new channel key is created always when
1584 new client joins to channel, whether the channel has existed previously
1585 or not. This way the new client on the channel is not able to decrypt
1586 any of the old traffic on the channel. Client who receives the reply to
1587 the join command must start using the received Channel ID in the channel
1588 message communication thereafter. Client also receives the key for the
1589 channel in the command reply.
1593 4.4 Channel Key Generation
1595 Channel keys are created by router who creates the channel by taking
1596 enough randomness from cryptographically strong random number generator.
1597 The key is generated always when channel is created, when new client
1598 joins a channel and after the key has expired. Key could expire for
1601 The key must also be re-generated whenever some client leaves a channel.
1602 In this case the key is created from scratch by taking enough randomness
1603 from the random number generator. After that the key is distributed to
1604 all clients on the channel. However, channel keys are cell specific thus
1605 the key is created only on the cell where the client, who left the
1606 channel, exists. While the server or router is creating the new channel
1607 key, no other client may join to the channel. Messages that are sent
1608 while creating the new key are still processed with the old key. After
1609 server has sent the SILC_PACKET_CHANNEL_KEY packet must client start
1610 using the new key. If server creates the new key the server must also
1611 send the new key to its router. See [SILC2] on more information about
1612 how channel messages must be encrypted and decrypted when router is
1615 When client receives the SILC_PACKET_CHANNEL_KEY packet with the
1616 Channel Key Payload it must process the key data to create encryption
1617 and decryption key, and to create the HMAC key that is used to compute
1618 the MACs of the channel messages. The processing is as follows:
1620 channel_key = raw key data
1621 HMAC key = hash(raw key data)
1623 The raw key data is the key data received in the Channel Key Payload.
1624 The hash() function is the hash function used in the HMAC of the channel.
1628 4.5 Private Message Sending and Reception
1630 Private messages are sent point to point. Client explicitly destines
1631 a private message to specific client that is delivered to only to that
1632 client. No other client may receive the private message. The receiver
1633 of the private message is destined in the SILC Packet Header as any
1634 other packet as well.
1636 If the sender of a private message does not know the receiver's Client
1637 ID, it must resolve it from server. There are two ways to resolve the
1638 client ID from server; it is recommended that client implementations
1639 send SILC_COMMAND_IDENTIFY command to receive the Client ID. Client
1640 may also send SILC_COMMAND_WHOIS command to receive the Client ID.
1641 If the sender has received earlier a private message from the receiver
1642 it should have cached the Client ID from the SILC Packet Header.
1644 Receiver of a private message should not explicitly trust the nickname
1645 that it receives in the Private Message Payload, described in [SILC2].
1646 Implementations could resolve the nickname from server, as described
1647 previously, and compare the received Client ID and the SILC Packet
1648 Header's Client ID. The nickname in the payload is merely provided
1649 to be displayed for end user.
1651 See [SILC2] for description of private message encryption and decryption
1656 4.6 Private Message Key Generation
1658 Private message may be protected by key generated by client. The key
1659 may be generated and sent to the other client by sending packet
1660 SILC_PACKET_PRIVATE_MESSAGE_KEY which travels through the network
1661 and is secured by session keys. After that the private message key
1662 is used in the private message communication between those clients.
1664 Other choice is to entirely use keys that are not sent through
1665 the SILC network at all. This significantly adds security. This key
1666 would be pre-shared-key that is known by both of the clients. Both
1667 agree about using the key and starts sending packets that indicate
1668 that the private message is secured using private message key.
1670 The key material used as private message key is implementation issue.
1671 However, SILC_PACKET_KEY_AGREEMENT packet may be used to negotiate
1672 the key material. If the key is normal pre-shared-key or randomly
1673 generated key, and the SILC_PACKET_KEY_AGREEMENT was not used, then
1674 the key material should be processed as defined in the [SILC3]. In
1675 the processing, however, the HASH, as defined in [SILC3] must be
1676 ignored. After processing the key material it is employed as defined
1677 in [SILC3], however, the HMAC key material must be discarded.
1679 If the key is pre-shared-key or randomly generated the implementations
1680 should use the SILC protocol's mandatory cipher as the cipher. If the
1681 SKE was used to negotiate key material the cipher was negotiated as well.
1684 4.7 Channel Message Sending and Reception
1686 Channel messages are delivered to group of users. The group forms a
1687 channel and all clients on the channel receives messages sent to the
1690 Channel messages are destined to channel by specifying the Channel ID
1691 as Destination ID in the SILC Packet Header. The server must then
1692 distribute the message to all clients on the channel by sending the
1693 channel message destined explicitly to a client on the channel.
1695 See [SILC2] for description of channel message encryption and decryption
1700 4.8 Session Key Regeneration
1702 Session keys should be regenerated periodically, say, once in an hour.
1703 The re-key process is started by sending SILC_PACKET_REKEY packet to
1704 other end, to indicate that re-key must be performed.
1706 If perfect forward secrecy (PFS) flag was selected in the SILC Key
1707 Exchange protocol [SILC3] the re-key must cause new key exchange with
1708 SKE protocol. In this case the protocol is secured with the old key
1709 and the protocol results to new key material. See [SILC3] for more
1710 information. After the SILC_PACKET_REKEY packet is sent the sender
1711 will perform the SKE protocol.
1713 If PFS flag was not set, which is the default case, then re-key is done
1714 without executing SKE protocol. In this case, the new key is created by
1715 hashing the old key with hash function selected earlier in the SKE
1716 protocol. If the digest length of the hash function is too short for the
1717 key, then the key is distributed as described in section Processing the
1718 Key Material in [SILC3]. After both parties has regenerated the session
1719 key, both send SILC_PACKET_REKEY_DONE packet to each other. These packets
1720 are still secured with the old key. After these packets, following
1721 packets must be protected with the new key.
1725 4.9 Command Sending and Reception
1727 Client usually sends the commands in the SILC network. In this case
1728 the client simply sends the command packet to server and the server
1729 processes it and replies with command reply packet.
1731 However, if the server is not able to process the command, it is sent
1732 to the server's router. This is case for example with commands such
1733 as, SILC_COMMAND_JOIN and SILC_COMMAND_WHOIS commands. However, there
1734 are other commands as well. For example, if client sends the WHOIS
1735 command requesting specific information about some client the server must
1736 send the WHOIS command to router so that all clients in SILC network
1737 are searched. The router, on the other hand, sends the WHOIS command
1738 further to receive the exact information about the requested client.
1739 The WHOIS command travels all the way to the server who owns the client
1740 and it replies with command reply packet. Finally, the server who
1741 sent the command receives the command reply and it must be able to
1742 determine which client sent the original command. The server then
1743 sends command reply to the client. Implementations should have some
1744 kind of cache to handle, for example, WHOIS information. Servers
1745 and routers along the route could all cache the information for faster
1746 referencing in the future.
1748 The commands sent by server may be sent hop by hop until someone is able
1749 to process the command. However, it is preferred to destine the command
1750 as precisely as it is possible. In this case, other routers en route
1751 must route the command packet by checking the true sender and true
1752 destination of the packet. However, servers and routers must not route
1753 command reply packets to clients coming from other server. Client
1754 must not accept command reply packet originated from anyone else but
1755 from its own server.
1762 5.1 SILC Commands Syntax
1764 This section briefly describes the syntax of the command notions
1765 in this document. Every field in command is separated from each
1766 other by whitespaces (` ') indicating that each field is independent
1767 argument and each argument must have own Command Argument Payload.
1768 The number of maximum arguments are defined with each command
1769 separately. The Command Argument Payload is described in [SILC2].
1771 Every command defines specific number for each argument. Currently,
1772 they are defined in ascending order; first argument has number one
1773 (1), second has number two (2) and so on. This number is set into the
1774 Argument Type field in the Command Argument Payload. This makes it
1775 possible to send the arguments in free order as the number must be
1776 used to identify the type of the argument. This makes is it also
1777 possible to have multiple optional arguments in commands and in
1778 command replies. The number of argument is marked in parentheses
1779 before the actual argument.
1784 Example: Arguments: (1) <nickname> (2) <username@host>
1788 Every command replies with Status Payload. This payload tells the
1789 sender of the command whether the command was completed successfully or
1790 whether there was an error. If error occured the payload includes the
1791 error type. In the next section the Status Payload is not described
1792 as it is common to all commands and has been described here. Commands
1793 may reply with other arguments as well. These arguments are command
1794 specific and are described in the next section.
1803 Arguments: (1) <nickname>[@<server>] (2) <message>
1806 The command has maximum of 3 arguments. However, only first
1807 and second arguments are mandatory.
1809 First argument <nickname> is mandatory but may have optional
1810 <nickname@server> format as well. Second argument is mandatory
1811 <message> argument. Third argument is optional <count> argument.
1813 The numbers in parentheses are the argument specific numbers
1814 that specify the type of the argument in Command Argument Payload.
1815 The receiver always knows that, say, argument number two (2) is
1816 <message> argument, regardless of the ordering of the arguments in
1817 the Command Payload.
1819 Reply messages to the command:
1822 Arguments: (1) <Status Payload> (2) [<channel list>]
1823 (3) <idle time> (4) [<away message>]
1825 This command may reply with maximum of 4 arguments. However,
1826 only the first and third arguments are mandatory. The numbers
1827 in the parentheses have the same meaning as in the upper
1828 command sending specification.
1830 Every command reply with <Status Payload>, it is mandatory
1831 argument for all command replies and for this reason it is not
1832 described in the command reply descriptions.
1839 SILC_STATUS_ERR_TOO_MANY_TARGETS
1840 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
1841 SILC_STATUS_ERR_NO_SUCH_NICK
1843 Every command reply also defines set of status message that it
1844 may return inside the <Status Payload>. All status messages
1845 are defined in the section 5.3 SILC Command Status Types.
1848 Every command that has some kind of ID as argument (for example
1849 <Client ID>) are actually ID Payloads, defined in [SILC2] that includes
1850 the type of the ID, length of the ID and the actual ID data. This
1851 way variable length ID's can be sent as arguments.
1855 5.2 SILC Commands List
1857 This section lists all SILC commands, however, it is expected that a
1858 implementation and especially client implementation has many more
1859 commands that has only local affect. These commands are official
1860 SILC commands that has both client and server sides and cannot be
1861 characterized as local commands.
1863 List of all defined commands in SILC follows.
1868 None. This is reserved command and must not be sent.
1871 1 SILC_COMMAND_WHOIS
1874 Arguments: (1) [<nickname>[@<server>]] (2) [<count>]
1875 (3) [<Client ID>] (n) [...]
1877 Whois command is used to query various information about specific
1878 user. The user maybe requested by their nickname and server name.
1879 The query may find multiple matching users as there are no unique
1880 nicknames in the SILC. The <count> option maybe given to narrow
1881 down the number of accepted results. If this is not defined there
1882 are no limit of accepted results. The query may also be narrowed
1883 down by defining the server name of the nickname.
1885 It is also possible to search the user by Client ID. If <Client ID>
1886 is provided server must use it as the search value instead of
1887 the <nickname>. One of the arguments must be given. It is also
1888 possible to define multiple Client ID's to search multiple users
1889 sending only one WHOIS command. In this case the Client ID's are
1890 appended as normal arguments. The server replies in this case
1891 with only one reply message for all requested users.
1893 To prevent miss-use of this service wildcards in the nickname
1894 or in the servername are not permitted. It is not allowed
1895 to request all users on some server. The WHOIS requests must
1896 be based on specific nickname request.
1898 The WHOIS request must be always sent to the router by server
1899 so that all users are searched. However, the server still must
1900 search its locally connected clients. The router must send
1901 this command to the server who owns the requested client. That
1902 server must reply to the command. Server should not send whois
1903 replies to the client until it has received the reply from its
1906 Reply messages to the command:
1909 Arguments: (1) <Status Payload> (2) <Client ID>
1910 (3) <nickname>[@<server>] (4) <username@host>
1911 (5) <real name> (6) [<channel list>]
1914 This command may reply with several command reply messages to
1915 form a list of results. In this case the status payload will
1916 include STATUS_LIST_START status in the first reply and
1917 STATUS_LIST_END in the last reply to indicate the end of the
1918 list. If there are only one reply the status is set to normal
1921 The command replies include the Client ID of the nickname,
1922 nickname and servername, username and hostname and users real
1923 name. Client should process these replies only after the last
1924 reply has been received with the STATUS_LIST_END status. If the
1925 <count> option were defined in the query there will be only
1926 <count> many replies from the server.
1931 SILC_STATUS_LIST_START
1932 SILC_STATUS_LIST_END
1933 SILC_STATUS_ERR_NO_SUCH_NICK
1934 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
1935 SILC_STATUS_ERR_WILDCARDS
1936 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
1937 SILC_STATUS_ERR_TOO_MANY_PARAMS
1942 2 SILC_COMMAND_WHOWAS
1945 Arguments: (1) <nickname>[@<server>] (2) [<count>]
1947 Whowas. This command is used to query history information about
1948 specific user. The user maybe requested by their nickname and
1949 server name. The query may find multiple matching users as there
1950 are no unique nicknames in the SILC. The <count> option maybe
1951 given to narrow down the number of accepted results. If this
1952 is not defined there are no limit of accepted results. The query
1953 may also be narrowed down by defining the server name of the
1956 To prevent miss-use of this service wildcards in the nickname
1957 or in the servername are not permitted. The WHOWAS requests must
1958 be based on specific nickname request.
1960 The WHOWAS request must be always sent to the router by server
1961 so that all users are searched. However, the server still must
1962 search its locally connected clients.
1964 Reply messages to the command:
1967 Arguments: (1) <Status Payload> (2) <nickname>[@<server>]
1968 (3) <username@host> (4) [<real name>]
1970 This command may reply with several command reply messages to form
1971 a list of results. In this case the status payload will include
1972 STATUS_LIST_START status in the first reply and STATUS_LIST_END in
1973 the last reply to indicate the end of the list. If there are only
1974 one reply the status is set to normal STATUS_OK.
1976 The command replies with nickname and username and hostname.
1977 Every server must keep history for some period of time of its
1978 locally connected clients.
1983 SILC_STATUS_LIST_START
1984 SILC_STATUS_LIST_END
1985 SILC_STATUS_ERR_NO_SUCH_NICK
1986 SILC_STATUS_ERR_WILDCARDS
1987 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
1988 SILC_STATUS_ERR_TOO_MANY_PARAMS
1991 3 SILC_COMMAND_IDENTIFY
1994 Arguments: (1) [<nickname>[@<server>]] (2) [<count>]
1995 (3) [<Client ID>] (n) [...]
1997 Identify. Identify command is almost analogous to WHOIS command,
1998 except that it does not return as much information. Only relevant
1999 information such as Client ID is returned. This is usually used
2000 to get the Client ID of a client used in the communication with
2003 The query may find multiple matching users as there are no unique
2004 nicknames in the SILC. The <count> option maybe given to narrow
2005 down the number of accepted results. If this is not defined there
2006 are no limit of accepted results. The query may also be narrowed
2007 down by defining the server name of the nickname.
2009 It is also possible to search the user by Client ID. If <Client ID>
2010 is provided server must use it as the search value instead of
2011 the <nickname>. One of the arguments must be given. It is also
2012 possible to define multiple Client ID's to search multiple users
2013 sending only one IDENTIFY command. In this case the Client ID's are
2014 appended as normal arguments. The server replies in this case
2015 with only one reply message for all requested users.
2017 To prevent miss-use of this service wildcards in the nickname
2018 or in the servername are not permitted. It is not allowed
2019 to request all users on some server. The IDENTIFY requests must
2020 be based on specific nickname request.
2022 Implementations may not want to give interface access to this
2023 command as it is hardly a command that would be used by an end user.
2024 However, it must be implemented as it is used with private message
2027 The IDENTIFY must be always sent to the router by server so that
2028 all users are searched. However, server must still search its
2029 locally connected clients.
2031 Reply messages to the command:
2034 Arguments: (1) <Status Payload> (2) <Client ID>
2035 (3) [<nickname>[@<server>]] (4) [<username@host>]
2037 This command may reply with several command reply messages to form
2038 a list of results. In this case the status payload will include
2039 STATUS_LIST_START status in the first reply and STATUS_LIST_END in
2040 the last reply to indicate the end of the list. If there are only
2041 one reply the status is set to normal STATUS_OK.
2043 The command replies with Client ID of the nickname and if more
2044 information is available it may reply with nickname and username
2045 and hostname. If the <count> option were defined in the query
2046 there will be only <count> many replies from the server.
2051 SILC_STATUS_LIST_START
2052 SILC_STATUS_LIST_END
2053 SILC_STATUS_ERR_NO_SUCH_NICK
2054 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2055 SILC_STATUS_ERR_WILDCARDS
2056 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2057 SILC_STATUS_ERR_TOO_MANY_PARAMS
2063 Arguments: (1) <nickname>
2065 Set/change nickname. This command is used to set nickname for
2066 user. There is no limit of the length of the nickname in SILC.
2067 Nickname must not include any spaces (` '), non-printable
2068 characters, commas (`,') and any wildcard characters. Note:
2069 nicknames in SILC are case-sensitive which must be taken into
2070 account when searching clients by nickname.
2072 When nickname is changed new Client ID is generated. Server must
2073 distribute SILC_NOTIFY_TYPE_NICK_CHANGE to local clients on the
2074 channels (if any) the client is joined on. Then it must send
2075 SILC_PACKET_REPLACE_ID to its primary route to replace the old
2076 Client ID with the new one.
2078 Reply messages to the command:
2081 Arguments: (1) <Status Payload> (2) <New ID Payload>
2083 This command is replied always with New ID Payload that is
2084 generated by the server every time user changes their nickname.
2085 Client receiving this payload must start using the received
2086 Client ID as its current valid Client ID. The New ID Payload
2087 is described in [SILC2].
2092 SILC_STATUS_ERR_WILDCARDS
2093 SILC_STATUS_ERR_NICKNAME_IN_USE
2094 SILC_STATUS_ERR_BAD_NICKNAME
2095 SILC_STATUS_ERR_NOT_REGISTERED
2096 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2097 SILC_STATUS_ERR_TOO_MANY_PARAMS
2103 Arguments: (1) [<Channel ID>] [<server>]
2105 The list command is used to list channels and their topics on
2106 current server. If the <Channel ID> parameter is used, only the
2107 status of that channel is displayed. Secret channels are not
2108 listed at all. Private channels are listed with status indicating
2109 that the channel is private.
2111 If the <server> argument is specified the specified server's
2112 channels are listed. In this case the command must be sent to
2113 the server who owns the channel that was requested.
2115 Reply messages to the command:
2118 Arguments: (1) <Status Payload> (2) <Channel ID>
2119 (3) <channel> (4) <topic>
2121 This command may reply with several command reply messages to form
2122 a list of results. In this case the status payload will include
2123 STATUS_LIST_START status in the first reply and STATUS_LIST_END in
2124 the last reply to indicate the end of the list. If there are only
2125 one reply the status is set to normal STATUS_OK.
2127 This command replies with Channel ID, name and the topic of the
2128 channel. If the channel is private channel the <topic> includes
2134 SILC_STATUS_LIST_START
2135 SILC_STATUS_LIST_END
2136 SILC_STATUS_ERR_WILDCARDS
2137 SILC_STATUS_ERR_NOT_REGISTERED
2138 SILC_STATUS_ERR_TOO_MANY_PARAMS
2139 SILC_STATUS_ERR_NO_SUCH_CHANNEL
2140 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2141 SILC_STATUS_ERR_NO_SUCH_SERVER
2144 6 SILC_COMMAND_TOPIC
2147 Arguments: (1) <Channel ID> (2) [<topic>]]
2149 This command is used to change or view the topic of a channel.
2150 The topic for channel <Channel ID> is returned if there is no
2151 <topic> given. If the <topic> parameter is present, the topic
2152 for that channel will be changed, if the channel modes permit
2155 Reply messages to the command:
2158 Arguments: (1) <Status Payload> (2) <Channel ID>
2161 The command may reply with the topic of the channel if it is
2167 SILC_STATUS_ERR_NOT_ON_CHANNEL
2168 SILC_STATUS_ERR_WILDCARDS
2169 SILC_STATUS_ERR_NOT_REGISTERED
2170 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2171 SILC_STATUS_ERR_NO_SUCH_CHANNEL
2172 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2173 SILC_STATUS_ERR_NO_CHANNEL_ID
2174 SILC_STATUS_ERR_BAD_CHANNEL_ID
2175 SILC_STATUS_ERR_TOO_MANY_PARAMS
2176 SILC_STATUS_ERR_NO_CHANNEL_PRIV
2179 7 SILC_COMMAND_INVITE
2182 Arguments: (1) <Client ID> (2) <Channel ID>
2184 This command is used to invite other clients to join to the
2185 channel. The <Client ID> argument is the target client's ID that
2186 is being invited. The <Channel ID> is the Channel ID of the
2187 requested channel. The sender of this command must be on the
2188 channel. This command must fail if the requested channel does
2189 not exist, the requested client is already on the channel or if
2190 the channel is invite only channel and the caller of this command
2191 does not have at least channel operator privileges.
2193 Reply messages to the command:
2196 Arguments: (1) <Status Payload>
2198 This command replies only with Status Payload.
2203 SILC_STATUS_ERR_NOT_REGISTERED
2204 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2205 SILC_STATUS_ERR_TOO_MANY_PARAMS
2206 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2207 SILC_STATUS_ERR_NO_CLIENT_ID
2208 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2209 SILC_STATUS_ERR_NO_CHANNEL_ID
2210 SILC_STATUS_ERR_NOT_ON_CHANNEL
2211 SILC_STATUS_ERR_USER_ON_CHANNEL
2217 Arguments: (1) [<quit message>]
2219 This command is used by client to end SILC session. The server
2220 must close the connection to a client which sends this command.
2221 if <quit message> is given it will be sent to other clients on
2222 channel if the client is on channel when quitting.
2224 Reply messages to the command:
2226 This command does not reply anything.
2232 Arguments: (1) <Client ID> (2) [<comment>]
2234 This command is used by SILC operators to remove a client from
2235 SILC network. The removing has temporary effects and client may
2236 reconnect to SILC network. The <Client ID> is the client to be
2237 removed from SILC. The <comment> argument may be provided to
2238 give to the removed client some information why it was removed
2241 Reply messages to the command:
2244 Arguments: (1) <Status Payload>
2246 This command replies only with Status Payload.
2251 SILC_STATUS_ERR_WILDCARDS
2252 SILC_STATUS_ERR_NOT_REGISTERED
2253 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2254 SILC_STATUS_ERR_TOO_MANY_PARAMS
2255 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2256 SILC_STATUS_ERR_NO_CLIENT_ID
2257 SILC_STATUS_ERR_NO_ROUTER_PRIV
2260 10 SILC_COMMAND_INFO
2263 Arguments: (1) [<server>]
2265 This command is used to fetch various information about a server.
2266 If <server> argument is specified the command must be sent to
2267 the requested server.
2269 Reply messages to the command:
2272 Arguments: (1) <Status Payload> (2) <Server ID>
2275 This command replies with the Server ID of the server and a
2276 string which tells the information about the server.
2281 SILC_STATUS_ERR_WILDCARDS
2282 SILC_STATUS_ERR_NOT_REGISTERED
2283 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2284 SILC_STATUS_ERR_TOO_MANY_PARAMS
2285 SILC_STATUS_ERR_NO_SUCH_SERVER
2288 11 SILC_COMMAND_CONNECT
2291 Arguments: (1) <remote server/router> (2) [<port>]
2293 This command is used by operators to force a server to try to
2294 establish a new connection to remote server or router. The
2295 Operator must specify the server/router to be connected by
2296 setting <remote server> argument. The port is 32 bit MSB value.
2298 Reply messages to the command:
2301 Arguments: (1) <Status Payload>
2303 This command replies only with Status Payload.
2310 SILC_STATUS_ERR_WILDCARDS
2311 SILC_STATUS_ERR_NOT_REGISTERED
2312 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2313 SILC_STATUS_ERR_TOO_MANY_PARAMS
2314 SILC_STATUS_ERR_NO_SERVER_PRIV
2315 SILC_STATUS_ERR_NO_ROUTER_PRIV
2318 12 SILC_COMMAND_PING
2321 Arguments: (1) <Server ID>
2323 This command is used by client and server to test the communication
2324 channel to its server if one suspects that the communication is not
2325 working correctly. The <Server ID> is the ID of the server the
2326 sender is connected to.
2328 Reply messages to the command:
2331 Arguments: (1) <Status Payload>
2333 This command replies only with Status Payload. Server returns
2334 SILC_STATUS_OK in Status Payload if pinging was successful.
2341 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2342 SILC_STATUS_ERR_TOO_MANY_PARAMS
2343 SILC_STATUS_ERR_NO_SERVER_ID
2344 SILC_STATUS_ERR_NO_SUCH_SERVER
2345 SILC_STATUS_ERR_NOT_REGISTERED
2348 13 SILC_COMMAND_OPER
2351 Arguments: (1) <username> (2) <authentication data>
2353 This command is used by normal client to obtain server operator
2354 privileges on some server or router. Note that router operator
2355 has router privileges that supersedes the server operator
2356 privileges and this does not obtain those privileges. Client
2357 must use SILCOPER command to obtain router level privileges.
2359 The <username> is the username set in the server configurations
2360 as operator. The <authentication data> is the data that the
2361 client is authenticated against. It may be passphrase prompted
2362 for user on client's screen or it may be public key
2363 authentication data (data signed with private key), or
2366 Reply messages to the command:
2369 Arguments: (1) <Status Payload>
2371 This command replies only with Status Payload.
2376 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2377 SILC_STATUS_ERR_TOO_MANY_PARAMS
2378 SILC_STATUS_ERR_NOT_REGISTERED
2379 SILC_STATUS_ERR_BAD_PASSWORD
2380 SILC_STATUS_ERR_AUTH_FAILED
2383 14 SILC_COMMAND_JOIN
2386 Arguments: (1) <channel> (2) <Client ID>
2387 (3) [<passphrase>] (4) [<cipher>]
2390 Join to channel/create new channel. This command is used to
2391 join to a channel. If the channel does not exist the channel is
2392 created. If server is normal server this command must be sent
2393 to router who will create the channel. The channel may be
2394 protected with passphrase. If this is the case the passphrase
2395 must be sent along the join command.
2397 The name of the <channel> must not include any spaces (` '),
2398 non-printable characters, commas (`,') or any wildcard characters.
2400 The second argument <Client ID> is the Client ID of the client who
2401 is joining to the client. When client sends this command to the
2402 server the <Client ID> must be the client's own ID.
2404 Cipher to be used to secure the traffic on the channel may be
2405 requested by sending the name of the requested <cipher>. This
2406 is used only if the channel does not exist and is created. If
2407 the channel already exists the cipher set previously for the
2408 channel will be used to secure the traffic. The computed MACs
2409 of the channel message are produced by the default HMAC or by
2410 the <hmac> provided for the command.
2412 The server must check whether the user is allowed to join to
2413 the requested channel. Various modes set to the channel affect
2414 the ability of the user to join the channel. These conditions
2417 o The user must be invited to the channel if the channel
2418 is invite-only channel.
2420 o The Client ID/nickname/username/hostname must not match
2423 o The correct passphrase must be provided if passphrase
2424 is set to the channel.
2426 o The user count limit, if set, must not be reached.
2428 Reply messages to the command:
2431 Arguments: (1) <Status Payload> (2) <channel>
2432 (3) <Channel ID> (4) <Client ID>
2433 (5) <channel mode mask> (6) <created>
2434 (7) <Channel Key Payload> (8) [<ban mask>]
2435 (9) [<invite list>] (10) [<topic>]
2436 (11) [<hmac>] (12) <list count>
2437 (13) <Client ID list> (14) <client mode list>
2439 This command replies with the channel name requested by the
2440 client, channel ID of the channel and topic of the channel
2441 if it exists. The <Client ID> is the Client ID which was joined
2442 to the channel. It also replies with the channel mode mask
2443 which tells all the modes set on the channel. If the
2444 channel is created the mode mask is zero (0). If ban mask
2445 and/or invite list is set they are sent as well.
2447 The <list count>, <Client ID list> and <client mode list> are
2448 the clients curerntly on the channel and their modes on the
2451 Client receives the channel key in the reply message as well
2452 inside <Channel Key Payload>.
2457 SILC_STATUS_ERR_WILDCARDS
2458 SILC_STATUS_ERR_NOT_REGISTERED
2459 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2460 SILC_STATUS_ERR_TOO_MANY_PARAMS
2461 SILC_STATUS_ERR_BAD_PASSWORD
2462 SILC_STATUS_ERR_CHANNEL_IS_FULL
2463 SILC_STATUS_ERR_NOT_INVITED
2464 SILC_STATUS_ERR_BANNED_FROM_CHANNEL
2465 SILC_STATUS_ERR_BAD_CHANNEL
2466 SILC_STATUS_ERR_USER_ON_CHANNEL
2469 15 SILC_COMMAND_MOTD
2472 Arguments: (1) <server>
2474 This command is used to query the Message of the Day of the server.
2476 Reply messages to the command:
2479 Arguments: (1) <Status Payload> (2) [<motd>]
2481 This command replies with the motd message if it exists.
2486 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2487 SILC_STATUS_ERR_TOO_MANY_PARAMS
2488 SILC_STATUS_ERR_NOT_REGISTERED
2489 SILC_STATUS_ERR_NO_SUCH_SERVER
2492 16 SILC_COMMAND_UMODE
2495 Arguments: (1) <Client ID> (2) <client mode mask>
2497 This command is used by client to set/unset modes for itself.
2498 However, there are some modes that the client may not set itself,
2499 but they will be set by server. However, client may unset any
2500 mode. Modes may be masked together ORing them thus having
2501 several modes set. Client must keep its client mode mask
2502 locally so that the mode setting/unsetting would work without
2503 problems. Client may change only its own modes.
2505 Following client modes are defined:
2507 0x0000 SILC_UMODE_NONE
2509 No specific mode for client. This is the initial
2510 setting when new client is created. The client is
2514 0x0001 SILC_UMODE_SERVER_OPERATOR
2516 Marks the user as server operator. Client cannot
2517 set this mode itself. Server sets this mode to the
2518 client when client attains the server operator
2519 privileges by SILC_COMMAND_OPER command. Client
2520 may unset the mode itself.
2523 0x0002 SILC_UMODE_ROUTER_OPERATOR
2525 Marks the user as router (SILC) operator. Client
2526 cannot this mode itself. Router sets this mode to
2527 the client when client attains the router operator
2528 privileges by SILC_COMMAND_SILCOPER command. Client
2529 may unset the mode itself.
2531 Reply messages to the command:
2534 Arguments: (1) <Status Payload> (2) <client mode mask>
2536 This command replies with the changed client mode mask that
2537 the client is required to keep locally.
2543 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2544 SILC_STATUS_ERR_TOO_MANY_PARAMS
2545 SILC_STATUS_ERR_NOT_REGISTERED
2546 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2547 SILC_STATUS_ERR_BAD_CLIENT_ID
2548 SILC_STATUS_ERR_NOT_YOU
2549 SILC_STATUS_ERR_UNKNOWN_MODE
2550 SILC_STATUS_ERR_NO_RECIPIENT
2551 SILC_STATUS_ERR_NO_CLIENT_ID
2554 17 SILC_COMMAND_CMODE
2557 Arguments: (1) <Channel ID> (2) <channel mode mask>
2558 (3) [<user limit>] (4) [<passphrase>]
2559 (5) [<ban mask>] (6) [<invite list>]
2560 (7) [<cipher>] (8) [<hmac>]
2562 This command is used by client to set or change channel flags on
2563 a channel. Channel has several modes that set various properties
2564 of a channel. Modes may be masked together by ORing them thus
2565 having several modes set. The <Channel ID> is the ID of the
2566 target channel. The client changing channel mode must be on
2567 the same channel and poses sufficient privileges to be able to
2570 When the mode is changed SILC_NOTIFY_TYPE_CMODE_CHANGE notify
2571 type is distributed to the channel.
2573 Following channel modes are defined:
2575 0x0000 SILC_CMODE_NONE
2577 No specific mode on channel. This is the default when
2578 channel is created. This means that channel is just plain
2582 0x0001 SILC_CMODE_PRIVATE
2584 Channel is private channel. Private channels are shown
2585 in the channel list listed with SILC_COMMAND_LIST command
2586 with indication that the channel is private. Also,
2587 client on private channel will no be detected to be on
2588 the channel as the channel is not shown in the client's
2589 currently joined channel list. Channel founder and
2590 channel operator may set/unset this mode.
2592 Typical implementation would use [+|-]p on user interface
2593 to set/unset this mode.
2596 0x0002 SILC_CMODE_SECRET
2598 Channel is secret channel. Secret channels are not shown
2599 in the list listed with SILC_COMMAND_LIST command. Secret
2600 channels can be considered to be invisible channels.
2601 Channel founder and channel operator may set/unset this
2604 Typical implementation would use [+|-]s on user interface
2605 to set/unset this mode.
2608 0x0004 SILC_CMODE_PRIVKEY
2610 Channel uses private channel key to protect the traffic
2611 on the channel. When this mode is set the client will be
2612 responsible to set the key it wants to use to encrypt and
2613 decrypt the traffic on channel. Server generated channel
2614 keys are not used at all. This mode provides additional
2615 security as clients on channel may agree to use private
2616 channel key that even servers do not know. Naturally,
2617 this requires that every client on the channel knows
2618 the key before hand (it is considered to be pre-shared-
2619 key). This specification does not define how the private
2620 channel key is set as it is entirely local setting on
2623 As it is local setting it is possible to have several
2624 private channel keys on one channel. In this case several
2625 clients can talk on same channel but only those clients
2626 that share the key with the message sender will be able
2627 to hear the talking. Client should not display those
2628 message for the end user that it is not able to decrypt
2629 when this mode is set.
2631 Only channel founder may set/unset this mode. If this
2632 mode is unset the server will distribute new channel
2633 key to all clients on the channel which will be used
2636 Typical implementation would use [+|-]k on user interface
2637 to set/unset this mode.
2640 0x0008 SILC_CMODE_INVITE
2642 Channel is invite only channel. Client may join to this
2643 channel only if it is invited to the channel. Channel
2644 founder and channel operator may set/unset this mode.
2646 Typical implementation would use [+|-]i on user interface
2647 to set/unset this mode.
2650 0x0010 SILC_CMODE_TOPIC
2652 The topic of the channel may only be set by client that
2653 is channel founder or channel operator. Normal clients
2654 on channel will not be able to set topic when this mode
2655 is set. Channel founder and channel operator may set/
2658 Typical implementation would use [+|-]t on user interface
2659 to set/unset this mode.
2662 0x0020 SILC_CMODE_ULIMIT
2664 User limit has been set to the channel. New clients
2665 may not join to the channel when the limit set is
2666 reached. Channel founder and channel operator may set/
2667 unset the limit. The <user limit> argument is the
2668 number of limited users.
2670 Typical implementation would use [+|-]l on user interface
2671 to set/unset this mode.
2674 0x0040 SILC_CMODE_PASSPHRASE
2676 Passphrase has been set to the channel. Client may
2677 join to the channel only if it is able to provide the
2678 correct passphrase. Setting passphrases to channel
2679 is entirely safe as all commands are protected in the
2680 SILC network. Only channel founder may set/unset
2681 the passphrase. The <passphrase> argument is the
2684 Typical implementation would use [+|-]a on user interface
2685 to set/unset this mode.
2688 0x0080 SILC_CMODE_BAN
2690 Ban mask has been set to the channel. The ban mask
2691 may be used to ban specific clients to join the channel.
2692 The <ban mask> argument is the set ban mask. When
2693 unsetting a ban mask the mask must be provided as
2694 argument. Channel founder and channel operator may
2695 set/unset this mode. Channel founder may not be
2696 added to the ban list. <ban mask> is an comma (`,')
2697 separated list of banned clients in the following format:
2699 [<nickname>[@<server>]!][<username>]@[<hostname>]
2701 Wildcards maybe used when banning clients.
2703 Typical implementation would use [+|-]b on user interface
2704 to set/unset this mode.
2707 0x0100 SILC_CMODE_INVITE_LIST
2709 Invite list has been set to the channel. The invite list
2710 can be used to mark the clients that is able to join
2711 channel without being invited when the channel is set to
2712 be invite-only channel. The <invite list> argument is the
2713 set invite mask. When unsetting entry from the invite list
2714 the entry must be provided as argument. Channel founder and
2715 channel operator may set/unset this mode. The <invite list>
2716 is command (`,') separated list of invited clients in the
2719 [<nickname>[@<server>]!][<username>]@[<hostname>]
2721 Wildcards maybe used when setting the invite list.
2723 Typical implementation would use [+|-]I on user interface
2724 to set/unset this mode.
2727 0x0200 SILC_CMODE_CIPHER
2729 Sets specific cipher to be used to protect channel
2730 traffic. The <cipher> argument is the requested cipher.
2731 When set or unset the server must re-generate new
2732 channel key. Only channel founder may set the cipher of
2733 the channel. When unset the new key is generated using
2734 default cipher for the channel.
2736 Typical implementation would use [+|-]c on user interface
2737 to set/unset this mode.
2740 0x0400 SILC_CMODE_HMAC
2742 Sets specific hmac to be used to compute the MACs of the
2743 channel message. The <hmac> argument is the requested hmac.
2744 Only channel founder may set the hmac of the channel.
2746 Typical implementation would use [+|-]h on user interface
2747 to set/unset this mode.
2750 To make the mode system work, client must keep the channel mode
2751 mask locally so that the mode setting and unsetting would work
2752 without problems. The client receives the initial channel mode
2753 mask when it joins to the channel. When the mode changes on
2754 channel the servers distributes the changed channel mode mask to
2755 all clients on the channel by sending SILC_NOTIFY_TYPE_CMODE_CHANGE
2759 Reply messages to the command:
2762 Arguments: (1) <Status Payload> (2) <channel mode mask>
2764 This command replies with the changed channel mode mask that
2765 client is required to keep locally.
2770 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2771 SILC_STATUS_ERR_TOO_MANY_PARAMS
2772 SILC_STATUS_ERR_NOT_REGISTERED
2773 SILC_STATUS_ERR_NOT_ON_CHANNEL
2774 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2775 SILC_STATUS_ERR_BAD_CHANNEL_ID
2776 SILC_STATUS_ERR_NO_CHANNEL_ID
2777 SILC_STATUS_ERR_NO_CHANNEL_PRIV
2778 SILC_STATUS_ERR_UNKNOWN_MODE
2779 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2782 19 SILC_COMMAND_CUMODE
2785 Arguments: (1) <Channel ID> (2) <mode mask>
2788 This command is used by client to change channel user modes on
2789 channel. Users on channel may have some special modes and this
2790 command is used by channel operators to set or change these modes.
2791 The <Channel ID> is the ID of the target channel. The <mode mask>
2792 is OR'ed mask of modes. The <Client ID> is the target client.
2793 The client changing channel user modes must be on the same channel
2794 as the target client and poses sufficient privileges to be able to
2797 When the mode is changed SILC_NOTIFY_TYPE_CUMODE_CHANGE notify
2798 type is distributed to the channel.
2800 Following channel modes are defined:
2802 0x0000 SILC_CUMODE_NONE
2804 No specific mode. This is the normal situation for client.
2805 Also, this is the mode set when removing all modes from client.
2808 0x0001 SILC_CUMODE_FOUNDER
2810 The client is channel founder of the channel. This mode
2811 cannot be set by other client, it is set by the server when
2812 the channel was founded (created). The mode is provided
2813 because client may remove the founder rights from itself.
2816 0x0002 SILC_CUMODE_OPERATOR
2818 Sets channel operator privileges on the channel for a
2819 client on the channel. Channel founder and channel operator
2820 may set/unset (promote/demote) this mode.
2823 Reply messages to the command:
2826 Arguments: (1) <Status Payload> (2) <channel user mode mask>
2829 This command replies with the changed channel user mode mask that
2830 client is required to keep locally. The <Client ID> is the target
2836 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2837 SILC_STATUS_ERR_TOO_MANY_PARAMS
2838 SILC_STATUS_ERR_NOT_REGISTERED
2839 SILC_STATUS_ERR_NOT_ON_CHANNEL
2840 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2841 SILC_STATUS_ERR_BAD_CHANNEL_ID
2842 SILC_STATUS_ERR_NO_CHANNEL_ID
2843 SILC_STATUS_ERR_NO_CHANNEL_PRIV
2844 SILC_STATUS_ERR_UNKNOWN_MODE
2845 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2848 19 SILC_COMMAND_KICK
2851 Arguments: (1) <Channel ID> (2) <Client ID>
2854 This command is used by channel operators to remove a client from
2855 channel. The <channel> argument is the channel the client to be
2856 removed is on currently. Note that the "kicker" must be on the same
2857 channel. If <comment> is provided it will be sent to the removed
2860 Reply messages to the command:
2863 Arguments: (1) <Status Payload>
2865 This command replies only with Status Payload.
2870 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2871 SILC_STATUS_ERR_TOO_MANY_PARAMS
2872 SILC_STATUS_ERR_NOT_REGISTERED
2873 SILC_STATUS_ERR_NO_SUCH_CHANNEL
2874 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2875 SILC_STATUS_ERR_NO_CHANNEL_PRIV
2876 SILC_STATUS_ERR_NO_CLIENT_ID
2879 20 SILC_COMMAND_RESTART
2884 This command may only be used by server operator to force a
2885 server to restart itself.
2887 Reply messages to the command:
2890 Arguments: (1) <Status Payload>
2892 This command replies only with Status Payload.
2897 SILC_STATUS_ERR_NOT_REGISTERED
2898 SILC_STATUS_ERR_NO_SERVER_PRIV
2904 21 SILC_COMMAND_CLOSE
2907 Arguments: (1) <remote server/router> (2) [<port>]
2909 This command is used only by operator to close connection to a
2912 Reply messages to the command:
2915 Arguments: (1) <Status Payload>
2917 This command replies only with Status Payload.
2922 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2923 SILC_STATUS_ERR_TOO_MANY_PARAMS
2924 SILC_STATUS_ERR_NOT_REGISTERED
2925 SILC_STATUS_ERR_NO_SUCH_SERVER
2926 SILC_STATUS_ERR_NO_SERVER_PRIV
2927 SILC_STATUS_ERR_NO_SUCH_SERVER_ID
2930 22 SILC_COMMAND_SHUTDOWN
2935 This command is used only by operator to shutdown the server.
2936 All connections to the server will be closed and the server is
2939 Reply messages to the command:
2944 Arguments: (1) <Status Payload>
2946 This command replies only with Status Payload.
2951 SILC_STATUS_ERR_NOT_REGISTERED
2952 SILC_STATUS_ERR_NO_SERVER_PRIV
2955 23 SILC_COMMAND_SILCOPER
2958 Arguments: (1) <username> (2) <authentication data>
2960 This command is used by normal client to obtain router operator
2961 privileges (also known as SILC operator) on some router. Note
2962 that router operator has router privileges that supersedes the
2963 server operator privileges.
2965 The <username> is the username set in the server configurations
2966 as operator. The <authentication data> is the data that the
2967 client is authenticated against. It may be passphrase prompted
2968 for user on client's screen or it may be public key
2969 authentication data (data signed with private key), or
2972 Difference between router operator and server operator is that
2973 router operator is able to handle cell level properties while
2974 server operator (even on router server) is able to handle only
2975 local properties, such as, local connections and normal server
2978 Reply messages to the command:
2981 Arguments: (1) <Status Payload>
2983 This command replies only with Status Payload.
2988 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2989 SILC_STATUS_ERR_TOO_MANY_PARAMS
2990 SILC_STATUS_ERR_NOT_REGISTERED
2991 SILC_STATUS_ERR_BAD_PASSWORD
2992 SILC_STATUS_ERR_AUTH_FAILED
2995 24 SILC_COMMAND_LEAVE
2998 Arguments: (1) <Channel ID>
3000 This command is used by client to leave a channel the client is
3001 joined to. After a client has leaved the channel the server
3002 must create new key for the channel and distribute to all clients
3003 still currently on the channel.
3005 Reply messages to the command:
3008 Arguments: (1) <Status Payload>
3010 This command replies only with Status Payload.
3015 SILC_STATUS_ERR_NOT_REGISTERED
3016 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
3017 SILC_STATUS_ERR_TOO_MANY_PARAMS
3018 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
3019 SILC_STATUS_ERR_BAD_CHANNEL_ID
3020 SILC_STATUS_ERR_NO_CHANNEL_ID
3023 25 SILC_COMMAND_USERS
3026 Arguments: (1) <Channel ID>
3028 This command is used to list user names currently on the requested
3029 channel; argument <Channel ID>. The server must resolve the
3030 user names and send a comma (`,') separated list of user names
3031 on the channel. Server or router may resolve the names by sending
3032 SILC_COMMAND_WHOIS commands.
3034 If the requested channel is a private or secret channel, this
3035 command must not send the list of users, as private and secret
3036 channels cannot be seen by outside. In this case the returned
3037 name list may include a indication that the server could not
3038 resolve the names of the users on the channel. Also, in this case
3039 Client ID's or client modes are not sent either.
3041 Reply messages to the command:
3044 Arguments: (1) <Status Payload> (2) <Channel ID>
3045 (3) <list count> (4) <Client ID list>
3046 (5) <client mode list>
3048 This command replies with the Channel ID of the requested channel
3049 Client ID list of the users on the channel and list of their modes.
3050 The Client ID list has Client ID's of all users in the list. The
3051 <Client ID list> is formed by adding Client ID's one after another.
3052 The <client mode list> is formed by adding client's user modes on
3053 the channel one after another (4 bytes (32 bits) each). The <list
3054 count> of length of 4 bytes (32 bits), tells the number of entries
3055 in the lists. Both lists must have equal number of entries.
3060 SILC_STATUS_ERR_NOT_REGISTERED
3061 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
3062 SILC_STATUS_ERR_TOO_MANY_PARAMS
3063 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
3064 SILC_STATUS_ERR_BAD_CHANNEL_ID
3065 SILC_STATUS_ERR_NO_CHANNEL_ID
3066 SILC_STATUS_ERR_NOT_ON_CHANNEL
3071 Currently undefined commands.
3076 These commands are reserved for private use and will not be defined
3080 255 SILC_COMMAND_MAX
3082 Reserved command. This must not be sent.
3087 5.3 SILC Command Status Types
3090 5.3.1 SILC Command Status Payload
3092 Command Status Payload is sent in command reply messages to indicate
3093 the status of the command. The payload is one of argument in the
3094 command thus this is the data area in Command Argument Payload described
3095 in [SILC2]. The payload is only 2 bytes of length. Following diagram
3096 represents the Command Status Payload (field is always in MSB order).
3105 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
3106 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3108 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3112 Figure 6: SILC Command Status Payload
3116 o Status Message (2 bytes) - Indicates the status message.
3117 All Status messages are described in the next section.
3122 5.3.2 SILC Command Status List
3124 Command Status messages are returned in the command reply messages
3125 to indicate whether the command were executed without errors. If error
3126 has occured the status tells which error occured. Status payload only
3127 sends numeric reply about the status. Receiver of the payload must
3128 convert the numeric values into human readable error messages. The
3129 list of status messages below has an example human readable error
3130 messages that client may display for the user.
3132 List of all defined command status messages following.
3135 Generic status messages:
3139 Ok status. Everything went Ok. The status payload maybe
3140 safely ignored in this case.
3142 1 SILC_STATUS_LIST_START
3144 Start of the list. There will be several command replies and
3145 this reply is the start of the list.
3147 2 SILC_STATUS_LIST_ITEM
3149 Item in the list. This is one of the item in the list but not the
3152 3 SILC_STATUS_LIST_END
3154 End of the list. There were several command replies and this
3155 reply is the last of the list. There won't be other replies
3156 belonging to this list after this one.
3160 Currently undefined and has been reserved for the future.
3163 Error status message:
3165 10 SILC_STATUS_ERR_NO_SUCH_NICK
3167 "No such nickname". Requested nickname does not exist.
3169 11 SILC_STATUS_ERR_NO_SUCH_CHANNEL
3171 "No such channel". Requested channel name does not exist.
3173 12 SILC_STATUS_ERR_NO_SUCH_SERVER
3175 "No such server". Requested server name does not exist.
3177 13 SILC_STATUS_ERR_TOO_MANY_TARGETS
3179 "Duplicate recipients. No message delivered". Message were
3180 tried to be sent to recipient which has several occurrences in
3183 14 SILC_STATUS_ERR_NO_RECIPIENT
3185 "No recipient given". Command required recipient which was
3188 15 SILC_STATUS_ERR_UNKNOWN_COMMAND
3190 "Unknown command". Command sent to server is unknown by the
3193 16 SILC_STATUS_ERR_WILDCARDS
3195 "Wildcards cannot be used". Wildcards were provided but they
3198 17 SILC_STATUS_ERR_NO_CLIENT_ID
3200 "No Client ID given". Client ID were expected as command
3201 parameter but were not found.
3203 18 SILC_STATUS_ERR_NO_CHANNEL_ID
3205 "No Channel ID given". Channel ID were expected as command
3206 parameter but were not found.
3208 19 SILC_STATUS_ERR_NO_SERVER_ID
3210 "No Serve ID given". Server ID were expected as command
3211 parameter but were not found.
3213 20 SILC_STATUS_ERR_BAD_CLIENT_ID
3215 "Bad Client ID". Client ID provided were erroneous.
3217 21 SILC_STATUS_ERR_BAD_CHANNEL_ID
3219 "Bad Channel ID". Channel ID provided were erroneous.
3221 22 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
3223 "No such Client ID". Client ID provided does not exist.
3225 23 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
3227 "No such Channel ID". Channel ID provided does not exist.
3229 24 SILC_STATUS_ERR_NICKNAME_IN_USE
3231 "Nickname already exists". Nickname created could not be
3232 registered because number of same nicknames were already set to
3233 maximum. This is not expected to happen in real life but is
3236 25 SILC_STATUS_ERR_NOT_ON_CHANNEL
3238 "You are not on that channel". The command were specified for
3239 channel user is not currently on.
3241 26 SILC_STATUS_ERR_USER_NOT_ON_CHANNEL
3243 "They are not on channel". The requested target client is not
3244 on requested channel.
3246 27 SILC_STATUS_ERR_USER_ON_CHANNEL
3248 "User already on channel". User were invited on channel they
3251 28 SILC_STATUS_ERR_NOT_REGISTERED
3253 "You have not registered". User executed command that requires
3254 the client to be registered on the server before it may be
3257 29 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
3259 "Not enough parameters". Command requires more parameters
3262 30 SILC_STATUS_ERR_TOO_MANY_PARAMS
3264 "Too many parameters". Too many parameters were provided
3267 31 SILC_STATUS_ERR_PERM_DENIED
3269 "Your host is not among the privileged". The client tried to
3270 register on server that does not allow this host to connect.
3272 32 SILC_STATUS_ERR_BANNED_FROM_SERVER
3274 "You are banned from this server". The client tried to register
3275 on server that has explicitly denied this host to connect.
3277 33 SILC_STATUS_ERR_BAD_PASSWORD
3279 "Cannot join channel. Incorrect password". Password provided for
3280 channel were not accepted.
3282 34 SILC_STATUS_ERR_CHANNEL_IS_FULL
3284 "Cannot join channel. Channel is full". The channel is full
3285 and client cannot be joined to it.
3287 35 SILC_STATUS_ERR_NOT_INVITED
3289 "Cannot join channel. You have not been invited". The channel
3290 is invite only channel and client has not been invited.
3292 36 SILC_STATUS_ERR_BANNED_FROM_CHANNEL
3294 "Cannot join channel. You have been banned". The client has
3295 been banned from the channel.
3297 37 SILC_STATUS_ERR_UNKNOWN_MODE
3299 "Unknown mode". Mode provided by the client were unknown to
3302 38 SILC_STATUS_ERR_NOT_YOU
3304 "Cannot change mode for other users". User tried to change
3305 someone else's mode.
3307 39 SILC_STATUS_ERR_NO_CHANNEL_PRIV
3309 "Permission denied. You are not channel operator". Command may
3310 be executed only by channel operator.
3312 40 SILC_STATUS_ERR_NO_CHANNEL_FOPRIV
3314 "Permission denied. You are not channel founder". Command may
3315 be executed only by channel operator.
3317 41 SILC_STATUS_ERR_NO_SERVER_PRIV
3319 "Permission denied. You are not server operator". Command may
3320 be executed only by server operator.
3322 42 SILC_STATUS_ERR_NO_ROUTER_PRIV
3324 "Permission denied. You are not SILC operator". Command may be
3325 executed only by router (SILC) operator.
3327 43 SILC_STATUS_ERR_BAD_NICKNAME
3329 "Bad nickname". Nickname requested contained illegal characters
3332 44 SILC_STATUS_ERR_BAD_CHANNEL
3334 "Bad channel name". Channel requested contained illegal characters
3337 45 SILC_STATUS_ERR_AUTH_FAILED
3339 "Authentication failed". The authentication data sent as
3340 argument were wrong and thus authentication failed.
3342 46 SILC_STATUS_ERR_UNKOWN_ALGORITHM
3344 "The algorithm was not supported." The server does not support the
3345 requested algorithm.
3350 6 Security Considerations
3352 Security is central to the design of this protocol, and these security
3353 considerations permeate the specification. Common security considerations
3354 such as keeping private keys truly private and using adequate lengths for
3355 symmetric and asymmetric keys must be followed in order to maintain the
3356 security of this protocol.
3362 [SILC2] Riikonen, P., "SILC Packet Protocol", Internet Draft,
3365 [SILC3] Riikonen, P., "SILC Key Exchange and Authentication
3366 Protocols", Internet Draft, June 2000.
3368 [IRC] Oikarinen, J., and Reed D., "Internet Relay Chat Protocol",
3371 [IRC-ARCH] Kalt, C., "Internet Relay Chat: Architecture", RFC 2810,
3374 [IRC-CHAN] Kalt, C., "Internet Relay Chat: Channel Management", RFC
3377 [IRC-CLIENT] Kalt, C., "Internet Relay Chat: Client Protocol", RFC
3380 [IRC-SERVER] Kalt, C., "Internet Relay Chat: Server Protocol", RFC
3383 [SSH-TRANS] Ylonen, T., et al, "SSH Transport Layer Protocol",
3386 [PGP] Callas, J., et al, "OpenPGP Message Format", RFC 2440,
3389 [SPKI] Ellison C., et al, "SPKI Certificate Theory", RFC 2693,
3392 [PKIX-Part1] Housley, R., et al, "Internet X.509 Public Key
3393 Infrastructure, Certificate and CRL Profile", RFC 2459,
3396 [Schneier] Schneier, B., "Applied Cryptography Second Edition",
3397 John Wiley & Sons, New York, NY, 1996.
3399 [Menezes] Menezes, A., et al, "Handbook of Applied Cryptography",
3402 [OAKLEY] Orman, H., "The OAKLEY Key Determination Protocol",
3403 RFC 2412, November 1998.
3405 [ISAKMP] Maughan D., et al, "Internet Security Association and
3406 Key Management Protocol (ISAKMP)", RFC 2408, November
3409 [IKE] Harkins D., and Carrel D., "The Internet Key Exchange
3410 (IKE)", RFC 2409, November 1998.
3412 [HMAC] Krawczyk, H., "HMAC: Keyed-Hashing for Message
3413 Authentication", RFC 2104, February 1997.
3415 [PKCS1] Kalinski, B., and Staddon, J., "PKCS #1 RSA Cryptography
3416 Specifications, Version 2.0", RFC 2437, October 1998.
3428 EMail: priikone@poseidon.pspt.fi
3430 This Internet-Draft expires 6 Jun 2001