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. In this
1119 case the Public Data Lenght is set to zero (0).
1121 If the authentication method is public key based (or certificate)
1122 the Authentication Data is computed as follows:
1124 HASH = hash(random bytes | ID | public key (or certificate));
1125 Authentication Data = sign(HASH);
1127 The hash() and the sign() are the hash funtion and the public key
1128 cryptography function selected in the SKE protocol. The public key
1129 is SILC style public key unless certificates are used. The ID is the
1130 entity's ID (Client or Server ID) who is authenticating itself. The ID
1131 is raw ID data. The random bytes are non-zero random bytes of length
1132 between 128 and 4096 bytes, and will be included into the Public Data
1135 The receiver will compute the signature using the random data received
1136 in the payload, the ID associated to the connection and the public key
1137 (or certificate) received in the SKE protocol. After computing the
1138 receiver must verify the signature. In this case also, the entire
1139 payload is encrypted.
1145 This section defines all the allowed algorithms that can be used in
1146 the SILC protocol. This includes mandatory cipher, mandatory public
1147 key algorithm and MAC algorithms.
1153 Cipher is the encryption algorithm that is used to protect the data
1154 in the SILC packets. See [SILC2] of the actual encryption process and
1155 definition of how it must be done. SILC has a mandatory algorithm that
1156 must be supported in order to be compliant with this protocol.
1158 Following ciphers are defined in SILC protocol:
1161 aes-256-cbc AES in CBC mode, 256 bit key (mandatory)
1162 aes-192-cbc AES in CBC mode, 192 bit key (optional)
1163 aes-128-cbc AES in CBC mode, 128 bit key (optional)
1164 twofish-256-cbc Twofish in CBC mode, 256 bit key (optional)
1165 twofish-192-cbc Twofish in CBC mode, 192 bit key (optional)
1166 twofish-128-cbc Twofish in CBC mode, 128 bit key (optional)
1167 blowfish-128-cbc Blowfish in CBC mode, 128 bit key (optional)
1168 cast-256-cbc CAST-256 in CBC mode, 256 bit key (optional)
1169 cast-192-cbc CAST-256 in CBC mode, 192 bit key (optional)
1170 cast-128-cbc CAST-256 in CBC mode, 128 bit key (optional)
1171 rc6-256-cbc RC6 in CBC mode, 256 bit key (optional)
1172 rc6-192-cbc RC6 in CBC mode, 192 bit key (optional)
1173 rc6-128-cbc RC6 in CBC mode, 128 bit key (optional)
1174 mars-256-cbc Mars in CBC mode, 256 bit key (optional)
1175 mars-192-cbc Mars in CBC mode, 192 bit key (optional)
1176 mars-128-cbc Mars in CBC mode, 128 bit key (optional)
1177 none No encryption (optional)
1181 Algorithm none does not perform any encryption process at all and
1182 thus is not recommended to be used. It is recommended that no client
1183 or server implementation would accept none algorithms except in special
1186 Additional ciphers may be defined to be used in SILC by using the
1187 same name format as above.
1191 3.10.2 Public Key Algorithms
1193 Public keys are used in SILC to authenticate entities in SILC network
1194 and to perform other tasks related to public key cryptography. The
1195 public keys are also used in the SILC Key Exchange protocol [SILC3].
1197 Following public key algorithms are defined in SILC protocol:
1204 DSS is described in [Menezes]. The RSA must be implemented according
1205 PKCS #1 [PKCS1]. The mandatory PKCS #1 implementation in SILC must be
1206 compliant to either PKCS #1 version 1.5 or newer with the following
1207 notes: The signature encoding is always in same format as the encryption
1208 encoding regardles of the PKCS #1 version. The signature with appendix
1209 (with hash algorithm OID in the data) must not be used in the SILC. The
1210 rationale for this is that there is no binding between the PKCS #1 OIDs
1211 and the hash algorithms used in the SILC protocol. Hence, the encoding
1212 is always in PKCS #1 version 1.5 format.
1214 Additional public key algorithms may be defined to be used in SILC.
1218 3.10.3 Hash Functions
1220 Hash functions are used as part of MAC algorithms defined in the next
1221 section. They are also used in the SILC Key Exchange protocol defined
1224 Following Hash algorithm are defined in SILC protocol:
1226 sha1 SHA-1, length = 20 (mandatory)
1227 md5 MD5, length = 16 (optional)
1231 3.10.4 MAC Algorithms
1233 Data integrity is protected by computing a message authentication code
1234 (MAC) of the packet data. See [SILC2] for details how to compute the
1237 Following MAC algorithms are defined in SILC protocol:
1240 hmac-sha1-96 HMAC-SHA1, length = 12 (mandatory)
1241 hmac-md5-96 HMAC-MD5, length = 12 (optional)
1242 hmac-sha1 HMAC-SHA1, length = 20 (optional)
1243 hmac-md5 HMAC-MD5, length = 16 (optional)
1244 none No MAC (optional)
1247 The none MAC is not recommended to be used as the packet is not
1248 authenticated when MAC is not computed. It is recommended that no
1249 client or server would accept none MAC except in special debugging
1252 The HMAC algorithm is described in [HMAC] and hash algorithms that
1253 are used as part of the HMACs are described in [Scheneir] and in
1256 Additional MAC algorithms may be defined to be used in SILC.
1260 3.10.5 Compression Algorithms
1262 SILC protocol supports compression that may be applied to unencrypted
1263 data. It is recommended to use compression on slow links as it may
1264 significantly speed up the data transmission. By default, SILC does not
1265 use compression which is the mode that must be supported by all SILC
1268 Following compression algorithms are defined:
1271 none No compression (mandatory)
1272 zlib GNU ZLIB (LZ77) compression (optional)
1275 Additional compression algorithms may be defined to be used in SILC.
1279 3.11 SILC Public Key
1281 This section defines the type and format of the SILC public key. All
1282 implementations must support this public key type. See [SILC3] for
1283 other optional public key and certificate types allowed in SILC
1284 protocol. Public keys in SILC may be used to authenticate entities
1285 and to perform other tasks related to public key cryptography.
1287 The format of the SILC Public Key is as follows:
1293 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
1294 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1295 | Public Key Length |
1296 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1297 | Algorithm Name Length | |
1298 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1302 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1303 | Identifier Length | |
1304 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1308 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1312 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1316 Figure 5: SILC Public Key
1320 o Public Key Length (4 bytes) - Indicates the full length
1321 of the public key, not including this field.
1323 o Algorithm Name Length (2 bytes) - Indicates the length
1324 of the Algorithm Length field, not including this field.
1326 o Algorithm name (variable length) - Indicates the name
1327 of the public key algorithm that the key is. See the
1328 section 3.10.2 Public Key Algorithms for defined names.
1330 o Identifier Length (2 bytes) - Indicates the length of
1331 the Identifier field, not including this field.
1333 o Identifier (variable length) - Indicates the identifier
1334 of the public key. This data can be used to identify
1335 the owner of the key. The identifier is of following
1339 HN Host name or IP address
1346 Examples of an identifier:
1348 `UN=priikone, HN=poseidon.pspt.fi, E=priikone@poseidon.pspt.fi'
1350 `UN=sam, HN=dummy.fi, RN=Sammy Sam, O=Company XYZ, C=Finland'
1352 At least user name (UN) and host name (HN) must be provided as
1353 identifier. The fields are separated by commas (`,'). If
1354 comma is in the identifier string it must be written as `\\,',
1355 for example, `O=Company XYZ\\, Inc.'.
1357 o Public Data (variable length) - Includes the actual
1358 public data of the public key.
1360 The format of this field for RSA algorithm is
1369 The format of this field for DSS algorithm is
1381 The variable length fields are multiple precession
1382 integers encoded as strings in both examples.
1384 Other algorithms must define their own type of this
1385 field if they are used.
1388 All fields in the public key are in MSB (most significant byte first)
1393 3.12 SILC Version Detection
1395 The version detection of both client and server is performed at the
1396 connection phase while executing the SILC Key Exchange protocol. The
1397 version identifier is exchanged between initiator and responder. The
1398 version identifier is of following format:
1401 SILC-<protocol version>-<software version>
1404 The version strings are of following format:
1407 protocol version = <major>.<minor>
1408 software version = <major>[.<minor>[.<build>]]
1411 Protocol version may provide both major and minor version. Currently
1412 implementations must set the protocol version and accept the protocol
1413 version as SILC-1.0-<sotware version>.
1415 Software version may provide major, minor and build version. The
1416 software version may be freely set and accepted.
1419 Thus, the version string could be, for example:
1429 This section describes various SILC procedures such as how the
1430 connections are created and registered, how channels are created and
1431 so on. The section describes the procedures only generally as details
1432 are described in [SILC2] and [SILC3].
1436 4.1 Creating Client Connection
1438 This section describes the procedure when client connects to SILC server.
1439 When client connects to server the server must perform IP address lookup
1440 and reverse IP address lookup to assure that the origin host really is
1441 who it claims to be. Client, host, connecting to server must have
1442 both valid IP address and fully qualified domain name (FQDN).
1444 After that the client and server performs SILC Key Exchange protocol
1445 which will provide the key material used later in the communication.
1446 The key exchange protocol must be completed successfully before the
1447 connection registration may continue. The SILC Key Exchange protocol
1448 is described in [SILC3].
1450 Typical server implementation would keep a list of connections that it
1451 allows to connect to the server. The implementation would check, for
1452 example, the connecting client's IP address from the connection list
1453 before the SILC Key Exchange protocol has been started. Reason for
1454 this is that if the host is not allowed to connect to the server there
1455 is no reason to perform a key exchange protocol.
1457 After successful key exchange protocol the client and server performs
1458 connection authentication protocol. The purpose of the protocol is to
1459 authenticate the client connecting to the server. Flexible
1460 implementation could also accept the client to connect to the server
1461 without explicit authentication. However, if authentication is
1462 desired for a specific client it may be based on passphrase or
1463 public key authentication. If authentication fails the connection
1464 must be terminated. The connection authentication protocol is described
1467 After successful key exchange and authentication protocol the client
1468 registers itself by sending SILC_PACKET_NEW_CLIENT packet to the
1469 server. This packet includes various information about the client
1470 that the server uses to create the client. Server creates the client
1471 and sends SILC_PACKET_NEW_ID to the client which includes the created
1472 Client ID that the client must start using after that. After that
1473 all SILC packets from the client must have the Client ID as the
1474 Source ID in the SILC Packet Header, described in [SILC2].
1476 Client must also get the server's Server ID that is to be used as
1477 Destination ID in the SILC Packet Header when communicating with
1478 the server (for example when sending commands to the server). The
1479 ID may be resolved in two ways. Client can take the ID from an
1480 previously received packet from server that must include the ID,
1481 or to send SILC_COMMAND_INFO command and receive the Server ID as
1484 Server may choose not to use the information received in the
1485 SILC_PACKET_NEW_CLIENT packet. For example, if public key or
1486 certificate were used in the authentication, server may use those
1487 informations rather than what it received from client. This is suitable
1488 way to get the true information about client if it is available.
1490 The nickname of client is initially set to the username sent in the
1491 SILC_PACKET_NEW_CLIENT packet. User should set the nickname to more
1492 suitable by sending SILC_COMMAND_NICK command. However, this is not
1493 required as part of registration process.
1495 Server must also distribute the information about newly registered
1496 client to its router (or if the server is router, to all routers in
1497 the SILC network). More information about this in [SILC2].
1501 4.2 Creating Server Connection
1503 This section descibres the procedure when server connects to its
1504 router (or when router connects to other router, the cases are
1505 equivalent). The procedure is very much alike when client connects
1506 to the server thus it is not repeated here.
1508 One difference is that server must perform connection authentication
1509 protocol with proper authentication. Proper authentication is based
1510 on passphrase or public key authentication.
1512 After server and router has successfully performed the key exchange
1513 and connection authentication protocol, the server register itself
1514 to the router by sending SILC_PACKET_NEW_SERVER packet. This packet
1515 includes the server's Server ID that it has created by itself and
1516 other relevant information about the server.
1518 After router has received the SILC_PACKET_NEW_SERVER packet it
1519 distributes the information about newly registered server to all routers
1520 in the SILC network. More information about this in [SILC2].
1522 As client needed to resolve the destination ID this must be done by the
1523 server that connected to the router, as well. The way to resolve it is
1524 to get the ID from previously received packet. Server must also start
1525 using its own Server ID as Source ID in SILC Packet Header and the
1526 router's Server ID as Destination when communicating with the router.
1528 If the server has already connected clients and locally created
1529 channels the server must distribute these informations to the router.
1530 The distribution is done by sending packet SILC_PACKET_NEW_CHANNEL.
1531 See [SILC2] for more information on this.
1535 4.3 Joining to a Channel
1537 This section describes the procedure when client joins to a channel.
1538 Client may join to channel by sending command SILC_COMMAND_JOIN to the
1539 server. If the receiver receiving join command is normal server the
1540 server must check its local list whether this channel already exists
1541 locally. This would indicate that some client connected to the server
1542 has already joined to the channel. If this is case the client is
1543 joined to the client, new channel key is created and information about
1544 newly joined channel is sent to the router. The router is informed
1545 by sending SILC_NOTIFY_TYPE_JOIN notify type. The notify type must
1546 also be sent to the local clients on the channel. The new channel key
1547 is also sent to the router and to local clients on the channel.
1549 If the channel does not exist in the local list the client's command
1550 must be sent to the router which will then perform the actual joining
1551 procedure. When server receives the reply to the command from the
1552 router it must be sent to the client who sent the command originally.
1553 Server will also receive the channel key from the server that it must
1554 send to the client who originally requested the join command. The server
1555 must also save the channel key.
1557 If the receiver of the join command is router it must first check its
1558 local list whether anyone in the cell has already joined to the channel.
1559 If this is the case the client is joined to the channel and reply is
1560 sent to the client. If the command was sent by server the command reply
1561 is sent to the server who sent it. Then the router must also create
1562 new channel key and distribute it to all clients on the channel and
1563 all servers that has clients on the channel. Router must also send
1564 the SILC_NOTIFY_TYPE_JOIN notify type to local clients on the channel
1565 and to local servers that has clients on the channel.
1567 If the channel does not exist on the router's local list it must
1568 check the global list whether the channel exists at all. If it does
1569 the client is joined to the channel as described previously. If
1570 the channel does not exist the channel is created and the client
1571 is joined to the channel. The channel key is also created and
1572 distributed as previously described. The client joining to the created
1573 channel is made automatically channel founder and both channel founder
1574 and channel operator privileges is set for the client.
1576 If the router created the channel in the process, information about the
1577 new channel must be broadcasted to all routers. This is done by
1578 broadcasting SILC_PACKET_NEW_CHANNEL packet to the router's primary
1579 route. When the router joins the client to the channel it must also
1580 send information about newly joined client to all routers in the SILC
1581 network. This is done by broadcasting the SILC_NOTIFY_TYPE_JOIN notify
1582 type to the router's primary route.
1584 It is important to note that new channel key is created always when
1585 new client joins to channel, whether the channel has existed previously
1586 or not. This way the new client on the channel is not able to decrypt
1587 any of the old traffic on the channel. Client who receives the reply to
1588 the join command must start using the received Channel ID in the channel
1589 message communication thereafter. Client also receives the key for the
1590 channel in the command reply.
1594 4.4 Channel Key Generation
1596 Channel keys are created by router who creates the channel by taking
1597 enough randomness from cryptographically strong random number generator.
1598 The key is generated always when channel is created, when new client
1599 joins a channel and after the key has expired. Key could expire for
1602 The key must also be re-generated whenever some client leaves a channel.
1603 In this case the key is created from scratch by taking enough randomness
1604 from the random number generator. After that the key is distributed to
1605 all clients on the channel. However, channel keys are cell specific thus
1606 the key is created only on the cell where the client, who left the
1607 channel, exists. While the server or router is creating the new channel
1608 key, no other client may join to the channel. Messages that are sent
1609 while creating the new key are still processed with the old key. After
1610 server has sent the SILC_PACKET_CHANNEL_KEY packet must client start
1611 using the new key. If server creates the new key the server must also
1612 send the new key to its router. See [SILC2] on more information about
1613 how channel messages must be encrypted and decrypted when router is
1616 When client receives the SILC_PACKET_CHANNEL_KEY packet with the
1617 Channel Key Payload it must process the key data to create encryption
1618 and decryption key, and to create the HMAC key that is used to compute
1619 the MACs of the channel messages. The processing is as follows:
1621 channel_key = raw key data
1622 HMAC key = hash(raw key data)
1624 The raw key data is the key data received in the Channel Key Payload.
1625 The hash() function is the hash function used in the HMAC of the channel.
1629 4.5 Private Message Sending and Reception
1631 Private messages are sent point to point. Client explicitly destines
1632 a private message to specific client that is delivered to only to that
1633 client. No other client may receive the private message. The receiver
1634 of the private message is destined in the SILC Packet Header as any
1635 other packet as well.
1637 If the sender of a private message does not know the receiver's Client
1638 ID, it must resolve it from server. There are two ways to resolve the
1639 client ID from server; it is recommended that client implementations
1640 send SILC_COMMAND_IDENTIFY command to receive the Client ID. Client
1641 may also send SILC_COMMAND_WHOIS command to receive the Client ID.
1642 If the sender has received earlier a private message from the receiver
1643 it should have cached the Client ID from the SILC Packet Header.
1645 Receiver of a private message should not explicitly trust the nickname
1646 that it receives in the Private Message Payload, described in [SILC2].
1647 Implementations could resolve the nickname from server, as described
1648 previously, and compare the received Client ID and the SILC Packet
1649 Header's Client ID. The nickname in the payload is merely provided
1650 to be displayed for end user.
1652 See [SILC2] for description of private message encryption and decryption
1657 4.6 Private Message Key Generation
1659 Private message may be protected by key generated by client. The key
1660 may be generated and sent to the other client by sending packet
1661 SILC_PACKET_PRIVATE_MESSAGE_KEY which travels through the network
1662 and is secured by session keys. After that the private message key
1663 is used in the private message communication between those clients.
1665 Other choice is to entirely use keys that are not sent through
1666 the SILC network at all. This significantly adds security. This key
1667 would be pre-shared-key that is known by both of the clients. Both
1668 agree about using the key and starts sending packets that indicate
1669 that the private message is secured using private message key.
1671 The key material used as private message key is implementation issue.
1672 However, SILC_PACKET_KEY_AGREEMENT packet may be used to negotiate
1673 the key material. If the key is normal pre-shared-key or randomly
1674 generated key, and the SILC_PACKET_KEY_AGREEMENT was not used, then
1675 the key material should be processed as defined in the [SILC3]. In
1676 the processing, however, the HASH, as defined in [SILC3] must be
1677 ignored. After processing the key material it is employed as defined
1678 in [SILC3], however, the HMAC key material must be discarded.
1680 If the key is pre-shared-key or randomly generated the implementations
1681 should use the SILC protocol's mandatory cipher as the cipher. If the
1682 SKE was used to negotiate key material the cipher was negotiated as well.
1685 4.7 Channel Message Sending and Reception
1687 Channel messages are delivered to group of users. The group forms a
1688 channel and all clients on the channel receives messages sent to the
1691 Channel messages are destined to channel by specifying the Channel ID
1692 as Destination ID in the SILC Packet Header. The server must then
1693 distribute the message to all clients on the channel by sending the
1694 channel message destined explicitly to a client on the channel.
1696 See [SILC2] for description of channel message encryption and decryption
1701 4.8 Session Key Regeneration
1703 Session keys should be regenerated periodically, say, once in an hour.
1704 The re-key process is started by sending SILC_PACKET_REKEY packet to
1705 other end, to indicate that re-key must be performed.
1707 If perfect forward secrecy (PFS) flag was selected in the SILC Key
1708 Exchange protocol [SILC3] the re-key must cause new key exchange with
1709 SKE protocol. In this case the protocol is secured with the old key
1710 and the protocol results to new key material. See [SILC3] for more
1711 information. After the SILC_PACKET_REKEY packet is sent the sender
1712 will perform the SKE protocol.
1714 If PFS flag was not set, which is the default case, then re-key is done
1715 without executing SKE protocol. In this case, the new key is created by
1716 hashing the old key with hash function selected earlier in the SKE
1717 protocol. If the digest length of the hash function is too short for the
1718 key, then the key is distributed as described in section Processing the
1719 Key Material in [SILC3]. After both parties has regenerated the session
1720 key, both send SILC_PACKET_REKEY_DONE packet to each other. These packets
1721 are still secured with the old key. After these packets, following
1722 packets must be protected with the new key.
1726 4.9 Command Sending and Reception
1728 Client usually sends the commands in the SILC network. In this case
1729 the client simply sends the command packet to server and the server
1730 processes it and replies with command reply packet.
1732 However, if the server is not able to process the command, it is sent
1733 to the server's router. This is case for example with commands such
1734 as, SILC_COMMAND_JOIN and SILC_COMMAND_WHOIS commands. However, there
1735 are other commands as well. For example, if client sends the WHOIS
1736 command requesting specific information about some client the server must
1737 send the WHOIS command to router so that all clients in SILC network
1738 are searched. The router, on the other hand, sends the WHOIS command
1739 further to receive the exact information about the requested client.
1740 The WHOIS command travels all the way to the server who owns the client
1741 and it replies with command reply packet. Finally, the server who
1742 sent the command receives the command reply and it must be able to
1743 determine which client sent the original command. The server then
1744 sends command reply to the client. Implementations should have some
1745 kind of cache to handle, for example, WHOIS information. Servers
1746 and routers along the route could all cache the information for faster
1747 referencing in the future.
1749 The commands sent by server may be sent hop by hop until someone is able
1750 to process the command. However, it is preferred to destine the command
1751 as precisely as it is possible. In this case, other routers en route
1752 must route the command packet by checking the true sender and true
1753 destination of the packet. However, servers and routers must not route
1754 command reply packets to clients coming from other server. Client
1755 must not accept command reply packet originated from anyone else but
1756 from its own server.
1763 5.1 SILC Commands Syntax
1765 This section briefly describes the syntax of the command notions
1766 in this document. Every field in command is separated from each
1767 other by whitespaces (` ') indicating that each field is independent
1768 argument and each argument must have own Command Argument Payload.
1769 The number of maximum arguments are defined with each command
1770 separately. The Command Argument Payload is described in [SILC2].
1772 Every command defines specific number for each argument. Currently,
1773 they are defined in ascending order; first argument has number one
1774 (1), second has number two (2) and so on. This number is set into the
1775 Argument Type field in the Command Argument Payload. This makes it
1776 possible to send the arguments in free order as the number must be
1777 used to identify the type of the argument. This makes is it also
1778 possible to have multiple optional arguments in commands and in
1779 command replies. The number of argument is marked in parentheses
1780 before the actual argument.
1785 Example: Arguments: (1) <nickname> (2) <username@host>
1789 Every command replies with Status Payload. This payload tells the
1790 sender of the command whether the command was completed successfully or
1791 whether there was an error. If error occured the payload includes the
1792 error type. In the next section the Status Payload is not described
1793 as it is common to all commands and has been described here. Commands
1794 may reply with other arguments as well. These arguments are command
1795 specific and are described in the next section.
1804 Arguments: (1) <nickname>[@<server>] (2) <message>
1807 The command has maximum of 3 arguments. However, only first
1808 and second arguments are mandatory.
1810 First argument <nickname> is mandatory but may have optional
1811 <nickname@server> format as well. Second argument is mandatory
1812 <message> argument. Third argument is optional <count> argument.
1814 The numbers in parentheses are the argument specific numbers
1815 that specify the type of the argument in Command Argument Payload.
1816 The receiver always knows that, say, argument number two (2) is
1817 <message> argument, regardless of the ordering of the arguments in
1818 the Command Payload.
1820 Reply messages to the command:
1823 Arguments: (1) <Status Payload> (2) [<channel list>]
1824 (3) <idle time> (4) [<away message>]
1826 This command may reply with maximum of 4 arguments. However,
1827 only the first and third arguments are mandatory. The numbers
1828 in the parentheses have the same meaning as in the upper
1829 command sending specification.
1831 Every command reply with <Status Payload>, it is mandatory
1832 argument for all command replies and for this reason it is not
1833 described in the command reply descriptions.
1840 SILC_STATUS_ERR_TOO_MANY_TARGETS
1841 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
1842 SILC_STATUS_ERR_NO_SUCH_NICK
1844 Every command reply also defines set of status message that it
1845 may return inside the <Status Payload>. All status messages
1846 are defined in the section 5.3 SILC Command Status Types.
1849 Every command that has some kind of ID as argument (for example
1850 <Client ID>) are actually ID Payloads, defined in [SILC2] that includes
1851 the type of the ID, length of the ID and the actual ID data. This
1852 way variable length ID's can be sent as arguments.
1856 5.2 SILC Commands List
1858 This section lists all SILC commands, however, it is expected that a
1859 implementation and especially client implementation has many more
1860 commands that has only local affect. These commands are official
1861 SILC commands that has both client and server sides and cannot be
1862 characterized as local commands.
1864 List of all defined commands in SILC follows.
1869 None. This is reserved command and must not be sent.
1872 1 SILC_COMMAND_WHOIS
1875 Arguments: (1) [<nickname>[@<server>]] (2) [<count>]
1876 (3) [<Client ID>] (n) [...]
1878 Whois command is used to query various information about specific
1879 user. The user maybe requested by their nickname and server name.
1880 The query may find multiple matching users as there are no unique
1881 nicknames in the SILC. The <count> option maybe given to narrow
1882 down the number of accepted results. If this is not defined there
1883 are no limit of accepted results. The query may also be narrowed
1884 down by defining the server name of the nickname.
1886 It is also possible to search the user by Client ID. If <Client ID>
1887 is provided server must use it as the search value instead of
1888 the <nickname>. One of the arguments must be given. It is also
1889 possible to define multiple Client ID's to search multiple users
1890 sending only one WHOIS command. In this case the Client ID's are
1891 appended as normal arguments. The server replies in this case
1892 with only one reply message for all requested users.
1894 To prevent miss-use of this service wildcards in the nickname
1895 or in the servername are not permitted. It is not allowed
1896 to request all users on some server. The WHOIS requests must
1897 be based on specific nickname request.
1899 The WHOIS request must be always sent to the router by server
1900 so that all users are searched. However, the server still must
1901 search its locally connected clients. The router must send
1902 this command to the server who owns the requested client. That
1903 server must reply to the command. Server should not send whois
1904 replies to the client until it has received the reply from its
1907 Reply messages to the command:
1910 Arguments: (1) <Status Payload> (2) <Client ID>
1911 (3) <nickname>[@<server>] (4) <username@host>
1912 (5) <real name> (6) [<channel list>]
1915 This command may reply with several command reply messages to
1916 form a list of results. In this case the status payload will
1917 include STATUS_LIST_START status in the first reply and
1918 STATUS_LIST_END in the last reply to indicate the end of the
1919 list. If there are only one reply the status is set to normal
1922 The command replies include the Client ID of the nickname,
1923 nickname and servername, username and hostname and users real
1924 name. Client should process these replies only after the last
1925 reply has been received with the STATUS_LIST_END status. If the
1926 <count> option were defined in the query there will be only
1927 <count> many replies from the server.
1932 SILC_STATUS_LIST_START
1933 SILC_STATUS_LIST_END
1934 SILC_STATUS_ERR_NO_SUCH_NICK
1935 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
1936 SILC_STATUS_ERR_WILDCARDS
1937 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
1938 SILC_STATUS_ERR_TOO_MANY_PARAMS
1943 2 SILC_COMMAND_WHOWAS
1946 Arguments: (1) <nickname>[@<server>] (2) [<count>]
1948 Whowas. This command is used to query history information about
1949 specific user. The user maybe requested by their nickname and
1950 server name. The query may find multiple matching users as there
1951 are no unique nicknames in the SILC. The <count> option maybe
1952 given to narrow down the number of accepted results. If this
1953 is not defined there are no limit of accepted results. The query
1954 may also be narrowed down by defining the server name of the
1957 To prevent miss-use of this service wildcards in the nickname
1958 or in the servername are not permitted. The WHOWAS requests must
1959 be based on specific nickname request.
1961 The WHOWAS request must be always sent to the router by server
1962 so that all users are searched. However, the server still must
1963 search its locally connected clients.
1965 Reply messages to the command:
1968 Arguments: (1) <Status Payload> (2) <Client ID>
1969 (3) <nickname>[@<server>] (4) <username@host>
1972 This command may reply with several command reply messages to form
1973 a list of results. In this case the status payload will include
1974 STATUS_LIST_START status in the first reply and STATUS_LIST_END in
1975 the last reply to indicate the end of the list. If there are only
1976 one reply the status is set to normal STATUS_OK.
1978 The command replies with nickname and username and hostname.
1979 Every server must keep history for some period of time of its
1980 locally connected clients.
1985 SILC_STATUS_LIST_START
1986 SILC_STATUS_LIST_END
1987 SILC_STATUS_ERR_NO_SUCH_NICK
1988 SILC_STATUS_ERR_WILDCARDS
1989 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
1990 SILC_STATUS_ERR_TOO_MANY_PARAMS
1993 3 SILC_COMMAND_IDENTIFY
1996 Arguments: (1) [<nickname>[@<server>]] (2) [<count>]
1997 (3) [<Client ID>] (n) [...]
1999 Identify. Identify command is almost analogous to WHOIS command,
2000 except that it does not return as much information. Only relevant
2001 information such as Client ID is returned. This is usually used
2002 to get the Client ID of a client used in the communication with
2005 The query may find multiple matching users as there are no unique
2006 nicknames in the SILC. The <count> option maybe given to narrow
2007 down the number of accepted results. If this is not defined there
2008 are no limit of accepted results. The query may also be narrowed
2009 down by defining the server name of the nickname.
2011 It is also possible to search the user by Client ID. If <Client ID>
2012 is provided server must use it as the search value instead of
2013 the <nickname>. One of the arguments must be given. It is also
2014 possible to define multiple Client ID's to search multiple users
2015 sending only one IDENTIFY command. In this case the Client ID's are
2016 appended as normal arguments. The server replies in this case
2017 with only one reply message for all requested users.
2019 To prevent miss-use of this service wildcards in the nickname
2020 or in the servername are not permitted. It is not allowed
2021 to request all users on some server. The IDENTIFY requests must
2022 be based on specific nickname request.
2024 Implementations may not want to give interface access to this
2025 command as it is hardly a command that would be used by an end user.
2026 However, it must be implemented as it is used with private message
2029 The IDENTIFY must be always sent to the router by server so that
2030 all users are searched. However, server must still search its
2031 locally connected clients.
2033 Reply messages to the command:
2036 Arguments: (1) <Status Payload> (2) <Client ID>
2037 (3) [<nickname>[@<server>]] (4) [<username@host>]
2039 This command may reply with several command reply messages to form
2040 a list of results. In this case the status payload will include
2041 STATUS_LIST_START status in the first reply and STATUS_LIST_END in
2042 the last reply to indicate the end of the list. If there are only
2043 one reply the status is set to normal STATUS_OK.
2045 The command replies with Client ID of the nickname and if more
2046 information is available it may reply with nickname and username
2047 and hostname. If the <count> option were defined in the query
2048 there will be only <count> many replies from the server.
2053 SILC_STATUS_LIST_START
2054 SILC_STATUS_LIST_END
2055 SILC_STATUS_ERR_NO_SUCH_NICK
2056 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2057 SILC_STATUS_ERR_WILDCARDS
2058 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2059 SILC_STATUS_ERR_TOO_MANY_PARAMS
2065 Arguments: (1) <nickname>
2067 Set/change nickname. This command is used to set nickname for
2068 user. There is no limit of the length of the nickname in SILC.
2069 Nickname must not include any spaces (` '), non-printable
2070 characters, commas (`,') and any wildcard characters. Note:
2071 nicknames in SILC are case-sensitive which must be taken into
2072 account when searching clients by nickname.
2074 When nickname is changed new Client ID is generated. Server must
2075 distribute SILC_NOTIFY_TYPE_NICK_CHANGE to local clients on the
2076 channels (if any) the client is joined on. Then it must send
2077 SILC_PACKET_REPLACE_ID to its primary route to replace the old
2078 Client ID with the new one.
2080 Reply messages to the command:
2083 Arguments: (1) <Status Payload> (2) <New ID Payload>
2085 This command is replied always with New ID Payload that is
2086 generated by the server every time user changes their nickname.
2087 Client receiving this payload must start using the received
2088 Client ID as its current valid Client ID. The New ID Payload
2089 is described in [SILC2].
2094 SILC_STATUS_ERR_WILDCARDS
2095 SILC_STATUS_ERR_NICKNAME_IN_USE
2096 SILC_STATUS_ERR_BAD_NICKNAME
2097 SILC_STATUS_ERR_NOT_REGISTERED
2098 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2099 SILC_STATUS_ERR_TOO_MANY_PARAMS
2105 Arguments: (1) [<Channel ID>] [<server>]
2107 The list command is used to list channels and their topics on
2108 current server. If the <Channel ID> parameter is used, only the
2109 status of that channel is displayed. Secret channels are not
2110 listed at all. Private channels are listed with status indicating
2111 that the channel is private.
2113 If the <server> argument is specified the specified server's
2114 channels are listed. In this case the command must be sent to
2115 the server who owns the channel that was requested.
2117 Reply messages to the command:
2120 Arguments: (1) <Status Payload> (2) <Channel ID>
2121 (3) <channel> (4) <topic>
2123 This command may reply with several command reply messages to form
2124 a list of results. In this case the status payload will include
2125 STATUS_LIST_START status in the first reply and STATUS_LIST_END in
2126 the last reply to indicate the end of the list. If there are only
2127 one reply the status is set to normal STATUS_OK.
2129 This command replies with Channel ID, name and the topic of the
2130 channel. If the channel is private channel the <topic> includes
2136 SILC_STATUS_LIST_START
2137 SILC_STATUS_LIST_END
2138 SILC_STATUS_ERR_WILDCARDS
2139 SILC_STATUS_ERR_NOT_REGISTERED
2140 SILC_STATUS_ERR_TOO_MANY_PARAMS
2141 SILC_STATUS_ERR_NO_SUCH_CHANNEL
2142 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2143 SILC_STATUS_ERR_NO_SUCH_SERVER
2146 6 SILC_COMMAND_TOPIC
2149 Arguments: (1) <Channel ID> (2) [<topic>]]
2151 This command is used to change or view the topic of a channel.
2152 The topic for channel <Channel ID> is returned if there is no
2153 <topic> given. If the <topic> parameter is present, the topic
2154 for that channel will be changed, if the channel modes permit
2157 Reply messages to the command:
2160 Arguments: (1) <Status Payload> (2) <Channel ID>
2163 The command may reply with the topic of the channel if it is
2169 SILC_STATUS_ERR_NOT_ON_CHANNEL
2170 SILC_STATUS_ERR_WILDCARDS
2171 SILC_STATUS_ERR_NOT_REGISTERED
2172 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2173 SILC_STATUS_ERR_NO_SUCH_CHANNEL
2174 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2175 SILC_STATUS_ERR_NO_CHANNEL_ID
2176 SILC_STATUS_ERR_BAD_CHANNEL_ID
2177 SILC_STATUS_ERR_TOO_MANY_PARAMS
2178 SILC_STATUS_ERR_NO_CHANNEL_PRIV
2181 7 SILC_COMMAND_INVITE
2184 Arguments: (1) <Client ID> (2) <Channel ID>
2186 This command is used to invite other clients to join to the
2187 channel. The <Client ID> argument is the target client's ID that
2188 is being invited. The <Channel ID> is the Channel ID of the
2189 requested channel. The sender of this command must be on the
2190 channel. This command must fail if the requested channel does
2191 not exist, the requested client is already on the channel or if
2192 the channel is invite only channel and the caller of this command
2193 does not have at least channel operator privileges.
2195 Reply messages to the command:
2198 Arguments: (1) <Status Payload>
2200 This command replies only with Status Payload.
2205 SILC_STATUS_ERR_NOT_REGISTERED
2206 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2207 SILC_STATUS_ERR_TOO_MANY_PARAMS
2208 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2209 SILC_STATUS_ERR_NO_CLIENT_ID
2210 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2211 SILC_STATUS_ERR_NO_CHANNEL_ID
2212 SILC_STATUS_ERR_NOT_ON_CHANNEL
2213 SILC_STATUS_ERR_USER_ON_CHANNEL
2219 Arguments: (1) [<quit message>]
2221 This command is used by client to end SILC session. The server
2222 must close the connection to a client which sends this command.
2223 if <quit message> is given it will be sent to other clients on
2224 channel if the client is on channel when quitting.
2226 Reply messages to the command:
2228 This command does not reply anything.
2234 Arguments: (1) <Client ID> (2) [<comment>]
2236 This command is used by SILC operators to remove a client from
2237 SILC network. The removing has temporary effects and client may
2238 reconnect to SILC network. The <Client ID> is the client to be
2239 removed from SILC. The <comment> argument may be provided to
2240 give to the removed client some information why it was removed
2243 Reply messages to the command:
2246 Arguments: (1) <Status Payload>
2248 This command replies only with Status Payload.
2253 SILC_STATUS_ERR_WILDCARDS
2254 SILC_STATUS_ERR_NOT_REGISTERED
2255 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2256 SILC_STATUS_ERR_TOO_MANY_PARAMS
2257 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2258 SILC_STATUS_ERR_NO_CLIENT_ID
2259 SILC_STATUS_ERR_NO_ROUTER_PRIV
2262 10 SILC_COMMAND_INFO
2265 Arguments: (1) [<server>]
2267 This command is used to fetch various information about a server.
2268 If <server> argument is specified the command must be sent to
2269 the requested server.
2271 Reply messages to the command:
2274 Arguments: (1) <Status Payload> (2) <Server ID>
2277 This command replies with the Server ID of the server and a
2278 string which tells the information about the server.
2283 SILC_STATUS_ERR_WILDCARDS
2284 SILC_STATUS_ERR_NOT_REGISTERED
2285 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2286 SILC_STATUS_ERR_TOO_MANY_PARAMS
2287 SILC_STATUS_ERR_NO_SUCH_SERVER
2290 11 SILC_COMMAND_CONNECT
2293 Arguments: (1) <remote server/router> (2) [<port>]
2295 This command is used by operators to force a server to try to
2296 establish a new connection to remote server or router. The
2297 Operator must specify the server/router to be connected by
2298 setting <remote server> argument. The port is 32 bit MSB value.
2300 Reply messages to the command:
2303 Arguments: (1) <Status Payload>
2305 This command replies only with Status Payload.
2312 SILC_STATUS_ERR_WILDCARDS
2313 SILC_STATUS_ERR_NOT_REGISTERED
2314 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2315 SILC_STATUS_ERR_TOO_MANY_PARAMS
2316 SILC_STATUS_ERR_NO_SERVER_PRIV
2317 SILC_STATUS_ERR_NO_ROUTER_PRIV
2320 12 SILC_COMMAND_PING
2323 Arguments: (1) <Server ID>
2325 This command is used by client and server to test the communication
2326 channel to its server if one suspects that the communication is not
2327 working correctly. The <Server ID> is the ID of the server the
2328 sender is connected to.
2330 Reply messages to the command:
2333 Arguments: (1) <Status Payload>
2335 This command replies only with Status Payload. Server returns
2336 SILC_STATUS_OK in Status Payload if pinging was successful.
2343 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2344 SILC_STATUS_ERR_TOO_MANY_PARAMS
2345 SILC_STATUS_ERR_NO_SERVER_ID
2346 SILC_STATUS_ERR_NO_SUCH_SERVER
2347 SILC_STATUS_ERR_NOT_REGISTERED
2350 13 SILC_COMMAND_OPER
2353 Arguments: (1) <username> (2) <authentication data>
2355 This command is used by normal client to obtain server operator
2356 privileges on some server or router. Note that router operator
2357 has router privileges that supersedes the server operator
2358 privileges and this does not obtain those privileges. Client
2359 must use SILCOPER command to obtain router level privileges.
2361 The <username> is the username set in the server configurations
2362 as operator. The <authentication data> is the data that the
2363 client is authenticated against. It may be passphrase prompted
2364 for user on client's screen or it may be public key
2365 authentication data (data signed with private key), or
2368 Reply messages to the command:
2371 Arguments: (1) <Status Payload>
2373 This command replies only with Status Payload.
2378 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2379 SILC_STATUS_ERR_TOO_MANY_PARAMS
2380 SILC_STATUS_ERR_NOT_REGISTERED
2381 SILC_STATUS_ERR_BAD_PASSWORD
2382 SILC_STATUS_ERR_AUTH_FAILED
2385 14 SILC_COMMAND_JOIN
2388 Arguments: (1) <channel> (2) <Client ID>
2389 (3) [<passphrase>] (4) [<cipher>]
2392 Join to channel/create new channel. This command is used to
2393 join to a channel. If the channel does not exist the channel is
2394 created. If server is normal server this command must be sent
2395 to router who will create the channel. The channel may be
2396 protected with passphrase. If this is the case the passphrase
2397 must be sent along the join command.
2399 The name of the <channel> must not include any spaces (` '),
2400 non-printable characters, commas (`,') or any wildcard characters.
2402 The second argument <Client ID> is the Client ID of the client who
2403 is joining to the client. When client sends this command to the
2404 server the <Client ID> must be the client's own ID.
2406 Cipher to be used to secure the traffic on the channel may be
2407 requested by sending the name of the requested <cipher>. This
2408 is used only if the channel does not exist and is created. If
2409 the channel already exists the cipher set previously for the
2410 channel will be used to secure the traffic. The computed MACs
2411 of the channel message are produced by the default HMAC or by
2412 the <hmac> provided for the command.
2414 The server must check whether the user is allowed to join to
2415 the requested channel. Various modes set to the channel affect
2416 the ability of the user to join the channel. These conditions
2419 o The user must be invited to the channel if the channel
2420 is invite-only channel.
2422 o The Client ID/nickname/username/hostname must not match
2425 o The correct passphrase must be provided if passphrase
2426 is set to the channel.
2428 o The user count limit, if set, must not be reached.
2430 Reply messages to the command:
2433 Arguments: (1) <Status Payload> (2) <channel>
2434 (3) <Channel ID> (4) <Client ID>
2435 (5) <channel mode mask> (6) <created>
2436 (7) <Channel Key Payload> (8) [<ban mask>]
2437 (9) [<invite list>] (10) [<topic>]
2438 (11) [<hmac>] (12) <list count>
2439 (13) <Client ID list> (14) <client mode list>
2441 This command replies with the channel name requested by the
2442 client, channel ID of the channel and topic of the channel
2443 if it exists. The <Client ID> is the Client ID which was joined
2444 to the channel. It also replies with the channel mode mask
2445 which tells all the modes set on the channel. If the
2446 channel is created the mode mask is zero (0). If ban mask
2447 and/or invite list is set they are sent as well.
2449 The <list count>, <Client ID list> and <client mode list> are
2450 the clients curerntly on the channel and their modes on the
2453 Client receives the channel key in the reply message as well
2454 inside <Channel Key Payload>.
2459 SILC_STATUS_ERR_WILDCARDS
2460 SILC_STATUS_ERR_NOT_REGISTERED
2461 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2462 SILC_STATUS_ERR_TOO_MANY_PARAMS
2463 SILC_STATUS_ERR_BAD_PASSWORD
2464 SILC_STATUS_ERR_CHANNEL_IS_FULL
2465 SILC_STATUS_ERR_NOT_INVITED
2466 SILC_STATUS_ERR_BANNED_FROM_CHANNEL
2467 SILC_STATUS_ERR_BAD_CHANNEL
2468 SILC_STATUS_ERR_USER_ON_CHANNEL
2471 15 SILC_COMMAND_MOTD
2474 Arguments: (1) <server>
2476 This command is used to query the Message of the Day of the server.
2478 Reply messages to the command:
2481 Arguments: (1) <Status Payload> (2) [<motd>]
2483 This command replies with the motd message if it exists.
2488 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2489 SILC_STATUS_ERR_TOO_MANY_PARAMS
2490 SILC_STATUS_ERR_NOT_REGISTERED
2491 SILC_STATUS_ERR_NO_SUCH_SERVER
2494 16 SILC_COMMAND_UMODE
2497 Arguments: (1) <Client ID> (2) <client mode mask>
2499 This command is used by client to set/unset modes for itself.
2500 However, there are some modes that the client may not set itself,
2501 but they will be set by server. However, client may unset any
2502 mode. Modes may be masked together ORing them thus having
2503 several modes set. Client must keep its client mode mask
2504 locally so that the mode setting/unsetting would work without
2505 problems. Client may change only its own modes.
2507 Following client modes are defined:
2509 0x0000 SILC_UMODE_NONE
2511 No specific mode for client. This is the initial
2512 setting when new client is created. The client is
2516 0x0001 SILC_UMODE_SERVER_OPERATOR
2518 Marks the user as server operator. Client cannot
2519 set this mode itself. Server sets this mode to the
2520 client when client attains the server operator
2521 privileges by SILC_COMMAND_OPER command. Client
2522 may unset the mode itself.
2525 0x0002 SILC_UMODE_ROUTER_OPERATOR
2527 Marks the user as router (SILC) operator. Client
2528 cannot this mode itself. Router sets this mode to
2529 the client when client attains the router operator
2530 privileges by SILC_COMMAND_SILCOPER command. Client
2531 may unset the mode itself.
2533 Reply messages to the command:
2536 Arguments: (1) <Status Payload> (2) <client mode mask>
2538 This command replies with the changed client mode mask that
2539 the client is required to keep locally.
2545 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2546 SILC_STATUS_ERR_TOO_MANY_PARAMS
2547 SILC_STATUS_ERR_NOT_REGISTERED
2548 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2549 SILC_STATUS_ERR_BAD_CLIENT_ID
2550 SILC_STATUS_ERR_NOT_YOU
2551 SILC_STATUS_ERR_UNKNOWN_MODE
2552 SILC_STATUS_ERR_NO_RECIPIENT
2553 SILC_STATUS_ERR_NO_CLIENT_ID
2556 17 SILC_COMMAND_CMODE
2559 Arguments: (1) <Channel ID> (2) <channel mode mask>
2560 (3) [<user limit>] (4) [<passphrase>]
2561 (5) [<ban mask>] (6) [<invite list>]
2562 (7) [<cipher>] (8) [<hmac>]
2564 This command is used by client to set or change channel flags on
2565 a channel. Channel has several modes that set various properties
2566 of a channel. Modes may be masked together by ORing them thus
2567 having several modes set. The <Channel ID> is the ID of the
2568 target channel. The client changing channel mode must be on
2569 the same channel and poses sufficient privileges to be able to
2572 When the mode is changed SILC_NOTIFY_TYPE_CMODE_CHANGE notify
2573 type is distributed to the channel.
2575 Following channel modes are defined:
2577 0x0000 SILC_CMODE_NONE
2579 No specific mode on channel. This is the default when
2580 channel is created. This means that channel is just plain
2584 0x0001 SILC_CMODE_PRIVATE
2586 Channel is private channel. Private channels are shown
2587 in the channel list listed with SILC_COMMAND_LIST command
2588 with indication that the channel is private. Also,
2589 client on private channel will no be detected to be on
2590 the channel as the channel is not shown in the client's
2591 currently joined channel list. Channel founder and
2592 channel operator may set/unset this mode.
2594 Typical implementation would use [+|-]p on user interface
2595 to set/unset this mode.
2598 0x0002 SILC_CMODE_SECRET
2600 Channel is secret channel. Secret channels are not shown
2601 in the list listed with SILC_COMMAND_LIST command. Secret
2602 channels can be considered to be invisible channels.
2603 Channel founder and channel operator may set/unset this
2606 Typical implementation would use [+|-]s on user interface
2607 to set/unset this mode.
2610 0x0004 SILC_CMODE_PRIVKEY
2612 Channel uses private channel key to protect the traffic
2613 on the channel. When this mode is set the client will be
2614 responsible to set the key it wants to use to encrypt and
2615 decrypt the traffic on channel. Server generated channel
2616 keys are not used at all. This mode provides additional
2617 security as clients on channel may agree to use private
2618 channel key that even servers do not know. Naturally,
2619 this requires that every client on the channel knows
2620 the key before hand (it is considered to be pre-shared-
2621 key). This specification does not define how the private
2622 channel key is set as it is entirely local setting on
2625 As it is local setting it is possible to have several
2626 private channel keys on one channel. In this case several
2627 clients can talk on same channel but only those clients
2628 that share the key with the message sender will be able
2629 to hear the talking. Client should not display those
2630 message for the end user that it is not able to decrypt
2631 when this mode is set.
2633 Only channel founder may set/unset this mode. If this
2634 mode is unset the server will distribute new channel
2635 key to all clients on the channel which will be used
2638 Typical implementation would use [+|-]k on user interface
2639 to set/unset this mode.
2642 0x0008 SILC_CMODE_INVITE
2644 Channel is invite only channel. Client may join to this
2645 channel only if it is invited to the channel. Channel
2646 founder and channel operator may set/unset this mode.
2648 Typical implementation would use [+|-]i on user interface
2649 to set/unset this mode.
2652 0x0010 SILC_CMODE_TOPIC
2654 The topic of the channel may only be set by client that
2655 is channel founder or channel operator. Normal clients
2656 on channel will not be able to set topic when this mode
2657 is set. Channel founder and channel operator may set/
2660 Typical implementation would use [+|-]t on user interface
2661 to set/unset this mode.
2664 0x0020 SILC_CMODE_ULIMIT
2666 User limit has been set to the channel. New clients
2667 may not join to the channel when the limit set is
2668 reached. Channel founder and channel operator may set/
2669 unset the limit. The <user limit> argument is the
2670 number of limited users.
2672 Typical implementation would use [+|-]l on user interface
2673 to set/unset this mode.
2676 0x0040 SILC_CMODE_PASSPHRASE
2678 Passphrase has been set to the channel. Client may
2679 join to the channel only if it is able to provide the
2680 correct passphrase. Setting passphrases to channel
2681 is entirely safe as all commands are protected in the
2682 SILC network. Only channel founder may set/unset
2683 the passphrase. The <passphrase> argument is the
2686 Typical implementation would use [+|-]a on user interface
2687 to set/unset this mode.
2690 0x0080 SILC_CMODE_BAN
2692 Ban mask has been set to the channel. The ban mask
2693 may be used to ban specific clients to join the channel.
2694 The <ban mask> argument is the set ban mask. When
2695 unsetting a ban mask the mask must be provided as
2696 argument. Channel founder and channel operator may
2697 set/unset this mode. Channel founder may not be
2698 added to the ban list. <ban mask> is an comma (`,')
2699 separated list of banned clients in the following format:
2701 [<nickname>[@<server>]!][<username>]@[<hostname>]
2703 Wildcards maybe used when banning clients.
2705 Typical implementation would use [+|-]b on user interface
2706 to set/unset this mode.
2709 0x0100 SILC_CMODE_INVITE_LIST
2711 Invite list has been set to the channel. The invite list
2712 can be used to mark the clients that is able to join
2713 channel without being invited when the channel is set to
2714 be invite-only channel. The <invite list> argument is the
2715 set invite mask. When unsetting entry from the invite list
2716 the entry must be provided as argument. Channel founder and
2717 channel operator may set/unset this mode. The <invite list>
2718 is command (`,') separated list of invited clients in the
2721 [<nickname>[@<server>]!][<username>]@[<hostname>]
2723 Wildcards maybe used when setting the invite list.
2725 Typical implementation would use [+|-]I on user interface
2726 to set/unset this mode.
2729 0x0200 SILC_CMODE_CIPHER
2731 Sets specific cipher to be used to protect channel
2732 traffic. The <cipher> argument is the requested cipher.
2733 When set or unset the server must re-generate new
2734 channel key. Only channel founder may set the cipher of
2735 the channel. When unset the new key is generated using
2736 default cipher for the channel.
2738 Typical implementation would use [+|-]c on user interface
2739 to set/unset this mode.
2742 0x0400 SILC_CMODE_HMAC
2744 Sets specific hmac to be used to compute the MACs of the
2745 channel message. The <hmac> argument is the requested hmac.
2746 Only channel founder may set the hmac of the channel.
2748 Typical implementation would use [+|-]h on user interface
2749 to set/unset this mode.
2752 To make the mode system work, client must keep the channel mode
2753 mask locally so that the mode setting and unsetting would work
2754 without problems. The client receives the initial channel mode
2755 mask when it joins to the channel. When the mode changes on
2756 channel the servers distributes the changed channel mode mask to
2757 all clients on the channel by sending SILC_NOTIFY_TYPE_CMODE_CHANGE
2761 Reply messages to the command:
2764 Arguments: (1) <Status Payload> (2) <channel mode mask>
2766 This command replies with the changed channel mode mask that
2767 client is required to keep locally.
2772 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2773 SILC_STATUS_ERR_TOO_MANY_PARAMS
2774 SILC_STATUS_ERR_NOT_REGISTERED
2775 SILC_STATUS_ERR_NOT_ON_CHANNEL
2776 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2777 SILC_STATUS_ERR_BAD_CHANNEL_ID
2778 SILC_STATUS_ERR_NO_CHANNEL_ID
2779 SILC_STATUS_ERR_NO_CHANNEL_PRIV
2780 SILC_STATUS_ERR_UNKNOWN_MODE
2781 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2784 19 SILC_COMMAND_CUMODE
2787 Arguments: (1) <Channel ID> (2) <mode mask>
2790 This command is used by client to change channel user modes on
2791 channel. Users on channel may have some special modes and this
2792 command is used by channel operators to set or change these modes.
2793 The <Channel ID> is the ID of the target channel. The <mode mask>
2794 is OR'ed mask of modes. The <Client ID> is the target client.
2795 The client changing channel user modes must be on the same channel
2796 as the target client and poses sufficient privileges to be able to
2799 When the mode is changed SILC_NOTIFY_TYPE_CUMODE_CHANGE notify
2800 type is distributed to the channel.
2802 Following channel modes are defined:
2804 0x0000 SILC_CUMODE_NONE
2806 No specific mode. This is the normal situation for client.
2807 Also, this is the mode set when removing all modes from client.
2810 0x0001 SILC_CUMODE_FOUNDER
2812 The client is channel founder of the channel. This mode
2813 cannot be set by other client, it is set by the server when
2814 the channel was founded (created). The mode is provided
2815 because client may remove the founder rights from itself.
2818 0x0002 SILC_CUMODE_OPERATOR
2820 Sets channel operator privileges on the channel for a
2821 client on the channel. Channel founder and channel operator
2822 may set/unset (promote/demote) this mode.
2825 Reply messages to the command:
2828 Arguments: (1) <Status Payload> (2) <channel user mode mask>
2831 This command replies with the changed channel user mode mask that
2832 client is required to keep locally. The <Client ID> is the target
2838 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2839 SILC_STATUS_ERR_TOO_MANY_PARAMS
2840 SILC_STATUS_ERR_NOT_REGISTERED
2841 SILC_STATUS_ERR_NOT_ON_CHANNEL
2842 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2843 SILC_STATUS_ERR_BAD_CHANNEL_ID
2844 SILC_STATUS_ERR_NO_CHANNEL_ID
2845 SILC_STATUS_ERR_NO_CHANNEL_PRIV
2846 SILC_STATUS_ERR_UNKNOWN_MODE
2847 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2850 19 SILC_COMMAND_KICK
2853 Arguments: (1) <Channel ID> (2) <Client ID>
2856 This command is used by channel operators to remove a client from
2857 channel. The <channel> argument is the channel the client to be
2858 removed is on currently. Note that the "kicker" must be on the same
2859 channel. If <comment> is provided it will be sent to the removed
2862 Reply messages to the command:
2865 Arguments: (1) <Status Payload>
2867 This command replies only with Status Payload.
2872 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2873 SILC_STATUS_ERR_TOO_MANY_PARAMS
2874 SILC_STATUS_ERR_NOT_REGISTERED
2875 SILC_STATUS_ERR_NO_SUCH_CHANNEL
2876 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2877 SILC_STATUS_ERR_NO_CHANNEL_PRIV
2878 SILC_STATUS_ERR_NO_CLIENT_ID
2881 20 SILC_COMMAND_RESTART
2886 This command may only be used by server operator to force a
2887 server to restart itself.
2889 Reply messages to the command:
2892 Arguments: (1) <Status Payload>
2894 This command replies only with Status Payload.
2899 SILC_STATUS_ERR_NOT_REGISTERED
2900 SILC_STATUS_ERR_NO_SERVER_PRIV
2906 21 SILC_COMMAND_CLOSE
2909 Arguments: (1) <remote server/router> (2) [<port>]
2911 This command is used only by operator to close connection to a
2914 Reply messages to the command:
2917 Arguments: (1) <Status Payload>
2919 This command replies only with Status Payload.
2924 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2925 SILC_STATUS_ERR_TOO_MANY_PARAMS
2926 SILC_STATUS_ERR_NOT_REGISTERED
2927 SILC_STATUS_ERR_NO_SUCH_SERVER
2928 SILC_STATUS_ERR_NO_SERVER_PRIV
2929 SILC_STATUS_ERR_NO_SUCH_SERVER_ID
2932 22 SILC_COMMAND_SHUTDOWN
2937 This command is used only by operator to shutdown the server.
2938 All connections to the server will be closed and the server is
2941 Reply messages to the command:
2946 Arguments: (1) <Status Payload>
2948 This command replies only with Status Payload.
2953 SILC_STATUS_ERR_NOT_REGISTERED
2954 SILC_STATUS_ERR_NO_SERVER_PRIV
2957 23 SILC_COMMAND_SILCOPER
2960 Arguments: (1) <username> (2) <authentication data>
2962 This command is used by normal client to obtain router operator
2963 privileges (also known as SILC operator) on some router. Note
2964 that router operator has router privileges that supersedes the
2965 server operator privileges.
2967 The <username> is the username set in the server configurations
2968 as operator. The <authentication data> is the data that the
2969 client is authenticated against. It may be passphrase prompted
2970 for user on client's screen or it may be public key
2971 authentication data (data signed with private key), or
2974 Difference between router operator and server operator is that
2975 router operator is able to handle cell level properties while
2976 server operator (even on router server) is able to handle only
2977 local properties, such as, local connections and normal server
2980 Reply messages to the command:
2983 Arguments: (1) <Status Payload>
2985 This command replies only with Status Payload.
2990 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2991 SILC_STATUS_ERR_TOO_MANY_PARAMS
2992 SILC_STATUS_ERR_NOT_REGISTERED
2993 SILC_STATUS_ERR_BAD_PASSWORD
2994 SILC_STATUS_ERR_AUTH_FAILED
2997 24 SILC_COMMAND_LEAVE
3000 Arguments: (1) <Channel ID>
3002 This command is used by client to leave a channel the client is
3003 joined to. After a client has leaved the channel the server
3004 must create new key for the channel and distribute to all clients
3005 still currently on the channel.
3007 Reply messages to the command:
3010 Arguments: (1) <Status Payload>
3012 This command replies only with Status Payload.
3017 SILC_STATUS_ERR_NOT_REGISTERED
3018 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
3019 SILC_STATUS_ERR_TOO_MANY_PARAMS
3020 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
3021 SILC_STATUS_ERR_BAD_CHANNEL_ID
3022 SILC_STATUS_ERR_NO_CHANNEL_ID
3025 25 SILC_COMMAND_USERS
3028 Arguments: (1) <Channel ID>
3030 This command is used to list user names currently on the requested
3031 channel; argument <Channel ID>. The server must resolve the
3032 user names and send a comma (`,') separated list of user names
3033 on the channel. Server or router may resolve the names by sending
3034 SILC_COMMAND_WHOIS commands.
3036 If the requested channel is a private or secret channel, this
3037 command must not send the list of users, as private and secret
3038 channels cannot be seen by outside. In this case the returned
3039 name list may include a indication that the server could not
3040 resolve the names of the users on the channel. Also, in this case
3041 Client ID's or client modes are not sent either.
3043 Reply messages to the command:
3046 Arguments: (1) <Status Payload> (2) <Channel ID>
3047 (3) <list count> (4) <Client ID list>
3048 (5) <client mode list>
3050 This command replies with the Channel ID of the requested channel
3051 Client ID list of the users on the channel and list of their modes.
3052 The Client ID list has Client ID's of all users in the list. The
3053 <Client ID list> is formed by adding Client ID's one after another.
3054 The <client mode list> is formed by adding client's user modes on
3055 the channel one after another (4 bytes (32 bits) each). The <list
3056 count> of length of 4 bytes (32 bits), tells the number of entries
3057 in the lists. Both lists must have equal number of entries.
3062 SILC_STATUS_ERR_NOT_REGISTERED
3063 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
3064 SILC_STATUS_ERR_TOO_MANY_PARAMS
3065 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
3066 SILC_STATUS_ERR_BAD_CHANNEL_ID
3067 SILC_STATUS_ERR_NO_CHANNEL_ID
3068 SILC_STATUS_ERR_NOT_ON_CHANNEL
3073 Currently undefined commands.
3078 These commands are reserved for private use and will not be defined
3082 255 SILC_COMMAND_MAX
3084 Reserved command. This must not be sent.
3089 5.3 SILC Command Status Types
3092 5.3.1 SILC Command Status Payload
3094 Command Status Payload is sent in command reply messages to indicate
3095 the status of the command. The payload is one of argument in the
3096 command thus this is the data area in Command Argument Payload described
3097 in [SILC2]. The payload is only 2 bytes of length. Following diagram
3098 represents the Command Status Payload (field is always in MSB order).
3107 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
3108 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3110 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3114 Figure 6: SILC Command Status Payload
3118 o Status Message (2 bytes) - Indicates the status message.
3119 All Status messages are described in the next section.
3124 5.3.2 SILC Command Status List
3126 Command Status messages are returned in the command reply messages
3127 to indicate whether the command were executed without errors. If error
3128 has occured the status tells which error occured. Status payload only
3129 sends numeric reply about the status. Receiver of the payload must
3130 convert the numeric values into human readable error messages. The
3131 list of status messages below has an example human readable error
3132 messages that client may display for the user.
3134 List of all defined command status messages following.
3137 Generic status messages:
3141 Ok status. Everything went Ok. The status payload maybe
3142 safely ignored in this case.
3144 1 SILC_STATUS_LIST_START
3146 Start of the list. There will be several command replies and
3147 this reply is the start of the list.
3149 2 SILC_STATUS_LIST_ITEM
3151 Item in the list. This is one of the item in the list but not the
3154 3 SILC_STATUS_LIST_END
3156 End of the list. There were several command replies and this
3157 reply is the last of the list. There won't be other replies
3158 belonging to this list after this one.
3162 Currently undefined and has been reserved for the future.
3165 Error status message:
3167 10 SILC_STATUS_ERR_NO_SUCH_NICK
3169 "No such nickname". Requested nickname does not exist.
3171 11 SILC_STATUS_ERR_NO_SUCH_CHANNEL
3173 "No such channel". Requested channel name does not exist.
3175 12 SILC_STATUS_ERR_NO_SUCH_SERVER
3177 "No such server". Requested server name does not exist.
3179 13 SILC_STATUS_ERR_TOO_MANY_TARGETS
3181 "Duplicate recipients. No message delivered". Message were
3182 tried to be sent to recipient which has several occurrences in
3185 14 SILC_STATUS_ERR_NO_RECIPIENT
3187 "No recipient given". Command required recipient which was
3190 15 SILC_STATUS_ERR_UNKNOWN_COMMAND
3192 "Unknown command". Command sent to server is unknown by the
3195 16 SILC_STATUS_ERR_WILDCARDS
3197 "Wildcards cannot be used". Wildcards were provided but they
3200 17 SILC_STATUS_ERR_NO_CLIENT_ID
3202 "No Client ID given". Client ID were expected as command
3203 parameter but were not found.
3205 18 SILC_STATUS_ERR_NO_CHANNEL_ID
3207 "No Channel ID given". Channel ID were expected as command
3208 parameter but were not found.
3210 19 SILC_STATUS_ERR_NO_SERVER_ID
3212 "No Serve ID given". Server ID were expected as command
3213 parameter but were not found.
3215 20 SILC_STATUS_ERR_BAD_CLIENT_ID
3217 "Bad Client ID". Client ID provided were erroneous.
3219 21 SILC_STATUS_ERR_BAD_CHANNEL_ID
3221 "Bad Channel ID". Channel ID provided were erroneous.
3223 22 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
3225 "No such Client ID". Client ID provided does not exist.
3227 23 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
3229 "No such Channel ID". Channel ID provided does not exist.
3231 24 SILC_STATUS_ERR_NICKNAME_IN_USE
3233 "Nickname already exists". Nickname created could not be
3234 registered because number of same nicknames were already set to
3235 maximum. This is not expected to happen in real life but is
3238 25 SILC_STATUS_ERR_NOT_ON_CHANNEL
3240 "You are not on that channel". The command were specified for
3241 channel user is not currently on.
3243 26 SILC_STATUS_ERR_USER_NOT_ON_CHANNEL
3245 "They are not on channel". The requested target client is not
3246 on requested channel.
3248 27 SILC_STATUS_ERR_USER_ON_CHANNEL
3250 "User already on channel". User were invited on channel they
3253 28 SILC_STATUS_ERR_NOT_REGISTERED
3255 "You have not registered". User executed command that requires
3256 the client to be registered on the server before it may be
3259 29 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
3261 "Not enough parameters". Command requires more parameters
3264 30 SILC_STATUS_ERR_TOO_MANY_PARAMS
3266 "Too many parameters". Too many parameters were provided
3269 31 SILC_STATUS_ERR_PERM_DENIED
3271 "Your host is not among the privileged". The client tried to
3272 register on server that does not allow this host to connect.
3274 32 SILC_STATUS_ERR_BANNED_FROM_SERVER
3276 "You are banned from this server". The client tried to register
3277 on server that has explicitly denied this host to connect.
3279 33 SILC_STATUS_ERR_BAD_PASSWORD
3281 "Cannot join channel. Incorrect password". Password provided for
3282 channel were not accepted.
3284 34 SILC_STATUS_ERR_CHANNEL_IS_FULL
3286 "Cannot join channel. Channel is full". The channel is full
3287 and client cannot be joined to it.
3289 35 SILC_STATUS_ERR_NOT_INVITED
3291 "Cannot join channel. You have not been invited". The channel
3292 is invite only channel and client has not been invited.
3294 36 SILC_STATUS_ERR_BANNED_FROM_CHANNEL
3296 "Cannot join channel. You have been banned". The client has
3297 been banned from the channel.
3299 37 SILC_STATUS_ERR_UNKNOWN_MODE
3301 "Unknown mode". Mode provided by the client were unknown to
3304 38 SILC_STATUS_ERR_NOT_YOU
3306 "Cannot change mode for other users". User tried to change
3307 someone else's mode.
3309 39 SILC_STATUS_ERR_NO_CHANNEL_PRIV
3311 "Permission denied. You are not channel operator". Command may
3312 be executed only by channel operator.
3314 40 SILC_STATUS_ERR_NO_CHANNEL_FOPRIV
3316 "Permission denied. You are not channel founder". Command may
3317 be executed only by channel operator.
3319 41 SILC_STATUS_ERR_NO_SERVER_PRIV
3321 "Permission denied. You are not server operator". Command may
3322 be executed only by server operator.
3324 42 SILC_STATUS_ERR_NO_ROUTER_PRIV
3326 "Permission denied. You are not SILC operator". Command may be
3327 executed only by router (SILC) operator.
3329 43 SILC_STATUS_ERR_BAD_NICKNAME
3331 "Bad nickname". Nickname requested contained illegal characters
3334 44 SILC_STATUS_ERR_BAD_CHANNEL
3336 "Bad channel name". Channel requested contained illegal characters
3339 45 SILC_STATUS_ERR_AUTH_FAILED
3341 "Authentication failed". The authentication data sent as
3342 argument were wrong and thus authentication failed.
3344 46 SILC_STATUS_ERR_UNKOWN_ALGORITHM
3346 "The algorithm was not supported." The server does not support the
3347 requested algorithm.
3352 6 Security Considerations
3354 Security is central to the design of this protocol, and these security
3355 considerations permeate the specification. Common security considerations
3356 such as keeping private keys truly private and using adequate lengths for
3357 symmetric and asymmetric keys must be followed in order to maintain the
3358 security of this protocol.
3364 [SILC2] Riikonen, P., "SILC Packet Protocol", Internet Draft,
3367 [SILC3] Riikonen, P., "SILC Key Exchange and Authentication
3368 Protocols", Internet Draft, June 2000.
3370 [IRC] Oikarinen, J., and Reed D., "Internet Relay Chat Protocol",
3373 [IRC-ARCH] Kalt, C., "Internet Relay Chat: Architecture", RFC 2810,
3376 [IRC-CHAN] Kalt, C., "Internet Relay Chat: Channel Management", RFC
3379 [IRC-CLIENT] Kalt, C., "Internet Relay Chat: Client Protocol", RFC
3382 [IRC-SERVER] Kalt, C., "Internet Relay Chat: Server Protocol", RFC
3385 [SSH-TRANS] Ylonen, T., et al, "SSH Transport Layer Protocol",
3388 [PGP] Callas, J., et al, "OpenPGP Message Format", RFC 2440,
3391 [SPKI] Ellison C., et al, "SPKI Certificate Theory", RFC 2693,
3394 [PKIX-Part1] Housley, R., et al, "Internet X.509 Public Key
3395 Infrastructure, Certificate and CRL Profile", RFC 2459,
3398 [Schneier] Schneier, B., "Applied Cryptography Second Edition",
3399 John Wiley & Sons, New York, NY, 1996.
3401 [Menezes] Menezes, A., et al, "Handbook of Applied Cryptography",
3404 [OAKLEY] Orman, H., "The OAKLEY Key Determination Protocol",
3405 RFC 2412, November 1998.
3407 [ISAKMP] Maughan D., et al, "Internet Security Association and
3408 Key Management Protocol (ISAKMP)", RFC 2408, November
3411 [IKE] Harkins D., and Carrel D., "The Internet Key Exchange
3412 (IKE)", RFC 2409, November 1998.
3414 [HMAC] Krawczyk, H., "HMAC: Keyed-Hashing for Message
3415 Authentication", RFC 2104, February 1997.
3417 [PKCS1] Kalinski, B., and Staddon, J., "PKCS #1 RSA Cryptography
3418 Specifications, Version 2.0", RFC 2437, October 1998.
3430 EMail: priikone@poseidon.pspt.fi
3432 This Internet-Draft expires 6 Jun 2001