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 MAC Algorithms ..................................... 21
108 3.10.4 Compression Algorithms ............................. 22
109 3.11 SILC Public Key .......................................... 22
110 3.12 SILC Version Detection ................................... 24
111 4 SILC Procedures ............................................... 25
112 4.1 Creating Client Connection ................................ 25
113 4.2 Creating Server Connection ................................ 26
114 4.3 Joining to a Channel ...................................... 27
115 4.4 Channel Key Generation .................................... 28
116 4.5 Private Message Sending and Reception ..................... 29
117 4.6 Private Message Key Generation ............................ 29
118 4.7 Channel Message Sending and Reception ..................... 30
119 4.8 Session Key Regeneration .................................. 30
120 4.9 Command Sending and Reception ............................. 30
121 5 SILC Commands ................................................. 31
122 5.1 SILC Commands Syntax ...................................... 31
123 5.2 SILC Commands List ........................................ 33
124 5.3 SILC Command Status Types ................................. 56
125 5.3.1 SILC Command Status Payload ......................... 56
126 5.3.2 SILC Command Status List ............................ 57
127 6 Security Considerations ....................................... 61
128 7 References .................................................... 61
129 8 Author's Address .............................................. 62
136 Figure 1: SILC Network Topology
137 Figure 2: Communication Inside cell
138 Figure 3: Communication Between Cells
139 Figure 4: Router Connections
140 Figure 5: SILC Public Key
141 Figure 6: SILC Command Status Payload
147 This document describes a Secure Internet Live Conferencing (SILC)
148 protocol which provides secure conferencing services over insecure
149 network channel. SILC is IRC [IRC] like protocol, however, it is
150 not equivalent to IRC and does not support IRC.
152 Strong cryptographic methods are used to protect SILC packets inside
153 SILC network. Two other Internet Drafts relates very closely to this
154 memo; SILC Packet Protocol [SILC2] and SILC Key Exchange and
155 Authentication Protocols [SILC3].
157 The protocol uses extensively packets as conferencing protocol
158 requires message and command sending. The SILC Packet Protocol is
159 described in [SILC2] and should be read to fully comprehend this
160 document and protocol. [SILC2] also describes the packet encryption
161 and decryption in detail.
163 The security of SILC protocol and for any security protocol for that
164 matter is based on strong and secure key exchange protocol. The SILC
165 Key Exchange protocol is described in [SILC3] along with connection
166 authentication protocol and should be read to fully comprehend this
167 document and protocol.
169 The SILC protocol has been developed to work on TCP/IP network
170 protocol, although it could be made to work on other network protocols
171 with only minor changes. However, it is recommended that TCP/IP
172 protocol is used under SILC protocol. Typical implementation would
173 be made in client-server model.
179 This section describes various SILC protocol concepts that forms the
180 actual protocol, and in the end, the actual SILC network. The mission
181 of the protocol is to deliver messages from clients to other clients
182 through routers and servers in secure manner. The messages may also
183 be delivered from one client to many clients forming a group, also
186 This section does not focus to security issues, instead basic network
187 concepts are introduced to make the topology of the SILC network
192 2.1 SILC Network Topology
194 SILC network is a cellular network as opposed to tree style network
195 topology. The rationale for this is to have servers that can perform
196 specific kind of tasks what other servers cannot perform. This leads
197 to two kinds of servers; normal SILC servers and SILC routers.
199 A difference between normal server and router server is that routers
200 knows everything about everything in the network. They also do the
201 actual routing of the messages to the correct receiver. Normal servers
202 knows only about local information and nothing about global information.
203 This makes the network faster as there are less servers that needs to
204 keep global information up to date at all time.
206 This, on the other hand, leads to cellular like network, where routers
207 are in the center of the cell and servers are connected to the router.
209 Following diagram represents SILC network topology.
229 ---- ---- ---- ---- ---- ----
230 | S8 | S5 | S4 | | S7 | S5 | S6 |
231 ----- ---- ----- ----- ---- -----
232 | S7 | S/R1 | S2 | --- | S8 | S/R2 | S4 |
233 ---- ------ ---- ---- ------ ----
234 | S6 | S3 | S1 | | S1 | S3 | S2 | ---- ----
235 ---- ---- ---- ---- ---- ---- | S3 | S1 |
236 Cell 1. \\ Cell 2. | \\____ ----- -----
238 ---- ---- ---- ---- ---- ---- ---- ------
239 | S7 | S4 | S2 | | S1 | S3 | S2 | | S2 | S5 |
240 ----- ---- ----- ----- ---- ----- ---- ----
241 | S6 | S/R3 | S1 | --- | S4 | S/R5 | S5 | ____/ Cell 4.
242 ---- ------ ---- ---- ------ ----
243 | S8 | S5 | S3 | | S6 | S7 | S8 | ... etc ...
244 ---- ---- ---- ---- ---- ----
249 Figure 1: SILC Network Topology
252 A cell is formed when a server or servers connect to one router. In
253 SILC network normal server cannot directly connect to other normal
254 server. Normal server may only connect to SILC router which then
255 routes the messages to the other servers in the cell. Router servers
256 on the other hand may connect to other routers to form the actual SILC
257 network, as seen in above figure. However, router is also normal SILC
258 server; clients may connect to it the same way as to normal SILC
259 servers. Normal server also cannot have active connections to more
260 than one router. Normal server cannot be connected to two different
261 cells. Router servers, on the other hand, may have as many router to
262 router connections as needed.
264 There are many issues in this network topology that needs to be careful
265 about. Issues like the size of the cells, the number of the routers in
266 the SILC network and the capacity requirements of the routers. These
267 issues should be discussed in the Internet Community and additional
268 documents on the issue will be written.
272 2.2 Communication Inside a Cell
274 It is always guaranteed that inside a cell message is delivered to the
275 recipient with at most two server hops. Client who is connected to
276 server in the cell and is talking on channel to other client connected
277 to other server in the same cell, will have its messages delivered from
278 its local server first to the router of the cell, and from the router
279 to the other server in the cell.
281 Following diagram represents this scenario:
295 Figure 2: Communication Inside cell
298 Example: Client 1. connected to Server 1. message sent to
299 Client 4. connected to Server 2. travels from Server 1.
300 first to Router which routes the message to Server 2.
301 which then sends it to the Client 4. All the other
302 servers in the cell will not see the routed message.
305 If client is connected directly to the router, as router is also normal
306 SILC server, the messages inside the cell are always delivered only with
307 one server hop. If clients communicating with each other are connected
308 to the same server, no router interaction is needed. This is the optimal
309 situation of message delivery in the SILC network.
313 2.3 Communication in the Network
315 If the message is destined to server that does not belong to local cell
316 the message is routed to the router server to which the destination
317 server belongs, if the local router is connected to destination router.
318 If there is no direct connection to the destination router, the local
319 router routes the message to its primary route. Following diagram
320 represents message sending between cells.
325 1 --- S1 S4 --- 5 S2 --- 1
326 S/R - - - - - - - - S/R
336 Figure 3: Communication Between Cells
339 Example: Client 5. connected to Server 4. in Cell 1. message sent
340 to Client 2. connected to Server 1. in Cell 2. travels
341 from Server 4. to Router which routes the message to
342 Router in Cell 2, which then routes the message to
343 Server 1. All the other servers and routers in the
344 network will not see the routed message.
347 The optimal case of message delivery from client point of view is
348 when clients are connected directly to the routers and the messages
349 are delivered from one router to the other router.
353 2.4 Channel Communication
355 Messages may be sent to group of clients as well. Sending messages to
356 many clients works the same way as sending messages point to point, from
357 message delivery point of view. Security issues are another matter
358 which are not discussed in this section.
360 Router server handles the message routing to multiple recipients. If
361 any recipient is not in the same cell as the sender the messages are
364 Server distributes the channel message to its local clients who are
365 joined to the channel. Also, router distributes the message to its
366 local clients on the channel.
370 2.5 Router Connections
372 Router connections play very important role in making the SILC like
373 network topology to work. For example, sending broadcast packets in
374 SILC network require special connections between routers; routers must
375 be connected in specific way.
377 Every router has their primary route which is a connection to another
378 router in the network. Unless there is only two routers in the network
379 must not routers use each other as their primary routes. The router
380 connections in the network must form a circular.
382 Example with three routers in the network:
392 S/R1 - > - > - > - > - > - > - S/R2
395 \\ - < - < - S/R3 - < - < - /
400 Figure 4: Router Connections
403 Example: Network with three routers. Router 1. uses Router 2. as its
404 primary router. Router 2. uses Router 3. as its primary router,
405 and Router 3. uses Router 1. as its primary router. There may
406 be other direct connections between the routers but they must
407 not be used as primary routes.
409 The above example is applicable to any amount of routers in the network
410 except for two routers. If there are only two routers in the network both
411 routers must be able to handle situation where they use each other as their
414 The issue of router connections are very important especially with SILC
415 broadcast packets. Usually all router wide information in the network is
416 distributed by SILC broadcast packets.
420 3. SILC Specification
422 This section describes the SILC protocol. However, [SILC2] and
423 [SILC3] describes other important protocols that are part of this SILC
424 specification and must be read.
430 A client is a piece of software connecting to SILC server. SILC client
431 cannot be SILC server. Purpose of clients is to provide the user
432 interface of the SILC services for end user. Clients are distinguished
433 from other clients by unique Client ID. Client ID is a 128 bit ID that
434 is used in the communication in the SILC network. The client ID is
435 based on the nickname selected by the user. User uses logical nicknames
436 in communication which are then mapped to the corresponding Client ID.
437 Client ID's are low level identifications and must not be seen by the
440 Clients provide other information about the end user as well. Information
441 such as the nickname of the user, username and the hostname of the end
442 user and user's real name. See section 3.2 Server for information of
443 the requirements of keeping this information.
445 The nickname selected by the user is not unique in the SILC network.
446 There can be 2^8 same nicknames for one IP address. As for comparison
447 to IRC [IRC] where nicknames are unique this is a fundamental difference
448 between SILC and IRC. This causes the server names to be used along
449 with the nicknames to identify specific users when sending messages.
450 This feature of SILC makes IRC style nickname-wars obsolete as no one
451 owns their nickname; there can always be someone else with the same
452 nickname. The maximum length of nickname is 128 characters.
458 Client ID is used to identify users in the SILC network. The Client ID
459 is unique to the extent that there can be 2^128 different Client ID's,
460 and ID's based on IPv6 addresses extends this to 2^224 different Client
461 ID's. Collisions are not expected to happen. The Client ID is defined
465 128 bit Client ID based on IPv4 addresses:
467 32 bit Server ID IP address (bits 1-32)
468 8 bit Random number or counter
469 88 bit Truncated MD5 hash value of the nickname
471 224 bit Client ID based on IPv6 addresses:
473 128 bit Server ID IP address (bits 1-128)
474 8 bit Random number or counter
475 88 bit Truncated MD5 hash value of the nickname
477 o Server ID IP address - Indicates the server where this
478 client is coming from. The IP address hence equals the
479 server IP address where to the client has connected.
481 o Random number or counter - Random number to further
482 randomize the Client ID. Another choice is to use
483 a counter starting from the zero (0). This makes it
484 possible to have 2^8 same nicknames from the same
487 o MD5 hash - MD5 hash value of the nickname is truncated
488 taking 88 bits from the start of the hash value. This
489 hash value is used to search the user's Client ID from
493 Collisions could occur when more than 2^8 clients using same nickname
494 from the same server IP address is connected to the SILC network.
495 Server must be able to handle this situation by refusing to accept
496 anymore of that nickname.
498 Another possible collision may happen with the truncated hash value of
499 the nickname. It could be possible to have same truncated hash value for
500 two different nicknames. However, this is not expected to happen nor
501 cause any problems if it would occur. Nicknames are usually logical and
502 it is unlikely to have two distinct logical nicknames produce same
503 truncated hash value.
509 Servers are the most important parts of the SILC network. They form the
510 basis of the SILC, providing a point to which clients may connect to.
511 There are two kinds of servers in SILC; normal servers and router servers.
512 This section focus on the normal server and router server is described
513 in the section 3.3 Router.
515 Normal servers may not directly connect to other normal server. Normal
516 servers may only directly connect to router server. If the message sent
517 by the client is destined outside the local server it is always sent to
518 the router server for further routing. Server may only have one active
519 connection to router on same port. Normal server may not connect to other
520 cell's router except in situations where its cell's router is unavailable.
522 Servers and routers in the SILC network are considered to be trusted.
523 With out a doubt, servers that are set to work on ports above 1023 are
524 not considered to be trusted. Also, the service provider acts important
525 role in the server's trustworthy.
529 3.2.1 Server's Local ID List
531 Normal server keeps various information about the clients and their end
532 users connected to it. Every normal server must keep list of all locally
533 connected clients, Client ID's, nicknames, usernames and hostnames and
534 user's real name. Normal servers only keeps local information and it
535 does not keep any global information. Hence, normal servers knows only
536 about their locally connected clients. This makes servers efficient as
537 they don't have to worry about global clients. Server is also responsible
538 of creating the Client ID's for their clients.
540 Normal server also keeps information about locally created channels and
544 Hence, local list for normal server includes:
547 server list - Router connection
558 client list - All clients in server
566 channel list - All channels in server
569 o Client ID's on channel
570 o Client ID modes on channel
579 Servers are distinguished from other servers by unique 64 bit Server ID
580 (for IPv4) or 160 bit Server ID (for IPv6). The Server ID is used in
581 the SILC to route messages to correct servers. Server ID's also provide
582 information for Client ID's, see section 3.1.1 Client ID. Server ID is
586 64 bit Server ID based on IPv4 addresses:
588 32 bit IP address of the server
592 160 bit Server ID based on IPv6 addresses:
594 128 bit IP address of the server
598 o IP address of the server - This is the real IP address of
601 o Port - This is the port the server is bound to.
603 o Random number - This is used to further randomize the Server ID.
606 Collisions are not expected to happen in any conditions. The Server ID
607 is always created by the server itself and server is responsible of
608 distributing it to the router.
612 3.2.3 SILC Server Ports
614 Following ports has been assigned by IANA for the SILC protocol:
621 If there are needs to create new SILC networks in the future the port
622 numbers must be officially assigned by the IANA.
624 Server on network above privileged ports (>1023) should not be trusted
625 as they could have been set up by untrusted party.
631 Router server in SILC network is responsible for keeping the cell together
632 and routing messages to other servers and to other routers. Router server
633 is also a normal server thus clients may connect to it as it would be
634 just normal SILC server.
636 However, router servers has a lot of important tasks that normal servers
637 do not have. Router server knows everything about everything in the SILC.
638 They know all clients currently on SILC, all servers and routers and all
639 channels in SILC. Routers are the only servers in SILC that care about
640 global information and keeping them up to date at all time. And, this
641 is what they must do.
645 3.3.1 Router's Local ID List
647 Router server as well must keep local list of connected clients and
648 locally created channels. However, this list is extended to include all
649 the informations of the entire cell, not just the server itself as for
652 However, on router this list is a lot smaller since routers do not keep
653 information about user's nickname, username and hostname and real name
654 since these are not needed by the router. Router keeps only information
658 Hence, local list for router includes:
661 server list - All servers in the cell
668 client list - All clients in the cell
672 channel list - All channels in the cell
674 o Client ID's on channel
675 o Client ID modes on channel
680 Note that locally connected clients and other information include all the
681 same information as defined in section section 3.2.1 Server's Local ID
686 3.3.2 Router's Global ID List
688 Router server must also keep global list. Normal servers do not have
689 global list as they know only about local information. Global list
690 includes all the clients on SILC, their Client ID's, all created channels
691 and their Channel ID's and all servers and routers on SILC and their
692 Server ID's. That is said, global list is for global information and the
693 list must not include the local information already on the router's local
696 Note that the global list does not include information like nicknames,
697 usernames and hostnames or user's real names. Router does not keep
698 these informations as they are not needed by the router. This
699 information is available from the client's server which maybe queried
702 Hence, global list includes:
705 server list - All servers in SILC
711 client list - All clients in SILC
714 channel list - All channels in SILC
716 o Client ID's on channel
717 o Client ID modes on channel
722 3.3.3 Router's Server ID
724 Router's Server ID's are equivalent to normal Server ID's. As routers
725 are normal servers as well same types of ID's applies for routers as well.
726 Thus, see section 3.2.2 Server ID. Server ID's for routers are always
727 created by the remote router where the router is connected to.
733 A channel is a named group of one or more clients which will all receive
734 messages addressed to that channel. The channel is created when first
735 client requests JOIN command to the channel, and the channel ceases to
736 exist when the last client has left it. When channel exists, any client
737 can reference it using the name of the channel.
739 Channel names are unique although the real uniqueness comes from 64 bit
740 Channel ID that unifies each channel. However, channel names are still
741 unique and no two global channels with same name may exist. The Channel
742 name is a string of maximum length of 256 characters. Channel names may
743 not contain any spaces (` '), any non-printable ASCII characters,
744 commas (`,') and wildcard characters.
746 Channels can have operators that can administrate the channel and
747 operate all of its modes. Following operators on channel exist on SILC
751 o Channel founder - When channel is created the joining client becomes
752 channel founder. Channel founder is channel operator with some more
753 privileges. Basically, channel founder can fully operate the channel
754 and all of its modes. The privileges are limited only to the particular
755 channel. There can be only one channel founder per channel. Channel
756 founder supersedes channel operator's privileges.
758 Channel founder privileges cannot be removed by any other operator on
759 channel. When channel founder leaves the channel there is no channel
760 founder on the channel. Channel founder also cannot be removed by
761 force from the channel.
763 o Channel operator - When client joins to channel that has not existed
764 previously it will become automatically channel operator (and channel
765 founder discussed above). Channel operator is able administrate the
766 channel, set some modes on channel, remove a badly behaving client from
767 the channel and promote other clients to become channel operator.
768 The privileges are limited only to the particular channel.
770 Normal channel user may be promoted (opped) to channel operator
771 gaining channel operator privileges. Channel founder or other channel
772 operator may also demote (deop) channel operator to normal channel
780 Channels are distinguished from other channels by unique Channel ID.
781 The Channel ID is a 64 bit ID (for IPv4) or 160 bit ID (for IPv6), and
782 collisions are not expected to happen in any conditions. Channel names
783 are just for logical use of channels. The Channel ID is created by the
784 server where the channel is created. The Channel ID is defined as
788 64 bit Channel ID based on IPv4 addresses:
790 32 bit Router's Server ID IP address (bits 1-32)
791 16 bit Router's Server ID port (bits 33-48)
794 160 bit Channel ID based on IPv6 addresses:
796 128 bit Router's Server ID IP address (bits 1-128)
797 16 bit Router's Server ID port (bits 129-144)
800 o Router's Server ID IP address - Indicates the IP address of
801 the router of the cell where this channel is created. This is
802 taken from the router's Server ID. This way SILC router knows
803 where this channel resides in the SILC network.
805 o Router's Server ID port - Indicates the port of the channel on
806 the server. This is taken from the router's Server ID.
808 o Random number - To further randomize the Channel ID. This makes
809 sure that there are no collisions. This also means that
810 in a cell there can be 2^16 channels.
817 Operators are normal users with extra privileges to their server or
818 router. Usually these people are SILC server and router administrators
819 that take care of their own server and clients on them. The purpose of
820 operators is to administrate the SILC server or router. However, even
821 an operator with highest privileges is not able to enter invite-only
822 channel, to gain access to the contents of a encrypted and authenticated
823 packets traveling in the SILC network or to gain channel operator
824 privileges on public channels without being promoted. They have the
825 same privileges as everyone else except they are able to administrate
826 their server or router.
832 Commands are very important part on SILC network especially for client
833 which uses commands to operate on the SILC network. Commands are used
834 to set nickname, join to channel, change modes and many other things.
836 Client usually sends the commands and server replies by sending a reply
837 packet to the command. Server may also send commands usually to serve
838 the original client's request. However, server may not send command
839 to client and there are some commands that server must not send.
841 Note that the command reply is usually sent only after client has sent
842 the command request but server is allowed to send command reply packet
843 to client even if client has not requested the command. Client may,
844 however, choose ignore the command reply, but should not.
846 It is expected that some of the commands may be miss-used by clients
847 resulting various problems on the server side. Every implementation
848 should assure that commands may not be executed more than once, say,
849 in two (2) seconds. This should be sufficient to prevent the miss-use
852 SILC commands are described in section 5 SILC Commands.
858 Packets are naturally the most important part of the protocol and the
859 packets are what actually makes the protocol. Packets in SILC network
860 are always encrypted using, usually, the shared secret session key
861 or some other key, for example, channel key, when encrypting channel
862 messages. The SILC Packet Protocol is a wide protocol and is described
863 in [SILC2]. This document does not define or describe details of
869 3.8 Packet Encryption
871 All packets passed in SILC network must be encrypted. This section
872 defines how packets must be encrypted in the SILC network. The detailed
873 description of the actual encryption process of the packets are
874 described in [SILC2].
876 Client and its server shares secret symmetric session key which is
877 established by the SILC Key Exchange Protocol, described in [SILC3].
878 Every packet sent from client to server, with exception of packets for
879 channels, are encrypted with this session key.
881 Channels has their own key that are shared by every client on the channel.
882 However, the channel keys are cell specific thus one cell does not know
883 the channel key of the other cell, even if that key is for same channel.
884 Channel key is also known by the routers and all servers that has clients
885 on the channel. However, channels may have channel private keys that
886 are entirely local setting for client. All clients on the channel must
887 know the channel private key before hand to be able to talk on the
888 channel. In this case, no server or router knows the key for channel.
890 Server shares secret symmetric session key with router which is
891 established by the SILC Key Exchange Protocol. Every packet passed from
892 server to router, with exception of packets for channels, are encrypted
893 with the shared session key. Same way, router server shares secret
894 symmetric key with its primary route. However, every packet passed
895 from router to other router, including packets for channels, are
896 encrypted with the shared session key. Every router connection has
897 their own session keys.
901 3.8.1 Determination of the Source and the Destination
903 The source and the destination of the packet needs to be determined
904 to be able to route the packets to correct receiver. This information
905 is available in the SILC Packet Header which is included in all packets
906 sent in SILC network. The SILC Packet Header is described in [SILC2].
908 The header is always encrypted with the session key who is next receiver
909 of the packet along the route. The receiver of the packet, for example
910 a router along the route, is able to determine the sender and the
911 destination of the packet by decrypting the SILC Packet Header and
912 checking the ID's attached to the header. The ID's in the header will
913 tell to where the packet needs to be sent and where it is coming from.
915 The header in the packet does not change during the routing of the
916 packet. The original sender, for example client, assembles the packet
917 and the packet header and server or router between the sender and the
918 receiver must not change the packet header.
920 Note that the packet and the packet header may be encrypted with
921 different keys. For example, packets to channels are encrypted with
922 the channel key, however, the header is encrypted with the session key
923 as described above. However, the header and the packet may be encrypted
924 with same key. This is case, for example, with command packets.
928 3.8.2 Client To Client
930 Process of message delivery and encryption from client to another
931 client is as follows.
933 Example: Private message from client to another client on different
934 servers. Clients do not share private message delivery
935 keys; normal session keys are used.
937 o Client 1. sends encrypted packet to its server. The packet is
938 encrypted with the session key shared between client and its
941 o Server determines the destination of the packet and decrypts
942 the packet. Server encrypts the packet with session key shared
943 between the server and its router, and sends the packet to the
946 o Router determines the destination of the packet and decrypts
947 the packet. Router encrypts the packet with session key
948 shared between the router and the destination server, and sends
949 the packet to the server.
951 o Server determines the client to which the packet is destined
952 to and decrypts the packet. Server encrypts the packet with
953 session key shared between the server and the destination client,
954 and sends the packet to the client.
956 o Client 2. decrypts the packet.
959 Example: Private message from client to another client on different
960 servers. Clients has established secret shared private
961 message delivery key with each other and that is used in
962 the message encryption.
964 o Client 1. sends encrypted packet to its server. The packet is
965 encrypted with the private message delivery key shared between
968 o Server determines the destination of the packet and sends the
969 packet to the router.
971 o Router determines the destination of the packet and sends the
972 packet to the server.
974 o Server determines the client to which the packet is destined
975 to and sends the packet to the client.
977 o Client 2. decrypts the packet with the secret shared key.
980 If clients share secret key with each other the private message
981 delivery is much simpler since servers and routers between the
982 clients do not need to decrypt and re-encrypt the packet.
984 The process for clients on same server is much simpler as there are
985 no need to send the packet to the router. The process for clients
986 on different cells is same as above except that the packet is routed
987 outside the cell. The router of the destination cell routes the
988 packet to the destination same way as described above.
992 3.8.3 Client To Channel
994 Process of message delivery from client on channel to all the clients
997 Example: Channel of four users; two on same server, other two on
998 different cells. Client sends message to the channel.
1000 o Client 1. encrypts the packet with channel key and sends the
1001 packet to its server.
1003 o Server determines local clients on the channel and sends the
1004 packet to the Client on the same server. Server then sends
1005 the packet to its router for further routing.
1007 o Router determines local clients on the channel, if found
1008 sends packet to the local clients. Router determines global
1009 clients on the channel and sends the packet to its primary
1010 router or fastest route.
1012 o (Other router(s) do the same thing and sends the packet to
1015 o Server determines local clients on the channel and sends the
1016 packet to the client.
1018 o All clients receiving the packet decrypts the packet.
1022 3.8.4 Server To Server
1024 Server to server packet delivery and encryption is described in above
1025 examples. Router to router packet delivery is analogous to server to
1026 server. However, some packets, such as channel packets, are processed
1027 differently. These cases are described later in this document and
1028 more in detail in [SILC2].
1032 3.9 Key Exchange And Authentication
1034 Key exchange is done always when for example client connects to server
1035 but also when server and router and router and router connects to each
1036 other. The purpose of key exchange protocol is to provide secure key
1037 material to be used in the communication. The key material is used to
1038 derive various security parameters used to secure SILC packets. The
1039 SILC Key Exchange protocol is described in detail in [SILC3].
1041 Authentication is done after key exchange protocol has been successfully
1042 completed. The purpose of authentication is to authenticate for example
1043 client connecting to the server. However, Usually clients are accepted
1044 to connect to server without explicit authentication. Servers are
1045 required use authentication protocol when connecting. The authentication
1046 may be based on passphrase (pre-shared-secret) or public key. The
1047 connection authentication protocol is described in detail in [SILC3].
1051 3.9.1 Authentication Payload
1053 Authentication payload is used separately from the SKE and the Connection
1054 authentication protocol. It is used during the session to authenticate
1055 with the remote. For example, the client can authenticate itself to the
1056 server to be server operator. In this case, Authentication Payload is
1059 The format of the Authentication Payload is as follows:
1065 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
1066 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1067 | Payload Length | Authentication Method |
1068 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1069 | Public Data Length | |
1070 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1074 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1075 | Authentication Data Length | |
1076 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1078 ~ Authentication Data ~
1080 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+|
1084 Figure 5: Authentication Payload
1088 o Payload Length (2 bytes) - Length of the entire payload.
1090 o Authentication Type (2) - The method of the authentication.
1091 The authentication methods are defined in [SILC2] in the
1092 Connection Auth Request Payload. The NONE authentication
1093 method is not recommended.
1095 o Public Data Length (2 bytes) - Indicates the length of
1096 the Public Data field.
1098 o Public Data (variable length) - This is defined only if
1099 the authentication method is public key. If it is any other
1100 this field does not exist and the Public Data Length field
1103 When the authentication method is public key this includes
1104 128 to 4096 bytes of non-zero random data that is used in
1105 the signature process, described subsequently.
1107 o Authentication Data Length (2 bytes) - Indicates the
1108 length of the Authentication Data field.
1110 o Authentication Data (variable length) - Authentication
1111 method dependent authentication data.
1115 If the authentication method is password based, the Authentication
1116 Data field includes the plaintext password. It is safe to send
1117 plaintext password since the entire payload is encrypted.
1119 If the authentication method is public key based (or certificate)
1120 the Authentication Data is computed as follows:
1122 HASH = hash(random bytes | ID | public key (or certificate));
1123 Authentication Data = sign(HASH);
1125 The hash() and the sign() are the hash funtion and the public key
1126 cryptography function selected in the SKE protocol. The public key
1127 is SILC style public key unless certificates are used. The ID is the
1128 entity's ID (Client or Server ID) who is authenticating itself. The ID
1129 is raw ID data. The random bytes are non-zero random bytes of length
1130 between 128 and 4096 bytes, and will be included into the Public Data
1133 The receiver will compute the signature using the random data received
1134 in the payload, the ID associated to the connection and the public key
1135 (or certificate) received in the SKE protocol. After computing the
1136 receiver must verify the signature. In this case also, the entire
1137 payload is encrypted.
1143 This section defines all the allowed algorithms that can be used in
1144 the SILC protocol. This includes mandatory cipher, mandatory public
1145 key algorithm and MAC algorithms.
1151 Cipher is the encryption algorithm that is used to protect the data
1152 in the SILC packets. See [SILC2] of the actual encryption process and
1153 definition of how it must be done. SILC has a mandatory algorithm that
1154 must be supported in order to be compliant with this protocol.
1156 Following ciphers are defined in SILC protocol:
1159 aes-256-cbc AES in CBC mode, 256 bit key (mandatory)
1160 aes-192-cbc AES in CBC mode, 192 bit key (optional)
1161 aes-128-cbc AES in CBC mode, 128 bit key (optional)
1162 twofish-256-cbc Twofish in CBC mode, 256 bit key (optional)
1163 twofish-192-cbc Twofish in CBC mode, 192 bit key (optional)
1164 twofish-128-cbc Twofish in CBC mode, 128 bit key (optional)
1165 blowfish-128-cbc Blowfish in CBC mode, 128 bit key (optional)
1166 cast-256-cbc CAST-256 in CBC mode, 256 bit key (optional)
1167 cast-192-cbc CAST-256 in CBC mode, 192 bit key (optional)
1168 cast-128-cbc CAST-256 in CBC mode, 128 bit key (optional)
1169 rc6-256-cbc RC6 in CBC mode, 256 bit key (optional)
1170 rc6-192-cbc RC6 in CBC mode, 192 bit key (optional)
1171 rc6-128-cbc RC6 in CBC mode, 128 bit key (optional)
1172 mars-256-cbc Mars in CBC mode, 256 bit key (optional)
1173 mars-192-cbc Mars in CBC mode, 192 bit key (optional)
1174 mars-128-cbc Mars in CBC mode, 128 bit key (optional)
1175 none No encryption (optional)
1179 Algorithm none does not perform any encryption process at all and
1180 thus is not recommended to be used. It is recommended that no client
1181 or server implementation would accept none algorithms except in special
1184 Additional ciphers may be defined to be used in SILC by using the
1185 same name format as above.
1189 3.10.2 Public Key Algorithms
1191 Public keys are used in SILC to authenticate entities in SILC network
1192 and to perform other tasks related to public key cryptography. The
1193 public keys are also used in the SILC Key Exchange protocol [SILC3].
1195 Following public key algorithms are defined in SILC protocol:
1202 DSS is described in [Menezes]. The RSA must be implemented according
1203 PKCS #1 [PKCS1]. The mandatory PKCS #1 implementation in SILC must be
1204 compliant to either PKCS #1 version 1.5 or newer with the following
1205 notes: The signature encoding is always in same format as the encryption
1206 encoding regardles of the PKCS #1 version. The signature with appendix
1207 (with hash algorithm OID in the data) must not be used in the SILC. The
1208 rationale for this is that there is no binding between the PKCS #1 OIDs
1209 and the hash algorithms used in the SILC protocol. Hence, the encoding
1210 is always in PKCS #1 version 1.5 format.
1212 Additional public key algorithms may be defined to be used in SILC.
1216 3.10.3 MAC Algorithms
1218 Data integrity is protected by computing a message authentication code
1219 (MAC) of the packet data. See [SILC2] for details how to compute the
1222 Following MAC algorithms are defined in SILC protocol:
1225 hmac-sha1 HMAC-SHA1, length = 20 (mandatory)
1226 hmac-md5 HMAC-MD5, length = 16 (optional)
1227 none No MAC (optional)
1230 The none MAC is not recommended to be used as the packet is not
1231 authenticated when MAC is not computed. It is recommended that no
1232 client or server would accept none MAC except in special debugging
1235 The HMAC algorithm is described in [HMAC] and hash algorithms that
1236 are used as part of the HMACs are described in [Scheneir] and in
1239 Additional MAC algorithms may be defined to be used in SILC.
1243 3.10.4 Compression Algorithms
1245 SILC protocol supports compression that may be applied to unencrypted
1246 data. It is recommended to use compression on slow links as it may
1247 significantly speed up the data transmission. By default, SILC does not
1248 use compression which is the mode that must be supported by all SILC
1251 Following compression algorithms are defined:
1254 none No compression (mandatory)
1255 zlib GNU ZLIB (LZ77) compression (optional)
1258 Additional compression algorithms may be defined to be used in SILC.
1262 3.11 SILC Public Key
1264 This section defines the type and format of the SILC public key. All
1265 implementations must support this public key type. See [SILC3] for
1266 other optional public key and certificate types allowed in SILC
1267 protocol. Public keys in SILC may be used to authenticate entities
1268 and to perform other tasks related to public key cryptography.
1270 The format of the SILC Public Key is as follows:
1276 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
1277 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1278 | Public Key Length |
1279 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1280 | Algorithm Name Length | |
1281 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1285 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1286 | Identifier Length | |
1287 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1291 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1295 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1299 Figure 5: SILC Public Key
1303 o Public Key Length (4 bytes) - Indicates the full length
1304 of the public key, not including this field.
1306 o Algorithm Name Length (2 bytes) - Indicates the length
1307 of the Algorithm Length field, not including this field.
1309 o Algorithm name (variable length) - Indicates the name
1310 of the public key algorithm that the key is. See the
1311 section 3.10.2 Public Key Algorithms for defined names.
1313 o Identifier Length (2 bytes) - Indicates the length of
1314 the Identifier field, not including this field.
1316 o Identifier (variable length) - Indicates the identifier
1317 of the public key. This data can be used to identify
1318 the owner of the key. The identifier is of following
1322 HN Host name or IP address
1329 Examples of an identifier:
1331 `UN=priikone, HN=poseidon.pspt.fi, E=priikone@poseidon.pspt.fi'
1333 `UN=sam, HN=dummy.fi, RN=Sammy Sam, O=Company XYZ, C=Finland'
1335 At least user name (UN) and host name (HN) must be provided as
1336 identifier. The fields are separated by commas (`,'). If
1337 comma is in the identifier string it must be written as `\\,',
1338 for example, `O=Company XYZ\\, Inc.'.
1340 o Public Data (variable length) - Includes the actual
1341 public data of the public key.
1343 The format of this field for RSA algorithm is
1352 The format of this field for DSS algorithm is
1364 The variable length fields are multiple precession
1365 integers encoded as strings in both examples.
1367 Other algorithms must define their own type of this
1368 field if they are used.
1371 All fields in the public key are in MSB (most significant byte first)
1376 3.12 SILC Version Detection
1378 The version detection of both client and server is performed at the
1379 connection phase while executing the SILC Key Exchange protocol. The
1380 version identifier is exchanged between initiator and responder. The
1381 version identifier is of following format:
1384 SILC-<protocol version>-<software version>
1387 The version strings are of following format:
1390 protocol version = <major>.<minor>
1391 software version = <major>[.<minor>[.<build>]]
1394 Protocol version may provide both major and minor version. Currently
1395 implementations must set the protocol version and accept the protocol
1396 version as SILC-1.0-<sotware version>.
1398 Software version may provide major, minor and build version. The
1399 software version may be freely set and accepted.
1402 Thus, the version string could be, for example:
1412 This section describes various SILC procedures such as how the
1413 connections are created and registered, how channels are created and
1414 so on. The section describes the procedures only generally as details
1415 are described in [SILC2] and [SILC3].
1419 4.1 Creating Client Connection
1421 This section describes the procedure when client connects to SILC server.
1422 When client connects to server the server must perform IP address lookup
1423 and reverse IP address lookup to assure that the origin host really is
1424 who it claims to be. Client, host, connecting to server must have
1425 both valid IP address and fully qualified domain name (FQDN).
1427 After that the client and server performs SILC Key Exchange protocol
1428 which will provide the key material used later in the communication.
1429 The key exchange protocol must be completed successfully before the
1430 connection registration may continue. The SILC Key Exchange protocol
1431 is described in [SILC3].
1433 Typical server implementation would keep a list of connections that it
1434 allows to connect to the server. The implementation would check, for
1435 example, the connecting client's IP address from the connection list
1436 before the SILC Key Exchange protocol has been started. Reason for
1437 this is that if the host is not allowed to connect to the server there
1438 is no reason to perform a key exchange protocol.
1440 After successful key exchange protocol the client and server performs
1441 connection authentication protocol. The purpose of the protocol is to
1442 authenticate the client connecting to the server. Flexible
1443 implementation could also accept the client to connect to the server
1444 without explicit authentication. However, if authentication is
1445 desired for a specific client it may be based on passphrase or
1446 public key authentication. If authentication fails the connection
1447 must be terminated. The connection authentication protocol is described
1450 After successful key exchange and authentication protocol the client
1451 registers itself by sending SILC_PACKET_NEW_CLIENT packet to the
1452 server. This packet includes various information about the client
1453 that the server uses to create the client. Server creates the client
1454 and sends SILC_PACKET_NEW_ID to the client which includes the created
1455 Client ID that the client must start using after that. After that
1456 all SILC packets from the client must have the Client ID as the
1457 Source ID in the SILC Packet Header, described in [SILC2].
1459 Client must also get the server's Server ID that is to be used as
1460 Destination ID in the SILC Packet Header when communicating with
1461 the server (for example when sending commands to the server). The
1462 ID may be resolved in two ways. Client can take the ID from an
1463 previously received packet from server that must include the ID,
1464 or to send SILC_COMMAND_INFO command and receive the Server ID as
1467 Server may choose not to use the information received in the
1468 SILC_PACKET_NEW_CLIENT packet. For example, if public key or
1469 certificate were used in the authentication, server may use those
1470 informations rather than what it received from client. This is suitable
1471 way to get the true information about client if it is available.
1473 The nickname of client is initially set to the username sent in the
1474 SILC_PACKET_NEW_CLIENT packet. User should set the nickname to more
1475 suitable by sending SILC_COMMAND_NICK command. However, this is not
1476 required as part of registration process.
1478 Server must also distribute the information about newly registered
1479 client to its router (or if the server is router, to all routers in
1480 the SILC network). More information about this in [SILC2].
1484 4.2 Creating Server Connection
1486 This section descibres the procedure when server connects to its
1487 router (or when router connects to other router, the cases are
1488 equivalent). The procedure is very much alike when client connects
1489 to the server thus it is not repeated here.
1491 One difference is that server must perform connection authentication
1492 protocol with proper authentication. Proper authentication is based
1493 on passphrase or public key authentication.
1495 After server and router has successfully performed the key exchange
1496 and connection authentication protocol, the server register itself
1497 to the router by sending SILC_PACKET_NEW_SERVER packet. This packet
1498 includes the server's Server ID that it has created by itself and
1499 other relevant information about the server.
1501 After router has received the SILC_PACKET_NEW_SERVER packet it
1502 distributes the information about newly registered server to all routers
1503 in the SILC network. More information about this in [SILC2].
1505 As client needed to resolve the destination ID this must be done by the
1506 server that connected to the router, as well. The way to resolve it is
1507 to get the ID from previously received packet. Server must also start
1508 using its own Server ID as Source ID in SILC Packet Header and the
1509 router's Server ID as Destination when communicating with the router.
1511 If the server has already connected clients and locally created
1512 channels the server must distribute these informations to the router.
1513 The distribution is done by sending packet SILC_PACKET_NEW_CHANNEL.
1514 See [SILC2] for more information on this.
1518 4.3 Joining to a Channel
1520 This section describes the procedure when client joins to a channel.
1521 Client may join to channel by sending command SILC_COMMAND_JOIN to the
1522 server. If the receiver receiving join command is normal server the
1523 server must check its local list whether this channel already exists
1524 locally. This would indicate that some client connected to the server
1525 has already joined to the channel. If this is case the client is
1526 joined to the client, new channel key is created and information about
1527 newly joined channel is sent to the router. The router is informed
1528 by sending SILC_NOTIFY_TYPE_JOIN notify type. The notify type must
1529 also be sent to the local clients on the channel. The new channel key
1530 is also sent to the router and to local clients on the channel.
1532 If the channel does not exist in the local list the client's command
1533 must be sent to the router which will then perform the actual joining
1534 procedure. When server receives the reply to the command from the
1535 router it must be sent to the client who sent the command originally.
1536 Server will also receive the channel key from the server that it must
1537 send to the client who originally requested the join command. The server
1538 must also save the channel key.
1540 If the receiver of the join command is router it must first check its
1541 local list whether anyone in the cell has already joined to the channel.
1542 If this is the case the client is joined to the channel and reply is
1543 sent to the client. If the command was sent by server the command reply
1544 is sent to the server who sent it. Then the router must also create
1545 new channel key and distribute it to all clients on the channel and
1546 all servers that has clients on the channel. Router must also send
1547 the SILC_NOTIFY_TYPE_JOIN notify type to local clients on the channel
1548 and to local servers that has clients on the channel.
1550 If the channel does not exist on the router's local list it must
1551 check the global list whether the channel exists at all. If it does
1552 the client is joined to the channel as described previously. If
1553 the channel does not exist the channel is created and the client
1554 is joined to the channel. The channel key is also created and
1555 distributed as previously described. The client joining to the created
1556 channel is made automatically channel founder and both channel founder
1557 and channel operator privileges is set for the client.
1559 If the router created the channel in the process, information about the
1560 new channel must be broadcasted to all routers. This is done by
1561 broadcasting SILC_PACKET_NEW_CHANNEL packet to the router's primary
1562 route. When the router joins the client to the channel it must also
1563 send information about newly joined client to all routers in the SILC
1564 network. This is done by broadcasting the SILC_NOTIFY_TYPE_JOIN notify
1565 type to the router's primary route.
1567 After joining the client to the channel server or router must send
1568 command reply packet for SILC_COMMAND_USERS command. This way the
1569 client gets the list of users on the channel. If the router joined
1570 the client to the channel then the router sends this command reply
1571 to the server which must send it further to the original client.
1573 It is important to note that new channel key is created always when
1574 new client joins to channel, whether the channel has existed previously
1575 or not. This way the new client on the channel is not able to decrypt
1576 any of the old traffic on the channel. Client who receives the reply to
1577 the join command must start using the received Channel ID in the channel
1578 message communication thereafter. Client also receives the key for the
1579 channel in the command reply.
1583 4.4 Channel Key Generation
1585 Channel keys are created by router who creates the channel by taking
1586 enough randomness from cryptographically strong random number generator.
1587 The key is generated always when channel is created, when new client
1588 joins a channel and after the key has expired. Key could expire for
1591 The key must also be re-generated whenever some client leaves a channel.
1592 In this case the key is created from scratch by taking enough randomness
1593 from the random number generator. After that the key is distributed to
1594 all clients on the channel. However, channel keys are cell specific thus
1595 the key is created only on the cell where the client, who left the
1596 channel, exists. While the server or router is creating the new channel
1597 key, no other client may join to the channel. Messages that are sent
1598 while creating the new key are still processed with the old key. After
1599 server has sent the SILC_PACKET_CHANNEL_KEY packet must client start
1600 using the new key. If server creates the new key the server must also
1601 send the new key to its router. See [SILC2] on more information about
1602 how channel messages must be encrypted and decrypted when router is
1607 4.5 Private Message Sending and Reception
1609 Private messages are sent point to point. Client explicitly destines
1610 a private message to specific client that is delivered to only to that
1611 client. No other client may receive the private message. The receiver
1612 of the private message is destined in the SILC Packet Header as any
1613 other packet as well.
1615 If the sender of a private message does not know the receiver's Client
1616 ID, it must resolve it from server. There are two ways to resolve the
1617 client ID from server; it is recommended that client implementations
1618 send SILC_COMMAND_IDENTIFY command to receive the Client ID. Client
1619 may also send SILC_COMMAND_WHOIS command to receive the Client ID.
1620 If the sender has received earlier a private message from the receiver
1621 it should have cached the Client ID from the SILC Packet Header.
1623 Receiver of a private message should not explicitly trust the nickname
1624 that it receives in the Private Message Payload, described in [SILC2].
1625 Implementations could resolve the nickname from server, as described
1626 previously, and compare the received Client ID and the SILC Packet
1627 Header's Client ID. The nickname in the payload is merely provided
1628 to be displayed for end user.
1630 See [SILC2] for description of private message encryption and decryption
1635 4.6 Private Message Key Generation
1637 Private message may be protected by key generated by client. The key
1638 may be generated and sent to the other client by sending packet
1639 SILC_PACKET_PRIVATE_MESSAGE_KEY which travels through the network
1640 and is secured by session keys. After that the private message key
1641 is used in the private message communication between those clients.
1643 Other choice is to entirely use keys that are not sent through
1644 the SILC network at all. This significantly adds security. This key
1645 would be pre-shared-key that is known by both of the clients. Both
1646 agree about using the key and starts sending packets that indicate
1647 that the private message is secured using private message key.
1649 The key material used as private message key is implementation issue.
1650 However, SILC_PACKET_KEY_AGREEMENT packet may be used to negotiate
1651 the key material. If the key is normal pre-shared-key or randomly
1652 generated key, and the SILC_PACKET_KEY_AGREEMENT was not used, then
1653 the key material should be processed as defined in the [SILC3]. In
1654 the processing, however, the HASH, as defined in [SILC3] must be
1655 ignored. After processing the key material it is employed as defined
1656 in [SILC3], however, the HMAC key material must be discarded.
1658 If the key is pre-shared-key or randomly generated the implementations
1659 should use the SILC protocol's mandatory cipher as the cipher. If the
1660 SKE was used to negotiate key material the cipher was negotiated as well.
1663 4.7 Channel Message Sending and Reception
1665 Channel messages are delivered to group of users. The group forms a
1666 channel and all clients on the channel receives messages sent to the
1669 Channel messages are destined to channel by specifying the Channel ID
1670 as Destination ID in the SILC Packet Header. The server must then
1671 distribute the message to all clients on the channel by sending the
1672 channel message destined explicitly to a client on the channel.
1674 See [SILC2] for description of channel message encryption and decryption
1679 4.8 Session Key Regeneration
1681 Session keys should be regenerated periodically, say, once in an hour.
1682 The re-key process is started by sending SILC_PACKET_REKEY packet to
1683 other end, to indicate that re-key must be performed.
1685 If perfect forward secrecy (PFS) flag was selected in the SILC Key
1686 Exchange protocol [SILC3] the re-key must cause new key exchange with
1687 SKE protocol. In this case the protocol is secured with the old key
1688 and the protocol results to new key material. See [SILC3] for more
1689 information. After the SILC_PACKET_REKEY packet is sent the sender
1690 will perform the SKE protocol.
1692 If PFS flag was not set, which is the default case, then re-key is done
1693 without executing SKE protocol. In this case, the new key is created by
1694 hashing the old key with hash function selected earlier in the SKE
1695 protocol. If the digest length of the hash function is too short for the
1696 key, then the key is distributed as described in section Processing the
1697 Key Material in [SILC3]. After both parties has regenerated the session
1698 key, both send SILC_PACKET_REKEY_DONE packet to each other. These packets
1699 are still secured with the old key. After these packets, following
1700 packets must be protected with the new key.
1704 4.9 Command Sending and Reception
1706 Client usually sends the commands in the SILC network. In this case
1707 the client simply sends the command packet to server and the server
1708 processes it and replies with command reply packet.
1710 However, if the server is not able to process the command, it is sent
1711 to the server's router. This is case for example with commands such
1712 as, SILC_COMMAND_JOIN and SILC_COMMAND_WHOIS commands. However, there
1713 are other commands as well. For example, if client sends the WHOIS
1714 command requesting specific information about some client the server must
1715 send the WHOIS command to router so that all clients in SILC network
1716 are searched. The router, on the other hand, sends the WHOIS command
1717 further to receive the exact information about the requested client.
1718 The WHOIS command travels all the way to the server who owns the client
1719 and it replies with command reply packet. Finally, the server who
1720 sent the command receives the command reply and it must be able to
1721 determine which client sent the original command. The server then
1722 sends command reply to the client. Implementations should have some
1723 kind of cache to handle, for example, WHOIS information. Servers
1724 and routers along the route could all cache the information for faster
1725 referencing in the future.
1727 The commands sent by server may be sent hop by hop until someone is able
1728 to process the command. However, it is preferred to destine the command
1729 as precisely as it is possible. In this case, other routers en route
1730 must route the command packet by checking the true sender and true
1731 destination of the packet. However, servers and routers must not route
1732 command reply packets to clients coming from other server. Client
1733 must not accept command reply packet originated from anyone else but
1734 from its own server.
1741 5.1 SILC Commands Syntax
1743 This section briefly describes the syntax of the command notions
1744 in this document. Every field in command is separated from each
1745 other by whitespaces (` ') indicating that each field is independent
1746 argument and each argument must have own Command Argument Payload.
1747 The number of maximum arguments are defined with each command
1748 separately. The Command Argument Payload is described in [SILC2].
1750 Every command defines specific number for each argument. Currently,
1751 they are defined in ascending order; first argument has number one
1752 (1), second has number two (2) and so on. This number is set into the
1753 Argument Type field in the Command Argument Payload. This makes it
1754 possible to send the arguments in free order as the number must be
1755 used to identify the type of the argument. This makes is it also
1756 possible to have multiple optional arguments in commands and in
1757 command replies. The number of argument is marked in parentheses
1758 before the actual argument.
1763 Example: Arguments: (1) <nickname> (2) <username@host>
1767 Every command replies with Status Payload. This payload tells the
1768 sender of the command whether the command was completed successfully or
1769 whether there was an error. If error occured the payload includes the
1770 error type. In the next section the Status Payload is not described
1771 as it is common to all commands and has been described here. Commands
1772 may reply with other arguments as well. These arguments are command
1773 specific and are described in the next section.
1782 Arguments: (1) <nickname>[@<server>] (2) <message>
1785 The command has maximum of 3 arguments. However, only first
1786 and second arguments are mandatory.
1788 First argument <nickname> is mandatory but may have optional
1789 <nickname@server> format as well. Second argument is mandatory
1790 <message> argument. Third argument is optional <count> argument.
1792 The numbers in parentheses are the argument specific numbers
1793 that specify the type of the argument in Command Argument Payload.
1794 The receiver always knows that, say, argument number two (2) is
1795 <message> argument, regardless of the ordering of the arguments in
1796 the Command Payload.
1798 Reply messages to the command:
1801 Arguments: (1) <Status Payload> (2) [<channel list>]
1802 (3) <idle time> (4) [<away message>]
1804 This command may reply with maximum of 4 arguments. However,
1805 only the first and third arguments are mandatory. The numbers
1806 in the parentheses have the same meaning as in the upper
1807 command sending specification.
1809 Every command reply with <Status Payload>, it is mandatory
1810 argument for all command replies and for this reason it is not
1811 described in the command reply descriptions.
1818 SILC_STATUS_ERR_TOO_MANY_TARGETS
1819 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
1820 SILC_STATUS_ERR_NO_SUCH_NICK
1822 Every command reply also defines set of status message that it
1823 may return inside the <Status Payload>. All status messages
1824 are defined in the section 5.3 SILC Command Status Types.
1827 Every command that has some kind of ID as argument (for example
1828 <Client ID>) are actually ID Payloads, defined in [SILC2] that includes
1829 the type of the ID, length of the ID and the actual ID data. This
1830 way variable length ID's can be sent as arguments.
1834 5.2 SILC Commands List
1836 This section lists all SILC commands, however, it is expected that a
1837 implementation and especially client implementation has many more
1838 commands that has only local affect. These commands are official
1839 SILC commands that has both client and server sides and cannot be
1840 characterized as local commands.
1842 List of all defined commands in SILC follows.
1847 None. This is reserved command and must not be sent.
1850 1 SILC_COMMAND_WHOIS
1853 Arguments: (1) [<nickname>[@<server>]] (2) [<count>]
1854 (3) [<Client ID>] (n) [...]
1856 Whois command is used to query various information about specific
1857 user. The user maybe requested by their nickname and server name.
1858 The query may find multiple matching users as there are no unique
1859 nicknames in the SILC. The <count> option maybe given to narrow
1860 down the number of accepted results. If this is not defined there
1861 are no limit of accepted results. The query may also be narrowed
1862 down by defining the server name of the nickname.
1864 It is also possible to search the user by Client ID. If <Client ID>
1865 is provided server must use it as the search value instead of
1866 the <nickname>. One of the arguments must be given. It is also
1867 possible to define multiple Client ID's to search multiple users
1868 sending only one WHOIS command. In this case the Client ID's are
1869 appended as normal arguments. The server replies in this case
1870 with only one reply message for all requested users.
1872 To prevent miss-use of this service wildcards in the nickname
1873 or in the servername are not permitted. It is not allowed
1874 to request all users on some server. The WHOIS requests must
1875 be based on specific nickname request.
1877 The WHOIS request must be always sent to the router by server
1878 so that all users are searched. However, the server still must
1879 search its locally connected clients. The router must send
1880 this command to the server who owns the requested client. That
1881 server must reply to the command. Server should not send whois
1882 replies to the client until it has received the reply from its
1885 Reply messages to the command:
1888 Arguments: (1) <Status Payload> (2) <Client ID>
1889 (3) <nickname>[@<server>] (4) <username@host>
1890 (5) <real name> (6) [<channel list>]
1893 This command may reply with several command reply messages to
1894 form a list of results. In this case the status payload will
1895 include STATUS_LIST_START status in the first reply and
1896 STATUS_LIST_END in the last reply to indicate the end of the
1897 list. If there are only one reply the status is set to normal
1900 The command replies include the Client ID of the nickname,
1901 nickname and servername, username and hostname and users real
1902 name. Client should process these replies only after the last
1903 reply has been received with the STATUS_LIST_END status. If the
1904 <count> option were defined in the query there will be only
1905 <count> many replies from the server.
1910 SILC_STATUS_LIST_START
1911 SILC_STATUS_LIST_END
1912 SILC_STATUS_ERR_NO_SUCH_NICK
1913 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
1914 SILC_STATUS_ERR_WILDCARDS
1915 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
1916 SILC_STATUS_ERR_TOO_MANY_PARAMS
1921 2 SILC_COMMAND_WHOWAS
1924 Arguments: (1) <nickname>[@<server>] (2) [<count>]
1926 Whowas. This command is used to query history information about
1927 specific user. The user maybe requested by their nickname and
1928 server name. The query may find multiple matching users as there
1929 are no unique nicknames in the SILC. The <count> option maybe
1930 given to narrow down the number of accepted results. If this
1931 is not defined there are no limit of accepted results. The query
1932 may also be narrowed down by defining the server name of the
1935 To prevent miss-use of this service wildcards in the nickname
1936 or in the servername are not permitted. The WHOWAS requests must
1937 be based on specific nickname request.
1939 The WHOWAS request must be always sent to the router by server
1940 so that all users are searched. However, the server still must
1941 search its locally connected clients.
1943 Reply messages to the command:
1946 Arguments: (1) <Status Payload> (2) <nickname>[@<server>]
1949 This command may reply with several command reply messages to form
1950 a list of results. In this case the status payload will include
1951 STATUS_LIST_START status in the first reply and STATUS_LIST_END in
1952 the last reply to indicate the end of the list. If there are only
1953 one reply the status is set to normal STATUS_OK.
1955 The command replies with nickname and username and hostname.
1956 Every server must keep history for some period of time of its
1957 locally connected clients.
1962 SILC_STATUS_LIST_START
1963 SILC_STATUS_LIST_END
1964 SILC_STATUS_ERR_NO_SUCH_NICK
1965 SILC_STATUS_ERR_WILDCARDS
1966 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
1967 SILC_STATUS_ERR_TOO_MANY_PARAMS
1970 3 SILC_COMMAND_IDENTIFY
1973 Arguments: (1) [<nickname>[@<server>]] (2) [<count>]
1974 (3) [<Client ID>] (n) [...]
1976 Identify. Identify command is almost analogous to WHOIS command,
1977 except that it does not return as much information. Only relevant
1978 information such as Client ID is returned. This is usually used
1979 to get the Client ID of a client used in the communication with
1982 The query may find multiple matching users as there are no unique
1983 nicknames in the SILC. The <count> option maybe given to narrow
1984 down the number of accepted results. If this is not defined there
1985 are no limit of accepted results. The query may also be narrowed
1986 down by defining the server name of the nickname.
1988 It is also possible to search the user by Client ID. If <Client ID>
1989 is provided server must use it as the search value instead of
1990 the <nickname>. One of the arguments must be given. It is also
1991 possible to define multiple Client ID's to search multiple users
1992 sending only one IDENTIFY command. In this case the Client ID's are
1993 appended as normal arguments. The server replies in this case
1994 with only one reply message for all requested users.
1996 To prevent miss-use of this service wildcards in the nickname
1997 or in the servername are not permitted. It is not allowed
1998 to request all users on some server. The IDENTIFY requests must
1999 be based on specific nickname request.
2001 Implementations may not want to give interface access to this
2002 command as it is hardly a command that would be used by an end user.
2003 However, it must be implemented as it is used with private message
2006 The IDENTIFY must be always sent to the router by server so that
2007 all users are searched. However, server must still search its
2008 locally connected clients.
2010 Reply messages to the command:
2013 Arguments: (1) <Status Payload> (2) <Client ID>
2014 (3) [<nickname>[@<server>]] (4) [<username@host>]
2016 This command may reply with several command reply messages to form
2017 a list of results. In this case the status payload will include
2018 STATUS_LIST_START status in the first reply and STATUS_LIST_END in
2019 the last reply to indicate the end of the list. If there are only
2020 one reply the status is set to normal STATUS_OK.
2022 The command replies with Client ID of the nickname and if more
2023 information is available it may reply with nickname and username
2024 and hostname. If the <count> option were defined in the query
2025 there will be only <count> many replies from the server.
2030 SILC_STATUS_LIST_START
2031 SILC_STATUS_LIST_END
2032 SILC_STATUS_ERR_NO_SUCH_NICK
2033 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2034 SILC_STATUS_ERR_WILDCARDS
2035 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2036 SILC_STATUS_ERR_TOO_MANY_PARAMS
2042 Arguments: (1) <nickname>
2044 Set/change nickname. This command is used to set nickname for
2045 user. There is no limit of the length of the nickname in SILC.
2046 Nickname must not include any spaces (` '), non-printable
2047 characters, commas (`,') and any wildcard characters. Note:
2048 nicknames in SILC are case-sensitive which must be taken into
2049 account when searching clients by nickname.
2051 When nickname is changed new Client ID is generated. Server must
2052 distribute SILC_NOTIFY_TYPE_NICK_CHANGE to local clients on the
2053 channels (if any) the client is joined on. Then it must send
2054 SILC_PACKET_REPLACE_ID to its primary route to replace the old
2055 Client ID with the new one.
2057 Reply messages to the command:
2060 Arguments: (1) <Status Payload> (2) <New ID Payload>
2062 This command is replied always with New ID Payload that is
2063 generated by the server every time user changes their nickname.
2064 Client receiving this payload must start using the received
2065 Client ID as its current valid Client ID. The New ID Payload
2066 is described in [SILC2].
2071 SILC_STATUS_ERR_WILDCARDS
2072 SILC_STATUS_ERR_NICKNAME_IN_USE
2073 SILC_STATUS_ERR_BAD_NICKNAME
2074 SILC_STATUS_ERR_NOT_REGISTERED
2075 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2076 SILC_STATUS_ERR_TOO_MANY_PARAMS
2082 Arguments: (1) [<Channel ID>] [<server>]
2084 The list command is used to list channels and their topics on
2085 current server. If the <Channel ID> parameter is used, only the
2086 status of that channel is displayed. Secret channels are not
2087 listed at all. Private channels are listed with status indicating
2088 that the channel is private.
2090 If the <server> argument is specified the specified server's
2091 channels are listed. In this case the command must be sent to
2092 the server who owns the channel that was requested.
2094 Reply messages to the command:
2097 Arguments: (1) <Status Payload> (2) <Channel ID>
2098 (3) <channel> (4) <topic>
2100 This command may reply with several command reply messages to form
2101 a list of results. In this case the status payload will include
2102 STATUS_LIST_START status in the first reply and STATUS_LIST_END in
2103 the last reply to indicate the end of the list. If there are only
2104 one reply the status is set to normal STATUS_OK.
2106 This command replies with Channel ID, name and the topic of the
2107 channel. If the channel is private channel the <topic> includes
2113 SILC_STATUS_LIST_START
2114 SILC_STATUS_LIST_END
2115 SILC_STATUS_ERR_WILDCARDS
2116 SILC_STATUS_ERR_NOT_REGISTERED
2117 SILC_STATUS_ERR_TOO_MANY_PARAMS
2118 SILC_STATUS_ERR_NO_SUCH_CHANNEL
2119 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2120 SILC_STATUS_ERR_NO_SUCH_SERVER
2123 6 SILC_COMMAND_TOPIC
2126 Arguments: (1) <Channel ID> (2) [<topic>]]
2128 This command is used to change or view the topic of a channel.
2129 The topic for channel <Channel ID> is returned if there is no
2130 <topic> given. If the <topic> parameter is present, the topic
2131 for that channel will be changed, if the channel modes permit
2134 Reply messages to the command:
2137 Arguments: (1) <Status Payload> (2) <Channel ID>
2140 The command may reply with the topic of the channel if it is
2146 SILC_STATUS_ERR_NOT_ON_CHANNEL
2147 SILC_STATUS_ERR_WILDCARDS
2148 SILC_STATUS_ERR_NOT_REGISTERED
2149 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2150 SILC_STATUS_ERR_NO_SUCH_CHANNEL
2151 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2152 SILC_STATUS_ERR_NO_CHANNEL_ID
2153 SILC_STATUS_ERR_BAD_CHANNEL_ID
2154 SILC_STATUS_ERR_TOO_MANY_PARAMS
2155 SILC_STATUS_ERR_NO_CHANNEL_PRIV
2158 7 SILC_COMMAND_INVITE
2161 Arguments: (1) <Client ID> (2) <Channel ID>
2163 This command is used to invite other clients to join to the
2164 channel. The <Client ID> argument is the target client's ID that
2165 is being invited. The <Channel ID> is the Channel ID of the
2166 requested channel. The sender of this command must be on the
2167 channel. This command must fail if the requested channel does
2168 not exist, the requested client is already on the channel or if
2169 the channel is invite only channel and the caller of this command
2170 does not have at least channel operator privileges.
2172 Reply messages to the command:
2175 Arguments: (1) <Status Payload>
2177 This command replies only with Status Payload.
2182 SILC_STATUS_ERR_NOT_REGISTERED
2183 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2184 SILC_STATUS_ERR_TOO_MANY_PARAMS
2185 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2186 SILC_STATUS_ERR_NO_CLIENT_ID
2187 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2188 SILC_STATUS_ERR_NO_CHANNEL_ID
2189 SILC_STATUS_ERR_NOT_ON_CHANNEL
2190 SILC_STATUS_ERR_USER_ON_CHANNEL
2196 Arguments: (1) [<quit message>]
2198 This command is used by client to end SILC session. The server
2199 must close the connection to a client which sends this command.
2200 if <quit message> is given it will be sent to other clients on
2201 channel if the client is on channel when quitting.
2203 Reply messages to the command:
2205 This command does not reply anything.
2211 Arguments: (1) <Client ID> (2) [<comment>]
2213 This command is used by SILC operators to remove a client from
2214 SILC network. The removing has temporary effects and client may
2215 reconnect to SILC network. The <Client ID> is the client to be
2216 removed from SILC. The <comment> argument may be provided to
2217 give to the removed client some information why it was removed
2220 Reply messages to the command:
2223 Arguments: (1) <Status Payload>
2225 This command replies only with Status Payload.
2230 SILC_STATUS_ERR_WILDCARDS
2231 SILC_STATUS_ERR_NOT_REGISTERED
2232 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2233 SILC_STATUS_ERR_TOO_MANY_PARAMS
2234 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2235 SILC_STATUS_ERR_NO_CLIENT_ID
2236 SILC_STATUS_ERR_NO_ROUTER_PRIV
2239 10 SILC_COMMAND_INFO
2242 Arguments: (1) [<server>]
2244 This command is used to fetch various information about a server.
2245 If <server> argument is specified the command must be sent to
2246 the requested server.
2248 Reply messages to the command:
2251 Arguments: (1) <Status Payload> (2) <Server ID>
2254 This command replies with the Server ID of the server and a
2255 string which tells the information about the server.
2260 SILC_STATUS_ERR_WILDCARDS
2261 SILC_STATUS_ERR_NOT_REGISTERED
2262 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2263 SILC_STATUS_ERR_TOO_MANY_PARAMS
2264 SILC_STATUS_ERR_NO_SUCH_SERVER
2267 11 SILC_COMMAND_CONNECT
2270 Arguments: (1) <remote server/router> (2) [<port>]
2272 This command is used by operators to force a server to try to
2273 establish a new connection to remote server or router. The
2274 Operator must specify the server/router to be connected by
2275 setting <remote server> argument. The port is 32 bit MSB value.
2277 Reply messages to the command:
2280 Arguments: (1) <Status Payload>
2282 This command replies only with Status Payload.
2289 SILC_STATUS_ERR_WILDCARDS
2290 SILC_STATUS_ERR_NOT_REGISTERED
2291 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2292 SILC_STATUS_ERR_TOO_MANY_PARAMS
2293 SILC_STATUS_ERR_NO_SERVER_PRIV
2294 SILC_STATUS_ERR_NO_ROUTER_PRIV
2297 12 SILC_COMMAND_PING
2300 Arguments: (1) <Server ID>
2302 This command is used by client and server to test the communication
2303 channel to its server if one suspects that the communication is not
2304 working correctly. The <Server ID> is the ID of the server the
2305 sender is connected to.
2307 Reply messages to the command:
2310 Arguments: (1) <Status Payload>
2312 This command replies only with Status Payload. Server returns
2313 SILC_STATUS_OK in Status Payload if pinging was successful.
2320 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2321 SILC_STATUS_ERR_TOO_MANY_PARAMS
2322 SILC_STATUS_ERR_NO_SERVER_ID
2323 SILC_STATUS_ERR_NO_SUCH_SERVER
2324 SILC_STATUS_ERR_NOT_REGISTERED
2327 13 SILC_COMMAND_OPER
2330 Arguments: (1) <username> (2) <authentication data>
2332 This command is used by normal client to obtain server operator
2333 privileges on some server or router. Note that router operator
2334 has router privileges that supersedes the server operator
2335 privileges and this does not obtain those privileges. Client
2336 must use SILCOPER command to obtain router level privileges.
2338 The <username> is the username set in the server configurations
2339 as operator. The <authentication data> is the data that the
2340 client is authenticated against. It may be passphrase prompted
2341 for user on client's screen or it may be public key
2342 authentication data (data signed with private key), or
2345 Reply messages to the command:
2348 Arguments: (1) <Status Payload>
2350 This command replies only with Status Payload.
2355 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2356 SILC_STATUS_ERR_TOO_MANY_PARAMS
2357 SILC_STATUS_ERR_NOT_REGISTERED
2358 SILC_STATUS_ERR_BAD_PASSWORD
2359 SILC_STATUS_ERR_AUTH_FAILED
2362 14 SILC_COMMAND_JOIN
2365 Arguments: (1) <channel> (2) <Client ID>
2366 (3) [<passphrase>] (4) [<cipher>]
2368 Join to channel/create new channel. This command is used to
2369 join to a channel. If the channel does not exist the channel is
2370 created. If server is normal server this command must be sent
2371 to router who will create the channel. The channel may be
2372 protected with passphrase. If this is the case the passphrase
2373 must be sent along the join command.
2375 The name of the <channel> must not include any spaces (` '),
2376 non-printable characters, commas (`,') or any wildcard characters.
2378 The second argument <Client ID> is the Client ID of the client who
2379 is joining to the client. When client sends this command to the
2380 server the <Client ID> must be the client's own ID.
2382 Cipher to be used to secure the traffic on the channel may be
2383 requested by sending the name of the requested <cipher>. This
2384 is used only if the channel does not exist and is created. If
2385 the channel already exists the cipher set previously for the
2386 channel will be used to secure the traffic.
2388 The server must check whether the user is allowed to join to
2389 the requested channel. Various modes set to the channel affect
2390 the ability of the user to join the channel. These conditions
2393 o The user must be invited to the channel if the channel
2394 is invite-only channel.
2396 o The Client ID/nickname/username/hostname must not match
2399 o The correct passphrase must be provided if passphrase
2400 is set to the channel.
2402 o The user count limit, if set, must not be reached.
2404 Reply messages to the command:
2407 Arguments: (1) <Status Payload> (2) <channel>
2408 (3) <Channel ID> (4) <channel mode mask>
2409 (5) <created> (6) <Channel Key Payload>
2410 (7) [<ban mask>] (8) [<invite list>]
2413 This command replies with the channel name requested by the
2414 client, channel ID of the channel and topic of the channel
2415 if it exists. It also replies with the channel mode mask
2416 which tells all the modes set on the channel. If the
2417 channel is created the mode mask is zero (0). If ban mask
2418 and/or invite list is set they are sent as well.
2420 Client receives the channel key in the reply message as well
2421 inside <Channel Key Payload>.
2426 SILC_STATUS_ERR_WILDCARDS
2427 SILC_STATUS_ERR_NOT_REGISTERED
2428 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2429 SILC_STATUS_ERR_TOO_MANY_PARAMS
2430 SILC_STATUS_ERR_BAD_PASSWORD
2431 SILC_STATUS_ERR_CHANNEL_IS_FULL
2432 SILC_STATUS_ERR_NOT_INVITED
2433 SILC_STATUS_ERR_BANNED_FROM_CHANNEL
2434 SILC_STATUS_ERR_BAD_CHANNEL
2435 SILC_STATUS_ERR_USER_ON_CHANNEL
2438 15 SILC_COMMAND_MOTD
2441 Arguments: (1) <server>
2443 This command is used to query the Message of the Day of the server.
2445 Reply messages to the command:
2448 Arguments: (1) <Status Payload> (2) [<motd>]
2450 This command replies with the motd message if it exists.
2455 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2456 SILC_STATUS_ERR_TOO_MANY_PARAMS
2457 SILC_STATUS_ERR_NOT_REGISTERED
2458 SILC_STATUS_ERR_NO_SUCH_SERVER
2461 16 SILC_COMMAND_UMODE
2464 Arguments: (1) <Client ID> (2) <client mode mask>
2466 This command is used by client to set/unset modes for itself.
2467 However, there are some modes that the client may not set itself,
2468 but they will be set by server. However, client may unset any
2469 mode. Modes may be masked together ORing them thus having
2470 several modes set. Client must keep its client mode mask
2471 locally so that the mode setting/unsetting would work without
2472 problems. Client may change only its own modes.
2474 Following client modes are defined:
2476 0x0000 SILC_UMODE_NONE
2478 No specific mode for client. This is the initial
2479 setting when new client is created. The client is
2483 0x0001 SILC_UMODE_SERVER_OPERATOR
2485 Marks the user as server operator. Client cannot
2486 set this mode itself. Server sets this mode to the
2487 client when client attains the server operator
2488 privileges by SILC_COMMAND_OPER command. Client
2489 may unset the mode itself.
2492 0x0002 SILC_UMODE_ROUTER_OPERATOR
2494 Marks the user as router (SILC) operator. Client
2495 cannot this mode itself. Router sets this mode to
2496 the client when client attains the router operator
2497 privileges by SILC_COMMAND_SILCOPER command. Client
2498 may unset the mode itself.
2500 Reply messages to the command:
2503 Arguments: (1) <Status Payload> (2) <client mode mask>
2505 This command replies with the changed client mode mask that
2506 the client is required to keep locally.
2512 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2513 SILC_STATUS_ERR_TOO_MANY_PARAMS
2514 SILC_STATUS_ERR_NOT_REGISTERED
2515 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2516 SILC_STATUS_ERR_BAD_CLIENT_ID
2517 SILC_STATUS_ERR_NOT_YOU
2518 SILC_STATUS_ERR_UNKNOWN_MODE
2519 SILC_STATUS_ERR_NO_RECIPIENT
2520 SILC_STATUS_ERR_NO_CLIENT_ID
2523 17 SILC_COMMAND_CMODE
2526 Arguments: (1) <Channel ID> (2) <channel mode mask>
2527 (3) [<user limit>] (4) [<passphrase>]
2528 (5) [<ban mask>] (6) [<invite list>]
2529 (7) [<cipher>[:<key len>]]
2531 This command is used by client to set or change channel flags on
2532 a channel. Channel has several modes that set various properties
2533 of a channel. Modes may be masked together by ORing them thus
2534 having several modes set. The <Channel ID> is the ID of the
2535 target channel. The client changing channel mode must be on
2536 the same channel and poses sufficient privileges to be able to
2539 When the mode is changed SILC_NOTIFY_TYPE_CMODE_CHANGE notify
2540 type is distributed to the channel.
2542 Following channel modes are defined:
2544 0x0000 SILC_CMODE_NONE
2546 No specific mode on channel. This is the default when
2547 channel is created. This means that channel is just plain
2551 0x0001 SILC_CMODE_PRIVATE
2553 Channel is private channel. Private channels are shown
2554 in the channel list listed with SILC_COMMAND_LIST command
2555 with indication that the channel is private. Also,
2556 client on private channel will no be detected to be on
2557 the channel as the channel is not shown in the client's
2558 currently joined channel list. Channel founder and
2559 channel operator may set/unset this mode.
2561 Typical implementation would use [+|-]p on user interface
2562 to set/unset this mode.
2565 0x0002 SILC_CMODE_SECRET
2567 Channel is secret channel. Secret channels are not shown
2568 in the list listed with SILC_COMMAND_LIST command. Secret
2569 channels can be considered to be invisible channels.
2570 Channel founder and channel operator may set/unset this
2573 Typical implementation would use [+|-]s on user interface
2574 to set/unset this mode.
2577 0x0004 SILC_CMODE_PRIVKEY
2579 Channel uses private channel key to protect the traffic
2580 on the channel. When this mode is set the client will be
2581 responsible to set the key it wants to use to encrypt and
2582 decrypt the traffic on channel. Server generated channel
2583 keys are not used at all. This mode provides additional
2584 security as clients on channel may agree to use private
2585 channel key that even servers do not know. Naturally,
2586 this requires that every client on the channel knows
2587 the key before hand (it is considered to be pre-shared-
2588 key). This specification does not define how the private
2589 channel key is set as it is entirely local setting on
2592 As it is local setting it is possible to have several
2593 private channel keys on one channel. In this case several
2594 clients can talk on same channel but only those clients
2595 that share the key with the message sender will be able
2596 to hear the talking. Client should not display those
2597 message for the end user that it is not able to decrypt
2598 when this mode is set.
2600 Only channel founder may set/unset this mode. If this
2601 mode is unset the server will distribute new channel
2602 key to all clients on the channel which will be used
2605 Typical implementation would use [+|-]k on user interface
2606 to set/unset this mode.
2609 0x0008 SILC_CMODE_INVITE
2611 Channel is invite only channel. Client may join to this
2612 channel only if it is invited to the channel. Channel
2613 founder and channel operator may set/unset this mode.
2615 Typical implementation would use [+|-]i on user interface
2616 to set/unset this mode.
2619 0x0010 SILC_CMODE_TOPIC
2621 The topic of the channel may only be set by client that
2622 is channel founder or channel operator. Normal clients
2623 on channel will not be able to set topic when this mode
2624 is set. Channel founder and channel operator may set/
2627 Typical implementation would use [+|-]t on user interface
2628 to set/unset this mode.
2631 0x0020 SILC_CMODE_ULIMIT
2633 User limit has been set to the channel. New clients
2634 may not join to the channel when the limit set is
2635 reached. Channel founder and channel operator may set/
2636 unset the limit. The <user limit> argument is the
2637 number of limited users.
2639 Typical implementation would use [+|-]l on user interface
2640 to set/unset this mode.
2643 0x0040 SILC_CMODE_PASSPHRASE
2645 Passphrase has been set to the channel. Client may
2646 join to the channel only if it is able to provide the
2647 correct passphrase. Setting passphrases to channel
2648 is entirely safe as all commands are protected in the
2649 SILC network. Only channel founder may set/unset
2650 the passphrase. The <passphrase> argument is the
2653 Typical implementation would use [+|-]a on user interface
2654 to set/unset this mode.
2657 0x0080 SILC_CMODE_BAN
2659 Ban mask has been set to the channel. The ban mask
2660 may be used to ban specific clients to join the channel.
2661 The <ban mask> argument is the set ban mask. When
2662 unsetting a ban mask the mask must be provided as
2663 argument. Channel founder and channel operator may
2664 set/unset this mode. Channel founder may not be
2665 added to the ban list. <ban mask> is an comma (`,')
2666 separated list of banned clients in the following format:
2668 [<nickname>[@<server>]!][<username>]@[<hostname>]
2670 Wildcards maybe used when banning clients.
2672 Typical implementation would use [+|-]b on user interface
2673 to set/unset this mode.
2676 0x0100 SILC_CMODE_INVITE_LIST
2678 Invite list has been set to the channel. The invite list
2679 can be used to mark the clients that is able to join
2680 channel without being invited when the channel is set to
2681 be invite-only channel. The <invite list> argument is the
2682 set invite mask. When unsetting entry from the invite list
2683 the entry must be provided as argument. Channel founder and
2684 channel operator may set/unset this mode. The <invite list>
2685 is command (`,') separated list of invited clients in the
2688 [<nickname>[@<server>]!][<username>]@[<hostname>]
2690 Wildcards maybe used when setting the invite list.
2692 Typical implementation would use [+|-]I on user interface
2693 to set/unset this mode.
2696 0x0200 SILC_CMODE_CIPHER
2698 Sets specific cipher to be used to protect channel
2699 traffic. The <cipher> argument is the requested cipher.
2700 When set or unset the server must re-generate new
2701 channel key. If <key len> argument is specified with
2702 <cipher> argument the new key is generated of <key len>
2703 length in bits. Only channel founder may set the cipher of
2704 the channel. When unset the new key is generated using
2705 default cipher for the channel.
2707 Typical implementation would use [+|-]c on user interface
2708 to set/unset this mode.
2711 To make the mode system work, client must keep the channel mode
2712 mask locally so that the mode setting and unsetting would work
2713 without problems. The client receives the initial channel mode
2714 mask when it joins to the channel. When the mode changes on
2715 channel the servers distributes the changed channel mode mask to
2716 all clients on the channel by sending SILC_NOTIFY_TYPE_CMODE_CHANGE
2720 Reply messages to the command:
2723 Arguments: (1) <Status Payload> (2) <channel mode mask>
2725 This command replies with the changed channel mode mask that
2726 client is required to keep locally.
2731 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2732 SILC_STATUS_ERR_TOO_MANY_PARAMS
2733 SILC_STATUS_ERR_NOT_REGISTERED
2734 SILC_STATUS_ERR_NOT_ON_CHANNEL
2735 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2736 SILC_STATUS_ERR_BAD_CHANNEL_ID
2737 SILC_STATUS_ERR_NO_CHANNEL_ID
2738 SILC_STATUS_ERR_NO_CHANNEL_PRIV
2739 SILC_STATUS_ERR_UNKNOWN_MODE
2740 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2743 19 SILC_COMMAND_CUMODE
2746 Arguments: (1) <Channel ID> (2) <mode mask>
2749 This command is used by client to change channel user modes on
2750 channel. Users on channel may have some special modes and this
2751 command is used by channel operators to set or change these modes.
2752 The <Channel ID> is the ID of the target channel. The <mode mask>
2753 is OR'ed mask of modes. The <Client ID> is the target client.
2754 The client changing channel user modes must be on the same channel
2755 as the target client and poses sufficient privileges to be able to
2758 When the mode is changed SILC_NOTIFY_TYPE_CUMODE_CHANGE notify
2759 type is distributed to the channel.
2761 Following channel modes are defined:
2763 0x0000 SILC_CUMODE_NONE
2765 No specific mode. This is the normal situation for client.
2766 Also, this is the mode set when removing all modes from client.
2769 0x0001 SILC_CUMODE_FOUNDER
2771 The client is channel founder of the channel. This mode
2772 cannot be set by other client, it is set by the server when
2773 the channel was founded (created). The mode is provided
2774 because client may remove the founder rights from itself.
2777 0x0002 SILC_CUMODE_OPERATOR
2779 Sets channel operator privileges on the channel for a
2780 client on the channel. Channel founder and channel operator
2781 may set/unset (promote/demote) this mode.
2784 Reply messages to the command:
2787 Arguments: (1) <Status Payload> (2) <channel user mode mask>
2790 This command replies with the changed channel user mode mask that
2791 client is required to keep locally. The <Client ID> is the target
2797 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2798 SILC_STATUS_ERR_TOO_MANY_PARAMS
2799 SILC_STATUS_ERR_NOT_REGISTERED
2800 SILC_STATUS_ERR_NOT_ON_CHANNEL
2801 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2802 SILC_STATUS_ERR_BAD_CHANNEL_ID
2803 SILC_STATUS_ERR_NO_CHANNEL_ID
2804 SILC_STATUS_ERR_NO_CHANNEL_PRIV
2805 SILC_STATUS_ERR_UNKNOWN_MODE
2806 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2809 19 SILC_COMMAND_KICK
2812 Arguments: (1) <Channel ID> (2) <Client ID>
2815 This command is used by channel operators to remove a client from
2816 channel. The <channel> argument is the channel the client to be
2817 removed is on currently. Note that the "kicker" must be on the same
2818 channel. If <comment> is provided it will be sent to the removed
2821 Reply messages to the command:
2824 Arguments: (1) <Status Payload>
2826 This command replies only with Status Payload.
2831 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2832 SILC_STATUS_ERR_TOO_MANY_PARAMS
2833 SILC_STATUS_ERR_NOT_REGISTERED
2834 SILC_STATUS_ERR_NO_SUCH_CHANNEL
2835 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2836 SILC_STATUS_ERR_NO_CHANNEL_PRIV
2837 SILC_STATUS_ERR_NO_CLIENT_ID
2840 20 SILC_COMMAND_RESTART
2845 This command may only be used by server operator to force a
2846 server to restart itself.
2848 Reply messages to the command:
2851 Arguments: (1) <Status Payload>
2853 This command replies only with Status Payload.
2858 SILC_STATUS_ERR_NOT_REGISTERED
2859 SILC_STATUS_ERR_NO_SERVER_PRIV
2865 21 SILC_COMMAND_CLOSE
2868 Arguments: (1) <remote server/router> (2) [<port>]
2870 This command is used only by operator to close connection to a
2873 Reply messages to the command:
2876 Arguments: (1) <Status Payload>
2878 This command replies only with Status Payload.
2883 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2884 SILC_STATUS_ERR_TOO_MANY_PARAMS
2885 SILC_STATUS_ERR_NOT_REGISTERED
2886 SILC_STATUS_ERR_NO_SUCH_SERVER
2887 SILC_STATUS_ERR_NO_SERVER_PRIV
2888 SILC_STATUS_ERR_NO_SUCH_SERVER_ID
2891 22 SILC_COMMAND_SHUTDOWN
2896 This command is used only by operator to shutdown the server.
2897 All connections to the server will be closed and the server is
2900 Reply messages to the command:
2905 Arguments: (1) <Status Payload>
2907 This command replies only with Status Payload.
2912 SILC_STATUS_ERR_NOT_REGISTERED
2913 SILC_STATUS_ERR_NO_SERVER_PRIV
2916 23 SILC_COMMAND_SILCOPER
2919 Arguments: (1) <username> (2) <authentication data>
2921 This command is used by normal client to obtain router operator
2922 privileges (also known as SILC operator) on some router. Note
2923 that router operator has router privileges that supersedes the
2924 server operator privileges.
2926 The <username> is the username set in the server configurations
2927 as operator. The <authentication data> is the data that the
2928 client is authenticated against. It may be passphrase prompted
2929 for user on client's screen or it may be public key
2930 authentication data (data signed with private key), or
2933 Difference between router operator and server operator is that
2934 router operator is able to handle cell level properties while
2935 server operator (even on router server) is able to handle only
2936 local properties, such as, local connections and normal server
2939 Reply messages to the command:
2942 Arguments: (1) <Status Payload>
2944 This command replies only with Status Payload.
2949 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2950 SILC_STATUS_ERR_TOO_MANY_PARAMS
2951 SILC_STATUS_ERR_NOT_REGISTERED
2952 SILC_STATUS_ERR_BAD_PASSWORD
2953 SILC_STATUS_ERR_AUTH_FAILED
2956 24 SILC_COMMAND_LEAVE
2959 Arguments: (1) <Channel ID>
2961 This command is used by client to leave a channel the client is
2962 joined to. After a client has leaved the channel the server
2963 must create new key for the channel and distribute to all clients
2964 still currently on the channel.
2966 Reply messages to the command:
2969 Arguments: (1) <Status Payload>
2971 This command replies only with Status Payload.
2976 SILC_STATUS_ERR_NOT_REGISTERED
2977 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2978 SILC_STATUS_ERR_TOO_MANY_PARAMS
2979 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2980 SILC_STATUS_ERR_BAD_CHANNEL_ID
2981 SILC_STATUS_ERR_NO_CHANNEL_ID
2984 25 SILC_COMMAND_USERS
2987 Arguments: (1) <Channel ID>
2989 This command is used to list user names currently on the requested
2990 channel; argument <Channel ID>. The server must resolve the
2991 user names and send a comma (`,') separated list of user names
2992 on the channel. Server or router may resolve the names by sending
2993 SILC_COMMAND_WHOIS commands.
2995 If the requested channel is a private or secret channel, this
2996 command must not send the list of users, as private and secret
2997 channels cannot be seen by outside. In this case the returned
2998 name list may include a indication that the server could not
2999 resolve the names of the users on the channel. Also, in this case
3000 Client ID's or client modes are not sent either.
3002 Reply messages to the command:
3005 Arguments: (1) <Status Payload> (2) <Channel ID>
3006 (3) <list count> (4) <Client ID list>
3007 (5) <client mode list>
3009 This command replies with the Channel ID of the requested channel
3010 Client ID list of the users on the channel and list of their modes.
3011 The Client ID list has Client ID's of all users in the list. The
3012 <Client ID list> is formed by adding Client ID's one after another.
3013 The <client mode list> is formed by adding client's user modes on
3014 the channel one after another (4 bytes (32 bits) each). The <list
3015 count> of length of 4 bytes (32 bits), tells the number of entries
3016 in the lists. Both lists must have equal number of entries.
3021 SILC_STATUS_ERR_NOT_REGISTERED
3022 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
3023 SILC_STATUS_ERR_TOO_MANY_PARAMS
3024 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
3025 SILC_STATUS_ERR_BAD_CHANNEL_ID
3026 SILC_STATUS_ERR_NO_CHANNEL_ID
3027 SILC_STATUS_ERR_NOT_ON_CHANNEL
3032 Currently undefined commands.
3037 These commands are reserved for private use and will not be defined
3041 255 SILC_COMMAND_MAX
3043 Reserved command. This must not be sent.
3048 5.3 SILC Command Status Types
3051 5.3.1 SILC Command Status Payload
3053 Command Status Payload is sent in command reply messages to indicate
3054 the status of the command. The payload is one of argument in the
3055 command thus this is the data area in Command Argument Payload described
3056 in [SILC2]. The payload is only 2 bytes of length. Following diagram
3057 represents the Command Status Payload (field is always in MSB order).
3066 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
3067 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3069 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3073 Figure 6: SILC Command Status Payload
3077 o Status Message (2 bytes) - Indicates the status message.
3078 All Status messages are described in the next section.
3083 5.3.2 SILC Command Status List
3085 Command Status messages are returned in the command reply messages
3086 to indicate whether the command were executed without errors. If error
3087 has occured the status tells which error occured. Status payload only
3088 sends numeric reply about the status. Receiver of the payload must
3089 convert the numeric values into human readable error messages. The
3090 list of status messages below has an example human readable error
3091 messages that client may display for the user.
3093 List of all defined command status messages following.
3096 Generic status messages:
3100 Ok status. Everything went Ok. The status payload maybe
3101 safely ignored in this case.
3103 1 SILC_STATUS_LIST_START
3105 Start of the list. There will be several command replies and
3106 this reply is the start of the list.
3108 2 SILC_STATUS_LIST_ITEM
3110 Item in the list. This is one of the item in the list but not the
3113 3 SILC_STATUS_LIST_END
3115 End of the list. There were several command replies and this
3116 reply is the last of the list. There won't be other replies
3117 belonging to this list after this one.
3121 Currently undefined and has been reserved for the future.
3124 Error status message:
3126 10 SILC_STATUS_ERR_NO_SUCH_NICK
3128 "No such nickname". Requested nickname does not exist.
3130 11 SILC_STATUS_ERR_NO_SUCH_CHANNEL
3132 "No such channel". Requested channel name does not exist.
3134 12 SILC_STATUS_ERR_NO_SUCH_SERVER
3136 "No such server". Requested server name does not exist.
3138 13 SILC_STATUS_ERR_TOO_MANY_TARGETS
3140 "Duplicate recipients. No message delivered". Message were
3141 tried to be sent to recipient which has several occurrences in
3144 14 SILC_STATUS_ERR_NO_RECIPIENT
3146 "No recipient given". Command required recipient which was
3149 15 SILC_STATUS_ERR_UNKNOWN_COMMAND
3151 "Unknown command". Command sent to server is unknown by the
3154 16 SILC_STATUS_ERR_WILDCARDS
3156 "Wildcards cannot be used". Wildcards were provided but they
3159 17 SILC_STATUS_ERR_NO_CLIENT_ID
3161 "No Client ID given". Client ID were expected as command
3162 parameter but were not found.
3164 18 SILC_STATUS_ERR_NO_CHANNEL_ID
3166 "No Channel ID given". Channel ID were expected as command
3167 parameter but were not found.
3169 19 SILC_STATUS_ERR_NO_SERVER_ID
3171 "No Serve ID given". Server ID were expected as command
3172 parameter but were not found.
3174 20 SILC_STATUS_ERR_BAD_CLIENT_ID
3176 "Bad Client ID". Client ID provided were erroneous.
3178 21 SILC_STATUS_ERR_BAD_CHANNEL_ID
3180 "Bad Channel ID". Channel ID provided were erroneous.
3182 22 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
3184 "No such Client ID". Client ID provided does not exist.
3186 23 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
3188 "No such Channel ID". Channel ID provided does not exist.
3190 24 SILC_STATUS_ERR_NICKNAME_IN_USE
3192 "Nickname already exists". Nickname created could not be
3193 registered because number of same nicknames were already set to
3194 maximum. This is not expected to happen in real life but is
3197 25 SILC_STATUS_ERR_NOT_ON_CHANNEL
3199 "You are not on that channel". The command were specified for
3200 channel user is not currently on.
3202 26 SILC_STATUS_ERR_USER_NOT_ON_CHANNEL
3204 "They are not on channel". The requested target client is not
3205 on requested channel.
3207 27 SILC_STATUS_ERR_USER_ON_CHANNEL
3209 "User already on channel". User were invited on channel they
3212 28 SILC_STATUS_ERR_NOT_REGISTERED
3214 "You have not registered". User executed command that requires
3215 the client to be registered on the server before it may be
3218 29 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
3220 "Not enough parameters". Command requires more parameters
3223 30 SILC_STATUS_ERR_TOO_MANY_PARAMS
3225 "Too many parameters". Too many parameters were provided
3228 31 SILC_STATUS_ERR_PERM_DENIED
3230 "Your host is not among the privileged". The client tried to
3231 register on server that does not allow this host to connect.
3233 32 SILC_STATUS_ERR_BANNED_FROM_SERVER
3235 "You are banned from this server". The client tried to register
3236 on server that has explicitly denied this host to connect.
3238 33 SILC_STATUS_ERR_BAD_PASSWORD
3240 "Cannot join channel. Incorrect password". Password provided for
3241 channel were not accepted.
3243 34 SILC_STATUS_ERR_CHANNEL_IS_FULL
3245 "Cannot join channel. Channel is full". The channel is full
3246 and client cannot be joined to it.
3248 35 SILC_STATUS_ERR_NOT_INVITED
3250 "Cannot join channel. You have not been invited". The channel
3251 is invite only channel and client has not been invited.
3253 36 SILC_STATUS_ERR_BANNED_FROM_CHANNEL
3255 "Cannot join channel. You have been banned". The client has
3256 been banned from the channel.
3258 37 SILC_STATUS_ERR_UNKNOWN_MODE
3260 "Unknown mode". Mode provided by the client were unknown to
3263 38 SILC_STATUS_ERR_NOT_YOU
3265 "Cannot change mode for other users". User tried to change
3266 someone else's mode.
3268 39 SILC_STATUS_ERR_NO_CHANNEL_PRIV
3270 "Permission denied. You are not channel operator". Command may
3271 be executed only by channel operator.
3273 40 SILC_STATUS_ERR_NO_CHANNEL_FOPRIV
3275 "Permission denied. You are not channel founder". Command may
3276 be executed only by channel operator.
3278 41 SILC_STATUS_ERR_NO_SERVER_PRIV
3280 "Permission denied. You are not server operator". Command may
3281 be executed only by server operator.
3283 42 SILC_STATUS_ERR_NO_ROUTER_PRIV
3285 "Permission denied. You are not SILC operator". Command may be
3286 executed only by router (SILC) operator.
3288 43 SILC_STATUS_ERR_BAD_NICKNAME
3290 "Bad nickname". Nickname requested contained illegal characters
3293 44 SILC_STATUS_ERR_BAD_CHANNEL
3295 "Bad channel name". Channel requested contained illegal characters
3298 45 SILC_STATUS_ERR_AUTH_FAILED
3300 "Authentication failed". The authentication data sent as
3301 argument were wrong and thus authentication failed.
3303 46 SILC_STATUS_ERR_UNKOWN_ALGORITHM
3305 "The algorithm was not supported." The server does not support the
3306 requested algorithm.
3311 6 Security Considerations
3313 Security is central to the design of this protocol, and these security
3314 considerations permeate the specification. Common security considerations
3315 such as keeping private keys truly private and using adequate lengths for
3316 symmetric and asymmetric keys must be followed in order to maintain the
3317 security of this protocol.
3323 [SILC2] Riikonen, P., "SILC Packet Protocol", Internet Draft,
3326 [SILC3] Riikonen, P., "SILC Key Exchange and Authentication
3327 Protocols", Internet Draft, June 2000.
3329 [IRC] Oikarinen, J., and Reed D., "Internet Relay Chat Protocol",
3332 [IRC-ARCH] Kalt, C., "Internet Relay Chat: Architecture", RFC 2810,
3335 [IRC-CHAN] Kalt, C., "Internet Relay Chat: Channel Management", RFC
3338 [IRC-CLIENT] Kalt, C., "Internet Relay Chat: Client Protocol", RFC
3341 [IRC-SERVER] Kalt, C., "Internet Relay Chat: Server Protocol", RFC
3344 [SSH-TRANS] Ylonen, T., et al, "SSH Transport Layer Protocol",
3347 [PGP] Callas, J., et al, "OpenPGP Message Format", RFC 2440,
3350 [SPKI] Ellison C., et al, "SPKI Certificate Theory", RFC 2693,
3353 [PKIX-Part1] Housley, R., et al, "Internet X.509 Public Key
3354 Infrastructure, Certificate and CRL Profile", RFC 2459,
3357 [Schneier] Schneier, B., "Applied Cryptography Second Edition",
3358 John Wiley & Sons, New York, NY, 1996.
3360 [Menezes] Menezes, A., et al, "Handbook of Applied Cryptography",
3363 [OAKLEY] Orman, H., "The OAKLEY Key Determination Protocol",
3364 RFC 2412, November 1998.
3366 [ISAKMP] Maughan D., et al, "Internet Security Association and
3367 Key Management Protocol (ISAKMP)", RFC 2408, November
3370 [IKE] Harkins D., and Carrel D., "The Internet Key Exchange
3371 (IKE)", RFC 2409, November 1998.
3373 [HMAC] Krawczyk, H., "HMAC: Keyed-Hashing for Message
3374 Authentication", RFC 2104, February 1997.
3376 [PKCS1] Kalinski, B., and Staddon, J., "PKCS #1 RSA Cryptography
3377 Specifications, Version 2.0", RFC 2437, October 1998.
3389 EMail: priikone@poseidon.pspt.fi
3391 This Internet-Draft expires 6 Jun 2001