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 to
447 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. Another difference is that there are no limit of the length
453 of the nickname in the SILC.
459 Client ID is used to identify users in the SILC network. The Client ID
460 is unique to the extent that there can be 2^128 different Client ID's.
461 Collisions are not expected to happen. The Client ID is defined as
465 128 bit Client ID based on IPv4 addresses:
467 32 bit ServerID IP address (bits 1-32)
469 88 bit Truncated MD5 hash value of the nickname
471 o Server ID IP address - Indicates the server where this
472 client is coming from. The IP address hence equals the
473 server IP address where to the client has connected.
475 o Random number - Random number to further randomize the
476 Client ID. This makes it possible to have 2^8 same
477 nicknames from the same server IP address.
479 o MD5 hash - MD5 hash value of the nickname is truncated
480 taking 88 bits from the start of the hash value. This
481 hash value is used to search the user's Client ID from
485 Collisions could occur when more than 2^8 clients using same nickname
486 from the same server IP address is connected to the SILC network.
487 Server must be able to handle this situation by refusing to accept
488 anymore of that nickname.
490 Another possible collision may happen with the truncated hash value of
491 the nickname. It could be possible to have same truncated hash value for
492 two different nicknames. However, this is not expected to happen nor
493 cause any problems if it would occur. Nicknames are usually logical and
494 it is unlikely to have two distinct logical nicknames produce same
495 truncated hash value.
501 Servers are the most important parts of the SILC network. They form the
502 basis of the SILC, providing a point to which clients may connect to.
503 There are two kinds of servers in SILC; normal servers and router servers.
504 This section focus on the normal server and router server is described
505 in the section 3.3 Router.
507 Normal servers may not directly connect to other normal server. Normal
508 servers may only directly connect to router server. If the message sent
509 by the client is destined outside the local server it is always sent to
510 the router server for further routing. Server may only have one active
511 connection to router on same port. Normal server may not connect to other
512 cell's router except in situations where its cell's router is unavailable.
514 Servers and routers in the SILC network are considered to be trusted.
515 With out a doubt, servers that are set to work on ports above 1023 are
516 not considered to be trusted. Also, the service provider acts important
517 role in the server's trustworthy.
521 3.2.1 Server's Local ID List
523 Normal server keeps various information about the clients and their end
524 users connected to it. Every normal server must keep list of all locally
525 connected clients, Client ID's, nicknames, usernames and hostnames and
526 user's real name. Normal servers only keeps local information and it
527 does not keep any global information. Hence, normal servers knows only
528 about their locally connected clients. This makes servers efficient as
529 they don't have to worry about global clients. Server is also responsible
530 of creating the Client ID's for their clients.
532 Normal server also keeps information about locally created channels and
536 Hence, local list for normal server includes:
539 server list - Router connection
550 client list - All clients in server
558 channel list - All channels in server
561 o Client ID's on channel
562 o Client ID modes on channel
571 Servers are distinguished from other servers by unique 64 bit Server ID.
572 The Server ID is used in the SILC to route messages to correct servers.
573 Server ID's also provide information for Client ID's, see section 3.1.1
574 Client ID. Server ID is defined as follows.
577 64 bit Server ID based on IPv4 addresses:
579 32 bit IP address of the server
583 o IP address of the server - This is the real IP address of
586 o Port - This is the port the server is bound to.
588 o Random number - This is used to further randomize the Server ID.
591 Collisions are not expected to happen in any conditions. The Server ID
592 is always created by the server itself and server is responsible of
593 distributing it to the router.
597 3.2.3 SILC Server Ports
599 Following ports has been assigned by IANA for the SILC protocol:
606 If there are needs to create new SILC networks in the future the port
607 numbers must be officially assigned by the IANA.
609 Server on network above privileged ports (>1023) should not be trusted
610 as they could have been set up by untrusted party.
616 Router server in SILC network is responsible for keeping the cell together
617 and routing messages to other servers and to other routers. Router server
618 is also a normal server thus clients may connect to it as it would be
619 just normal SILC server.
621 However, router servers has a lot of important tasks that normal servers
622 do not have. Router server knows everything about everything in the SILC.
623 They know all clients currently on SILC, all servers and routers and all
624 channels in SILC. Routers are the only servers in SILC that care about
625 global information and keeping them up to date at all time. And, this
626 is what they must do.
630 3.3.1 Router's Local ID List
632 Router server as well must keep local list of connected clients and
633 locally created channels. However, this list is extended to include all
634 the informations of the entire cell, not just the server itself as for
637 However, on router this list is a lot smaller since routers do not keep
638 information about user's nickname, username and hostname and real name
639 since these are not needed by the router. Router keeps only information
643 Hence, local list for router includes:
646 server list - All servers in the cell
653 client list - All clients in the cell
657 channel list - All channels in the cell
659 o Client ID's on channel
660 o Client ID modes on channel
665 Note that locally connected clients and other information include all the
666 same information as defined in section section 3.2.1 Server's Local ID
671 3.3.2 Router's Global ID List
673 Router server must also keep global list. Normal servers do not have
674 global list as they know only about local information. Global list
675 includes all the clients on SILC, their Client ID's, all created channels
676 and their Channel ID's and all servers and routers on SILC and their
677 Server ID's. That is said, global list is for global information and the
678 list must not include the local information already on the router's local
681 Note that the global list does not include information like nicknames,
682 usernames and hostnames or user's real names. Router does not keep
683 these informations as they are not needed by the router. This
684 information is available from the client's server which maybe queried
687 Hence, global list includes:
690 server list - All servers in SILC
696 client list - All clients in SILC
699 channel list - All channels in SILC
701 o Client ID's on channel
702 o Client ID modes on channel
707 3.3.3 Router's Server ID
709 Router's Server ID's are equivalent to normal Server ID's. As routers
710 are normal servers as well same types of ID's applies for routers as well.
711 Thus, see section 3.2.2 Server ID. Server ID's for routers are always
712 created by the remote router where the router is connected to.
718 A channel is a named group of one or more clients which will all receive
719 messages addressed to that channel. The channel is created when first
720 client requests JOIN command to the channel, and the channel ceases to
721 exist when the last client has left it. When channel exists, any client
722 can reference it using the name of the channel.
724 Channel names are unique although the real uniqueness comes from 64 bit
725 Channel ID that unifies each channel. However, channel names are still
726 unique and no two global channels with same name may exist. Channel name
727 is a string which begins with `#' character. There is no limit on the
728 length of the channel name. Channel names may not contain any spaces
729 (` '), any non-printable ASCII characters, commas (`,') and wildcard
732 Channels can have operators that can administrate the channel and
733 operate all of its modes. Following operators on channel exist on SILC
737 o Channel founder - When channel is created the joining client becomes
738 channel founder. Channel founder is channel operator with some more
739 privileges. Basically, channel founder can fully operate the channel
740 and all of its modes. The privileges are limited only to the particular
741 channel. There can be only one channel founder per channel. Channel
742 founder supersedes channel operator's privileges.
744 Channel founder privileges cannot be removed by any other operator on
745 channel. When channel founder leaves the channel there is no channel
746 founder on the channel. Channel founder also cannot be removed by
747 force from the channel.
749 o Channel operator - When client joins to channel that has not existed
750 previously it will become automatically channel operator (and channel
751 founder discussed above). Channel operator is able administrate the
752 channel, set some modes on channel, remove a badly behaving client from
753 the channel and promote other clients to become channel operator.
754 The privileges are limited only to the particular channel.
756 Normal channel user may be promoted (opped) to channel operator
757 gaining channel operator privileges. Channel founder or other channel
758 operator may also demote (deop) channel operator to normal channel
766 Channels are distinguished from other channels by unique Channel ID.
767 The Channel ID is a 64 bit ID and collisions are not expected to happen
768 in any conditions. Channel names are just for logical use of channels.
769 The Channel ID is created by the server where the channel is created.
770 The Channel ID is defined as follows.
773 64 bit Channel ID based on IPv4 addresses:
775 32 bit Router's Server ID IP address (bits 1-32)
776 16 bit Router's Server ID port (bits 33-48)
779 o Router's Server ID IP address - Indicates the IP address of
780 the router of the cell where this channel is created. This is
781 taken from the router's Server ID. This way SILC router knows
782 where this channel resides in the SILC network.
784 o Router's Server ID port - Indicates the port of the channel on
785 the server. This is taken from the router's Server ID.
787 o Random number - To further randomize the Channel ID. This makes
788 sure that there are no collisions. This also means that
789 in a cell there can be 2^16 channels.
796 Operators are normal users with extra privileges to their server or
797 router. Usually these people are SILC server and router administrators
798 that take care of their own server and clients on them. The purpose of
799 operators is to administrate the SILC server or router. However, even
800 an operator with highest privileges is not able to enter invite-only
801 channel, to gain access to the contents of a encrypted and authenticated
802 packets traveling in the SILC network or to gain channel operator
803 privileges on public channels without being promoted. They have the
804 same privileges as everyone else except they are able to administrate
805 their server or router.
811 Commands are very important part on SILC network especially for client
812 which uses commands to operate on the SILC network. Commands are used
813 to set nickname, join to channel, change modes and many other things.
815 Client usually sends the commands and server replies by sending a reply
816 packet to the command. Server may also send commands usually to serve
817 the original client's request. However, server may not send command
818 to client and there are some commands that server must not send. Server
819 is also able to send the forwarded command packets. For example,
820 SILC_COMMAND_JOIN is always forwarded packet. See [SILC2] for more
821 about packet forwarding.
823 Note that the command reply is usually sent only after client has sent
824 the command request but server is allowed to send command reply packet
825 to client even if client has not requested the command. Client may,
826 however, choose ignore the command reply, but should not.
828 It is expected that some of the commands may be miss-used by clients
829 resulting various problems on the server side. Every implementation
830 should assure that commands may not be executed more than once, say,
831 in two (2) seconds. This should be sufficient to prevent the miss-use
834 SILC commands are described in section 5 SILC Commands.
840 Packets are naturally the most important part of the protocol and the
841 packets are what actually makes the protocol. Packets in SILC network
842 are always encrypted using, usually, the shared secret session key
843 or some other key, for example, channel key, when encrypting channel
844 messages. The SILC Packet Protocol is a wide protocol and is described
845 in [SILC2]. This document does not define or describe details of
851 3.8 Packet Encryption
853 All packets passed in SILC network must be encrypted. This section
854 defines how packets must be encrypted in the SILC network. The detailed
855 description of the actual encryption process of the packets are
856 described in [SILC2].
858 Client and its server shares secret symmetric session key which is
859 established by the SILC Key Exchange Protocol, described in [SILC3].
860 Every packet sent from client to server, with exception of packets for
861 channels, are encrypted with this session key.
863 Channels has their own key that are shared by every client on the channel.
864 However, the channel keys are cell specific thus one cell does not know
865 the channel key of the other cell, even if that key is for same channel.
866 Channel key is also known by the routers and all servers that has clients
867 on the channel. However, channels may have channel private keys that
868 are entirely local setting for client. All clients on the channel must
869 know the channel private key before hand to be able to talk on the
870 channel. In this case, no server or router knows the key for channel.
872 Server shares secret symmetric session key with router which is
873 established by the SILC Key Exchange Protocol. Every packet passed from
874 server to router, with exception of packets for channels, are encrypted
875 with the shared session key. Same way, router server shares secret
876 symmetric key with its primary route. However, every packet passed
877 from router to other router, including packets for channels, are
878 encrypted with the shared session key. Every router connection has
879 their own session keys.
883 3.8.1 Determination of the Source and the Destination
885 The source and the destination of the packet needs to be determined
886 to be able to route the packets to correct receiver. This information
887 is available in the SILC Packet Header which is included in all packets
888 sent in SILC network. The SILC Packet Header is described in [SILC2].
890 The header is always encrypted with the session key who is next receiver
891 of the packet along the route. The receiver of the packet, for example
892 a router along the route, is able to determine the sender and the
893 destination of the packet by decrypting the SILC Packet Header and
894 checking the ID's attached to the header. The ID's in the header will
895 tell to where the packet needs to be sent and where it is coming from.
897 The header in the packet does not change during the routing of the
898 packet. The original sender, for example client, assembles the packet
899 and the packet header and server or router between the sender and the
900 receiver must not change the packet header.
902 Note that the packet and the packet header may be encrypted with
903 different keys. For example, packets to channels are encrypted with
904 the channel key, however, the header is encrypted with the session key
905 as described above. However, the header and the packet may be encrypted
906 with same key. This is case, for example, with command packets.
910 3.8.2 Client To Client
912 Process of message delivery and encryption from client to another
913 client is as follows.
915 Example: Private message from client to another client on different
916 servers. Clients do not share private message delivery
917 keys; normal session keys are used.
919 o Client 1. sends encrypted packet to its server. The packet is
920 encrypted with the session key shared between client and its
923 o Server determines the destination of the packet and decrypts
924 the packet. Server encrypts the packet with session key shared
925 between the server and its router, and sends the packet to the
928 o Router determines the destination of the packet and decrypts
929 the packet. Router encrypts the packet with session key
930 shared between the router and the destination server, and sends
931 the packet to the server.
933 o Server determines the client to which the packet is destined
934 to and decrypts the packet. Server encrypts the packet with
935 session key shared between the server and the destination client,
936 and sends the packet to the client.
938 o Client 2. decrypts the packet.
941 Example: Private message from client to another client on different
942 servers. Clients has established secret shared private
943 message delivery key with each other and that is used in
944 the message encryption.
946 o Client 1. sends encrypted packet to its server. The packet is
947 encrypted with the private message delivery key shared between
950 o Server determines the destination of the packet and sends the
951 packet to the router.
953 o Router determines the destination of the packet and sends the
954 packet to the server.
956 o Server determines the client to which the packet is destined
957 to and sends the packet to the client.
959 o Client 2. decrypts the packet with the secret shared key.
962 If clients share secret key with each other the private message
963 delivery is much simpler since servers and routers between the
964 clients do not need to decrypt and re-encrypt the packet.
966 The process for clients on same server is much simpler as there are
967 no need to send the packet to the router. The process for clients
968 on different cells is same as above except that the packet is routed
969 outside the cell. The router of the destination cell routes the
970 packet to the destination same way as described above.
974 3.8.3 Client To Channel
976 Process of message delivery from client on channel to all the clients
979 Example: Channel of four users; two on same server, other two on
980 different cells. Client sends message to the channel.
982 o Client 1. encrypts the packet with channel key and sends the
983 packet to its server.
985 o Server determines local clients on the channel and sends the
986 packet to the Client on the same server. Server then sends
987 the packet to its router for further routing.
989 o Router determines local clients on the channel, if found
990 sends packet to the local clients. Router determines global
991 clients on the channel and sends the packet to its primary
992 router or fastest route.
994 o (Other router(s) do the same thing and sends the packet to
997 o Server determines local clients on the channel and sends the
998 packet to the client.
1000 o All clients receiving the packet decrypts the packet.
1004 3.8.4 Server To Server
1006 Server to server packet delivery and encryption is described in above
1007 examples. Router to router packet delivery is analogous to server to
1008 server. However, some packets, such as channel packets, are processed
1009 differently. These cases are described later in this document and
1010 more in detail in [SILC2].
1014 3.9 Key Exchange And Authentication
1016 Key exchange is done always when for example client connects to server
1017 but also when server and router and router and router connects to each
1018 other. The purpose of key exchange protocol is to provide secure key
1019 material to be used in the communication. The key material is used to
1020 derive various security parameters used to secure SILC packets. The
1021 SILC Key Exchange protocol is described in detail in [SILC3].
1023 Authentication is done after key exchange protocol has been successfully
1024 completed. The purpose of authentication is to authenticate for example
1025 client connecting to the server. However, Usually clients are accepted
1026 to connect to server without explicit authentication. Servers are
1027 required use authentication protocol when connecting. The authentication
1028 may be based on passphrase (pre-shared-secret) or public key. The
1029 connection authentication protocol is described in detail in [SILC3].
1033 3.9.1 Authentication Payload
1035 Authentication payload is used separately from the SKE and the Connection
1036 authentication protocol. It is used during the session to authenticate
1037 with the remote. For example, the client can authenticate itself to the
1038 server to be server operator. In this case, Authentication Payload is
1041 The format of the Authentication Payload is as follows:
1047 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
1048 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1049 | Payload Length | Authentication Method |
1050 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1051 | Public Data Length | |
1052 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1056 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1057 | Authentication Data Length | |
1058 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1060 ~ Authentication Data ~
1062 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+|
1066 Figure 5: Authentication Payload
1070 o Payload Length (2 bytes) - Length of the entire payload.
1072 o Authentication Type (2) - The method of the authentication.
1073 The authentication methods are defined in [SILC2] in the
1074 Connection Auth Request Payload. The NONE authentication
1075 method is not recommended.
1077 o Public Data Length (2 bytes) - Indicates the length of
1078 the Public Data field.
1080 o Public Data (variable length) - This is defined only if
1081 the authentication method is public key. If it is any other
1082 this field does not exist and the Public Data Length field
1085 When the authentication method is public key this includes
1086 128 to 4096 bytes of non-zero random data that is used in
1087 the signature process, described subsequently.
1089 o Authentication Data Length (2 bytes) - Indicates the
1090 length of the Authentication Data field.
1092 o Authentication Data (variable length) - Authentication
1093 method dependent authentication data.
1097 If the authentication method is password based, the Authentication
1098 Data field includes the plaintext password. It is safe to send
1099 plaintext password since the entire payload is encrypted.
1101 If the authentication method is public key based (or certificate)
1102 the Authentication Data is computed as follows:
1104 HASH = hash(random bytes | ID | public key (or certificate));
1105 Authentication Data = sign(HASH);
1107 The hash() and the sign() are the hash funtion and the public key
1108 cryptography function selected in the SKE protocol. The public key
1109 is SILC style public key unless certificates are used. The ID is the
1110 entity's ID (Client or Server ID) who is authenticating itself. The ID
1111 is raw ID data. The random bytes are non-zero random bytes of length
1112 between 128 and 4096 bytes, and will be included into the Public Data
1115 The receiver will compute the signature using the random data received
1116 in the payload, the ID associated to the connection and the public key
1117 (or certificate) received in the SKE protocol. After computing the
1118 receiver must verify the signature. In this case also, the entire
1119 payload is encrypted.
1125 This section defines all the allowed algorithms that can be used in
1126 the SILC protocol. This includes mandatory cipher, mandatory public
1127 key algorithm and MAC algorithms.
1133 Cipher is the encryption algorithm that is used to protect the data
1134 in the SILC packets. See [SILC2] of the actual encryption process and
1135 definition of how it must be done. SILC has a mandatory algorithm that
1136 must be supported in order to be compliant with this protocol.
1138 Following ciphers are defined in SILC protocol:
1141 aes-cbc AES in CBC mode (mandatory)
1142 twofish-cbc Twofish in CBC mode (optional)
1143 blowfish-cbc Blowfish in CBC mode (optional)
1144 rc6-cbc RC6 in CBC mode (optional)
1145 rc5-cbc RC5 in CBC mode (optional)
1146 mars-cbc Mars in CBC mode (optional)
1147 none No encryption (optional)
1151 All algorithms must use minimum of 128 bit key, by default. Several
1152 algorithms, however, supports longer keys and it is recommended to use
1153 longer keys if they are available.
1155 Algorithm none does not perform any encryption process at all and
1156 thus is not recommended to be used. It is recommended that no client
1157 or server implementation would accept none algorithms except in special
1160 Additional ciphers may be defined to be used in SILC by using the
1161 same name format as above.
1165 3.10.2 Public Key Algorithms
1167 Public keys are used in SILC to authenticate entities in SILC network
1168 and to perform other tasks related to public key cryptography. The
1169 public keys are also used in the SILC Key Exchange protocol [SILC3].
1171 Following public key algorithms are defined in SILC protocol:
1178 Both of the algorithms are described in [Scheneir] and [Menezes].
1180 Additional public key algorithms may be defined to be used in SILC.
1184 3.10.3 MAC Algorithms
1186 Data integrity is protected by computing a message authentication code
1187 (MAC) of the packet data. See [SILC2] for details how to compute the
1190 Following MAC algorithms are defined in SILC protocol:
1193 hmac-sha1 HMAC-SHA1, length = 20 (mandatory)
1194 hmac-md5 HMAC-MD5, length = 16 (optional)
1195 none No MAC (optional)
1198 The none MAC is not recommended to be used as the packet is not
1199 authenticated when MAC is not computed. It is recommended that no
1200 client or server would accept none MAC except in special debugging
1203 The HMAC algorithm is described in [HMAC] and hash algorithms that
1204 are used as part of the HMACs are described in [Scheneir] and in
1207 Additional MAC algorithms may be defined to be used in SILC.
1211 3.10.4 Compression Algorithms
1213 SILC protocol supports compression that may be applied to unencrypted
1214 data. It is recommended to use compression on slow links as it may
1215 significantly speed up the data transmission. By default, SILC does not
1216 use compression which is the mode that must be supported by all SILC
1219 Following compression algorithms are defined:
1222 none No compression (mandatory)
1223 zlib GNU ZLIB (LZ77) compression (optional)
1226 Additional compression algorithms may be defined to be used in SILC.
1230 3.11 SILC Public Key
1232 This section defines the type and format of the SILC public key. All
1233 implementations must support this public key type. See [SILC3] for
1234 other optional public key and certificate types allowed in SILC
1235 protocol. Public keys in SILC may be used to authenticate entities
1236 and to perform other tasks related to public key cryptography.
1238 The format of the SILC Public Key is as follows:
1244 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
1245 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1246 | Public Key Length |
1247 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1248 | Algorithm Name Length | |
1249 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1253 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1254 | Identifier Length | |
1255 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1259 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1263 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1267 Figure 5: SILC Public Key
1271 o Public Key Length (4 bytes) - Indicates the full length
1272 of the public key, not including this field.
1274 o Algorithm Name Length (2 bytes) - Indicates the length
1275 of the Algorithm Length field, not including this field.
1277 o Algorithm name (variable length) - Indicates the name
1278 of the public key algorithm that the key is. See the
1279 section 3.10.2 Public Key Algorithms for defined names.
1281 o Identifier Length (2 bytes) - Indicates the length of
1282 the Identifier field, not including this field.
1284 o Identifier (variable length) - Indicates the identifier
1285 of the public key. This data can be used to identify
1286 the owner of the key. The identifier is of following
1290 HN Host name or IP address
1297 Examples of an identifier:
1299 `UN=priikone, HN=poseidon.pspt.fi, E=priikone@poseidon.pspt.fi'
1301 `UN=sam, HN=dummy.fi, RN=Sammy Sam, O=Company XYZ, C=Finland'
1303 At least user name (UN) and host name (HN) must be provided as
1304 identifier. The fields are separated by commas (`,'). If
1305 comma is in the identifier string it must be written as `\\,',
1306 for example, `O=Company XYZ\\, Inc.'.
1308 o Public Data (variable length) - Includes the actual
1309 public data of the public key.
1311 The format of this field for RSA algorithm is
1320 The format of this field for DSS algorithm is
1332 The variable length fields are multiple precession
1333 integers encoded as strings in both examples.
1335 Other algorithms must define their own type of this
1336 field if they are used.
1339 All fields in the public key are in MSB (most significant byte first)
1344 3.12 SILC Version Detection
1346 The version detection of both client and server is performed at the
1347 connection phase while executing the SILC Key Exchange protocol. The
1348 version identifier is exchanged between initiator and responder. The
1349 version identifier is of following format:
1352 SILC-<protocol version>-<software version>
1355 The version strings are of following format:
1358 protocol version = <major>.<minor>
1359 software version = <major>[.<minor>[.<build>]]
1362 Protocol version may provide both major and minor version. Currently
1363 implementations must set the protocol version and accept the protocol
1364 version as SILC-1.0-<sotware version>.
1366 Software version may provide major, minor and build version. The
1367 software version may be freely set and accepted.
1370 Thus, the version string could be, for example:
1380 This section describes various SILC procedures such as how the
1381 connections are created and registered, how channels are created and
1382 so on. The section describes the procedures only generally as details
1383 are described in [SILC2] and [SILC3].
1387 4.1 Creating Client Connection
1389 This section describes the procedure when client connects to SILC server.
1390 When client connects to server the server must perform IP address lookup
1391 and reverse IP address lookup to assure that the origin host really is
1392 who it claims to be. Client, host, connecting to server must have
1393 both valid IP address and fully qualified domain name (FQDN).
1395 After that client and server performs SILC Key Exchange protocol which
1396 will provide the key material used later in the communication. The
1397 key exchange protocol must be completed successfully before the connection
1398 registration may continue. The SILC Key Exchange protocol is described
1401 Typical server implementation would keep a list of connections that it
1402 allows to connect to the server. The implementation would check, for
1403 example, the connecting client's IP address from the connection list
1404 before the SILC Key Exchange protocol has been started. Reason for
1405 this is that if the host is not allowed to connect to the server there
1406 is no reason to perform a key exchange protocol.
1408 After successful key exchange protocol the client and server performs
1409 connection authentication protocol. The purpose of the protocol is to
1410 authenticate the client connecting to the server. Flexible
1411 implementation could also accept the client to connect to the server
1412 without explicit authentication. However, if authentication is
1413 desired for a specific client it may be based on passphrase or
1414 public key authentication. If authentication fails the connection
1415 must be terminated. The connection authentication protocol is described
1418 After successful key exchange and authentication protocol the client
1419 registers itself by sending SILC_PACKET_NEW_CLIENT packet to the
1420 server. This packet includes various information about the client
1421 that the server uses to create the client. Server creates the client
1422 and sends SILC_PACKET_NEW_ID to the client which includes the created
1423 Client ID that the client must start using after that. After that
1424 all SILC packets from the client must have the Client ID as the
1425 Source ID in the SILC Packet Header, described in [SILC2].
1427 Client must also get the server's Server ID that is to be used as
1428 Destination ID in the SILC Packet Header when communicating with
1429 the server (for example when sending commands to the server). The
1430 ID may be resolved in two ways. Client can take the ID from an
1431 previously received packet from server that must include the ID,
1432 or to send SILC_COMMAND_INFO command and receive the Server ID as
1435 Server may choose not to use the information received in the
1436 SILC_PACKET_NEW_CLIENT packet. For example, if public key or
1437 certificate were used in the authentication, server may use those
1438 informations rather than what it received from client. This is suitable
1439 way to get the true information about client if it is available.
1441 The nickname of client is initially set to the username sent in the
1442 SILC_PACKET_NEW_CLIENT packet. User should set the nickname to more
1443 suitable by sending SILC_COMMAND_NICK command. However, this is not
1444 required as part of registration process.
1446 Server must also distribute the information about newly registered
1447 client to its router (or if the server is router, to all routers in
1448 the SILC network). More information about this in [SILC2].
1452 4.2 Creating Server Connection
1454 This section descibres the procedure when server connects to its
1455 router (or when router connects to other router, the cases are
1456 equivalent). The procedure is very much alike when client connects
1457 to the server thus it is not repeated here.
1459 One difference is that server must perform connection authentication
1460 protocol with proper authentication. Proper authentication is based
1461 on passphrase or public key authentication.
1463 After server and router has successfully performed the key exchange
1464 and connection authentication protocol, the server register itself
1465 to the router by sending SILC_PACKET_NEW_SERVER packet. This packet
1466 includes the server's Server ID that it has created by itself and
1467 other relevant information about the server.
1469 After router has received the SILC_PACKET_NEW_SERVER packet it
1470 distributes the information about newly registered server to all routers
1471 in the SILC network. More information about this in [SILC2].
1473 As client needed to resolve the destination ID this must be done by the
1474 server that connected to the router, as well. The way to resolve it is
1475 to get the ID from previously received packet. Server must also start
1476 using its own Server ID as Source ID in SILC Packet Header and the
1477 router's Server ID as Destination when communicating with the router.
1479 If the server has already connected clients and locally created
1480 channels the server must distribute these informations to the router.
1481 The distribution is done by sending packet SILC_PACKET_NEW_CHANNEL.
1482 See [SILC2] for more information on this.
1486 4.3 Joining to a Channel
1488 This section describes the procedure when client joins to a channel.
1489 Client may join to channel by sending command SILC_COMMAND_JOIN to the
1490 server. If the receiver receiving join command is normal server the
1491 server must check its local list whether this channel already exists
1492 locally. This would indicate that some client connected to the server
1493 has already joined to the channel. If this is case the client is
1494 joined to the client, new channel key is created and information about
1495 newly joined channel is sent to the router. The new channel key is
1496 also distributed to the router and to all clients on the channel.
1498 If the channel does not exist in the local list the command must be
1499 forwarded to the router which will then perform the actual joining
1500 procedure. When server receives the reply to the command from the
1501 router it must be distributed to the client who sent the command
1502 originally. Server will also receive the channel key from the server
1503 that it must distribute to the client who originally requested the
1504 join command. The server must also save the channel key.
1506 If the receiver of the join command is router it must first check its
1507 local list whether anyone in the cell has already joined to the channel.
1508 If this is the case the client is joined to the channel and reply is
1509 sent to the client. If the command was sent by server the command reply
1510 is sent to the server who sent it. Then the router must also create
1511 new channel key and distribute it to all clients on the channel and
1512 all servers that has clients on the channel.
1514 If the channel does not exist on the router's local list it must
1515 check the global list whether the channel exists at all. If it does
1516 the client is joined to the channel as described previously. If
1517 the channel does not exist the channel is created and the client
1518 is joined to the channel. The channel key is also created and
1519 distributed as previously described. The client joining to the created
1520 channel is made automatically channel founder and both channel founder
1521 and channel operator privileges is set for the client.
1523 When the router joins the client to the channel it must send
1524 information about newly joined client to all routers in the SILC
1525 network. Also, if the channel was created in the process, information
1526 about newly created channel must also be distributed to all routers.
1527 The distribution of newly created channel is done by sending packet
1528 SILC_PACKET_NEW_CHANNEL.
1530 It is important to note that new channel key is created always when
1531 new client joins to channel, whether the channel has existed previously
1532 or not. This way the new client on the channel is not able to decrypt
1533 any of the old traffic on the channel. Client who receives the reply to
1534 the join command must start using the received Channel ID in the channel
1535 message communication thereafter. Client also receives the key for the
1536 channel in the command reply.
1538 If client wants to know the other clients currently on the channel
1539 the client must send SILC_COMMAND_USERS command to receive a list of
1540 channel users. Server implementation, however, may send command reply
1541 packet to SILC_COMMAND_USERS command after client has joined to the
1542 channel even if the client has not sent the command. Server should also
1543 send SILC_NOTIFY_TYPE_JOIN to all clients on the channel about a new
1544 client on the channel.
1548 4.4 Channel Key Generation
1550 Channel keys are created by router who creates the channel by taking
1551 enough randomness from cryptographically strong random number generator.
1552 The key is generated always when channel is created, when new client
1553 joins a channel and after the key has expired. Key could expire for
1556 The key must also be re-generated whenever some client leaves a channel.
1557 In this case the key is created from scratch by taking enough randomness
1558 from the random number generator. After that the key is distributed to
1559 all clients on the channel. However, channel keys are cell specific thus
1560 the key is created only on the cell where the client, who left the
1561 channel, exists. While the server or router is creating the new channel
1562 key, no other client may join to the channel. Messages that are sent
1563 while creating the new key are still processed with the old key. After
1564 server has sent the SILC_PACKET_CHANNEL_KEY packet must client start
1565 using the new key. If server creates the new key the server must also
1566 send the new key to its router. See [SILC2] on more information about
1567 how channel messages must be encrypted and decrypted when router is
1572 4.5 Private Message Sending and Reception
1574 Private messages are sent point to point. Client explicitly destines
1575 a private message to specific client that is delivered to only to that
1576 client. No other client may receive the private message. The receiver
1577 of the private message is destined in the SILC Packet Header as any
1578 other packet as well.
1580 If the sender of a private message does not know the receiver's Client
1581 ID, it must resolve it from server. There are two ways to resolve the
1582 client ID from server; it is recommended that client implementations
1583 send SILC_COMMAND_IDENTIFY command to receive the Client ID. Client
1584 may also send SILC_COMMAND_WHOIS command to receive the Client ID.
1585 If the sender has received earlier a private message from the receiver
1586 it should have cached the Client ID from the SILC Packet Header.
1588 Receiver of a private message should not explicitly trust the nickname
1589 that it receives in the Private Message Payload, described in [SILC2].
1590 Implementations could resolve the nickname from server, as described
1591 previously, and compare the received Client ID and the SILC Packet
1592 Header's Client ID. The nickname in the payload is merely provided
1593 to be displayed for end user.
1595 See [SILC2] for description of private message encryption and decryption
1600 4.6 Private Message Key Generation
1602 Private message may be protected by key generated by client. The key
1603 may be generated and sent to the other client by sending packet
1604 SILC_PACKET_PRIVATE_MESSAGE_KEY which travels through the network
1605 and is secured by session keys. After that the private message key
1606 is used in the private message communication between those clients.
1607 See more information about how this works technically in [SILC2].
1609 Other choice is to entirely use keys that are not sent through
1610 the SILC network at all. This significantly adds security. This key
1611 would be pre-shared-key that is known by both of the clients. Both
1612 agree about using the key and starts sending packets that indicate
1613 that the private message is secured using private message key. This
1614 is the technical aspect mentioned previously that is described
1617 If the private message keys are not set to be used, which is the
1618 case by default in SILC, the private messages are secured by using
1619 normal session keys established by SILC Key Exchange protocol.
1625 4.7 Channel Message Sending and Reception
1627 Channel messages are delivered to group of users. The group forms a
1628 channel and all clients on the channel receives messages sent to the
1631 Channel messages are destined to channel by specifying the Channel ID
1632 as Destination ID in the SILC Packet Header. The server must then
1633 distribute the message to all clients on the channel by sending the
1634 channel message destined explicitly to a client on the channel.
1636 See [SILC2] for description of channel message encryption and decryption
1641 4.8 Session Key Regeneration
1643 Session keys should be regenerated periodically, say, once in an hour.
1644 The re-key process is started by sending SILC_PACKET_REKEY packet to
1645 other end, to indicate that re-key must be performed.
1647 If perfect forward secrecy (PFS) flag was selected in the SILC Key
1648 Exchange protocol [SILC3] the re-key must cause new key exchange with
1649 SKE protocol. In this case the protocol is secured with the old key
1650 and the protocol results to new key material. See [SILC3] for more
1651 information. After the SILC_PACKET_REKEY packet is sent the sender
1652 will perform the SKE protocol.
1654 If PFS flag was not set, which is the default case, then re-key is done
1655 without executing SKE protocol. In this case, the new key is created by
1656 hashing the old key with hash function selected earlier in the SKE
1657 protocol. If the digest length of the hash function is too short for the
1658 key, then the key is distributed as described in section Processing the
1659 Key Material in [SILC3]. After both parties has regenerated the session
1660 key, both send SILC_PACKET_REKEY_DONE packet to each other. These packets
1661 are still secured with the old key. After these packets, following
1662 packets must be protected with the new key.
1666 4.9 Command Sending and Reception
1668 Client usually sends the commands in the SILC network. In this case
1669 the client simply sends the command packet to server and the server
1670 processes it and replies with command reply packet.
1672 However, if the server is not able to process the command, it is sent
1673 to the server's router. This is case for example with commands such
1674 as, SILC_COMMAND_JOIN and SILC_COMMAND_WHOIS commands. However, there
1675 are other commands as well. For example, if client sends the WHOIS
1676 command requesting specific information about some client the server must
1677 send the WHOIS command to router so that all clients in SILC network
1678 are searched. The router, on the other hand, sends the WHOIS command
1679 further to receive the exact information about the requested client.
1680 The WHOIS command travels all the way to the server who owns the client
1681 and it replies with command reply packet. Finally, the server who
1682 sent the command receives the command reply and it must be able to
1683 determine which client sent the original command. The server then
1684 sends command reply to the client. Implementations should have some
1685 kind of cache to handle, for example, WHOIS information. Servers
1686 and routers along the route could all cache the information for faster
1687 referencing in the future.
1689 The commands sent by server may be sent hop by hop until someone is able
1690 to process the command. However, it is preferred to destine the command
1691 as precisely as it is possible. In this case, other routers en route
1692 must route the command packet by checking the true sender and true
1693 destination of the packet. However, servers and routers must not route
1694 command reply packets to clients coming from other server. Client
1695 must not accept command reply packet originated from anyone else but
1696 from its own server.
1703 5.1 SILC Commands Syntax
1705 This section briefly describes the syntax of the command notions
1706 in this document. Every field in command is separated from each
1707 other by whitespaces (` ') indicating that each field is independent
1708 argument and each argument must have own Command Argument Payload.
1709 The number of maximum arguments are defined with each command
1710 separately. The Command Argument Payload is described in [SILC2].
1712 Every command defines specific number for each argument. Currently,
1713 they are defined in ascending order; first argument has number one
1714 (1), second has number two (2) and so on. This number is set into the
1715 Argument Type field in the Command Argument Payload. This makes it
1716 possible to send the arguments in free order as the number must be
1717 used to identify the type of the argument. This makes is it also
1718 possible to have multiple optional arguments in commands and in
1719 command replies. The number of argument is marked in parentheses
1720 before the actual argument.
1725 Example: Arguments: (1) <nickname> (2) <username@host>
1729 Every command replies with Status Payload. This payload tells the
1730 sender of the command whether the command was completed successfully or
1731 whether there was an error. If error occured the payload includes the
1732 error type. In the next section the Status Payload is not described
1733 as it is common to all commands and has been described here. Commands
1734 may reply with other arguments as well. These arguments are command
1735 specific and are described in the next section.
1744 Arguments: (1) <nickname>[@<server>] (2) <message>
1747 The command has maximum of 3 arguments. However, only first
1748 and second arguments are mandatory.
1750 First argument <nickname> is mandatory but may have optional
1751 <nickname@server> format as well. Second argument is mandatory
1752 <message> argument. Third argument is optional <count> argument.
1754 The numbers in parentheses are the argument specific numbers
1755 that specify the type of the argument in Command Argument Payload.
1756 The receiver always knows that, say, argument number two (2) is
1757 <message> argument, regardless of the ordering of the arguments in
1758 the Command Payload.
1760 Reply messages to the command:
1763 Arguments: (1) <Status Payload> (2) [<channel list>]
1764 (3) <idle time> (4) [<away message>]
1766 This command may reply with maximum of 4 arguments. However,
1767 only the first and third arguments are mandatory. The numbers
1768 in the parentheses have the same meaning as in the upper
1769 command sending specification.
1771 Every command reply with <Status Payload>, it is mandatory
1772 argument for all command replies and for this reason it is not
1773 described in the command reply descriptions.
1780 SILC_STATUS_ERR_TOO_MANY_TARGETS
1781 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
1782 SILC_STATUS_ERR_NO_SUCH_NICK
1784 Every command reply also defines set of status message that it
1785 may return inside the <Status Payload>. All status messages
1786 are defined in the section 5.3 SILC Command Status Types.
1789 Every command that has some kind of ID as argument (for example
1790 <Client ID>) are actually ID Payloads, defined in [SILC2] that includes
1791 the type of the ID, length of the ID and the actual ID data. This
1792 way variable length ID's can be sent as arguments.
1796 5.2 SILC Commands List
1798 This section lists all SILC commands, however, it is expected that a
1799 implementation and especially client implementation has many more
1800 commands that has only local affect. These commands are official
1801 SILC commands that has both client and server sides and cannot be
1802 characterized as local commands.
1804 List of all defined commands in SILC follows.
1809 None. This is reserved command and must not be sent.
1812 1 SILC_COMMAND_WHOIS
1815 Arguments: (1) [<nickname>[@<server>]] (2) [<count>]
1816 (3) [<Client ID>] (n) [...]
1818 Whois command is used to query various information about specific
1819 user. The user maybe requested by their nickname and server name.
1820 The query may find multiple matching users as there are no unique
1821 nicknames in the SILC. The <count> option maybe given to narrow
1822 down the number of accepted results. If this is not defined there
1823 are no limit of accepted results. The query may also be narrowed
1824 down by defining the server name of the nickname.
1826 It is also possible to search the user by Client ID. If <Client ID>
1827 is provided server must use it as the search value instead of
1828 the <nickname>. One of the arguments must be given. It is also
1829 possible to define multiple Client ID's to search multiple users
1830 sending only one WHOIS command. In this case the Client ID's are
1831 appended as normal arguments. The server replies in this case
1832 with only one reply message for all requested users.
1834 To prevent miss-use of this service wildcards in the nickname
1835 or in the servername are not permitted. It is not allowed
1836 to request all users on some server. The WHOIS requests must
1837 be based on specific nickname request.
1839 The WHOIS request must be always forwarded to router by server
1840 so that all users are searched. However, the server still must
1841 search its locally connected clients. The router must send
1842 this command to the server who owns the requested client. That
1843 server must reply to the command. Server should not send whois
1844 replies to the client until it has received the reply from its
1847 Reply messages to the command:
1850 Arguments: (1) <Status Payload> (2) <Client ID>
1851 (3) <nickname>[@<server>] (4) <username@host>
1852 (5) <real name> (6) [<channel list>]
1855 This command may reply with several command reply messages to
1856 form a list of results. In this case the status payload will
1857 include STATUS_LIST_START status in the first reply and
1858 STATUS_LIST_END in the last reply to indicate the end of the
1859 list. If there are only one reply the status is set to normal
1862 The command replies include the Client ID of the nickname,
1863 nickname and servername, username and hostname and users real
1864 name. Client should process these replies only after the last
1865 reply has been received with the STATUS_LIST_END status. If the
1866 <count> option were defined in the query there will be only
1867 <count> many replies from the server.
1872 SILC_STATUS_LIST_START
1873 SILC_STATUS_LIST_END
1874 SILC_STATUS_ERR_NO_SUCH_NICK
1875 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
1876 SILC_STATUS_ERR_WILDCARDS
1877 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
1878 SILC_STATUS_ERR_TOO_MANY_PARAMS
1883 2 SILC_COMMAND_WHOWAS
1886 Arguments: (1) <nickname>[@<server>] (2) [<count>]
1888 Whowas. This command is used to query history information about
1889 specific user. The user maybe requested by their nickname and
1890 server name. The query may find multiple matching users as there
1891 are no unique nicknames in the SILC. The <count> option maybe
1892 given to narrow down the number of accepted results. If this
1893 is not defined there are no limit of accepted results. The query
1894 may also be narrowed down by defining the server name of the
1897 To prevent miss-use of this service wildcards in the nickname
1898 or in the servername are not permitted. The WHOWAS requests must
1899 be based on specific nickname request.
1901 The WHOWAS request must be always forwarded to router by server
1902 so that all users are searched. However, the server still must
1903 search its locally connected clients.
1905 Reply messages to the command:
1908 Arguments: (1) <Status Payload> (2) <nickname>[@<server>]
1911 This command may reply with several command reply messages to form
1912 a list of results. In this case the status payload will include
1913 STATUS_LIST_START status in the first reply and STATUS_LIST_END in
1914 the last reply to indicate the end of the list. If there are only
1915 one reply the status is set to normal STATUS_OK.
1917 The command replies with nickname and username and hostname.
1918 Every server must keep history for some period of time of its
1919 locally connected clients.
1924 SILC_STATUS_LIST_START
1925 SILC_STATUS_LIST_END
1926 SILC_STATUS_ERR_NO_SUCH_NICK
1927 SILC_STATUS_ERR_WILDCARDS
1928 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
1929 SILC_STATUS_ERR_TOO_MANY_PARAMS
1932 3 SILC_COMMAND_IDENTIFY
1935 Arguments: (1) [<nickname>[@<server>]] (2) [<count>]
1936 (3) [<Client ID>] (n) [...]
1938 Identify. Identify command is almost analogous to WHOIS command,
1939 except that it does not return as much information. Only relevant
1940 information such as Client ID is returned. This is usually used
1941 to get the Client ID of a client used in the communication with
1944 The query may find multiple matching users as there are no unique
1945 nicknames in the SILC. The <count> option maybe given to narrow
1946 down the number of accepted results. If this is not defined there
1947 are no limit of accepted results. The query may also be narrowed
1948 down by defining the server name of the nickname.
1950 It is also possible to search the user by Client ID. If <Client ID>
1951 is provided server must use it as the search value instead of
1952 the <nickname>. One of the arguments must be given. It is also
1953 possible to define multiple Client ID's to search multiple users
1954 sending only one IDENTIFY command. In this case the Client ID's are
1955 appended as normal arguments. The server replies in this case
1956 with only one reply message for all requested users.
1958 To prevent miss-use of this service wildcards in the nickname
1959 or in the servername are not permitted. It is not allowed
1960 to request all users on some server. The IDENTIFY requests must
1961 be based on specific nickname request.
1963 Implementations may not want to give interface access to this
1964 command as it is hardly a command that would be used by an end user.
1965 However, it must be implemented as it is used with private message
1968 The IDENTIFY must be always forwarded to router by server so that
1969 all users are searched. However, server must still search its
1970 locally connected clients.
1972 Reply messages to the command:
1975 Arguments: (1) <Status Payload> (2) <Client ID>
1976 (3) [<nickname>[@<server>]] (4) [<username@host>]
1978 This command may reply with several command reply messages to form
1979 a list of results. In this case the status payload will include
1980 STATUS_LIST_START status in the first reply and STATUS_LIST_END in
1981 the last reply to indicate the end of the list. If there are only
1982 one reply the status is set to normal STATUS_OK.
1984 The command replies with Client ID of the nickname and if more
1985 information is available it may reply with nickname and username
1986 and hostname. If the <count> option were defined in the query
1987 there will be only <count> many replies from the server.
1992 SILC_STATUS_LIST_START
1993 SILC_STATUS_LIST_END
1994 SILC_STATUS_ERR_NO_SUCH_NICK
1995 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
1996 SILC_STATUS_ERR_WILDCARDS
1997 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
1998 SILC_STATUS_ERR_TOO_MANY_PARAMS
2004 Arguments: (1) <nickname>
2006 Set/change nickname. This command is used to set nickname for
2007 user. There is no limit of the length of the nickname in SILC.
2008 Nickname must not include any spaces (` '), non-printable
2009 characters, commas (`,') and any wildcard characters. Note:
2010 nicknames in SILC are case-sensitive which must be taken into
2011 account when searching clients by nickname.
2013 When nickname is changed new Client ID is generated. Server must
2014 distribute SILC_NOTIFY_TYPE_NICK_CHANGE to local clients on the
2015 channels (if any) the client is joined on. Then it must send
2016 SILC_PACKET_REPLACE_ID to its primary route to replace the old
2017 Client ID with the new one.
2019 Reply messages to the command:
2022 Arguments: (1) <Status Payload> (2) <New ID Payload>
2024 This command is replied always with New ID Payload that is
2025 generated by the server every time user changes their nickname.
2026 Client receiving this payload must start using the received
2027 Client ID as its current valid Client ID. The New ID Payload
2028 is described in [SILC2].
2033 SILC_STATUS_ERR_WILDCARDS
2034 SILC_STATUS_ERR_NICKNAME_IN_USE
2035 SILC_STATUS_ERR_BAD_NICKNAME
2036 SILC_STATUS_ERR_NOT_REGISTERED
2037 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2038 SILC_STATUS_ERR_TOO_MANY_PARAMS
2044 Arguments: (1) [<Channel ID>] [<server>]
2046 The list command is used to list channels and their topics on
2047 current server. If the <Channel ID> parameter is used, only the
2048 status of that channel is displayed. Secret channels are not
2049 listed at all. Private channels are listed with status indicating
2050 that the channel is private.
2052 If the <server> argument is specified the specified server's
2053 channels are listed. In this case the command must be sent to
2054 the server who owns the channel that was requested.
2056 Reply messages to the command:
2059 Arguments: (1) <Status Payload> (2) <Channel ID>
2060 (3) <channel> (4) <topic>
2062 This command may reply with several command reply messages to form
2063 a list of results. In this case the status payload will include
2064 STATUS_LIST_START status in the first reply and STATUS_LIST_END in
2065 the last reply to indicate the end of the list. If there are only
2066 one reply the status is set to normal STATUS_OK.
2068 This command replies with Channel ID, name and the topic of the
2069 channel. If the channel is private channel the <topic> includes
2075 SILC_STATUS_LIST_START
2076 SILC_STATUS_LIST_END
2077 SILC_STATUS_ERR_WILDCARDS
2078 SILC_STATUS_ERR_NOT_REGISTERED
2079 SILC_STATUS_ERR_TOO_MANY_PARAMS
2080 SILC_STATUS_ERR_NO_SUCH_CHANNEL
2081 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2082 SILC_STATUS_ERR_NO_SUCH_SERVER
2085 6 SILC_COMMAND_TOPIC
2088 Arguments: (1) <Channel ID> (2) [<topic>]]
2090 This command is used to change or view the topic of a channel.
2091 The topic for channel <Channel ID> is returned if there is no
2092 <topic> given. If the <topic> parameter is present, the topic
2093 for that channel will be changed, if the channel modes permit
2096 Reply messages to the command:
2099 Arguments: (1) <Status Payload> (2) <Channel ID>
2102 The command may reply with the topic of the channel if it is
2108 SILC_STATUS_ERR_NOT_ON_CHANNEL
2109 SILC_STATUS_ERR_WILDCARDS
2110 SILC_STATUS_ERR_NOT_REGISTERED
2111 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2112 SILC_STATUS_ERR_NO_SUCH_CHANNEL
2113 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2114 SILC_STATUS_ERR_NO_CHANNEL_ID
2115 SILC_STATUS_ERR_BAD_CHANNEL_ID
2116 SILC_STATUS_ERR_TOO_MANY_PARAMS
2117 SILC_STATUS_ERR_NO_CHANNEL_PRIV
2120 7 SILC_COMMAND_INVITE
2123 Arguments: (1) <Client ID> (2) <Channel ID>
2125 This command is used to invite other clients to join to the
2126 channel. The <Client ID> argument is the target client's ID that
2127 is being invited. The <Channel ID> is the Channel ID of the
2128 requested channel. The sender of this command must be on the
2129 channel. This command must fail if the requested channel does
2130 not exist, the requested client is already on the channel or if
2131 the channel is invite only channel and the caller of this command
2132 does not have at least channel operator privileges.
2134 Reply messages to the command:
2137 Arguments: (1) <Status Payload>
2139 This command replies only with Status Payload.
2144 SILC_STATUS_ERR_NOT_REGISTERED
2145 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2146 SILC_STATUS_ERR_TOO_MANY_PARAMS
2147 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2148 SILC_STATUS_ERR_NO_CLIENT_ID
2149 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2150 SILC_STATUS_ERR_NO_CHANNEL_ID
2151 SILC_STATUS_ERR_NOT_ON_CHANNEL
2152 SILC_STATUS_ERR_USER_ON_CHANNEL
2158 Arguments: (1) [<quit message>]
2160 This command is used by client to end SILC session. The server
2161 must close the connection to a client which sends this command.
2162 if <quit message> is given it will be sent to other clients on
2163 channel if the client is on channel when quitting.
2165 Reply messages to the command:
2167 This command does not reply anything.
2173 Arguments: (1) <Client ID> (2) [<comment>]
2175 This command is used by SILC operators to remove a client from
2176 SILC network. The removing has temporary effects and client may
2177 reconnect to SILC network. The <Client ID> is the client to be
2178 removed from SILC. The <comment> argument may be provided to
2179 give to the removed client some information why it was removed
2182 Reply messages to the command:
2185 Arguments: (1) <Status Payload>
2187 This command replies only with Status Payload.
2192 SILC_STATUS_ERR_WILDCARDS
2193 SILC_STATUS_ERR_NOT_REGISTERED
2194 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2195 SILC_STATUS_ERR_TOO_MANY_PARAMS
2196 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2197 SILC_STATUS_ERR_NO_CLIENT_ID
2200 10 SILC_COMMAND_INFO
2203 Arguments: (1) [<server>]
2205 This command is used to fetch various information about a server.
2206 If <server> argument is specified the command must be sent to
2207 the requested server.
2209 Reply messages to the command:
2212 Arguments: (1) <Status Payload> (2) <Server ID>
2215 This command replies with the Server ID of the server and a
2216 string which tells the information about the server.
2221 SILC_STATUS_ERR_WILDCARDS
2222 SILC_STATUS_ERR_NOT_REGISTERED
2223 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2224 SILC_STATUS_ERR_TOO_MANY_PARAMS
2225 SILC_STATUS_ERR_NO_SUCH_SERVER
2228 11 SILC_COMMAND_CONNECT
2231 Arguments: (1) <Server ID>
2232 (2) [<remote server/router>[ <port>]]
2234 This command is used by operators to force a server to try to
2235 establish a new connection to another router (if the connecting
2236 server is normal server) or server (if the connecting server is
2237 router server). Operator may specify the server/router to be
2238 connected by setting <remote server> argument. The separator
2239 between <remote server address> and <port> is whitespace (` ').
2241 Reply messages to the command:
2244 Arguments: (1) <Status Payload>
2246 This command replies only with Status Payload.
2253 SILC_STATUS_ERR_WILDCARDS
2254 SILC_STATUS_ERR_NOT_REGISTERED
2255 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2256 SILC_STATUS_ERR_TOO_MANY_PARAMS
2257 SILC_STATUS_ERR_NO_SUCH_SERVER_ID
2258 SILC_STATUS_ERR_NO_SERVER_PRIV
2259 SILC_STATUS_ERR_NO_ROUTER_PRIV
2262 12 SILC_COMMAND_PING
2265 Arguments: (1) <Server ID>
2267 This command is used by client and server to test the communication
2268 channel to its server if one suspects that the communication is not
2269 working correctly. The <Server ID> is the ID of the server the
2270 sender is connected to.
2272 Reply messages to the command:
2275 Arguments: (1) <Status Payload>
2277 This command replies only with Status Payload. Server returns
2278 SILC_STATUS_OK in Status Payload if pinging was successful.
2285 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2286 SILC_STATUS_ERR_TOO_MANY_PARAMS
2287 SILC_STATUS_ERR_NO_SERVER_ID
2288 SILC_STATUS_ERR_NO_SUCH_SERVER
2289 SILC_STATUS_ERR_NOT_REGISTERED
2292 13 SILC_COMMAND_OPER
2295 Arguments: (1) <username> (2) <authentication data>
2297 This command is used by normal client to obtain server operator
2298 privileges on some server or router. Note that router operator
2299 has router privileges that supersedes the server operator
2300 privileges and this does not obtain those privileges. Client
2301 must use SILCOPER command to obtain router level privileges.
2303 The <username> is the username set in the server configurations
2304 as operator. The <authentication data> is the data that the
2305 client is authenticated against. It may be passphrase prompted
2306 for user on client's screen or it may be public key
2307 authentication data (data signed with private key), or
2310 Reply messages to the command:
2313 Arguments: (1) <Status Payload>
2315 This command replies only with Status Payload.
2320 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2321 SILC_STATUS_ERR_TOO_MANY_PARAMS
2322 SILC_STATUS_ERR_NOT_REGISTERED
2323 SILC_STATUS_ERR_BAD_PASSWORD
2324 SILC_STATUS_ERR_AUTH_FAILED
2327 14 SILC_COMMAND_JOIN
2330 Arguments: (1) <channel> (2) <Client ID>
2331 (3) [<passphrase>] (4) [<cipher>]
2333 Join to channel/create new channel. This command is used to
2334 join to a channel. If the channel does not exist the channel is
2335 created. If server is normal server this command must be forwarded
2336 to router who will create the channel. The channel may be protected
2337 with passphrase. If this is the case the passphrase must be sent
2338 along the join command.
2340 The name of the <channel> must not include any spaces (` '),
2341 non-printable characters, commas (`,') or any wildcard characters.
2343 The second argument <Client ID> is the Client ID of the client who
2344 is joining to the client. When client sends this command to the
2345 server the <Client ID> must be the client's own ID.
2347 Cipher to be used to secure the traffic on the channel may be
2348 requested by sending the name of the requested <cipher>. This
2349 is used only if the channel does not exist and is created. If
2350 the channel already exists the cipher set previously for the
2351 channel will be used to secure the traffic.
2353 The server must check whether the user is allowed to join to
2354 the requested channel. Various modes set to the channel affect
2355 the ability of the user to join the channel. These conditions
2358 o The user must be invited to the channel if the channel
2359 is invite-only channel.
2361 o The Client ID/nickname/username/hostname must not match
2364 o The correct passphrase must be provided if passphrase
2365 is set to the channel.
2367 o The user count limit, if set, must not be reached.
2369 Reply messages to the command:
2372 Arguments: (1) <Status Payload> (2) <channel>
2373 (3) <Channel ID> (4) <channel mode mask>
2374 (5) <created> (6) <Channel Key Payload>
2375 (7) [<ban mask>] (8) [<invite list>]
2378 This command replies with the channel name requested by the
2379 client, channel ID of the channel and topic of the channel
2380 if it exists. It also replies with the channel mode mask
2381 which tells all the modes set on the channel. If the
2382 channel is created the mode mask is zero (0). If ban mask
2383 and/or invite list is set they are sent as well.
2385 Client receives the channel key in the reply message as well
2386 inside <Channel Key Payload>.
2391 SILC_STATUS_ERR_WILDCARDS
2392 SILC_STATUS_ERR_NOT_REGISTERED
2393 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2394 SILC_STATUS_ERR_TOO_MANY_PARAMS
2395 SILC_STATUS_ERR_BAD_PASSWORD
2396 SILC_STATUS_ERR_CHANNEL_IS_FULL
2397 SILC_STATUS_ERR_NOT_INVITED
2398 SILC_STATUS_ERR_BANNED_FROM_CHANNEL
2399 SILC_STATUS_ERR_BAD_CHANNEL
2400 SILC_STATUS_ERR_USER_ON_CHANNEL
2403 15 SILC_COMMAND_MOTD
2406 Arguments: (1) <server>
2408 This command is used to query the Message of the Day of the server.
2410 Reply messages to the command:
2413 Arguments: (1) <Status Payload> (2) [<motd>]
2415 This command replies with the motd message if it exists.
2420 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2421 SILC_STATUS_ERR_TOO_MANY_PARAMS
2422 SILC_STATUS_ERR_NOT_REGISTERED
2423 SILC_STATUS_ERR_NO_SUCH_SERVER
2426 16 SILC_COMMAND_UMODE
2429 Arguments: (1) <Client ID> (2) <client mode mask>
2431 This command is used by client to set/unset modes for itself.
2432 However, there are some modes that the client may not set itself,
2433 but they will be set by server. However, client may unset any
2434 mode. Modes may be masked together ORing them thus having
2435 several modes set. Client must keep its client mode mask
2436 locally so that the mode setting/unsetting would work without
2437 problems. Client may change only its own modes.
2439 Following client modes are defined:
2441 0x0000 SILC_UMODE_NONE
2443 No specific mode for client. This is the initial
2444 setting when new client is created. The client is
2448 0x0001 SILC_UMODE_SERVER_OPERATOR
2450 Marks the user as server operator. Client cannot
2451 set this mode itself. Server sets this mode to the
2452 client when client attains the server operator
2453 privileges by SILC_COMMAND_OPER command. Client
2454 may unset the mode itself.
2457 0x0002 SILC_UMODE_ROUTER_OPERATOR
2459 Marks the user as router (SILC) operator. Client
2460 cannot this mode itself. Router sets this mode to
2461 the client when client attains the router operator
2462 privileges by SILC_COMMAND_SILCOPER command. Client
2463 may unset the mode itself.
2465 Reply messages to the command:
2468 Arguments: (1) <Status Payload> (2) <client mode mask>
2470 This command replies with the changed client mode mask that
2471 the client is required to keep locally.
2477 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2478 SILC_STATUS_ERR_TOO_MANY_PARAMS
2479 SILC_STATUS_ERR_NOT_REGISTERED
2480 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2481 SILC_STATUS_ERR_BAD_CLIENT_ID
2482 SILC_STATUS_ERR_NOT_YOU
2483 SILC_STATUS_ERR_UNKNOWN_MODE
2484 SILC_STATUS_ERR_NO_RECIPIENT
2485 SILC_STATUS_ERR_NO_CLIENT_ID
2488 17 SILC_COMMAND_CMODE
2491 Arguments: (1) <Channel ID> (2) <channel mode mask>
2492 (3) [<user limit>] (4) [<passphrase>]
2493 (5) [<ban mask>] (6) [<invite list>]
2494 (7) [<cipher>[:<key len>]]
2496 This command is used by client to set or change channel flags on
2497 a channel. Channel has several modes that set various properties
2498 of a channel. Modes may be masked together by ORing them thus
2499 having several modes set. The <Channel ID> is the ID of the
2500 target channel. The client changing channel mode must be on
2501 the same channel and poses sufficient privileges to be able to
2504 When the mode is changed SILC_NOTIFY_TYPE_CMODE_CHANGE notify
2505 type is distributed to the channel.
2507 Following channel modes are defined:
2509 0x0000 SILC_CMODE_NONE
2511 No specific mode on channel. This is the default when
2512 channel is created. This means that channel is just plain
2516 0x0001 SILC_CMODE_PRIVATE
2518 Channel is private channel. Private channels are shown
2519 in the channel list listed with SILC_COMMAND_LIST command
2520 with indication that the channel is private. Also,
2521 client on private channel will no be detected to be on
2522 the channel as the channel is not shown in the client's
2523 currently joined channel list. Channel founder and
2524 channel operator may set/unset this mode.
2526 Typical implementation would use [+|-]p on user interface
2527 to set/unset this mode.
2530 0x0002 SILC_CMODE_SECRET
2532 Channel is secret channel. Secret channels are not shown
2533 in the list listed with SILC_COMMAND_LIST command. Secret
2534 channels can be considered to be invisible channels.
2535 Channel founder and channel operator may set/unset this
2538 Typical implementation would use [+|-]s on user interface
2539 to set/unset this mode.
2542 0x0004 SILC_CMODE_PRIVKEY
2544 Channel uses private channel key to protect the traffic
2545 on the channel. When this mode is set the client will be
2546 responsible to set the key it wants to use to encrypt and
2547 decrypt the traffic on channel. Server generated channel
2548 keys are not used at all. This mode provides additional
2549 security as clients on channel may agree to use private
2550 channel key that even servers do not know. Naturally,
2551 this requires that every client on the channel knows
2552 the key before hand (it is considered to be pre-shared-
2553 key). This specification does not define how the private
2554 channel key is set as it is entirely local setting on
2557 As it is local setting it is possible to have several
2558 private channel keys on one channel. In this case several
2559 clients can talk on same channel but only those clients
2560 that share the key with the message sender will be able
2561 to hear the talking. Client should not display those
2562 message for the end user that it is not able to decrypt
2563 when this mode is set.
2565 Only channel founder may set/unset this mode. If this
2566 mode is unset the server will distribute new channel
2567 key to all clients on the channel which will be used
2570 Typical implementation would use [+|-]k on user interface
2571 to set/unset this mode.
2574 0x0008 SILC_CMODE_INVITE
2576 Channel is invite only channel. Client may join to this
2577 channel only if it is invited to the channel. Channel
2578 founder and channel operator may set/unset this mode.
2580 Typical implementation would use [+|-]i on user interface
2581 to set/unset this mode.
2584 0x0010 SILC_CMODE_TOPIC
2586 The topic of the channel may only be set by client that
2587 is channel founder or channel operator. Normal clients
2588 on channel will not be able to set topic when this mode
2589 is set. Channel founder and channel operator may set/
2592 Typical implementation would use [+|-]t on user interface
2593 to set/unset this mode.
2596 0x0020 SILC_CMODE_ULIMIT
2598 User limit has been set to the channel. New clients
2599 may not join to the channel when the limit set is
2600 reached. Channel founder and channel operator may set/
2601 unset the limit. The <user limit> argument is the
2602 number of limited users.
2604 Typical implementation would use [+|-]l on user interface
2605 to set/unset this mode.
2608 0x0040 SILC_CMODE_PASSPHRASE
2610 Passphrase has been set to the channel. Client may
2611 join to the channel only if it is able to provide the
2612 correct passphrase. Setting passphrases to channel
2613 is entirely safe as all commands are protected in the
2614 SILC network. Only channel founder may set/unset
2615 the passphrase. The <passphrase> argument is the
2618 Typical implementation would use [+|-]a on user interface
2619 to set/unset this mode.
2622 0x0080 SILC_CMODE_BAN
2624 Ban mask has been set to the channel. The ban mask
2625 may be used to ban specific clients to join the channel.
2626 The <ban mask> argument is the set ban mask. When
2627 unsetting a ban mask the mask must be provided as
2628 argument. Channel founder and channel operator may
2629 set/unset this mode. Channel founder may not be
2630 added to the ban list. <ban mask> is comma (`,') separated
2631 list of banned clients in following format:
2633 [<nickname>!][<username>]@[<hostname>]
2635 Wildcards maybe used when banning clients.
2637 Typical implementation would use [+|-]b on user interface
2638 to set/unset this mode.
2641 0x0100 SILC_CMODE_INVITE_LIST
2643 Invite list has been set to the channel. The invite list
2644 can be used to mark the clients that is able to join
2645 channel without being invited when the channel is set to
2646 be invite-only channel. The <invite list> argument is the
2647 set invite mask. When unsetting entry from the invite list
2648 the entry must be provided as argument. Channel founder and
2649 channel operator may set/unset this mode. The <invite list>
2650 is command (`,') separated list of invited clients in following
2653 [<nickname>!][<username>]@[<hostname>]
2655 Wildcards maybe used when setting the invite list.
2657 Typical implementation would use [+|-]I on user interface
2658 to set/unset this mode.
2661 0x0200 SILC_CMODE_CIPHER
2663 Sets specific cipher to be used to protect channel
2664 traffic. The <cipher> argument is the requested cipher.
2665 When set or unset the server must re-generate new
2666 channel key. If <key len> argument is specified with
2667 <cipher> argument the new key is generated of <key len>
2668 length in bits. Only channel founder may set the cipher of
2669 the channel. When unset the new key is generated using
2670 default cipher for the channel.
2672 Typical implementation would use [+|-]c on user interface
2673 to set/unset this mode.
2676 To make the mode system work, client must keep the channel mode
2677 mask locally so that the mode setting and unsetting would work
2678 without problems. The client receives the initial channel mode
2679 mask when it joins to the channel. When the mode changes on
2680 channel the server distributes the changed channel mode mask to
2681 all clients on the channel by sending SILC_COMMAND_CMODE command
2685 Reply messages to the command:
2688 Arguments: (1) <Status Payload> (2) <channel mode mask>
2690 This command replies with the changed channel mode mask that
2691 client is required to keep locally.
2696 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2697 SILC_STATUS_ERR_TOO_MANY_PARAMS
2698 SILC_STATUS_ERR_NOT_REGISTERED
2699 SILC_STATUS_ERR_NOT_ON_CHANNEL
2700 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2701 SILC_STATUS_ERR_BAD_CHANNEL_ID
2702 SILC_STATUS_ERR_NO_CHANNEL_ID
2703 SILC_STATUS_ERR_NO_CHANNEL_PRIV
2704 SILC_STATUS_ERR_UNKNOWN_MODE
2705 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2708 19 SILC_COMMAND_CUMODE
2711 Arguments: (1) <Channel ID> (2) <mode mask>
2714 This command is used by client to change channel user modes on
2715 channel. Users on channel may have some special modes and this
2716 command is used by channel operators to set or change these modes.
2717 The <Channel ID> is the ID of the target channel. The <mode mask>
2718 is OR'ed mask of modes. The <Client ID> is the target client.
2719 The client changing channel user modes must be on the same channel
2720 as the target client and poses sufficient privileges to be able to
2723 When the mode is changed SILC_NOTIFY_TYPE_CUMODE_CHANGE notify
2724 type is distributed to the channel.
2726 Following channel modes are defined:
2728 0x0000 SILC_CUMODE_NONE
2730 No specific mode. This is the normal situation for client.
2731 Also, this is the mode set when removing all modes from client.
2734 0x0001 SILC_CUMODE_FOUNDER
2736 The client is channel founder of the channel. This mode
2737 cannot be set by other client, it is set by the server when
2738 the channel was founded (created). The mode is provided
2739 because client may remove the founder rights from itself.
2742 0x0002 SILC_CUMODE_OPERATOR
2744 Sets channel operator privileges on the channel for a
2745 client on the channel. Channel founder and channel operator
2746 may set/unset (promote/demote) this mode.
2749 Reply messages to the command:
2752 Arguments: (1) <Status Payload> (2) <channel user mode mask>
2755 This command replies with the changed channel user mode mask that
2756 client is required to keep locally. The <Client ID> is the target
2762 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2763 SILC_STATUS_ERR_TOO_MANY_PARAMS
2764 SILC_STATUS_ERR_NOT_REGISTERED
2765 SILC_STATUS_ERR_NOT_ON_CHANNEL
2766 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2767 SILC_STATUS_ERR_BAD_CHANNEL_ID
2768 SILC_STATUS_ERR_NO_CHANNEL_ID
2769 SILC_STATUS_ERR_NO_CHANNEL_PRIV
2770 SILC_STATUS_ERR_UNKNOWN_MODE
2771 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2774 19 SILC_COMMAND_KICK
2777 Arguments: (1) <channel> (2) <Client ID>
2780 This command is used by channel operators to remove a client from
2781 channel. The <channel> argument is the channel the client to be
2782 removed is on currently. Note that the "kicker" must be on the same
2783 channel. If <comment> is provided it will be sent to the removed
2786 Reply messages to the command:
2789 Arguments: (1) <Status Payload>
2791 This command replies only with Status Payload.
2796 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2797 SILC_STATUS_ERR_TOO_MANY_PARAMS
2798 SILC_STATUS_ERR_NOT_REGISTERED
2799 SILC_STATUS_ERR_NO_SUCH_CHANNEL
2800 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
2801 SILC_STATUS_ERR_NO_CHANNEL_PRIV
2802 SILC_STATUS_ERR_NO_CLIENT_ID
2805 20 SILC_COMMAND_RESTART
2810 This command may only be used by server operator to force a
2811 server to restart itself.
2813 Reply messages to the command:
2816 Arguments: (1) <Status Payload>
2818 This command replies only with Status Payload.
2823 SILC_STATUS_ERR_NOT_REGISTERED
2824 SILC_STATUS_ERR_NO_SERVER_PRIV
2830 21 SILC_COMMAND_CLOSE
2833 Arguments: (1) <Server ID>
2835 This command is used only by operator to close connection to a
2836 remote site. The <Server ID> argument is the ID of the remote
2837 site and must be valid.
2839 Reply messages to the command:
2842 Arguments: (1) <Status Payload>
2844 This command replies only with Status Payload.
2849 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2850 SILC_STATUS_ERR_TOO_MANY_PARAMS
2851 SILC_STATUS_ERR_NOT_REGISTERED
2852 SILC_STATUS_ERR_NO_SUCH_SERVER
2853 SILC_STATUS_ERR_NO_SERVER_PRIV
2854 SILC_STATUS_ERR_NO_SUCH_SERVER_ID
2862 This command is used only by operator to shutdown the server.
2863 All connections to the server will be closed and the server is
2866 Reply messages to the command:
2871 Arguments: (1) <Status Payload>
2873 This command replies only with Status Payload.
2878 SILC_STATUS_ERR_NOT_REGISTERED
2879 SILC_STATUS_ERR_NO_SERVER_PRIV
2882 23 SILC_COMMAND_SILCOPER
2885 Arguments: (1) <username> (2) <authentication data>
2887 This command is used by normal client to obtain router operator
2888 privileges (also known as SILC operator) on some router. Note
2889 that router operator has router privileges that supersedes the
2890 server operator privileges.
2892 The <username> is the username set in the server configurations
2893 as operator. The <authentication data> is the data that the
2894 client is authenticated against. It may be passphrase prompted
2895 for user on client's screen or it may be public key
2896 authentication data (data signed with private key), or
2899 Difference between router operator and server operator is that
2900 router operator is able to handle cell level properties while
2901 server operator (even on router server) is able to handle only
2902 local properties, such as, local connections and normal server
2905 Reply messages to the command:
2908 Arguments: (1) <Status Payload>
2910 This command replies only with Status Payload.
2915 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2916 SILC_STATUS_ERR_TOO_MANY_PARAMS
2917 SILC_STATUS_ERR_NOT_REGISTERED
2918 SILC_STATUS_ERR_BAD_PASSWORD
2919 SILC_STATUS_ERR_AUTH_FAILED
2922 24 SILC_COMMAND_LEAVE
2925 Arguments: (1) <Channel ID>
2927 This command is used by client to leave a channel the client is
2928 joined to. After a client has leaved the channel the server
2929 must create new key for the channel and distribute to all clients
2930 still currently on the channel.
2932 Reply messages to the command:
2935 Arguments: (1) <Status Payload>
2937 This command replies only with Status Payload.
2942 SILC_STATUS_ERR_NOT_REGISTERED
2943 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2944 SILC_STATUS_ERR_TOO_MANY_PARAMS
2945 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2946 SILC_STATUS_ERR_BAD_CHANNEL_ID
2947 SILC_STATUS_ERR_NO_CHANNEL_ID
2950 25 SILC_COMMAND_USERS
2953 Arguments: (1) <Channel ID>
2955 This command is used to list user names currently on the requested
2956 channel; argument <Channel ID>. The server must resolve the
2957 user names and send a comma (`,') separated list of user names
2958 on the channel. Server or router may resolve the names by sending
2959 SILC_COMMAND_WHOIS commands.
2961 If the requested channel is a private or secret channel, this
2962 command must not send the list of users, as private and secret
2963 channels cannot be seen by outside. In this case the returned
2964 name list may include a indication that the server could not
2965 resolve the names of the users on the channel. Also, in this case
2966 Client ID's or client modes are not sent either.
2968 Reply messages to the command:
2971 Arguments: (1) <Status Payload> (2) <Channel ID>
2972 (3) <list count> (4) <Client ID list>
2973 (5) <client mode list>
2975 This command replies with the Channel ID of the requested channel
2976 Client ID list of the users on the channel and list of their modes.
2977 The Client ID list has Client ID's of all users in the list. The
2978 <Client ID list> is formed by adding Client ID's one after another.
2979 The <client mode list> is formed by adding client's user modes on
2980 the channel one after another (4 bytes (32 bits) each). The <list
2981 count> of length of 4 bytes (32 bits), tells the number of entries
2982 in the lists. Both lists must have equal number of entries.
2987 SILC_STATUS_ERR_NOT_REGISTERED
2988 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
2989 SILC_STATUS_ERR_TOO_MANY_PARAMS
2990 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
2991 SILC_STATUS_ERR_BAD_CHANNEL_ID
2992 SILC_STATUS_ERR_NO_CHANNEL_ID
2993 SILC_STATUS_ERR_NOT_ON_CHANNEL
2998 Currently undefined commands.
3003 These commands are reserved for private use and will not be defined
3007 255 SILC_COMMAND_MAX
3009 Reserved command. This must not be sent.
3014 5.3 SILC Command Status Types
3017 5.3.1 SILC Command Status Payload
3019 Command Status Payload is sent in command reply messages to indicate
3020 the status of the command. The payload is one of argument in the
3021 command thus this is the data area in Command Argument Payload described
3022 in [SILC2]. The payload is only 2 bytes of length. Following diagram
3023 represents the Command Status Payload (field is always in MSB order).
3032 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
3033 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3035 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3039 Figure 6: SILC Command Status Payload
3043 o Status Message (2 bytes) - Indicates the status message.
3044 All Status messages are described in the next section.
3049 5.3.2 SILC Command Status List
3051 Command Status messages are returned in the command reply messages
3052 to indicate whether the command were executed without errors. If error
3053 has occured the status tells which error occured. Status payload only
3054 sends numeric reply about the status. Receiver of the payload must
3055 convert the numeric values into human readable error messages. The
3056 list of status messages below has an example human readable error
3057 messages that client may display for the user.
3059 List of all defined command status messages following.
3062 Generic status messages:
3066 Ok status. Everything went Ok. The status payload maybe
3067 safely ignored in this case.
3069 1 SILC_STATUS_LIST_START
3071 Start of the list. There will be several command replies and
3072 this reply is the start of the list.
3074 2 SILC_STATUS_LIST_ITEM
3076 Item in the list. This is one of the item in the list but not the
3079 3 SILC_STATUS_LIST_END
3081 End of the list. There were several command replies and this
3082 reply is the last of the list. There won't be other replies
3083 belonging to this list after this one.
3087 Currently undefined and has been reserved for the future.
3090 Error status message:
3092 10 SILC_STATUS_ERR_NO_SUCH_NICK
3094 "No such nickname". Requested nickname does not exist.
3096 11 SILC_STATUS_ERR_NO_SUCH_CHANNEL
3098 "No such channel". Requested channel name does not exist.
3100 12 SILC_STATUS_ERR_NO_SUCH_SERVER
3102 "No such server". Requested server name does not exist.
3104 13 SILC_STATUS_ERR_TOO_MANY_TARGETS
3106 "Duplicate recipients. No message delivered". Message were
3107 tried to be sent to recipient which has several occurrences in
3110 14 SILC_STATUS_ERR_NO_RECIPIENT
3112 "No recipient given". Command required recipient which was
3115 15 SILC_STATUS_ERR_UNKNOWN_COMMAND
3117 "Unknown command". Command sent to server is unknown by the
3120 16 SILC_STATUS_ERR_WILDCARDS
3122 "Wildcards cannot be used". Wildcards were provided but they
3125 17 SILC_STATUS_ERR_NO_CLIENT_ID
3127 "No Client ID given". Client ID were expected as command
3128 parameter but were not found.
3130 18 SILC_STATUS_ERR_NO_CHANNEL_ID
3132 "No Channel ID given". Channel ID were expected as command
3133 parameter but were not found.
3135 19 SILC_STATUS_ERR_NO_SERVER_ID
3137 "No Serve ID given". Server ID were expected as command
3138 parameter but were not found.
3140 20 SILC_STATUS_ERR_BAD_CLIENT_ID
3142 "Bad Client ID". Client ID provided were erroneous.
3144 21 SILC_STATUS_ERR_BAD_CHANNEL_ID
3146 "Bad Channel ID". Channel ID provided were erroneous.
3148 22 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
3150 "No such Client ID". Client ID provided does not exist.
3152 23 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
3154 "No such Channel ID". Channel ID provided does not exist.
3156 24 SILC_STATUS_ERR_NICKNAME_IN_USE
3158 "Nickname already exists". Nickname created could not be
3159 registered because number of same nicknames were already set to
3160 maximum. This is not expected to happen in real life but is
3163 25 SILC_STATUS_ERR_NOT_ON_CHANNEL
3165 "You are not on that channel". The command were specified for
3166 channel user is not currently on.
3168 26 SILC_STATUS_ERR_USER_NOT_ON_CHANNEL
3170 "They are not on channel". The requested target client is not
3171 on requested channel.
3173 27 SILC_STATUS_ERR_USER_ON_CHANNEL
3175 "User already on channel". User were invited on channel they
3178 28 SILC_STATUS_ERR_NOT_REGISTERED
3180 "You have not registered". User executed command that requires
3181 the client to be registered on the server before it may be
3184 29 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
3186 "Not enough parameters". Command requires more parameters
3189 30 SILC_STATUS_ERR_TOO_MANY_PARAMS
3191 "Too many parameters". Too many parameters were provided
3194 31 SILC_STATUS_ERR_PERM_DENIED
3196 "Your host is not among the privileged". The client tried to
3197 register on server that does not allow this host to connect.
3199 32 SILC_STATUS_ERR_BANNED_FROM_SERVER
3201 "You are banned from this server". The client tried to register
3202 on server that has explicitly denied this host to connect.
3204 33 SILC_STATUS_ERR_BAD_PASSWORD
3206 "Cannot join channel. Incorrect password". Password provided for
3207 channel were not accepted.
3209 34 SILC_STATUS_ERR_CHANNEL_IS_FULL
3211 "Cannot join channel. Channel is full". The channel is full
3212 and client cannot be joined to it.
3214 35 SILC_STATUS_ERR_NOT_INVITED
3216 "Cannot join channel. You have not been invited". The channel
3217 is invite only channel and client has not been invited.
3219 36 SILC_STATUS_ERR_BANNED_FROM_CHANNEL
3221 "Cannot join channel. You have been banned". The client has
3222 been banned from the channel.
3224 37 SILC_STATUS_ERR_UNKNOWN_MODE
3226 "Unknown mode". Mode provided by the client were unknown to
3229 38 SILC_STATUS_ERR_NOT_YOU
3231 "Cannot change mode for other users". User tried to change
3232 someone else's mode.
3234 39 SILC_STATUS_ERR_NO_CHANNEL_PRIV
3236 "Permission denied. You are not channel operator". Command may
3237 be executed only by channel operator.
3239 40 SILC_STATUS_ERR_NO_SERVER_PRIV
3241 "Permission denied. You are not server operator". Command may
3242 be executed only by server operator.
3244 41 SILC_STATUS_ERR_NO_ROUTER_PRIV
3246 "Permission denied. You are not SILC operator". Command may be
3247 executed only by router (SILC) operator.
3249 42 SILC_STATUS_ERR_BAD_NICKNAME
3251 "Bad nickname". Nickname requested contained illegal characters
3254 43 SILC_STATUS_ERR_BAD_CHANNEL
3256 "Bad channel name". Channel requested contained illegal characters
3259 44 SILC_STATUS_ERR_AUTH_FAILED
3261 "Authentication failed". The authentication data sent as
3262 argument were wrong and thus authentication failed.
3267 6 Security Considerations
3269 Security is central to the design of this protocol, and these security
3270 considerations permeate the specification. Common security considerations
3271 such as keeping private keys truly private and using adequate lengths for
3272 symmetric and asymmetric keys must be followed in order to maintain the
3273 security of this protocol.
3279 [SILC2] Riikonen, P., "SILC Packet Protocol", Internet Draft,
3282 [SILC3] Riikonen, P., "SILC Key Exchange and Authentication
3283 Protocols", Internet Draft, June 2000.
3285 [IRC] Oikarinen, J., and Reed D., "Internet Relay Chat Protocol",
3288 [SSH-TRANS] Ylonen, T., et al, "SSH Transport Layer Protocol",
3291 [PGP] Callas, J., et al, "OpenPGP Message Format", RFC 2440,
3294 [SPKI] Ellison C., et al, "SPKI Certificate Theory", RFC 2693,
3297 [PKIX-Part1] Housley, R., et al, "Internet X.509 Public Key
3298 Infrastructure, Certificate and CRL Profile", RFC 2459,
3301 [Schneier] Schneier, B., "Applied Cryptography Second Edition",
3302 John Wiley & Sons, New York, NY, 1996.
3304 [Menezes] Menezes, A., et al, "Handbook of Applied Cryptography",
3307 [OAKLEY] Orman, H., "The OAKLEY Key Determination Protocol",
3308 RFC 2412, November 1998.
3310 [ISAKMP] Maughan D., et al, "Internet Security Association and
3311 Key Management Protocol (ISAKMP)", RFC 2408, November
3314 [IKE] Harkins D., and Carrel D., "The Internet Key Exchange
3315 (IKE)", RFC 2409, November 1998.
3317 [HMAC] Krawczyk, H., "HMAC: Keyed-Hashing for Message
3318 Authentication", RFC 2104, February 1997.
3331 EMail: priikone@poseidon.pspt.fi
3333 This Internet-Draft expires 6 Jun 2001