8 .ds RF FORMFEED[Page %]
17 Network Working Group P. Riikonen
19 draft-riikonen-silc-pp-08.txt 11 August 2003
20 Expires: 11 February 2004
26 <draft-riikonen-silc-pp-08.txt>
31 This document is an Internet-Draft and is in full conformance with
32 all provisions of Section 10 of RFC 2026. Internet-Drafts are
33 working documents of the Internet Engineering Task Force (IETF), its
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35 distribute working documents as Internet-Drafts.
37 Internet-Drafts are draft documents valid for a maximum of six months
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39 time. It is inappropriate to use Internet-Drafts as reference
40 material or to cite them other than as "work in progress."
42 The list of current Internet-Drafts can be accessed at
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45 The list of Internet-Draft Shadow Directories can be accessed at
46 http://www.ietf.org/shadow.html
48 The distribution of this memo is unlimited.
54 This memo describes a Packet Protocol used in the Secure Internet Live
55 Conferencing (SILC) protocol, specified in the Secure Internet Live
56 Conferencing, Protocol Specification [SILC1]. This protocol describes
57 the packet types and packet payloads which defines the contents of the
58 packets. The protocol provides secure binary packet protocol that
59 assures that the contents of the packets are secured and authenticated.
73 1 Introduction .................................................. 3
74 1.1 Requirements Terminology .................................. 4
75 2 SILC Packet Protocol .......................................... 4
76 2.1 SILC Packet ............................................... 4
77 2.2 SILC Packet Header ........................................ 5
78 2.3 SILC Packet Types ......................................... 7
79 2.3.1 SILC Packet Payloads ................................ 15
80 2.3.2 Generic payloads .................................... 15
81 2.3.2.1 ID Payload .................................. 15
82 2.3.2.2 Argument Payload ............................ 16
83 2.3.2.3 Argument List Payload ....................... 17
84 2.3.2.4 Channel Payload ............................. 18
85 2.3.2.5 Public Key Payload .......................... 19
86 2.3.2.6 Message Payload ............................. 19
87 2.3.3 Disconnect Payload .................................. 23
88 2.3.4 Success Payload ..................................... 23
89 2.3.5 Failure Payload ..................................... 24
90 2.3.6 Reject Payload ...................................... 24
91 2.3.7 Notify Payload ...................................... 25
92 2.3.8 Error Payload ....................................... 34
93 2.3.9 Channel Message Payload ............................. 34
94 2.3.10 Channel Key Payload ................................ 35
95 2.3.11 Private Message Payload ............................ 37
96 2.3.12 Private Message Key Payload ........................ 37
97 2.3.13 Command Payload .................................... 39
98 2.3.14 Command Reply Payload .............................. 40
99 2.3.15 Connection Auth Request Payload .................... 40
100 2.3.16 New ID Payload ..................................... 41
101 2.3.17 New Client Payload ................................. 42
102 2.3.18 New Server Payload ................................. 43
103 2.3.19 New Channel Payload ................................ 44
104 2.3.20 Key Agreement Payload .............................. 45
105 2.3.21 Resume Router Payload .............................. 46
106 2.3.22 File Transfer Payload .............................. 46
107 2.3.23 Resume Client Payload .............................. 48
108 2.4 SILC ID Types ............................................. 49
109 2.5 Packet Encryption And Decryption .......................... 49
110 2.5.1 Normal Packet Encryption And Decryption ............. 50
111 2.5.2 Channel Message Encryption And Decryption ........... 50
112 2.5.3 Private Message Encryption And Decryption ........... 51
113 2.6 Packet MAC Generation ..................................... 52
114 2.7 Packet Padding Generation ................................. 52
115 2.8 Packet Compression ........................................ 53
116 2.9 Packet Sending ............................................ 53
117 2.10 Packet Reception ......................................... 54
118 2.11 Packet Routing ........................................... 54
119 2.12 Packet Broadcasting ...................................... 55
120 3 Security Considerations ....................................... 56
121 4 References .................................................... 56
122 5 Author's Address .............................................. 58
123 6 Full Copyright Statement ...................................... 58
129 Figure 1: Typical SILC Packet
130 Figure 2: SILC Packet Header
132 Figure 4: Argument Payload
133 Figure 5: Argument List Payload
134 Figure 6: Channel Payload
135 Figure 7: Public Key Payload
136 Figure 8: Message Payload
137 Figure 9: Disconnect Payload
138 Figure 10: Success Payload
139 Figure 11: Failure Payload
140 Figure 12: Reject Payload
141 Figure 13: Notify Payload
142 Figure 14: Error Payload
143 Figure 15: Channel Key Payload
144 Figure 16: Private Message Key Payload
145 Figure 17: Command Payload
146 Figure 18: Connection Auth Request Payload
147 Figure 19: New Client Payload
148 Figure 20: New Server Payload
149 Figure 21: Key Agreement Payload
150 Figure 22: Resume Router Payload
151 Figure 23: File Transfer Payload
152 Figure 24: Resume Client Payload
158 This document describes a Packet Protocol used in the Secure Internet
159 Live Conferencing (SILC) protocol specified in the Secure Internet Live
160 Conferencing, Protocol Specification [SILC1]. This protocol describes
161 the packet types and packet payloads which defines the contents of the
162 packets. The protocol provides secure binary packet protocol that
163 assures that the contents of the packets are secured and authenticated.
164 The packet protocol is designed to be compact to avoid unnecessary
165 overhead as much as possible. This makes the SILC suitable also in
166 environment of low bandwidth requirements such as mobile networks. All
167 packet payloads can also be compressed to further reduce the size of
170 All packets in SILC network are always encrypted and their integrity
171 is assured by computed MACs. The protocol defines several packet types
172 and packet payloads. Each packet type usually has a specific packet
173 payload that actually defines the contents of the packet. Each packet
174 also includes a default SILC Packet Header that provides sufficient
175 information about the origin and the destination of the packet.
179 1.1 Requirements Terminology
181 The keywords MUST, MUST NOT, REQUIRED, SHOULD, SHOULD NOT, RECOMMENDED,
182 MAY, and OPTIONAL, when they appear in this document, are to be
183 interpreted as described in [RFC2119].
187 2 SILC Packet Protocol
192 SILC packets deliver messages from sender to receiver securely by
193 encrypting important fields of the packet. The packet consists of
194 default SILC Packet Header, Padding, Packet Payload data, and, packet
197 The following diagram illustrates typical SILC packet.
201 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
202 | n bytes | 1 - n bytes | n bytes | n bytes
203 | SILC Header | Padding | Data Payload | MAC
204 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
208 Figure 1: Typical SILC Packet
211 SILC Header is always the first part of the packet and its purpose
212 is to provide information about the packet. It provides for example
213 the packet type, origin of the packet and the destination of the packet.
214 The header is variable in length. See the following section for
215 description of SILC Packet header. Packets without SILC header or
216 with malformed SILC header MUST be dropped.
218 Padding follows the packet header. The purpose of the padding is to
219 make the packet multiple by eight (8) or by the block size of the
220 cipher used in the encryption, which ever is larger. The maximum
221 length of padding is currently 128 bytes. The padding is always
222 encrypted. The padding is applied always, even if the packet is
223 not encrypted. See the section 2.7 Padding Generation for more
224 detailed information.
226 Data payload area follows padding and it is the actual data of the
227 packet. The packet data is the packet payloads defined in this
228 protocol. The data payload area is always encrypted.
230 The last part of SILC packet is the packet MAC that assures the
231 integrity of the packet. See the section 2.6 Packet MAC Generation
232 for more information. If compression is used the compression is
233 always applied before encryption.
235 All fields in all packet payloads are always in MSB (most significant
240 2.2 SILC Packet Header
242 The SILC packet header is applied to all SILC packets and it is
243 variable in length. The purpose of SILC Packet header is to provide
244 detailed information about the packet. The receiver of the packet
245 uses the packet header to parse the packet and gain other relevant
246 parameters of the packet.
248 The following diagram represents the SILC packet header.
253 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
254 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
255 | Payload Length | Flags | Packet Type |
256 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
257 | Pad Length | RESERVED | Source ID Len | Dest ID Len |
258 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
264 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
270 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
274 Figure 2: SILC Packet Header
277 o Payload Length (2 bytes) - Indicates the length of the
278 packet not including the padding of the packet.
280 o Flags (1 byte) - Indicates flags to be used in packet
281 processing. Several flags may be set by ORing the flags
284 The following flags are reserved for this field:
289 In this case the field is ignored.
292 Private Message Key 0x01
294 Indicates that the packet data MUST include private
295 message that is encrypted using private key set by
296 client. Servers does not know this key and cannot
297 handle the packet, but passes it along. See section
298 2.5.3 Private Message Encryption And Decryption for
304 Indicates that the packet consists of list of
305 packet payloads indicated by the Packet Type field.
306 The payloads are added one after the other. Note that
307 there are packet types that must not be used as
308 list. Parsing of list packet is done by calculating
309 the length of each payload and parsing them one by
315 Marks the packet to be broadcasted. Client and normal
316 server cannot send broadcast packets. Only router server
317 may send broadcast packet. The router receiving of packet
318 with this flag set MUST send (broadcast) the packet to
319 its primary route. If router has several router connections
320 the packet may be sent only to the primary route. See
321 section 2.12 Packet Broadcasting for description of
327 Marks that the payload of the packet is compressed.
328 The sender of the packet marks this flag when it
329 compresses the payload, and any server or router
330 en route to the recipient MUST NOT unset this flag.
331 See section 2.8 Packet Compression for description of
336 o Packet Type (1 byte) - Indicates the type of the packet.
337 Receiver uses this field to parse the packet. See section
338 2.3 SILC Packets for list of defined packet types.
340 o Pad Length (1 byte) - Indicates the length of the padding
341 applied after the SILC Packet header. Maximum length for
342 padding is 128 bytes.
344 o RESERVED (1 byte) - Reserved field and must include a
347 o Source ID Length (1 byte) - Indicates the length of the
348 Source ID field in the header, not including this or any
351 o Destination ID Length (1 byte) - Indicates the length of the
352 Destination ID field in the header, not including this or
355 o Src ID Type (1 byte) - Indicates the type of ID in the
356 Source ID field. See section 2.4 SILC ID Types for
359 o Source ID (variable length) - The actual source ID that
360 indicates which is the original sender of the packet.
362 o Dst ID Type (1 byte) - Indicates the type of ID in the
363 Destination ID field. See section 2.4 SILC ID Types for
366 o Destination ID (variable length) - The actual destination
367 ID that indicates which is the end receiver of the packet.
372 2.3 SILC Packet Types
374 SILC packet types defines the contents of the packet and it is used by
375 the receiver to parse the packet. The packet type is 8 bits in length.
376 The range for the packet types are from 0 - 255, where 0 is never sent and
377 255 is currently reserved for future extensions and MUST NOT be defined to
378 any other purpose. Every SILC specification compliant implementation
379 SHOULD support all the following packet types.
381 The below list of the SILC Packet types includes reference to the packet
382 payload as well. Packet payloads are the actual packet data area. Each
383 packet type defines packet payload which usually may only be sent with
384 the specific packet type.
386 Most of the packets are packets that must be destined directly to entity
387 that is connected to the sender. It is not allowed, for example, for a
388 router to send SILC_PACKET_DISCONNECT packet to client that is not
389 directly connected to the router. However, there are some special packet
390 types that may be destined to some entity that the sender does not have
391 direct connection with. These packets are for example private message
392 packets, channel message packets, command packets and some other packets
393 that may be broadcasted in the SILC network. The following packet
394 desription list will define it separately if a packet is allowed to be
395 sent to indirectly connected entity. Other packets MUST NOT be sent or
396 accepted, if sent, to indirectly connected entities.
398 Some packets MAY be sent as lists by adding the List flag to the Packet
399 Header and constructing multiple packet payloads one after the other.
400 When this is allowed it is separately defined in the following list.
401 Other packets MUST NOT be sent as list and the List flag MUST NOT be set.
404 List of SILC Packet types are defined as follows.
409 This type is reserved and it is never sent.
412 1 SILC_PACKET_DISCONNECT
414 This packet is sent to disconnect the remote end. Reason of
415 the disconnection is sent inside the packet payload.
417 Payload of the packet: See section 2.3.3 Disconnect Payload
420 2 SILC_PACKET_SUCCESS
422 This packet is sent upon successful execution of a protocol.
423 The status of the success is sent in the packet payload.
425 Payload of the packet: See section 2.3.4 Success Payload
428 3 SILC_PACKET_FAILURE
430 This packet is sent upon failure of a protocol. The status
431 of the failure is sent in the packet payload.
433 Payload of the packet: See section 2.3.5 Failure Payload
438 This packet MAY be sent upon rejection of a protocol. The
439 status of the rejection is sent in the packet payload.
441 Payload of the packet: See section 2.3.6 Reject Payload
446 This packet is used to send notify message. The packet is
447 usually sent between server and client, but also between
448 server and router. Client MUST NOT send this packet. Server
449 MAY destine this packet to channel as well when the packet is
450 distributed to all clients on the channel. This packet MAY
453 Payload of the packet: See section 2.3.7 Notify Payload.
458 This packet is sent when an error occurs. Server MAY
459 send this packet. Client MUST NOT send this packet. The
460 client MAY entirely ignore the packet, however, server is
461 most likely to take action anyway. This packet MAY be sent
462 to entity that is indirectly connected to the sender.
464 Payload of the packet: See section 2.3.8 Error Payload.
467 7 SILC_PACKET_CHANNEL_MESSAGE
469 This packet is used to send messages to channels. The packet
470 includes Channel ID of the channel and the actual message to
471 the channel. Messages sent to the channel are always protected
472 by channel specific keys. This packet MAY be sent to entity
473 that is indirectly connected to the sender.
475 Payload of the packet: See section 2.3.9 Channel Message
479 8 SILC_PACKET_CHANNEL_KEY
481 This packet is used to distribute new key for particular
482 channel when server generates it. Each channel has their own
483 independent keys that is used to protect the traffic on the
484 channel. It is also possible to use channel private keys that
485 are not server generated. In this case this packet is not used.
486 Client MUST NOT send this packet. This packet MAY be sent to
487 entity that is indirectly connected to the sender.
489 Payload of the packet: See section 2.3.10 Channel Key Payload
492 9 SILC_PACKET_PRIVATE_MESSAGE
494 This packet is used to send private messages from client
495 to another client. By default, private messages are protected
496 by session keys established by normal key exchange protocol.
497 However, it is possible to use specific key to protect private
498 messages. See [SILC1] for private message key generation.
499 This packet MAY be sent to entity that is indirectly connected
502 Payload of the packet: See section 2.3.11 Private Message
506 10 SILC_PACKET_PRIVATE_MESSAGE_KEY
508 This packet can be used to agree about a key to be used to
509 protect private messages between two clients. This packet
510 is sent inside the SILC network and protected with session
511 keys. There are other means of agreeing to use private message
512 keys as well, than sending this packet which may not be
513 desirable on all situations. See the [SILC1] for private
514 message key generation. This packet MAY be sent to entity
515 that is indirectly connected to the sender.
517 Payload of the packet: See section 2.3.12 Private Message
521 11 SILC_PACKET_COMMAND
523 This packet is used to send commands from client to server.
524 Server MAY send this packet to other servers as well. All
525 commands are listed in their own section SILC Command Types
526 in [SILC4]. The contents of this packet is command specific.
527 This packet MAY be sent to entity that is indirectly connected
530 Payload of the packet: See section 2.3.13 Command Payload
533 12 SILC_PACKET_COMMAND_REPLY
535 This packet is sent as reply to the SILC_PACKET_COMMAND packet.
536 The contents of this packet is command specific. This packet
537 MAY be sent to entity that is indirectly connected to the
538 sender. This packet MAY be sent as list.
540 Payload of the packet: See section 2.3.14 Command Reply
541 Payload and section 2.3.13 Command
546 13 SILC_PACKET_KEY_EXCHANGE
548 This packet is used to start SILC Key Exchange Protocol,
549 described in detail in [SILC3].
551 Payload of the packet: Payload of this packet is described
552 in the section SILC Key Exchange
553 Protocol and its sub sections in
557 14 SILC_PACKET_KEY_EXCHANGE_1
559 This packet is used as part of the SILC Key Exchange Protocol.
561 Payload of the packet: Payload of this packet is described
562 in the section SILC Key Exchange
563 Protocol and its sub sections in
567 15 SILC_PACKET_KEY_EXCHANGE_2
569 This packet is used as part of the SILC Key Exchange Protocol.
571 Payload of the packet: Payload of this packet is described
572 in the section SILC Key Exchange
573 Protocol and its sub sections in
577 16 SILC_PACKET_CONNECTION_AUTH_REQUEST
579 This packet is used to request an authentication method to
580 be used in the SILC Connection Authentication Protocol. If
581 initiator of the protocol does not know the mandatory
582 authentication method this packet MAY be used to determine it.
583 The party receiving this payload SHOULD respond with the same
584 packet including the mandatory authentication method.
586 Payload of the packet: See section 2.3.15 Connection Auth
590 17 SILC_PACKET_CONNECTION_AUTH
592 This packet is used to start and perform the SILC Connection
593 Authentication Protocol. This protocol is used to authenticate
594 the connecting party. The protocol is described in detail in
597 Payload of the packet: Payload of this packet is described
598 in the section SILC Authentication
599 Protocol and it sub sections in [SILC].
602 18 SILC_PACKET_NEW_ID
604 This packet is used to distribute new IDs from server to
605 router and from router to all other routers in SILC network.
606 This is used when for example new client is registered to
607 SILC network. The newly created IDs of these operations are
608 distributed by this packet. Only server may send this packet,
609 however, client MUST be able to receive this packet. This
610 packet MAY be sent to entity that is indirectly connected
611 to the sender. This packet MAY be sent as list.
613 Payload of the packet: See section 2.3.16 New ID Payload
616 19 SILC_PACKET_NEW_CLIENT
618 This packet is used by client to register itself to the
619 SILC network. This is sent after key exchange and
620 authentication protocols has been completed. Client sends
621 various information about itself in this packet to the server.
623 Payload of the packet: See section 2.3.17 New Client Payload
626 20 SILC_PACKET_NEW_SERVER
628 This packet is used by server to register itself to the
629 SILC network. This is sent after key exchange and
630 authentication protocols has been completed. Server sends
631 this to the router it connected to, or, if router was
632 connecting, to the connected router. Server sends its
633 Server ID and other information in this packet. The client
634 MUST NOT send or receive this packet.
636 Payload of the packet: See section 2.3.18 New Server Payload
639 21 SILC_PACKET_NEW_CHANNEL
641 This packet is used to notify routers about newly created
642 channel. Channels are always created by the router and it MUST
643 notify other routers about the created channel. Router sends
644 this packet to its primary route. Client MUST NOT send this
645 packet. This packet MAY be sent to entity that is indirectly
646 connected to the sender. This packet MAY be sent as list.
648 Payload of the packet: See section 2.3.19 New Channel Payload
653 This packet is used to indicate that re-key must be performed
654 for session keys. See section Session Key Regeneration in
655 [SILC1] for more information. This packet does not have
659 23 SILC_PACKET_REKEY_DONE
661 This packet is used to indicate that re-key is performed and
662 new keys must be used hereafter. This packet does not have a
666 24 SILC_PACKET_HEARTBEAT
668 This packet is used by clients, servers and routers to keep the
669 connection alive. It is RECOMMENDED that all servers implement
670 keepalive actions and perform it to both direction in a link.
671 This packet does not have a payload.
674 25 SILC_PACKET_KEY_AGREEMENT
676 This packet is used by clients to request key negotiation
677 between another client in the SILC network. If the negotiation
678 is started it is performed using the SKE protocol. The result of
679 the negotiation, the secret key material, can be used for
680 example as private message key. The server and router MUST NOT
683 Payload of the packet: See section 2.3.20 Key Agreement Payload
686 26 SILC_PACKET_RESUME_ROUTER
688 This packet is used during backup router protocol when the
689 original primary router of the cell comes back online and wishes
690 to resume the position as being the primary router of the cell.
692 Payload of the packet: See section 2.3.21 Resume Router Payload
697 This packet is used to perform an file transfer protocol in the
698 SILC session with some entity in the network. The packet is
699 multi purpose. The packet is used to tell other entity in the
700 network that the sender wishes to perform an file transfer
701 protocol. The packet is also used to actually tunnel the
702 file transfer protocol stream. The file transfer protocol
703 stream is always protected with the SILC binary packet protocol.
705 Payload of the packet: See section 2.3.22 File Transfer Payload
708 28 SILC_PACKET_RESUME_CLIENT
710 This packet is used to resume a client back to the network
711 after it has been detached. A client is able to detach from
712 the network but the client is still valid client in the network.
713 The client may then later resume its session back by sending
714 this packet to a server. Routers also use this packet to notify
715 other routers in the network that the detached client has resumed.
717 Payload of the packet: See section 2.3.23 Resume Client Payload
722 Currently undefined commands.
727 These packet types are reserved for private use and they will
728 not be defined by this document.
733 This type is reserved for future extensions and currently it
739 2.3.1 SILC Packet Payloads
741 All payloads resides in the main data area of the SILC packet. However
742 all payloads MUST be at the start of the data area after the SILC
743 packet header and padding. All fields in the packet payload are always
744 encrypted, as they reside in the data area of the packet which is
745 always encrypted. Most of the payloads may only be sent with specific
746 packet type which is defined in the description of the payload.
748 There are some other payloads in SILC as well. However, they are not
749 common in the sense that they could be sent at any time. These payloads
750 are not described in this section. These are payloads such as SILC
751 Key Exchange payloads and so on. These are described in [SILC1],
756 2.3.2 Generic payloads
758 This section describes generic payloads that are not associated to any
759 specific packet type. They can be used for example inside some other
766 This payload can be used to send an ID. ID's are variable in length
767 thus this payload provides a way to send variable length ID.
769 The following diagram represents the ID Payload.
774 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
775 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
776 | ID Type | ID Length |
777 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
781 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
789 o ID Type (2 bytes) - Indicates the type of the ID. See
790 section 2.4 SILC ID Types for list of defined ID types.
792 o ID Length (2 bytes) - Length of the ID Data area not
793 including the length of any other fields in the payload.
795 o ID Data (variable length) - The actual ID data. The encoding
796 of the ID data is defined in section 2.4 SILC ID Types.
801 2.3.2.2 Argument Payload
803 Argument Payload is used to set arguments for any packet payload that
804 need and support arguments, such as commands. Number of arguments
805 associated with a packet MUST be indicated by the packet payload which
806 need the arguments. Argument Payloads MUST always reside right after
807 the packet payload needing the arguments. Incorrect amount of argument
808 payloads MUST cause rejection of the packet.
810 The following diagram represents the Argument Payload.
815 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
816 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
817 | Data Length | Argument Type | |
818 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
822 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
826 Figure 4: Argument Payload
830 o Data Length (2 bytes) - Length of the Argument Data field
831 not including the length of any other field in the payload.
833 o Argument Type (1 byte) - Indicates the type of the argument.
834 Every argument can have a specific type that are defined
835 by the packet payload needing the argument. For example
836 every command specify a number for each argument that may be
837 associated with the command. By using this number the receiver
838 of the packet knows what type of argument this is. If there is
839 no specific argument type this field is set to zero (0) value.
841 o Argument Data (variable length) - Argument data.
846 2.3.2.3 Argument List Payload
848 Argument List Payload is a list of Argument Payloads appended one
849 after the other. The number of arguments is indicated in the
852 The following diagram represents the Argument List Payload.
857 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
858 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
860 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
862 ~ Argument Payloads ~
864 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
868 Figure 5: Argument List Payload
872 o Argument Nums (2 bytes) - Indicates the number of Argument
873 Payloads. If zero (0) value is found in this field no
874 arguments are present.
876 o Argument Payloads (variable length) - The Argument Payloads
877 appended one after the other. The payloads can be decoded
878 since the length of the payload is indicated in each of
879 the Argument Payload.
886 2.3.2.4 Channel Payload
888 Generic Channel Payload may be used to send information about a channel,
889 its name, the Channel ID and a mode.
891 The following diagram represents the Channel Payload.
897 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
898 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
899 | Channel Name Length | |
900 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
904 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
905 | Channel ID Length | |
906 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
910 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
912 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
916 Figure 6: New Channel Payload
920 o Channel Name Length (2 bytes) - Length of the Channel Name
923 o Channel Name (variable length) - The name of the channel.
925 o Channel ID Length (2 bytes) - Length of the Channel ID field.
927 o Channel ID (variable length) - The encoded Channel ID.
929 o Mode Mask (4 bytes) - A mode. This can be the mode of the
930 channel but it can also be the mode of a client on the
931 channel. The contents of this field is dependent of the
932 usage of this payload. The usage is defined separately
933 when this payload is used. This is a 32 bit MSB first value.
942 2.3.2.5 Public Key Payload
944 Generic Public Key Payload may be used to send different type of
945 public keys and certificates.
947 The following diagram represents the Public Key Payload.
952 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
953 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
954 | Public Key Length | Public Key Type |
955 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
957 ~ Public Key (or certificate) ~
959 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
963 Figure 7: Public Key Payload
967 o Public Key Length (2 bytes) - The length of the Public Key
968 (or certificate) field, not including any other field.
970 o Public Key Type (2 bytes) - The public key (or certificate)
971 type. This field indicates the type of the public key in
972 the packet. See the [SILC3] for defined public key types.
974 o Public Key (or certificate) (variable length) - The
975 encoded public key or certificate data.
980 2.3.2.6 Message Payload
982 Generic Message Payload can be used to send messages in SILC. It
983 is used to send channel messages and private messages.
985 The following diagram represents the Message Payload.
987 (*) indicates that the field is not encrypted.
1000 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
1001 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1002 | Message Flags | Message Length |
1003 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1007 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1008 | Padding Length | |
1009 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1013 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1015 ~ Initial Vector * ~
1017 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1021 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1025 Figure 8: Message Payload
1029 o Message Flags (2 bytes) - Includes the Message Flags of the
1030 message. The flags can indicate a reason or a purpose for
1031 the message. The following Message Flags are defined:
1033 0x0000 SILC_MESSAGE_FLAG_NONE
1035 No specific flags set.
1037 0x0001 SILC_MESSAGE_FLAG_AUTOREPLY
1039 This message is an automatic reply to an earlier
1042 0x0002 SILC_MESSAGE_FLAG_NOREPLY
1044 There should not be reply messages to this
1047 0x0004 SILC_MESSAGE_FLAG_ACTION
1049 The sender is performing an action and the message
1050 is the indication of the action.
1052 0x0008 SILC_MESSAGE_FLAG_NOTICE
1054 The message is for example an informational notice
1057 0x0010 SILC_MESSAGE_FLAG_REQUEST
1059 This is a generic request flag to send request
1060 messages. A separate document should define any
1061 payloads associated to this flag.
1063 0x0020 SILC_MESSAGE_FLAG_SIGNED
1065 This flag indicates that the message is signed
1066 with sender's private key and thus can be verified
1067 by the receiver using the sender's public key. A
1068 separate document should define the detailed procedure
1069 of the signing process and any associated payloads
1072 0x0040 SILC_MESSAGE_FLAG_REPLY
1074 This is a generic reply flag to send a reply to
1075 previously received request. A separate document
1076 should define any payloads associated to this flag.
1078 0x0080 SILC_MESSAGE_FLAG_DATA
1080 This is a generic data flag, indicating that the
1081 message includes some data which can be interpreted
1082 in a specific way. Using this flag any kind of data
1083 can be delivered inside message payload. A separate
1084 document should define how this flag is interpreted
1085 and define any associated payloads.
1087 0x0100 SILC_MESSAGE_FLAG_UTF8
1089 This flag indicates that the message is UTF-8 encoded
1090 textual message. When sending text messages in SILC
1091 this flag SHOULD be used. When this flag is used the
1092 text sent as message MUST be UTF-8 encoded.
1094 0x0200 - 0x0800 RESERVED
1096 Reserved for future flags.
1098 0x1000 - 0x8000 PRIVATE RANGE
1100 Private range for free use.
1102 o Message Length (2 bytes) - Indicates the length of the
1103 Message Data field in the payload, not including any
1106 o Message Data (variable length) - The actual message data.
1108 o Padding Length (2 bytes) - Indicates the length of the
1109 Padding field in the payload, not including any other
1112 o Padding (variable length) - If this payload is used as
1113 channel messages, the padding MUST be applied because
1114 this payload is encrypted separately from other parts
1115 of the packet. If this payload is used as private
1116 messages, the padding is present only when the payload
1117 is encrypted with private message key. If encrypted
1118 with session keys this field MUST NOT be present and the
1119 Padding Length field includes a zero (0) value. The
1120 padding SHOULD be random data.
1122 o Initial Vector (variable length) - This field MUST be
1123 present when this payload is used as channel messages.
1124 The IV SHOULD be random data for each channel message.
1126 When encrypting private messages with session keys this
1127 field MUST NOT be present. For private messages this
1128 field is present only when encrypting with a static
1129 private message key (pre-shared key). If randomly
1130 generated key material is used this field MUST NOT be
1131 present. Also, If Key Agreement (SKE) was used to
1132 negotiate fresh key material for private message key
1133 this field MUST NOT be present. See the section 4.6
1134 in [SILC1] for more information about IVs when
1135 encrypting private messages.
1137 This field includes the initial vector used in message
1138 encryption. It need to be used in the packet decryption
1139 as well. Contents of this field depends on the encryption
1140 algorithm and encryption mode. This field is not encrypted,
1141 is not included in padding calculation and its length
1142 equals to cipher's block size. This field is authenticated
1145 o MAC (variable length) - The MAC computed from the
1146 Message Flags, Message Length, Message Data, Padding Length,
1147 Padding and Initial Vector fields in that order. The MAC
1148 is computed after the payload is encrypted. This is so
1149 called Encrypt-Then-MAC order; first encrypt, then compute
1150 MAC from ciphertext. The MAC protects the integrity of
1151 the Message Payload. Also, when used as channel messages
1152 it is possible to have multiple private channel keys set,
1153 and receiver can use the MAC to verify which of the keys
1154 must be used in decryption. This field is not present
1155 when encrypting private messages with session key. This
1156 field is not encrypted. This field is authenticated by
1157 the SILC packet MAC.
1162 2.3.3 Disconnect Payload
1164 Disconnect payload is sent upon disconnection. Reason of the
1165 disconnection is sent to the disconnected party in the payload.
1167 The payload may only be sent with SILC_PACKET_DISCONNECT packet. It
1168 MUST NOT be sent in any other packet type. The following diagram
1169 represents the Disconnect Payload.
1175 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
1176 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1180 ~ Disconnect Message ~
1182 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1186 Figure 9: Disconnect Payload
1189 o Status (1 byte) - Indicates the Status Type, defined in [SILC3]
1190 for the reason of disconnection.
1192 o Disconnect Message (variable length) - Human readable UTF-8
1193 encoded string indicating reason of the disconnection. This
1194 field MAY be omitted.
1199 2.3.4 Success Payload
1201 Success payload is sent when some protocol execution is successfully
1202 completed. The payload is simple; indication of the success is sent.
1203 This may be any data, including binary or human readable data, and
1204 it is protocol dependent.
1209 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
1210 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1212 ~ Success Indication ~
1214 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1218 Figure 10: Success Payload
1222 o Success Indication (variable length) - Indication of
1223 the success. This may be for example some flag that
1224 indicates the protocol and the success status or human
1225 readable success message. The true length of this
1226 payload is available by calculating it from the SILC
1232 2.3.5 Failure Payload
1234 This is opposite of Success Payload. Indication of failure of
1235 some protocol is sent in the payload.
1240 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
1241 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1243 ~ Failure Indication ~
1245 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1249 Figure 11: Failure Payload
1253 o Failure Indication (variable length) - Indication of
1254 the failure. This may be for example some flag that
1255 indicates the protocol and the failure status or human
1256 readable failure message. The true length of this
1257 payload is available by calculating it from the SILC
1263 2.3.6 Reject Payload
1265 This payload is sent when some protocol is rejected to be executed.
1266 Other operations MAY send this as well that was rejected. The
1267 indication of the rejection is sent in the payload. The indication
1268 may be binary or human readable data and is protocol dependent.
1274 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
1275 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1277 ~ Reject Indication ~
1279 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1283 Figure 12: Reject Payload
1287 o Reject Indication (variable length) - Indication of
1288 the rejection. This maybe for example some flag that
1289 indicates the protocol and the rejection status or human
1290 readable rejection message. The true length of this
1291 payload is available by calculating it from the SILC
1298 2.3.7 Notify Payload
1300 Notify payload is used to send notify messages. The payload is usually
1301 sent from server to client and from server to router. It is also used
1302 by routers to notify other routers in the network. This payload MAY also
1303 be sent to a channel. Client MUST NOT send this payload. When this
1304 packet is received by client it SHOULD process it. Servers and routers
1305 MUST process notify packets.
1307 The payload may only be sent with SILC_PACKET_NOTIFY packet. It MUST
1308 NOT be sent in any other packet type. The following diagram represents
1316 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
1317 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1318 | Notify Type | Payload Length |
1319 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1325 Figure 13: Notify Payload
1329 o Notify Type (2 bytes) - Indicates the type of the notify
1332 o Payload Length (2 bytes) - Length of the entire Notify Payload
1333 including any associated Argument Payloads.
1335 o Argument Nums (1 byte) - Indicates the number of Argument
1336 Payloads associated to this payload. Notify types may define
1337 arguments to be sent along the notify message.
1340 The following list of currently defined notify types. The format for
1341 notify arguments is same as in SILC commands described in [SILC4].
1342 Note that all IDs sent in arguments are sent inside ID Payload. Also
1343 note that all passphrases that may be sent inside arguments MUST be
1344 UTF-8 [RFC2279] encoded. Also note that all public keys or certificates
1345 sent inside arguments are actually Public Key Payloads.
1349 0 SILC_NOTIFY_TYPE_NONE
1351 If no specific notify type apply for the notify message this type
1355 Arguments: (1) <message>
1357 The <message> is implementation specific free UTF-8 text string.
1358 Receiver MAY ignore this message.
1361 1 SILC_NOTIFY_TYPE_INVITE
1363 Sent when an client is invited to a channel. This is also sent
1364 when the invite list of the channel is changed. This notify type
1365 is sent to local servers on the channel, but MUST NOT be sent
1366 to clients on the channel. Router MUST broadcast this to its
1367 primary router and to local servers on the channel. When a client
1368 was directly invited to the channel this is also sent to that
1369 client. In this case the packet is destined to the client.
1372 Arguments: (1) <Channel ID> (2) <channel name>
1373 (3) [<sender Client ID>] (4) [<add | del>]
1376 The <Channel ID> is the channel. The <channel name> is the name
1377 of the channel and is provided because the client which receives
1378 this notify packet may not have a way to resolve the name of the
1379 channel from the <Channel ID>. The <sender Client ID> is the
1380 Client ID which invited the client to the channel. The
1381 <add | del> is an argument of size of 1 byte where 0x00 means
1382 adding a client to invite list, and 0x01 means deleting a client
1383 from invite list. The <invite list>, if present, indicates the
1384 information to be added to or removed from the invite list.
1385 The <invite list> format is defined in [SILC4] with
1386 SILC_COMMAND_INVITE command. When this notify is destined to
1387 a client the <add | del> and <invite list> MUST NOT be sent.
1388 When <add | del> is used to announce information during server
1389 connecting phase the argument type MUST be 0x03. See section
1390 4.2.1 in [SILC1] for more information.
1393 2 SILC_NOTIFY_TYPE_JOIN
1395 Sent when client has joined to a channel. The server MUST
1396 distribute this type to the local clients on the channel and then
1397 send it to its primary router. Note that, when router is joining
1398 the client on behalf of normal server then router MUST send this
1399 notify type locally and globally. The router or server receiving
1400 the packet distributes this type to the local clients on the
1401 channel and broadcast it to the network. This notify is sent
1402 also to the client that joined the channel.
1405 Arguments: (1) [<Client ID>] (2) <Channel ID>
1407 The <Client ID> is the client that joined to the channel
1408 indicated by the <Channel ID>.
1411 3 SILC_NOTIFY_TYPE_LEAVE
1413 Sent when client has left a channel. The server must distribute
1414 this type to the local clients on the channel and then send it
1415 to its primary router. The router or server receiving the
1416 packet distributes this type to the local clients on the channel
1417 and broadcast it to the network. This notify MUST NOT be sent to
1421 Arguments: (1) <Client ID>
1423 The <Client ID> is the client which left the channel.
1426 4 SILC_NOTIFY_TYPE_SIGNOFF
1428 Sent when client signoff from SILC network. The server MUST
1429 distribute this type to the local clients on the channel and
1430 then send it to its primary router. The router or server
1431 receiving the packet distributes this type to the local clients
1432 on the channel and broadcast it to the network. This notify
1433 MUST NOT be sent to the quitting client.
1436 Arguments: (1) <Client ID> (2) <message>
1438 The <Client ID> is the client which left SILC network. The
1439 <message> is free text string indicating the reason of the
1443 5 SILC_NOTIFY_TYPE_TOPIC_SET
1445 Sent when topic is set/changed on a channel. This type may be
1446 sent only to the clients which are joined on the channel which
1447 topic was just set or changed. The packet is destined to the
1451 Arguments: (1) <ID Payload> (2) <topic>
1453 The <ID Payload> is the ID of the entity who set the topic.
1454 It usually is Client ID but it can be Server ID and Channel ID
1458 6 SILC_NOTIFY_TYPE_NICK_CHANGE
1460 Sent when client changes nick on a channel. The server MUST
1461 distribute this type only to the local clients on the channel
1462 and then send it to its primary router. The router or server
1463 receiving the packet distributes this type to the local clients
1464 on the channel and broadcast it to the network. This packet is
1465 destined directly to the sent entity. This MUST be sent to those
1466 clients that are joined on same channels as the client that
1467 changed the nickname. This notify MUST NOT be sent multiple
1468 times to the same recipient. This notify MUST be sent also to
1469 the client that changed the nickname.
1472 Arguments: (1) <Old Client ID> (2) <New Client ID>
1475 The <Old Client ID> is the old ID of the client which changed
1476 the nickname. The <New Client ID> is the new ID generated by
1477 the change of the nickname. The <nickname> is the new nickname.
1478 Note that it is possible to send this notify even if the
1479 nickname has not changed, but client ID was changed.
1482 7 SILC_NOTIFY_TYPE_CMODE_CHANGE
1484 Sent when channel mode has changed. This type MUST be sent only
1485 to the clients which are joined on the channel which mode was
1486 changed. This packet is destined to the channel.
1489 Arguments: (1) <ID Payload> (2) <mode mask>
1490 (3) [<cipher>] (4) <[hmac>]
1491 (5) [<passphrase>] (6) [<founder public key>]
1492 (7) [<channel pubkey>]
1494 The <ID Payload> is the ID (usually Client ID but it can be
1495 Server ID as well when the router is enforcing channel mode
1496 change) of the entity which changed the mode. The <mode mask>
1497 is the new mode mask of the channel. The client can safely
1498 ignore the <cipher> argument since the SILC_PACKET_CHANNEL_KEY
1499 packet will force the new channel key change anyway. The <hmac>
1500 argument is important since the client is responsible of setting
1501 the new HMAC and the hmac key into use. The <passphrase> is
1502 the passphrase of the channel, if it was now set. The <founder
1503 public key> argument is sent when the founder mode on the
1504 channel was set. All routers and servers that receive the packet
1505 MUST save the founder's public key so that the founder can
1506 reclaim the channel founder rights back for the channel on any
1507 server in the network.
1509 The <channel pubkey> is an Argument List Payload and it is used
1510 to add and/or remove channel public keys from the channel. Also,
1511 when announcing channel information between servers and routers
1512 during connecting phase this argument includes the list of channel
1513 public keys. To add a public key to channel public key list the
1514 SILC_CMODE_CHANNEL_AUTH mode is set and the argument type is 0x00,
1515 and the argument is the public key. To remove a public key from
1516 the channel public key list the argument type is 0x01, and the
1517 argument is the public key to be removed. If the mode
1518 SILC_CMODE_CHANNEL_AUTH is unset (and was set earlier) all public
1519 keys are removed at once. Implementation MAY add and remove
1520 multiple public keys at the same time by including multiple
1521 arguments to the <channel pubkey> Argument List Payload where each
1522 argument is one Public Key Payload. When <channel pubkey> is used
1523 to announce information during server connecting phase the
1524 argument type MUST be 0x03. See section 4.2.1 in [SILC1] for
1528 8 SILC_NOTIFY_TYPE_CUMODE_CHANGE
1530 Sent when user mode on channel has changed. This type MUST be
1531 sent only to the clients which are joined on the channel where
1532 the target client is on. This packet is destined to the channel.
1535 Arguments: (1) <ID Payload> (2) <mode mask>
1536 (3) <Target Client ID> (4) [<founder pubkey>]
1538 The <ID Payload> is the ID (usually Client ID but it can be
1539 Server ID as well when the router is enforcing user's mode
1540 change) of the entity which changed the mode. The <mode mask>
1541 is the new mode mask of the channel. The <Target Client ID>
1542 is the client which mode was changed. The <founder pubkey>
1543 is the public key of the channel founder and may be sent only
1544 when first time setting the channel founder mode using the
1545 SILC_COMMAND_CUMODE command, and when sending this notify.
1548 9 SILC_NOTIFY_TYPE_MOTD
1550 Sent when Message of the Day (motd) is sent to a client.
1553 Arguments: (1) <motd>
1555 The <motd> is the Message of the Day. This notify MAY be
1559 10 SILC_NOTIFY_TYPE_CHANNEL_CHANGE
1561 Sent when channel's ID has changed for a reason or another.
1562 This is sent by normal server to the client. This can also be
1563 sent by router to other server to force the Channel ID change.
1564 The Channel ID MUST be changed to use the new one. When sent
1565 to clients, this type MUST be sent only to the clients which are
1566 joined on the channel. This packet is destined to the sent
1570 Arguments: (1) <Old Channel ID> (2) <New Channel ID>
1572 The <Old Channel ID> is the channel's old ID and the <New
1573 Channel ID> is the new one that MUST replace the old one.
1574 Server which receives this from router MUST re-announce the
1575 channel to the router by sending SILC_PACKET_NEW_CHANNEL packet
1576 with the new Channel ID.
1579 11 SILC_NOTIFY_TYPE_SERVER_SIGNOFF
1581 Sent when server quits SILC network. Those clients from this
1582 server that are on channels must be removed from the channel.
1583 This packet is destined to the sent entity.
1586 Arguments: (1) <Server ID> (n) [<Client ID>] [...]
1588 The <Server ID> is the server's ID. The rest of the arguments
1589 are the Client IDs of the clients which are coming from this
1590 server and are thus quitting the SILC network also. If the
1591 maximum number of arguments are reached another
1592 SILC_NOTIFY_TYPE_SERVER_SIGNOFF notify packet MUST be sent.
1593 When this notify packet is sent between routers the Client ID's
1594 MAY be omitted. Server receiving the Client ID's in the payload
1595 may use them directly to remove the client.
1598 12 SILC_NOTIFY_TYPE_KICKED
1600 Sent when a client has been kicked from a channel. This MUST
1601 also be sent to the client which was kicked from the channel.
1602 The client which was kicked from the channel MUST be removed
1603 from the channel. The client MUST also be removed from channel's
1604 invite list if it is explicitly added in the list. This packet
1605 is destined to the channel. The router or server receiving the
1606 packet distributes this type to the local clients on the channel
1607 and broadcast it to the network.
1610 Arguments: (1) <Client ID> (2) [<comment>]
1611 (3) <Kicker's Client ID>
1613 The <Client ID> is the client which was kicked from the channel.
1614 The kicker may have set the <comment> to indicate the reason for
1615 the kicking. The <Kicker's Client ID> is the kicker.
1618 13 SILC_NOTIFY_TYPE_KILLED
1620 Sent when a client has been killed from the network. This MUST
1621 also be sent to the client which was killed from the network.
1622 This notify MUST be sent to those clients which are joined on
1623 same channels as the killed client. The client which was killed
1624 MUST be removed from the network. This packet is destined
1625 directly to the sent entity. The router or server receiving
1626 the packet distributes this type to the local clients on the
1627 channel and broadcast it to the network. The client MUST also
1628 be removed from joined channels invite list if it is explicitly
1629 added in the lists. This notify MUST NOT be sent multiple
1630 times to same recipient.
1633 Arguments: (1) <Client ID> (2) [<comment>]
1636 The <Client ID> is the client which was killed from the network.
1637 The killer may have set the <comment> to indicate the reason for
1638 the killing. The <Killer's ID> is the killer, which may be
1639 client but also router server.
1642 14 SILC_NOTIFY_TYPE_UMODE_CHANGE
1644 Sent when user's mode in the SILC changes. This type is sent
1645 only between routers as broadcast packet.
1648 Arguments: (1) <Client ID> (2) <mode mask>
1650 The <Client ID> is the client which mode was changed. The
1651 <mode mask> is the new mode mask.
1654 15 SILC_NOTIFY_TYPE_BAN
1656 Sent when the ban list of the channel is changed. This notify
1657 type is sent to local servers on the channel, but MUST NOT be
1658 sent to clients on the channel. Router MUST broadcast this to
1659 its primary router and to local servers on the channel.
1662 Arguments: (1) <Channel ID> (2) [<add | del>]
1665 The <Channel ID> is the channel which ban list was changed.
1666 The <add | del> is an argument of size of 1 byte where 0x00 means
1667 adding a client to ban list, and 0x01 means deleting a client
1668 from ban list. The <ban list> indicates the information to be
1669 added to or removed from the ban list. The <ban list> format
1670 format is defined in [SILC4] with SILC_COMMAND_BAN command.
1671 When <add | del> is used to announce information during server
1672 connecting phase the argument type MUST be 0x03. See section
1673 4.2.1 in [SILC1] for more information.
1676 16 SILC_NOTIFY_TYPE_ERROR
1678 Sent when an error occurs during processing some SILC procedure.
1679 This is not used when error occurs during command processing, see
1680 [SILC4] for more information about commands and command replies.
1681 This type is sent directly to the sender of the packet whose
1682 packet caused the error. See [SILC1] for definition when this
1686 Arguments: (1) <Status Type> (n) [...]
1688 The <Status Type> is the error type defined in [SILC4]. Note
1689 that same types are also used with command replies to indicate
1690 the status of a command. Both commands and this notify type
1691 share same status types. Rest of the arguments are status type
1692 dependent and are specified with those status types that can be
1693 sent currently inside this notify type in [SILC4]. The <Status
1694 Type> is size of 1 byte.
1697 17 SILC_NOTIFY_TYPE_WATCH
1699 Sent to indicate change in a watched user. Client can set
1700 nicknames to be watched with SILC_COMMAND_WATCH command, and
1701 receive notifications when they login to network, signoff from
1702 the network or their user mode is changed. This notify type
1703 is used to deliver these notifications. The notify type is
1704 sent directly to the watching client.
1707 Arguments: (1) <Client ID> (2) [<nickname>]
1708 (3) <user mode> (4) [<Notify Type>]
1710 The <Client ID> is the user's Client ID which is being watched,
1711 and the <nickname> is its nickname. If the client just
1712 changed the nickname, then <nickname> is the new nickname, but
1713 the <Client ID> is the old client ID. The <user mode> is the
1714 user's current user mode. The <Notify Type> can be same as the
1715 Notify Payload's Notify Type, and is 16 bit MSB first order
1716 value. If provided it may indicate the notify that occurred
1717 for the client. If client logged in to the network the
1718 <Notify Type> MUST NOT be present.
1721 Notify types starting from 16384 are reserved for private notify
1724 Router server which receives SILC_NOTIFY_TYPE_SIGNOFF,
1725 SILC_NOTIFY_TYPE_SERVER_SIGNOFF, SILC_NOTIFY_TYPE_KILLED,
1726 SILC_NOTIFY_TYPE_NICK_CHANGE and SILC_NOTIFY_TYPE_UMODE_CHANGE
1727 MUST check whether someone in the local cell is watching the nickname
1728 the client has, and send the SILC_NOTIFY_TYPE_WATCH notify to the
1729 watcher, unless the watched client in case has the user mode
1730 SILC_UMODE_REJECT_WATCHING set. If the watcher client and the client
1731 that was watched is same the notify SHOULD NOT be sent.
1740 Error payload is sent upon error in protocol. Error may occur in
1741 various conditions when server sends this packet. Client MUST NOT
1742 send this payload but MUST be able to accept it. However, client
1743 MAY ignore the contents of the packet as server is going to take
1744 action on the error anyway. However, it is recommended that the
1745 client takes error packet seriously.
1751 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
1752 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1756 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1760 Figure 14: Error Payload
1764 o Error Message (variable length) - Human readable error
1765 message as UTF-8 string.
1770 2.3.9 Channel Message Payload
1772 Channel Message Payload is used to send message to channels, a group
1773 of users. These messages can only be sent if client has joined to
1774 some channel. Even though this packet is very common in SILC it
1775 is still special packet. Some special handling on sending and
1776 reception of channel message is required.
1778 Padding MUST be applied into this payload since the payload is
1779 encrypted separately from other parts of the packet with the
1780 channel specific key. Hence the requirement of the padding.
1781 The packet MUST be made multiple by eight (8) or by the block
1782 size of the cipher, which ever is larger.
1784 The SILC header in this packet is encrypted with the session key
1785 of the next receiver of the packet. Nothing else is encrypted
1786 with that key. Thus, the actual packet and padding to be
1787 encrypted with the session key is SILC Header plus padding to it.
1789 Receiver of the the channel message packet is able to determine
1790 the channel the message is destined to by checking the Destination
1791 ID from the SILC Packet header which tells the destination channel.
1792 The original sender of the packet is also determined by checking
1793 the source ID from the header which tells the client which sent
1794 the message. The Destination ID MUST be Channel ID in the SILC
1797 This packet use generic Message Payload as Channel Message Payload.
1798 See section 2.3.2.6 for generic Message Payload.
1802 2.3.10 Channel Key Payload
1804 All traffic in channels are protected by channel specific keys.
1805 Channel Key Payload is used to distribute channel keys to all
1806 clients on the particular channel. Channel keys are sent when
1807 the channel is created, when new user joins to the channel and
1808 whenever a user has left a channel. Server creates the new
1809 channel key and distributes it to the clients by encrypting this
1810 payload with the session key shared between the server and
1811 the client. After that, client MUST start using the key received
1812 in this payload to protect the traffic on the channel.
1814 The client which is joining to the channel receives its key in the
1815 SILC_COMMAND_JOIN command reply message thus it is not necessary to
1816 send this payload to the entity which sent the SILC_COMMAND_JOIN
1819 Channel keys are cell specific thus every router in the cell have
1820 to create a channel key and distribute it if any client in the
1821 cell has joined to a channel. Channel traffic between cell's
1822 are not encrypted using channel keys, they are encrypted using
1823 normal session keys between two routers. Inside a cell, all
1824 channel traffic is encrypted with the specified channel key.
1825 Channel key SHOULD expire periodically, say, in one hour, in
1826 which case new channel key is created and distributed.
1828 Note that, this packet is not used if SILC_CMODE_PRIVKEY mode is set
1829 on channel. This means that channel uses channel private keys which
1830 are not server generated. For this reason server cannot send this
1831 packet as it does not know the key.
1833 The payload may only be sent with SILC_PACKET_CHANNEL_KEY packet.
1834 It MUST NOT be sent in any other packet type. The following diagram
1835 represents the Channel Key Payload.
1846 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
1847 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1848 | Channel ID Length | |
1849 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1853 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1854 | Cipher Name Length | |
1855 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1859 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1860 | Channel Key Length | |
1861 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1865 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1869 Figure 15: Channel Key Payload
1874 o Channel ID Length (2 bytes) - Indicates the length of the
1875 Channel ID field in the payload, not including any other
1878 o Channel ID (variable length) - The Channel ID of the
1881 o Cipher Name Length (2 bytes) - Indicates the length of the
1882 Cipher name field in the payload, not including any other
1885 o Cipher Name (variable length) - Name of the cipher used
1886 in the protection of channel traffic. This name is
1887 initially decided by the creator of the channel but it
1888 may change during the life time of the channel as well.
1890 o Channel Key Length (2 bytes) - Indicates the length of the
1891 Channel Key field in the payload, not including any other
1894 o Channel Key (variable length) - The actual channel key
1900 2.3.11 Private Message Payload
1902 Private Message Payload is used to send private message between
1903 two clients. The messages are sent only to the specified user
1904 and no other user inside SILC network is able to see the message.
1906 The message can be protected by the session key established by the
1907 SILC Key Exchange Protocol. However, it is also possible to agree
1908 to use a private key to protect just the private messages. It is
1909 for example possible to perform Key Agreement between two clients.
1910 See section 2.3.20 Key Agreement Payload how to perform key
1911 agreement. See also section 2.3.12 Private Message Key Payload
1912 for another way of using private keys with private messages. See
1913 [SILC1] section 4.6 for detailed description for private message
1914 key generation procedure.
1916 If normal session key is used to protect the message, every server
1917 between the sender client and the receiving client MUST decrypt the
1918 packet and always re-encrypt it with the session key of the next
1919 receiver of the packet. See section Client To Client in [SILC1].
1921 When the private message key is used, and the Private Message Key
1922 flag was set in the SILC Packet header no server or router en route
1923 is able to decrypt or re-encrypt the packet. In this case only the
1924 SILC Packet header is processed by the servers and routers en route.
1925 Section Client To Client in [SILC1] gives example of this scheme.
1927 This packet use generic Message Payload as Private Message Payload.
1928 See section 2.3.2.6 for generic Message Payload.
1932 2.3.12 Private Message Key Payload
1934 This payload is OPTIONAL and can be used to send private message
1935 key between two clients in the network. The packet is secured with
1936 normal session keys. By default private messages are encrypted
1937 with session keys, and with this payload it is possible to set
1938 private key for private message encryption between two clients.
1940 The receiver of this payload SHOULD verify for example from user
1941 whether user want to receive private message key. Note that there
1942 are other, more secure ways of exchanging private message keys in
1943 the SILC network. Instead of sending this payload it is possible to
1944 negotiate the private message key with SKE protocol using the Key
1945 Agreement payload directly peer to peer, see section 2.3.20.
1947 This payload may only be sent by client to another client. Server
1948 MUST NOT send this payload. After sending this payload the sender of
1949 private messages must set the Private Message Key flag into SILC Packet
1952 The payload may only be sent with SILC_PACKET_PRIVATE_MESSAGE_KEY
1953 packet. It MUST NOT be sent in any other packet type. The following
1954 diagram represents the Private Message Key Payload.
1962 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
1963 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1964 | Private Message Key Length | |
1965 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1967 ~ Private Message Key ~
1969 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1970 | Cipher Name Length | |
1971 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1975 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1976 | HMAC Name Length | |
1977 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
1981 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1985 Figure 16: Private Message Key Payload
1990 o Private Message Key Length (2 bytes) - Indicates the length
1991 of the Private Message Key field in the payload, not including
1994 o Private Message Key (variable length) - The actual private
1995 message key material.
1997 o Cipher Name Length (2 bytes) - Indicates the length of the
1998 Cipher Name field in the payload, not including any other
2001 o Cipher Name (variable length) - Name of the cipher to use
2002 in the private message encryption. If this field does not
2003 exist then the default cipher of the SILC protocol is used.
2004 See the [SILC1] for defined ciphers.
2006 o HMAC Name Length (2 bytes) - Indicates the length of the
2007 HMAC Name field in the payload, not including any other
2010 o HMAC Name (variable length) - Name of the HMAC to use
2011 in the private message MAC computation. If this field does
2012 not exist then the default HMAC of the SILC protocol is used.
2013 See the [SILC1] for defined HMACs.
2018 2.3.13 Command Payload
2020 Command Payload is used to send SILC commands from client to server.
2021 Also server MAY send commands to other servers. The following diagram
2022 represents the Command Payload.
2028 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
2029 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2030 | Payload Length | SILC Command | Arguments Num |
2031 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2032 | Command Identifier |
2033 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2037 Figure 17: Command Payload
2041 o Payload Length (2 bytes) - Length of the entire command
2042 payload including any command argument payloads associated
2045 o SILC Command (1 byte) - Indicates the SILC command. This MUST
2046 be set to non-zero value. If zero (0) value is found in this
2047 field the packet MUST be discarded.
2049 o Arguments Num (1 byte) - Indicates the number of arguments
2050 associated with the command. If there are no arguments this
2051 field is set to zero (0). The arguments MUST follow the
2052 Command Payload. See section 2.3.2.2 for definition of the
2055 o Command Identifier (2 bytes) - Identifies this command at the
2056 sender's end. The entity which replies to this command MUST
2057 set the value found from this field into the Command Payload
2058 used to send the reply to the sender. This way the sender
2059 can identify which command reply belongs to which originally
2060 sent command. What this field includes is implementation
2061 issue but it is RECOMMENDED that wrapping counter value is
2065 See [SILC4] for detailed description of different SILC commands,
2066 their arguments and their reply messages.
2070 2.3.14 Command Reply Payload
2072 Command Reply Payload is used to send replies to the commands. The
2073 Command Reply Payload is identical to the Command Payload thus see
2074 the 2.3.13 section for the payload specification.
2076 The entity which sends the reply packet MUST set the Command Identifier
2077 field in the reply packet's Command Payload to the value it received
2078 in the original command packet.
2080 See SILC Commands in [SILC4] for detailed description of different
2081 SILC commands, their arguments and their reply messages.
2085 2.3.15 Connection Auth Request Payload
2087 Client MAY send this payload to server to request the authentication
2088 method that must be used in authentication protocol. If client knows
2089 this information beforehand this payload is not necessary to be sent.
2090 Server performing authentication with another server MAY also send
2091 this payload to request the authentication method. If the connecting
2092 server already knows this information this payload is not necessary
2095 Server receiving this request SHOULD reply with same payload sending
2096 the mandatory authentication method. Algorithms that may be required
2097 to be used by the authentication method are the ones already
2098 established by the SILC Key Exchange protocol. See section Key
2099 Exchange Start Payload in [SILC3] for detailed information.
2101 The payload may only be sent with SILC_PACKET_CONNECTION_AUTH_REQUEST
2102 packet. It MUST NOT be sent in any other packet type. The following
2103 diagram represents the Connection Auth Request Payload.
2111 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
2112 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2113 | Connection Type | Authentication Method |
2114 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2118 Figure 18: Connection Auth Request Payload
2122 o Connection Type (2 bytes) - Indicates the type of the
2123 connection. The following connection types are defined:
2130 If any other type is found in this field the packet MUST be
2131 discarded and the authentication MUST be failed.
2133 o Authentication Method (2 bytes) - Indicates the authentication
2134 method to be used in the authentication protocol. The following
2135 authentication methods are defined:
2138 1 password (mandatory)
2139 2 public key (mandatory)
2141 If any other type is found in this field the packet MUST be
2142 discarded and the authentication MUST be failed. If this
2143 payload is sent as request to receive the mandatory
2144 authentication method this field MUST be set to zero (0),
2145 indicating that receiver should send the mandatory
2146 authentication method. The receiver sending this payload
2147 to the requesting party, MAY also set this field to zero (0)
2148 to indicate that authentication is not required. In this
2149 case authentication protocol still MUST be started but
2150 server is most likely to respond with SILC_PACKET_SUCCESS
2156 2.3.16 New ID Payload
2158 New ID Payload is a multipurpose payload. It is used to send newly
2159 created ID's from clients and servers. When client connects to server
2160 and registers itself to the server by sending SILC_PACKET_NEW_CLIENT
2161 packet, server replies with this packet by sending the created ID for
2162 the client. Server always creates the ID for the client.
2164 This payload is also used when server tells its router that new client
2165 has registered to the SILC network. In this case the server sends
2166 the Client ID of the client to the router. Similarly when router
2167 distributes information to other routers about the client in the SILC
2168 network this payload is used.
2170 Also, when server connects to router, router use this payload to inform
2171 other routers about new server in the SILC network. However, every
2172 server (or router) creates their own ID's thus the ID distributed by
2173 this payload is not created by the distributor in this case. Servers
2174 create their own ID's. Server registers itself to the network by
2175 sending SILC_PACKET_NEW_SERVER to the router it connected to. The case
2176 is same when router connects to another router.
2178 This payload MUST NOT be used to send information about new channels.
2179 New channels are always distributed by sending the dedicated
2180 SILC_PACKET_NEW_CHANNEL packet. Client MUST NOT send this payload.
2181 Both client and server (and router) MAY receive this payload.
2183 The packet use generic ID Payload as New ID Payload. See section
2184 2.3.2.1 for generic ID Payload.
2188 2.3.17 New Client Payload
2190 When client is connected to the server, keys has been exchanged and
2191 connection has been authenticated, client MUST register itself to the
2192 server. Client's first packet after key exchange and authentication
2193 protocols MUST be SILC_PACKET_NEW_CLIENT. This payload tells server all
2194 the relevant information about the connected user. Server creates a new
2195 client ID for the client when received this payload and sends it to the
2196 client in New ID Payload.
2198 This payload sends username and real name of the user on the remote host
2199 which is connected to the SILC server with SILC client. The server
2200 creates the client ID according the information sent in this payload.
2201 The nickname of the user becomes the nickname sent in this payload.
2203 The payload may only be sent with SILC_PACKET_NEW_CLIENT packet. It
2204 MUST NOT be sent in any other packet type. The following diagram
2205 represents the New Client Payload.
2216 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
2217 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2218 | Username Length | |
2219 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
2223 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2224 | Real Name Length | |
2225 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
2229 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2233 Figure 19: New Client Payload
2237 o Username Length (2 bytes) - Length of the Username field.
2239 o Username (variable length) - The username of the user on
2240 the host where connecting to the SILC server.
2242 o Real Name Length (2 bytes) - Length of the Real Name field.
2244 o Real Name (variable length) - The real name of the user
2245 on the host where connecting to the SILC server.
2250 2.3.18 New Server Payload
2252 This payload is sent by server when it has completed successfully both
2253 key exchange and connection authentication protocols. The server
2254 MUST register itself to the SILC Network by sending this payload.
2255 The first packet after these key exchange and authentication protocols
2256 is SILC_PACKET_NEW_SERVER packet. The payload includes the Server ID
2257 of the server that it has created by itself. It also includes a
2258 name of the server that is associated to the Server ID.
2260 The payload may only be sent with SILC_PACKET_NEW_SERVER packet. It
2261 MUST NOT be sent in any other packet type. The following diagram
2262 represents the New Server Payload.
2271 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
2272 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2273 | Server ID Length | |
2274 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
2278 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2279 | Server Name Length | |
2280 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
2284 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2288 Figure 20: New Server Payload
2292 o Server ID Length (2 bytes) - Length of the Server ID Data
2295 o Server ID Data (variable length) - The encoded Server ID
2298 o Server Name Length (2 bytes) - Length of the server name
2301 o Server Name (variable length) - The server name string.
2306 2.3.19 New Channel Payload
2308 Information about newly created channel is broadcasted to all routers
2309 in the SILC network by sending this packet payload. Channels are
2310 created by router of the cell. Server never creates channels unless
2311 it is a standalone server and it does not have router connection,
2312 in this case server acts as router. Normal server send JOIN command
2313 to the router (after it has received JOIN command from client) which
2314 then processes the command and creates the channel. Client MUST NOT
2315 send this packet. Server MAY send this packet to a router when it is
2316 announcing its existing channels to the router after it has connected
2319 The packet use generic Channel Payload as New Channel Payload. See
2320 section 2.3.2.3 for generic Channel Payload. The Mode Mask field in the
2321 Channel Payload is the mode of the channel.
2325 2.3.20 Key Agreement Payload
2327 This payload is used by clients to request key negotiation between
2328 another client in the SILC Network. The key agreement protocol used
2329 is the SKE protocol. The result of the protocol, the secret key
2330 material, can be used for example as private message key between the
2331 two clients. This significantly adds security as the clients agree
2332 about the key without any server interaction. The protocol is executed
2333 peer to peer. The server and router MUST NOT send this payload.
2335 The sender MAY tell the receiver of this payload the hostname and the
2336 port where the SKE protocol is running in the sender's end. The
2337 receiver MAY then initiate the SKE negotiation with the sender. The
2338 sender MAY also optionally not to include the hostname and the port
2339 of its SKE protocol. In this case the receiver MAY reply to the
2340 request by sending the same payload filled with the receiver's hostname
2341 and the port where the SKE protocol is running. The sender MAY then
2342 initiate the SKE negotiation with the receiver.
2344 This payload may be sent with SILC_PACKET_KEY_AGREEMENT and
2345 SILC_PACKET_FTP packet types. It MUST NOT be sent in any other packet
2346 types. The following diagram represents the Key Agreement Payload.
2352 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
2353 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2354 | Hostname Length | |
2355 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
2359 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2361 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2365 Figure 21: Key Agreement Payload
2369 o Hostname Length (2 bytes) - Indicates the length of the
2372 o Hostname (variable length) - The hostname or IP address where
2373 the SKE protocol is running. The sender MAY fill this field
2374 when sending the payload. If the receiver sends this payload
2375 as reply to the request it MUST fill this field.
2377 o Port (4 bytes) - The port where the SKE protocol is bound.
2378 The sender MAY fill this field when sending the payload. If
2379 the receiver sends this payload as reply to the request it
2380 MUST fill this field. This is a 32 bit MSB first order value.
2384 After the key material has been received from the SKE protocol it is
2385 processed as the [SILC3] describes. If the key material is used as
2386 channel private key then the Sending Encryption Key, as defined in
2387 [SILC3] is used as the channel private key. Other key material must
2388 be discarded. The [SILC1] in section 4.6 defines the way to use the
2389 key material if it is intended to be used as private message keys.
2390 Any other use for the key material is undefined.
2394 2.3.21 Resume Router Payload
2396 See the [SILC1] for Resume Router protocol where this payload is
2397 used. The payload may only be sent with SILC_PACKET_RESUME_ROUTER
2398 packet. It MUST NOT be sent in any other packet type. The following
2399 diagram represents the Resume Router Payload.
2405 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
2406 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2407 | Type | Session ID |
2408 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2412 Figure 22: Resume Router Payload
2416 o Type (1 byte) - Indicates the type of the backup resume
2417 protocol packet. The type values are defined in [SILC1].
2419 o Session ID (1 bytes) - Indicates the session ID for the
2420 backup resume protocol. The sender of the packet sets this
2421 value and the receiver MUST set the same value in subsequent
2427 2.3.22 File Transfer Payload
2429 File Transfer Payload is used to perform file transfer protocol between
2430 two entities in the network. The actual file transfer protocol is always
2431 encapsulated inside the SILC Packet. The actual data stream is also sent
2432 peer to peer outside SILC network.
2434 When an entity, usually a client wishes to perform file transfer protocol
2435 with another client in the network, they perform Key Agreement protocol
2436 as described in the section 2.3.20 Key Agreement Payload and in [SILC3],
2437 inside File Transfer Payload. After the Key Agreement protocol has been
2438 performed the subsequent packets in the data stream will be protected
2439 using the new key material. The actual file transfer protocol is also
2440 initialized in this stage. All file transfer protocol packets are always
2441 encapsulated in the File Transfer Payload and protected with the
2442 negotiated key material.
2444 The payload may only be sent with SILC_PACKET_FTP packet. It MUST NOT
2445 be sent in any other packet type. The following diagram represents the
2446 File Transfer Payload.
2452 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
2453 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2459 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2463 Figure 23: File Transfer Payload
2467 o Type (1 byte) - Indicates the type of the file transfer
2468 protocol. The following file transfer protocols has been
2471 1 Secure File Transfer Protocol (SFTP) (mandatory)
2473 If zero (0) value or any unsupported file transfer protocol
2474 type is found in this field the packet MUST be discarded.
2475 The currently mandatory file transfer protocol is SFTP.
2476 The SFTP protocol is defined in [SFTP].
2478 o Data (variable length) - Arbitrary file transfer data. The
2479 contents and encoding of this field is dependent of the usage
2480 of this payload and the type of the file transfer protocol.
2481 When this payload is used to perform the Key Agreement
2482 protocol, this field include the Key Agreement Payload,
2483 as defined in the section 2.3.20 Key Agreement Payload.
2484 When this payload is used to send the actual file transfer
2485 protocol data, the encoding is defined in the corresponding
2486 file transfer protocol.
2491 2.3.23 Resume Client Payload
2493 This payload is used by client to resume its detached session in the
2494 SILC Network. A client is able to detach itself from the network by
2495 sending SILC_COMMAND_DETACH command to its server. The network
2496 connection to the client is lost but the client remains as valid
2497 client in the network. The client is able to resume the session back
2498 by sending this packet and including the old Client ID, and an
2499 Authentication Payload [SILC1] which the server use to verify with
2500 the detached client's public key. This also implies that the
2501 mandatory authentication method is public key authentication.
2503 Server or router that receives this from the client also sends this,
2504 without the Authentication Payload, to routers in the network so that
2505 they know the detached client has resumed. Refer to the [SILC1] for
2506 detailed description how the detaching and resuming procedure is
2509 The payload may only be sent with SILC_PACKET_RESUME CLIENT packet. It
2510 MUST NOT be sent in any other packet type. The following diagram
2511 represents the Resume Client Payload.
2516 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
2517 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2518 | Client ID Length | |
2519 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
2523 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2525 ~ Authentication Payload ~
2527 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2531 Figure 24: Resume Client Payload
2535 o Client ID Length (1 byte) - The length of the Client ID
2536 field not including any other field.
2538 o Client ID (variable length) - The detached client's Client
2539 ID. The client that sends this payload must know the Client
2542 o Authentication Payload (variable length) - The authentication
2543 payload that the server will verify with the detached client's
2544 public key. If the server doesn't know the public key, it must
2545 retrieve it for example with SILC_COMMAND_GETKEY command.
2553 ID's are used in the SILC network to associate different entities.
2554 The following ID's has been defined to be used in the SILC network.
2559 This is used when other ID type is available at the time.
2563 Server ID to associate servers. See the format of
2568 Client ID to associate clients. See the format of
2573 Channel ID to associate channels. See the format of
2577 When encoding different IDs into the ID Payload, all fields are always
2578 in MSB first order. The IP address, port, and/or the random number
2579 are encoded in the MSB first order.
2583 2.5 Packet Encryption And Decryption
2585 SILC packets are encrypted almost entirely. Only the MAC at the end
2586 of the packet is never encrypted. The SILC Packet header is the first
2587 part of a packet to be encrypted and it is always encrypted with the
2588 key of the next receiver of the packet. The data payload area of the
2589 packet is always entirely encrypted and it is usually encrypted with
2590 the next receiver's key. However, there are some special packet types
2591 and packet payloads that require special encryption process. These
2592 special cases are described in the next sections. First is described
2593 the normal packet encryption process.
2598 2.5.1 Normal Packet Encryption And Decryption
2600 Normal SILC packets are encrypted with the session key of the next
2601 receiver of the packet. The entire SILC Packet header and the packet
2602 data payload is is encrypted with the same key. Padding of the packet
2603 is also encrypted always with the session key, also in special cases.
2604 Computed MAC of the packet MUST NOT be encrypted.
2606 Decryption process in these cases are straightforward. The receiver
2607 of the packet MUST first decrypt the SILC Packet header, or some parts
2608 of it, usually first 16 bytes of it. Then the receiver checks the
2609 packet type from the decrypted part of the header and can determine
2610 how the rest of the packet must be decrypted. If the packet type is
2611 any of the special cases described in the following sections the packet
2612 decryption is special. If the packet type is not among those special
2613 packet types rest of the packet can be decrypted with the same key.
2614 At this point the receiver is also able to determine the length of the
2617 With out a doubt, this sort of decryption processing causes some
2618 overhead to packet decryption, but never the less, is required.
2620 The MAC of the packet is also verified at this point. The MAC is
2621 computed from the ciphertext of the packet so it can be verified
2622 at this stage. The length of the packet need to be known to be able
2623 to verify the MAC from the ciphertext so the first 16 bytes need to
2624 be decrypted to determine the packet length. However, the MAC MUST
2625 be verified from the entire ciphertext.
2629 2.5.2 Channel Message Encryption And Decryption
2631 Channel Messages (Channel Message Payload) are always encrypted with
2632 the channel specific key. However, the SILC Packet header is not
2633 encrypted with that key. As in normal case, the header is encrypted
2634 with the key of the next receiver of the packet. Note that, in this
2635 case the encrypted data area is not touched at all; it MUST NOT be
2636 re-encrypted with the session key.
2638 Receiver of a channel message, who ever that is, is REQUIRED to decrypt
2639 the SILC Packet header to be able to recognize the packet to be as
2640 channel message. This is same procedure as for normal SILC packets.
2641 As the receiver founds the packet to be channel message, rest of the
2642 packet processing is special. Rest of the SILC Packet header is
2643 decrypted with the same session key along with the padding of the
2644 packet. After that the packet is protected with the channel specific
2645 key and thus can be decrypted only if the receiver is the client on
2646 the channel. See section 2.7 Packet Padding Generation for more
2647 information about padding on special packets.
2649 If the receiver of the channel message is router which is routing the
2650 message to another router then it MUST decrypt the Channel Message
2651 payload too. Between routers (that is, between cells) channel messages
2652 are protected with session keys shared between the routers. This
2653 causes another special packet processing for channel messages. If
2654 the channel message is received from another router then the entire
2655 packet, including Channel Message payload, MUST be encrypted with the
2656 session key shared between the routers. In this case the packet
2657 decryption process is as with normal SILC packets. Hence, if the
2658 router is sending channel message to another router the Channel
2659 Message payload MUST have been decrypted and MUST be re-encrypted
2660 with the session key shared between the another router. In this
2661 case the packet encryption is as with any normal SILC packet.
2663 It must be noted that this is only when the channel messages are sent
2664 from router to another router. In all other cases the channel
2665 message encryption and decryption is as described before. This
2666 different processing of channel messages with router to router
2667 connection is because channel keys are cell specific. All cells have
2668 their own channel keys thus the channel message traveling from one
2669 cell to another MUST be protected as it would be any normal SILC
2672 If the SILC_CMODE_PRIVKEY channel mode has been set for the channel
2673 then the router cannot decrypt the packet as it does not know the
2674 private key. In this case the entire packet MUST be encrypted with
2675 the session key and sent to the router. The router receiving the
2676 packet MUST check the channel mode and decrypt the packet accordingly.
2680 2.5.3 Private Message Encryption And Decryption
2682 By default, private message in SILC are protected by session keys.
2683 In this case the private message encryption and decryption process is
2684 equivalent to normal packet encryption and decryption.
2686 However, private messages MAY be protected with private message key
2687 which causes the packet to be special packet. The procedure in this
2688 case is very much alike to channel packets. The actual private message
2689 is encrypted with the private message key and other parts of the
2690 packet is encrypted with the session key. See 2.7 Packet Padding
2691 Generation for more information about padding on special packets.
2693 The difference from channel message processing is that server or router
2694 en route never decrypts the actual private message, as it does not
2695 have the key to do that. Thus, when sending packets between router
2696 the processing is same as in any other case as well; the packet's header
2697 and padding is protected by the session key and the data area is not
2698 touched and is not re-encrypted.
2700 The true receiver of the private message is able to decrypt the private
2701 message as it shares the key with the sender of the message.
2705 2.6 Packet MAC Generation
2707 Data integrity of a packet is protected by including a message
2708 authentication code (MAC) at the end of the packet. The MAC is computed
2709 from shared secret MAC key, that is established by the SILC Key Exchange
2710 protocol, from packet sequence number, and from the encrypted packet
2711 data. The MAC is always computed after packet is encrypted. This is
2712 so called Encrypt-Then-MAC order; packet is first encrypted, then MAC
2713 is computed from the encrypted data.
2715 The MAC is computed from entire packet. Every bit of data in the packet,
2716 including SILC Packet Header is used in the MAC computing. This way
2717 the entire packet becomes authenticated.
2719 Hence, packet's MAC generation is as follows:
2721 mac = MAC(key, sequence number | Encrypted SILC packet)
2723 The MAC key is negotiated during the SKE protocol. The sequence number
2724 is a 32 bit MSB first value starting from zero for first packet and
2725 increasing for subsequent packets, finally wrapping after 2^32 packets.
2726 The value is never reset, not even after rekey has been performed.
2727 However, rekey MUST be performed before the sequence number wraps
2728 and repeats from zero. Note that the sequence number is incremented only
2729 when MAC is computed for a packet. If packet is not encrypted and MAC is
2730 not computed then the sequence number is not incremented. Hence, the
2731 sequence number is zero for the very first encrypted packet.
2733 See [SILC1] for defined and allowed MAC algorithms.
2737 2.7 Packet Padding Generation
2739 Padding is needed in the packet because the packet is encrypted. It
2740 always MUST be multiple by eight (8) or multiple by the block size
2741 of the cipher, which ever is larger. The padding is always encrypted.
2743 For normal packets the padding is added after the SILC Packet Header
2744 and between the Data Payload area. The padding for normal packets
2745 may be calculated as follows:
2748 padding_length = 16 - (packet_length mod block_size)
2749 if (padding_length < 8)
2750 padding_length += block_size
2753 The `block_size' is the block size of the cipher. The maximum padding
2754 length is 128 bytes, and minimum is 8 bytes. For example, packets that
2755 include a passphrase or a password for authentication purposes SHOULD
2756 pad the packet up to the maximum padding length. The maximum padding
2757 is calculated as follows:
2760 padding_length = 128 - (packet_length mod block_size)
2763 For special packets the padding calculation is different as special
2764 packets may be encrypted differently. In these cases the encrypted
2765 data area MUST already be multiple by the block size thus in this case
2766 the padding is calculated only for SILC Packet Header, not for any
2767 other area of the packet. The same algorithm works in this case as
2768 well, except that the `packet length' is now the SILC Packet Header
2771 The padding MUST be random data, preferably, generated by
2772 cryptographically strong random number generator for each packet
2777 2.8 Packet Compression
2779 SILC Packets MAY be compressed. In this case the data payload area
2780 is compressed and all other areas of the packet MUST remain as they
2781 are. After compression is performed for the data area, the length
2782 field of Packet Header MUST be set to the compressed length of the
2785 The compression MUST always be applied before encryption. When
2786 the packet is received and decrypted the data area MUST be decompressed.
2787 Note that the true sender of the packet MUST apply the compression and
2788 the true receiver of the packet MUST apply the decompression. Any
2789 server or router en route SHOULD NOT decompress the packet.
2795 The sender of the packet MUST assemble the SILC Packet Header with
2796 correct values. It MUST set the Source ID of the header as its own
2797 ID, unless it is forwarding the packet. It MUST also set the Destination
2798 ID of the header to the true destination. If the destination is client
2799 it will be Client ID, if it is server it will be Server ID and if it is
2800 channel it will be Channel ID.
2802 If the sender wants to compress the packet it MUST apply the
2803 compression now. Sender MUST also compute the padding as described
2804 in above sections. Then sender MUST encrypt the packet as has been
2805 described in above sections according whether the packet is normal
2806 packet or special packet. Then sender MUST compute the MAC of the
2807 packet. The computed MAC MUST NOT be encrypted.
2811 2.10 Packet Reception
2813 On packet reception the receiver MUST check that all fields in the
2814 SILC Packet Header are valid. It MUST check the flags of the
2815 header and act accordingly. It MUST also check the MAC of the packet
2816 and if it is to be failed the packet MUST be discarded. Also if the
2817 header of the packet includes any bad fields the packet MUST be
2820 See above sections on the decryption process of the received packet.
2822 The receiver MUST also check that the ID's in the header are valid
2823 ID's. Unsupported ID types or malformed ID's MUST cause packet
2824 rejection. The padding on the reception is always ignored.
2826 The receiver MUST also check the packet type and start parsing the
2827 packet according to the type. However, note the above sections on
2828 special packet types and their parsing.
2834 Routers are the primary entities in the SILC network that takes care
2835 of packet routing. However, normal servers routes packets as well, for
2836 example, when they are routing channel message to the local clients.
2837 Routing is quite simple as every packet tells the true origin and the
2838 true destination of the packet.
2840 It is still RECOMMENDED for routers that has several routing connections
2841 to create route cache for those destinations that has faster route than
2842 the router's primary route. This information is available for the router
2843 when other router connects to the router. The connecting party then
2844 sends all of its locally connected clients, servers and channels. These
2845 informations helps to create the route cache. Also, when new channels
2846 are created to a cell its information is broadcasted to all routers
2847 in the network. Channel ID's are based on router's ID thus it is easy
2848 to create route cache based on these informations. If faster route for
2849 destination does not exist in router's route cache the packet MUST be
2850 routed to the primary route (default route).
2852 However, there are some issues when routing channel messages to group
2853 of users. Routers are responsible of routing the channel message to
2854 other routers, local servers and local clients as well. Routers MUST
2855 send the channel message to only one router in the network, preferably
2856 to the shortest route to reach the channel users. The message can be
2857 routed into either upstream or downstream. After the message is sent
2858 to a router in the network it MUST NOT be sent to any other router in
2859 either same route or other route. The message MUST NOT be routed to
2860 the router it came from.
2862 When routing for example private messages they should be routed to the
2863 shortest route always to reach the destination client as fast as possible.
2865 For server which receives a packet to be routed to an entity that is
2866 indirectly connected to the sender, the server MUST check whether that
2867 particular packet type is allowed to be routed to that destination. Not
2868 all packets may be sent by some odd entity to for example a local client,
2869 or to some remote server or router, that is indirectly connected to the
2870 sender. See section 2.3 SILC Packet Types and paragraph about indirectly
2871 connected entities and sending packets to them. That section defines the
2872 packets that may be sent to indirectly connected entities. When a server
2873 or a router receives a packet that may be sent to indirectly connected
2874 entity and it is destined to other entity except that server, it MUST
2875 route it further either to shortest route or to the primary route to reach
2878 Routers form a ring in the SILC network. However, routers may have other
2879 direct connections to other routers in the network too. This can cause
2880 interesting routing problems in the network. Since the network is a ring,
2881 the packets usually should be routed into clock-wise direction, or if it
2882 cannot be used then always counter clock-wise (primary route) direction.
2883 Problems may arise when a faster direct route exists and router is routing
2884 a channel message. Currently channel messages must be routed either
2885 in upstream or downstream, they cannot be routed to other direct routes.
2886 The SILC protocol should have a shortest path discovery protocol, and some
2887 existing routing protocol, that can handle a ring network with other
2888 direct routes inside the ring (so called hybrid ring-mesh topology),
2889 MAY be defined to be used with the SILC protocol. Additional
2890 specifications MAY be written on the subject to permeate this
2895 2.12 Packet Broadcasting
2897 SILC packets MAY be broadcasted in SILC network. However, only router
2898 server may send or receive broadcast packets. Client and normal server
2899 MUST NOT send broadcast packets and they MUST ignore broadcast packets
2900 if they receive them. Broadcast packets are sent by setting Broadcast
2901 flag to the SILC packet header.
2903 Broadcasting packets means that the packet is sent to all routers in
2904 the SILC network, except to the router that sent the packet. The router
2905 receiving broadcast packet MUST send the packet to its primary route.
2906 The fact that SILC routers may have several router connections can
2907 cause problems, such as race conditions inside the SILC network, if
2908 care is not taken when broadcasting packets. Router MUST NOT send
2909 the broadcast packet to any other route except to its primary route.
2911 If the primary route of the router is the original sender of the packet
2912 the packet MUST NOT be sent to the primary route. This may happen
2913 if router has several router connections and some other router uses
2914 the router as its primary route.
2916 Routers use broadcast packets to broadcast for example information
2917 about newly registered clients, servers, channels etc. so that all the
2918 routers may keep these informations up to date.
2922 3 Security Considerations
2924 Security is central to the design of this protocol, and these security
2925 considerations permeate the specification. Common security considerations
2926 such as keeping private keys truly private and using adequate lengths for
2927 symmetric and asymmetric keys must be followed in order to maintain the
2928 security of this protocol.
2934 [SILC1] Riikonen, P., "Secure Internet Live Conferencing (SILC),
2935 Protocol Specification", Internet Draft, May 2002.
2937 [SILC3] Riikonen, P., "SILC Key Exchange and Authentication
2938 Protocols", Internet Draft, May 2002.
2940 [SILC4] Riikonen, P., "SILC Commands", Internet Draft, May 2002.
2942 [IRC] Oikarinen, J., and Reed D., "Internet Relay Chat Protocol",
2945 [IRC-ARCH] Kalt, C., "Internet Relay Chat: Architecture", RFC 2810,
2948 [IRC-CHAN] Kalt, C., "Internet Relay Chat: Channel Management", RFC
2951 [IRC-CLIENT] Kalt, C., "Internet Relay Chat: Client Protocol", RFC
2954 [IRC-SERVER] Kalt, C., "Internet Relay Chat: Server Protocol", RFC
2957 [SSH-TRANS] Ylonen, T., et al, "SSH Transport Layer Protocol",
2960 [PGP] Callas, J., et al, "OpenPGP Message Format", RFC 2440,
2963 [SPKI] Ellison C., et al, "SPKI Certificate Theory", RFC 2693,
2966 [PKIX-Part1] Housley, R., et al, "Internet X.509 Public Key
2967 Infrastructure, Certificate and CRL Profile", RFC 2459,
2970 [Schneier] Schneier, B., "Applied Cryptography Second Edition",
2971 John Wiley & Sons, New York, NY, 1996.
2973 [Menezes] Menezes, A., et al, "Handbook of Applied Cryptography",
2976 [OAKLEY] Orman, H., "The OAKLEY Key Determination Protocol",
2977 RFC 2412, November 1998.
2979 [ISAKMP] Maughan D., et al, "Internet Security Association and
2980 Key Management Protocol (ISAKMP)", RFC 2408, November
2983 [IKE] Harkins D., and Carrel D., "The Internet Key Exchange
2984 (IKE)", RFC 2409, November 1998.
2986 [HMAC] Krawczyk, H., "HMAC: Keyed-Hashing for Message
2987 Authentication", RFC 2104, February 1997.
2989 [PKCS1] Kalinski, B., and Staddon, J., "PKCS #1 RSA Cryptography
2990 Specifications, Version 2.0", RFC 2437, October 1998.
2992 [RFC2119] Bradner, S., "Key Words for use in RFCs to Indicate
2993 Requirement Levels", BCP 14, RFC 2119, March 1997.
2995 [SFTP] Ylonen T., and Lehtinen S., "Secure Shell File Transfer
2996 Protocol", Internet Draft, March 2001.
2998 [RFC2279] Yergeau, F., "UTF-8, a transformation format of ISO
2999 10646", RFC 2279, January 1998.
3007 Snellmaninkatu 34 A 15
3011 EMail: priikone@iki.fi
3015 6 Full Copyright Statement
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