X-Git-Url: http://git.silcnet.org/gitweb/?a=blobdiff_plain;f=doc%2Fdraft-riikonen-silc-pp-08.nroff;fp=doc%2Fdraft-riikonen-silc-pp-08.nroff;h=0000000000000000000000000000000000000000;hb=72c2de619079457f7a68100eb13385275a424a23;hp=017f49cafd7fdea8cd7944885c39bfd5ef40fd0a;hpb=e7b6c157b80152bf9fb9266e6bdd93f9fb0db776;p=runtime.git diff --git a/doc/draft-riikonen-silc-pp-08.nroff b/doc/draft-riikonen-silc-pp-08.nroff deleted file mode 100644 index 017f49ca..00000000 --- a/doc/draft-riikonen-silc-pp-08.nroff +++ /dev/null @@ -1,3028 +0,0 @@ -.pl 10.0i -.po 0 -.ll 7.2i -.lt 7.2i -.nr LL 7.2i -.nr LT 7.2i -.ds LF Riikonen -.ds RF FORMFEED[Page %] -.ds CF -.ds LH Internet Draft -.ds RH 11 February 2004 -.ds CH -.na -.hy 0 -.in 0 -.nf -Network Working Group P. Riikonen -Internet-Draft -draft-riikonen-silc-pp-08.txt 11 February 2004 -Expires: 11 August 2004 - -.in 3 - -.ce 2 -SILC Packet Protocol - - -.ti 0 -Status of this Memo - -This document is an Internet-Draft and is in full conformance with -all provisions of Section 10 of RFC 2026. Internet-Drafts are -working documents of the Internet Engineering Task Force (IETF), its -areas, and its working groups. Note that other groups may also -distribute working documents as Internet-Drafts. - -Internet-Drafts are draft documents valid for a maximum of six months -and may be updated, replaced, or obsoleted by other documents at any -time. It is inappropriate to use Internet-Drafts as reference -material or to cite them other than as "work in progress." - -The list of current Internet-Drafts can be accessed at -http://www.ietf.org/ietf/1id-abstracts.txt - -The list of Internet-Draft Shadow Directories can be accessed at -http://www.ietf.org/shadow.html - -The distribution of this memo is unlimited. - - -.ti 0 -Abstract - -This memo describes a Packet Protocol used in the Secure Internet Live -Conferencing (SILC) protocol, specified in the Secure Internet Live -Conferencing, Protocol Specification [SILC1]. This protocol describes -the packet types and packet payloads which defines the contents of the -packets. The protocol provides secure binary packet protocol that -assures that the contents of the packets are secured and authenticated. - - - - - - - - - -.ti 0 -Table of Contents - -.nf -1 Introduction .................................................. 3 - 1.1 Requirements Terminology .................................. 4 -2 SILC Packet Protocol .......................................... 4 - 2.1 SILC Packet ............................................... 4 - 2.2 SILC Packet Header ........................................ 5 - 2.3 SILC Packet Types ......................................... 7 - 2.3.1 SILC Packet Payloads ................................ 15 - 2.3.2 Generic payloads .................................... 15 - 2.3.2.1 ID Payload .................................. 15 - 2.3.2.2 Argument Payload ............................ 16 - 2.3.2.3 Argument List Payload ....................... 17 - 2.3.2.4 Channel Payload ............................. 18 - 2.3.2.5 Public Key Payload .......................... 19 - 2.3.2.6 Message Payload ............................. 19 - 2.3.3 Disconnect Payload .................................. 23 - 2.3.4 Success Payload ..................................... 23 - 2.3.5 Failure Payload ..................................... 24 - 2.3.6 Reject Payload ...................................... 25 - 2.3.7 Notify Payload ...................................... 25 - 2.3.8 Error Payload ....................................... 34 - 2.3.9 Channel Message Payload ............................. 35 - 2.3.10 Channel Key Payload ................................ 35 - 2.3.11 Private Message Payload ............................ 37 - 2.3.12 Private Message Key Payload ........................ 37 - 2.3.13 Command Payload .................................... 39 - 2.3.14 Command Reply Payload .............................. 40 - 2.3.15 Connection Auth Request Payload .................... 40 - 2.3.16 New ID Payload ..................................... 42 - 2.3.17 New Client Payload ................................. 42 - 2.3.18 New Server Payload ................................. 43 - 2.3.19 New Channel Payload ................................ 44 - 2.3.20 Key Agreement Payload .............................. 45 - 2.3.21 Resume Router Payload .............................. 46 - 2.3.22 File Transfer Payload .............................. 47 - 2.3.23 Resume Client Payload .............................. 48 - 2.4 SILC ID Types ............................................. 49 - 2.5 Packet Encryption And Decryption .......................... 49 - 2.5.1 Normal Packet Encryption And Decryption ............. 50 - 2.5.2 Channel Message Encryption And Decryption ........... 50 - 2.5.3 Private Message Encryption And Decryption ........... 51 - 2.6 Packet MAC Generation ..................................... 52 - 2.7 Packet Padding Generation ................................. 53 - 2.8 Packet Compression ........................................ 53 - 2.9 Packet Sending ............................................ 54 - 2.10 Packet Reception ......................................... 54 - 2.11 Packet Routing ........................................... 54 - 2.12 Packet Broadcasting ...................................... 56 -3 Security Considerations ....................................... 56 -4 References .................................................... 56 -5 Author's Address .............................................. 58 -6 Full Copyright Statement ...................................... 58 - -.ti 0 -List of Figures - -.nf -Figure 1: Typical SILC Packet -Figure 2: SILC Packet Header -Figure 3: ID Payload -Figure 4: Argument Payload -Figure 5: Argument List Payload -Figure 6: Channel Payload -Figure 7: Public Key Payload -Figure 8: Message Payload -Figure 9: Disconnect Payload -Figure 10: Success Payload -Figure 11: Failure Payload -Figure 12: Reject Payload -Figure 13: Notify Payload -Figure 14: Error Payload -Figure 15: Channel Key Payload -Figure 16: Private Message Key Payload -Figure 17: Command Payload -Figure 18: Connection Auth Request Payload -Figure 19: New Client Payload -Figure 20: New Server Payload -Figure 21: Key Agreement Payload -Figure 22: Resume Router Payload -Figure 23: File Transfer Payload -Figure 24: Resume Client Payload - - -.ti 0 -1. Introduction - -This document describes a Packet Protocol used in the Secure Internet -Live Conferencing (SILC) protocol specified in the Secure Internet Live -Conferencing, Protocol Specification [SILC1]. This protocol describes -the packet types and packet payloads which defines the contents of the -packets. The protocol provides secure binary packet protocol that -assures that the contents of the packets are secured and authenticated. -The packet protocol is designed to be compact to avoid unnecessary -overhead as much as possible. This makes the SILC suitable also in -environment of low bandwidth requirements such as mobile networks. All -packet payloads can also be compressed to further reduce the size of -the packets. - -All packets in SILC network are always encrypted and their integrity -is assured by computed MACs. The protocol defines several packet types -and packet payloads. Each packet type usually has a specific packet -payload that actually defines the contents of the packet. Each packet -also includes a default SILC Packet Header that provides sufficient -information about the origin and the destination of the packet. - - -.ti 0 -1.1 Requirements Terminology - -The keywords MUST, MUST NOT, REQUIRED, SHOULD, SHOULD NOT, RECOMMENDED, -MAY, and OPTIONAL, when they appear in this document, are to be -interpreted as described in [RFC2119]. - - -.ti 0 -2 SILC Packet Protocol - -.ti 0 -2.1 SILC Packet - -SILC packets deliver messages from sender to receiver securely by -encrypting important fields of the packet. The packet consists of -default SILC Packet Header, Padding, Packet Payload data, and, packet -MAC. - -The following diagram illustrates typical SILC packet. - -.in 5 -.nf - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -| n bytes | 1 - n bytes | n bytes | n bytes -| SILC Header | Padding | Data Payload | MAC - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -.in 3 - -.ce -Figure 1: Typical SILC Packet - - -SILC Header is always the first part of the packet and its purpose -is to provide information about the packet. It provides for example -the packet type, origin of the packet and the destination of the packet. -The header is variable in length. See the following section for -description of SILC Packet header. Packets without SILC header or -with malformed SILC header MUST be dropped. - -Padding follows the packet header. The purpose of the padding is to -make the packet multiple by eight (8) or by the block size of the -cipher used in the encryption, which ever is larger. The maximum -length of padding is currently 128 bytes. The padding is always -encrypted. The padding is applied always, even if the packet is -not encrypted. See the section 2.7 Padding Generation for more -detailed information. - -Data payload area follows padding and it is the actual data of the -packet. The packet data is the packet payloads defined in this -protocol. The data payload area is always encrypted. - -The last part of SILC packet is the packet MAC that assures the -integrity of the packet. See the section 2.6 Packet MAC Generation -for more information. If compression is used the compression is -always applied before encryption. - -All fields in all packet payloads are always in MSB (most significant -byte first) order. - - -.ti 0 -2.2 SILC Packet Header - -The SILC packet header is applied to all SILC packets and it is -variable in length. The purpose of SILC Packet header is to provide -detailed information about the packet. The receiver of the packet -uses the packet header to parse the packet and gain other relevant -parameters of the packet. - -The following diagram represents the SILC packet header. - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Payload Length | Flags | Packet Type | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Pad Length | RESERVED | Source ID Len | Dest ID Len | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Src ID Type | | -+-+-+-+-+-+-+-+-+ + -| | -~ Source ID ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Dst ID Type | | -+-+-+-+-+-+-+-+-+ + -| | -~ Destination ID ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 2: SILC Packet Header - -.in 6 -o Payload Length (2 bytes) - Indicates the length of the - packet not including the padding of the packet. - -o Flags (1 byte) - Indicates flags to be used in packet - processing. Several flags may be set by ORing the flags - together. - - The following flags are reserved for this field: - - - No flags 0x00 - - In this case the field is ignored. - - - Private Message Key 0x01 - - Indicates that the packet data MUST include private - message that is encrypted using private key set by - client. Servers does not know this key and cannot - handle the packet, but passes it along. See section - 2.5.3 Private Message Encryption And Decryption for - more information. - - - List 0x02 - - Indicates that the packet consists of list of - packet payloads indicated by the Packet Type field. - The payloads are added one after the other. Note that - there are packet types that must not be used as - list. Parsing of list packet is done by calculating - the length of each payload and parsing them one by - one. - - - Broadcast 0x04 - - Marks the packet to be broadcasted. Client and normal - server cannot send broadcast packets. Only router server - may send broadcast packet. The router receiving of packet - with this flag set MUST send (broadcast) the packet to - its primary route. If router has several router connections - the packet may be sent only to the primary route. See - section 2.12 Packet Broadcasting for description of - packet broadcasting. - - - Compressed 0x08 - - Marks that the payload of the packet is compressed. - The sender of the packet marks this flag when it - compresses the payload, and any server or router - en route to the recipient MUST NOT unset this flag. - See section 2.8 Packet Compression for description of - packet compressing. - -.in 3 - -o Packet Type (1 byte) - Indicates the type of the packet. - Receiver uses this field to parse the packet. See section - 2.3 SILC Packets for list of defined packet types. - -o Pad Length (1 byte) - Indicates the length of the padding - applied after the SILC Packet header. Maximum length for - padding is 128 bytes. - -o RESERVED (1 byte) - Reserved field and must include a - zero (0) value. - -o Source ID Length (1 byte) - Indicates the length of the - Source ID field in the header, not including this or any - other fields. - -o Destination ID Length (1 byte) - Indicates the length of the - Destination ID field in the header, not including this or - any other fields. - -o Src ID Type (1 byte) - Indicates the type of ID in the - Source ID field. See section 2.4 SILC ID Types for - defined ID types. - -o Source ID (variable length) - The actual source ID that - indicates which is the original sender of the packet. - -o Dst ID Type (1 byte) - Indicates the type of ID in the - Destination ID field. See section 2.4 SILC ID Types for - defined ID types. - -o Destination ID (variable length) - The actual destination - ID that indicates which is the end receiver of the packet. - - - -.ti 0 -2.3 SILC Packet Types - -SILC packet types defines the contents of the packet and it is used by -the receiver to parse the packet. The packet type is 8 bits in length. -The range for the packet types are from 0 - 255, where 0 is never sent and -255 is currently reserved for future extensions and MUST NOT be defined to -any other purpose. Every SILC specification compliant implementation -SHOULD support all the following packet types. - -The below list of the SILC Packet types includes reference to the packet -payload as well. Packet payloads are the actual packet data area. Each -packet type defines packet payload which usually may only be sent with -the specific packet type. - -Most of the packets are packets that must be destined directly to entity -that is connected to the sender. It is not allowed, for example, for a -router to send SILC_PACKET_DISCONNECT packet to client that is not -directly connected to the router. However, there are some special packet -types that may be destined to some entity that the sender does not have -direct connection with. These packets are for example private message -packets, channel message packets, command packets and some other packets -that may be broadcasted in the SILC network. The following packet -desription list will define it separately if a packet is allowed to be -sent to indirectly connected entity. Other packets MUST NOT be sent or -accepted, if sent, to indirectly connected entities. - -Some packets MAY be sent as lists by adding the List flag to the Packet -Header and constructing multiple packet payloads one after the other. -When this is allowed it is separately defined in the following list. -Other packets MUST NOT be sent as list and the List flag MUST NOT be set. - - -List of SILC Packet types are defined as follows. - -.in 1 - 0 SILC_PACKET_NONE - - This type is reserved and it is never sent. - - - 1 SILC_PACKET_DISCONNECT - - This packet is sent to disconnect the remote end. Reason of - the disconnection is sent inside the packet payload. - - Payload of the packet: See section 2.3.3 Disconnect Payload - - - 2 SILC_PACKET_SUCCESS - - This packet is sent upon successful execution of a protocol. - The status of the success is sent in the packet payload. - - Payload of the packet: See section 2.3.4 Success Payload - - - 3 SILC_PACKET_FAILURE - - This packet is sent upon failure of a protocol. The status - of the failure is sent in the packet payload. - - Payload of the packet: See section 2.3.5 Failure Payload - - - 4 SILC_PACKET_REJECT - - This packet MAY be sent upon rejection of a protocol. The - status of the rejection is sent in the packet payload. - - Payload of the packet: See section 2.3.6 Reject Payload - - - 5 SILC_PACKET_NOTIFY - - This packet is used to send notify message. The packet is - usually sent between server and client, but also between - server and router. Client MUST NOT send this packet. Server - MAY destine this packet to channel as well when the packet is - distributed to all clients on the channel. This packet MAY - be sent as list. - - Payload of the packet: See section 2.3.7 Notify Payload. - - - 6 SILC_PACKET_ERROR - - This packet is sent when an error occurs. Server MAY - send this packet. Client MUST NOT send this packet. The - client MAY entirely ignore the packet, however, server is - most likely to take action anyway. This packet MAY be sent - to entity that is indirectly connected to the sender. - - Payload of the packet: See section 2.3.8 Error Payload. - - - 7 SILC_PACKET_CHANNEL_MESSAGE - - This packet is used to send messages to channels. The packet - includes Channel ID of the channel and the actual message to - the channel. Messages sent to the channel are always protected - by channel specific keys. This packet MAY be sent to entity - that is indirectly connected to the sender. - - Payload of the packet: See section 2.3.9 Channel Message - Payload - - - 8 SILC_PACKET_CHANNEL_KEY - - This packet is used to distribute new key for particular - channel when server generates it. Each channel has their own - independent keys that is used to protect the traffic on the - channel. It is also possible to use channel private keys that - are not server generated. In this case this packet is not used. - Client MUST NOT send this packet. This packet MAY be sent to - entity that is indirectly connected to the sender. - - Payload of the packet: See section 2.3.10 Channel Key Payload - - - 9 SILC_PACKET_PRIVATE_MESSAGE - - This packet is used to send private messages from client - to another client. By default, private messages are protected - by session keys established by normal key exchange protocol. - However, it is possible to use specific key to protect private - messages. See [SILC1] for private message key generation. - This packet MAY be sent to entity that is indirectly connected - to the sender. - - Payload of the packet: See section 2.3.11 Private Message - Payload - - - 10 SILC_PACKET_PRIVATE_MESSAGE_KEY - - This packet is OPTIONAL and sender of the packet can indicate - that a private message key should be used in private message - communication. The actual key material is not sent in this - packet but must be either static or pre-shared key. The - receiver of the packet is considered to be the responder - when processing the static or pre-shared key material as - defined in [SILC1] and [SILC3] for private message keys. - This packet MAY be sent to entity that is indirectly connected - to the sender. - - Payload of the packet: See section 2.3.12 Private Message - Key Payload - - - 11 SILC_PACKET_COMMAND - - This packet is used to send commands from client to server. - Server MAY send this packet to other servers as well. All - commands are listed in their own section SILC Command Types - in [SILC4]. The contents of this packet is command specific. - This packet MAY be sent to entity that is indirectly connected - to the sender. - - Payload of the packet: See section 2.3.13 Command Payload - - - 12 SILC_PACKET_COMMAND_REPLY - - This packet is sent as reply to the SILC_PACKET_COMMAND packet. - The contents of this packet is command specific. This packet - MAY be sent to entity that is indirectly connected to the - sender. This packet MAY be sent as list. - - Payload of the packet: See section 2.3.14 Command Reply - Payload and section 2.3.13 Command - Payload - - - 13 SILC_PACKET_KEY_EXCHANGE - - This packet is used to start SILC Key Exchange Protocol, - described in detail in [SILC3]. - - Payload of the packet: Payload of this packet is described - in the section SILC Key Exchange - Protocol and its sub sections in - [SILC3]. - - - 14 SILC_PACKET_KEY_EXCHANGE_1 - - This packet is used as part of the SILC Key Exchange Protocol. - - Payload of the packet: Payload of this packet is described - in the section SILC Key Exchange - Protocol and its sub sections in - [SILC3]. - - - 15 SILC_PACKET_KEY_EXCHANGE_2 - - This packet is used as part of the SILC Key Exchange Protocol. - - Payload of the packet: Payload of this packet is described - in the section SILC Key Exchange - Protocol and its sub sections in - [SILC3]. - - - 16 SILC_PACKET_CONNECTION_AUTH_REQUEST - - This packet is used to request an authentication method to - be used in the SILC Connection Authentication Protocol. If - initiator of the protocol does not know the mandatory - authentication method this packet MAY be used to determine it. - The party receiving this payload SHOULD respond with the same - packet including the mandatory authentication method. - - Payload of the packet: See section 2.3.15 Connection Auth - Request Payload - - - 17 SILC_PACKET_CONNECTION_AUTH - - This packet is used to start and perform the SILC Connection - Authentication Protocol. This protocol is used to authenticate - the connecting party. The protocol is described in detail in - [SILC3]. - - Payload of the packet: Payload of this packet is described - in the section SILC Authentication - Protocol and it sub sections in [SILC]. - - - 18 SILC_PACKET_NEW_ID - - This packet is used to distribute new IDs from server to - router and from router to all other routers in SILC network. - This is used when for example new client is registered to - SILC network. The newly created IDs of these operations are - distributed by this packet. Only server may send this packet, - however, client MUST be able to receive this packet. This - packet MAY be sent to entity that is indirectly connected - to the sender. This packet MAY be sent as list. - - Payload of the packet: See section 2.3.16 New ID Payload - - - 19 SILC_PACKET_NEW_CLIENT - - This packet is used by client to register itself to the - SILC network. This is sent after key exchange and - authentication protocols has been completed. Client sends - various information about itself in this packet to the server. - - Payload of the packet: See section 2.3.17 New Client Payload - - - 20 SILC_PACKET_NEW_SERVER - - This packet is used by server to register itself to the - SILC network. This is sent after key exchange and - authentication protocols has been completed. Server sends - this to the router it connected to, or, if router was - connecting, to the connected router. Server sends its - Server ID and other information in this packet. The client - MUST NOT send or receive this packet. - - Payload of the packet: See section 2.3.18 New Server Payload - - - 21 SILC_PACKET_NEW_CHANNEL - - This packet is used to notify routers about newly created - channel. Channels are always created by the router and it MUST - notify other routers about the created channel. Router sends - this packet to its primary route. Client MUST NOT send this - packet. This packet MAY be sent to entity that is indirectly - connected to the sender. This packet MAY be sent as list. - - Payload of the packet: See section 2.3.19 New Channel Payload - - - 22 SILC_PACKET_REKEY - - This packet is used to indicate that re-key must be performed - for session keys. See section Session Key Regeneration in - [SILC1] for more information. This packet does not have - a payload. - - - 23 SILC_PACKET_REKEY_DONE - - This packet is used to indicate that re-key is performed and - new keys must be used hereafter. This packet does not have a - payload. - - - 24 SILC_PACKET_HEARTBEAT - - This packet is used by clients, servers and routers to keep the - connection alive. It is RECOMMENDED that all servers implement - keepalive actions and perform it to both direction in a link. - This packet does not have a payload. - - - 25 SILC_PACKET_KEY_AGREEMENT - - This packet is used by clients to request key negotiation - between another client in the SILC network. If the negotiation - is started it is performed using the SKE protocol. The result of - the negotiation, the secret key material, can be used for - example as private message key. The server and router MUST NOT - send this packet. - - Payload of the packet: See section 2.3.20 Key Agreement Payload - - - 26 SILC_PACKET_RESUME_ROUTER - - This packet is used during backup router protocol when the - original primary router of the cell comes back online and wishes - to resume the position as being the primary router of the cell. - - Payload of the packet: See section 2.3.21 Resume Router Payload - - - 27 SILC_PACKET_FTP - - This packet is used to perform an file transfer protocol in the - SILC session with some entity in the network. The packet is - multi purpose. The packet is used to tell other entity in the - network that the sender wishes to perform an file transfer - protocol. The packet is also used to actually tunnel the - file transfer protocol stream. The file transfer protocol - stream is always protected with the SILC binary packet protocol. - - Payload of the packet: See section 2.3.22 File Transfer Payload - - - 28 SILC_PACKET_RESUME_CLIENT - - This packet is used to resume a client back to the network - after it has been detached. A client is able to detach from - the network but the client is still valid client in the network. - The client may then later resume its session back by sending - this packet to a server. Routers also use this packet to notify - other routers in the network that the detached client has resumed. - - Payload of the packet: See section 2.3.23 Resume Client Payload - - - 29 - 199 - - Currently undefined commands. - - - 200 - 254 - - These packet types are reserved for private use and they will - not be defined by this document. - - - 255 SILC_PACKET_MAX - - This type is reserved for future extensions and currently it - MUST NOT be sent. -.in 3 - - -.ti 0 -2.3.1 SILC Packet Payloads - -All payloads resides in the main data area of the SILC packet. However -all payloads MUST be at the start of the data area after the SILC -packet header and padding. All fields in the packet payload are always -encrypted, as they reside in the data area of the packet which is -always encrypted. Most of the payloads may only be sent with specific -packet type which is defined in the description of the payload. - -There are some other payloads in SILC as well. However, they are not -common in the sense that they could be sent at any time. These payloads -are not described in this section. These are payloads such as SILC -Key Exchange payloads and so on. These are described in [SILC1], -[SILC3] and [SILC4]. - - -.ti 0 -2.3.2 Generic payloads - -This section describes generic payloads that are not associated to any -specific packet type. They can be used for example inside some other -packet payload. - - -.ti 0 -2.3.2.1 ID Payload - -This payload can be used to send an ID. ID's are variable in length -thus this payload provides a way to send variable length ID. - -The following diagram represents the ID Payload. - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| ID Type | ID Length | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| | -~ ID Data ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 3: ID Payload - - -.in 6 -o ID Type (2 bytes) - Indicates the type of the ID. See - section 2.4 SILC ID Types for list of defined ID types. - -o ID Length (2 bytes) - Length of the ID Data area not - including the length of any other fields in the payload. - -o ID Data (variable length) - The actual ID data. The encoding - of the ID data is defined in section 2.4 SILC ID Types. -.in 3 - - -.ti 0 -2.3.2.2 Argument Payload - -Argument Payload is used to set arguments for any packet payload that -need and support arguments, such as commands. Number of arguments -associated with a packet MUST be indicated by the packet payload which -need the arguments. Argument Payloads MUST always reside right after -the packet payload needing the arguments. Incorrect amount of argument -payloads MUST cause rejection of the packet. - -The following diagram represents the Argument Payload. - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Data Length | Argument Type | | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + -| | -~ Argument Data ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 4: Argument Payload - - -.in 6 -o Data Length (2 bytes) - Length of the Argument Data field - not including the length of any other field in the payload. - -o Argument Type (1 byte) - Indicates the type of the argument. - Every argument can have a specific type that are defined - by the packet payload needing the argument. For example - every command specify a number for each argument that may be - associated with the command. By using this number the receiver - of the packet knows what type of argument this is. If there is - no specific argument type this field is set to zero (0) value. - -o Argument Data (variable length) - Argument data. -.in 3 - - -.ti 0 -2.3.2.3 Argument List Payload - -Argument List Payload is a list of Argument Payloads appended one -after the other. The number of arguments is indicated in the -payload. - -The following diagram represents the Argument List Payload. - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Argument Nums | | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + -| | -~ Argument Payloads ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 5: Argument List Payload - - -.in 6 -o Argument Nums (2 bytes) - Indicates the number of Argument - Payloads. If zero (0) value is found in this field no - arguments are present. - -o Argument Payloads (variable length) - The Argument Payloads - appended one after the other. The payloads can be decoded - since the length of the payload is indicated in each of - the Argument Payload. -.in 3 - - - - - -.ti 0 -2.3.2.4 Channel Payload - -Generic Channel Payload may be used to send information about a channel, -its name, the Channel ID and a mode. - -The following diagram represents the Channel Payload. - - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Channel Name Length | | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + -| | -~ Channel Name ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Channel ID Length | | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + -| | -~ Channel ID ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Mode Mask | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 6: New Channel Payload - - -.in 6 -o Channel Name Length (2 bytes) - Length of the Channel Name - field. - -o Channel Name (variable length) - The name of the channel. - -o Channel ID Length (2 bytes) - Length of the Channel ID field. - -o Channel ID (variable length) - The encoded Channel ID. - -o Mode Mask (4 bytes) - A mode. This can be the mode of the - channel but it can also be the mode of a client on the - channel. The contents of this field is dependent of the - usage of this payload. The usage is defined separately - when this payload is used. This is a 32 bit MSB first value. -.in 3 - - - - - - -.ti 0 -2.3.2.5 Public Key Payload - -Generic Public Key Payload may be used to send different type of -public keys and certificates. - -The following diagram represents the Public Key Payload. - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Public Key Length | Public Key Type | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| | -~ Public Key (or certificate) ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 7: Public Key Payload - - -.in 6 -o Public Key Length (2 bytes) - The length of the Public Key - (or certificate) field, not including any other field. - -o Public Key Type (2 bytes) - The public key (or certificate) - type. This field indicates the type of the public key in - the packet. See the [SILC3] for defined public key types. - -o Public Key (or certificate) (variable length) - The - encoded public key or certificate data. -.in 3 - - -.ti 0 -2.3.2.6 Message Payload - -Generic Message Payload can be used to send messages in SILC. It -is used to send channel messages and private messages. - -The following diagram represents the Message Payload. - -(*) indicates that the field is not encrypted. - - - - - - - - - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Message Flags | Message Length | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| | -~ Message Data ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Padding Length | | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + -| | -~ Padding ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| | -~ Initialization Vector * ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| | -~ MAC * ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 8: Message Payload - - -.in 6 -o Message Flags (2 bytes) - Includes the Message Flags of the - message. The flags can indicate a reason or a purpose for - the message. The following Message Flags are defined: - - 0x0000 SILC_MESSAGE_FLAG_NONE - - No specific flags set. - - 0x0001 SILC_MESSAGE_FLAG_AUTOREPLY - - This message is an automatic reply to an earlier - received message. - - 0x0002 SILC_MESSAGE_FLAG_NOREPLY - - There should not be reply messages to this - message. - - 0x0004 SILC_MESSAGE_FLAG_ACTION - - The sender is performing an action and the message - is the indication of the action. - - 0x0008 SILC_MESSAGE_FLAG_NOTICE - - The message is for example an informational notice - type message. - - 0x0010 SILC_MESSAGE_FLAG_REQUEST - - This is a generic request flag to send request - messages. A separate document should define any - payloads associated to this flag. - - 0x0020 SILC_MESSAGE_FLAG_SIGNED - - This flag indicates that the message is signed - with sender's private key and thus can be verified - by the receiver using the sender's public key. A - separate document should define the detailed procedure - of the signing process and any associated payloads - for this flag. - - 0x0040 SILC_MESSAGE_FLAG_REPLY - - This is a generic reply flag to send a reply to - previously received request. A separate document - should define any payloads associated to this flag. - - 0x0080 SILC_MESSAGE_FLAG_DATA - - This is a generic data flag, indicating that the - message includes some data which can be interpreted - in a specific way. Using this flag any kind of data - can be delivered inside message payload. A separate - document should define how this flag is interpreted - and define any associated payloads. - - 0x0100 SILC_MESSAGE_FLAG_UTF8 - - This flag indicates that the message is UTF-8 encoded - textual message. When sending text messages in SILC - this flag SHOULD be used. When this flag is used the - text sent as message MUST be UTF-8 encoded. - - 0x0200 SILC_MESSAGE_FLAG_ACK - - This flag indicates the sender requires the recpipient - to acknowledge the received message. This same flag - is used in the acknowledgement. A separate document - should define how the acknowledgement is performed. - - 0x0400 - 0x1000 RESERVED - - Reserved for future flags. - - 0x2000 - 0x8000 PRIVATE RANGE - - Private range for free use. - -o Message Length (2 bytes) - Indicates the length of the - Message Data field in the payload, not including any - other field. - -o Message Data (variable length) - The actual message data. - -o Padding Length (2 bytes) - Indicates the length of the - Padding field in the payload, not including any other - field. - -o Padding (variable length) - If this payload is used as - channel messages, the padding MUST be applied because - this payload is encrypted separately from other parts - of the packet. If this payload is used as private - messages, the padding is present only when the payload - is encrypted with private message key. If encrypted - with session keys this field MUST NOT be present and the - Padding Length field includes a zero (0) value. The - padding SHOULD be random data. - -o Initialization Vector (variable length) - This field MUST - be present when this payload is used as channel messages. - The IV SHOULD be random data for each channel message. - - When encrypting private messages with session keys this - field MUST NOT be present. For private messages this - field is present only when encrypting with a static - private message key (pre-shared key). If randomly - generated key material is used this field MUST NOT be - present. Also, If Key Agreement (SKE) was used to - negotiate fresh key material for private message key - this field MUST NOT be present. See the section 4.6 - in [SILC1] for more information about IVs when - encrypting private messages. - - This field includes the initialization vector used in message - encryption. It need to be used in the packet decryption - as well. Contents of this field depends on the encryption - algorithm and encryption mode. This field is not encrypted, - is not included in padding calculation and its length - equals to cipher's block size. This field is authenticated - by the message MAC. - -o MAC (variable length) - The MAC computed from the - Message Flags, Message Length, Message Data, Padding Length, - Padding and Initialization Vector fields in that order. - The MAC is computed after the payload is encrypted. This - is so called Encrypt-Then-MAC order; first encrypt, then - compute MAC from ciphertext. The MAC protects the integrity - of the Message Payload. Also, when used as channel messages - it is possible to have multiple private channel keys set, - and receiver can use the MAC to verify which of the keys - must be used in decryption. This field is not present - when encrypting private messages with session key. This - field is not encrypted. This field is authenticated by - the SILC packet MAC. -.in 3 - - -.ti 0 -2.3.3 Disconnect Payload - -Disconnect payload is sent upon disconnection. Reason of the -disconnection is sent to the disconnected party in the payload. - -The payload may only be sent with SILC_PACKET_DISCONNECT packet. It -MUST NOT be sent in any other packet type. The following diagram -represents the Disconnect Payload. - - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Status | | -+-+-+-+-+-+-+-+-+ + -| | -~ Disconnect Message ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 9: Disconnect Payload - -.in 6 -o Status (1 byte) - Indicates the Status Type, defined in [SILC3] - for the reason of disconnection. - -o Disconnect Message (variable length) - Human readable UTF-8 - encoded string indicating reason of the disconnection. This - field MAY be omitted. -.in 3 - - -.ti 0 -2.3.4 Success Payload - -Success payload is sent when some protocol execution is successfully -completed. The payload is simple; indication of the success is sent. -This may be any data, including binary or human readable data, and -it is protocol dependent. - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| | -~ Success Indication ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 10: Success Payload - - -.in 6 -o Success Indication (variable length) - Indication of - the success. This may be for example some flag that - indicates the protocol and the success status or human - readable success message. The true length of this - payload is available by calculating it from the SILC - Packet Header. -.in 3 - - -.ti 0 -2.3.5 Failure Payload - -This is opposite of Success Payload. Indication of failure of -some protocol is sent in the payload. - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| | -~ Failure Indication ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 11: Failure Payload - - -.in 6 -o Failure Indication (variable length) - Indication of - the failure. This may be for example some flag that - indicates the protocol and the failure status or human - readable failure message. The true length of this - payload is available by calculating it from the SILC - Packet Header. -.in 3 - - -.ti 0 -2.3.6 Reject Payload - -This payload is sent when some protocol is rejected to be executed. -Other operations MAY send this as well that was rejected. The -indication of the rejection is sent in the payload. The indication -may be binary or human readable data and is protocol dependent. - - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| | -~ Reject Indication ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 12: Reject Payload - - -.in 6 -o Reject Indication (variable length) - Indication of - the rejection. This maybe for example some flag that - indicates the protocol and the rejection status or human - readable rejection message. The true length of this - payload is available by calculating it from the SILC - Packet Header. -.in 3 - - - -.ti 0 -2.3.7 Notify Payload - -Notify payload is used to send notify messages. The payload is usually -sent from server to client and from server to router. It is also used -by routers to notify other routers in the network. This payload MAY also -be sent to a channel. Client MUST NOT send this payload. When this -packet is received by client it SHOULD process it. Servers and routers -MUST process notify packets. - -The payload may only be sent with SILC_PACKET_NOTIFY packet. It MUST -NOT be sent in any other packet type. The following diagram represents -the Notify Payload. - - - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Notify Type | Payload Length | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Argument Nums | -+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 13: Notify Payload - - -.in 6 -o Notify Type (2 bytes) - Indicates the type of the notify - message. - -o Payload Length (2 bytes) - Length of the entire Notify Payload - including any associated Argument Payloads. - -o Argument Nums (1 byte) - Indicates the number of Argument - Payloads associated to this payload. Notify types may define - arguments to be sent along the notify message. -.in 3 - -Following the list of currently defined notify types. The format for -notify arguments is same as in SILC commands described in [SILC4]. -Note that all IDs sent in arguments are sent inside ID Payload. Also -note that all strings sent as arguments MUST be UTF-8 [RFC3629] encoded, -unless otherwise defined. Also note that all public keys or -certificates sent inside arguments are actually Public Key Payloads. - - -.in 6 -0 SILC_NOTIFY_TYPE_NONE - - If no specific notify type apply for the notify message this type - MAY be used. - - Max Arguments: 1 - Arguments: (1) - - The is implementation specific free text string. - Receiver MAY ignore this message. - - -1 SILC_NOTIFY_TYPE_INVITE - - Sent when an client is invited to a channel. This is also sent - when the invite list of the channel is changed. This notify type - is sent to local servers on the channel, but MUST NOT be sent - to clients on the channel. Router MUST broadcast this to its - primary router and to local servers on the channel. When a client - was directly invited to the channel this is also sent to that - client. In this case the packet is destined to the client. - - Max Arguments: 5 - Arguments: (1) (2) - (3) [] (4) [] - (5) [] - - The is the channel. The is the name - of the channel and is provided because the client which receives - this notify packet may not have a way to resolve the name of the - channel from the . The is the - Client ID which invited the client to the channel. The - is an argument of size of 1 byte where 0x00 means - adding a client to invite list, and 0x01 means deleting a client - from invite list. The , if present, indicates the - information to be added to or removed from the invite list. - The format is defined in [SILC4] with - SILC_COMMAND_INVITE command. When this notify is destined to - a client the and MUST NOT be sent. - When is used to announce information during server - connecting phase the argument type MUST be 0x03. See section - 4.2.1 in [SILC1] for more information. - - -2 SILC_NOTIFY_TYPE_JOIN - - Sent when client has joined to a channel. The server MUST - distribute this type to the local clients on the channel and then - send it to its primary router. Note that, when router is joining - the client on behalf of normal server then router MUST send this - notify type locally and globally. The router or server receiving - the packet distributes this type to the local clients on the - channel and broadcast it to the network. This notify is sent - also to the client that joined the channel. - - Max Arguments: 2 - Arguments: (1) [] (2) - - The is the client that joined to the channel - indicated by the . - - -3 SILC_NOTIFY_TYPE_LEAVE - - Sent when client has left a channel. The server must distribute - this type to the local clients on the channel and then send it - to its primary router. The router or server receiving the - packet distributes this type to the local clients on the channel - and broadcast it to the network. This notify MUST NOT be sent to - the leaving client. - - Max Arguments: 1 - Arguments: (1) - - The is the client which left the channel. - - -4 SILC_NOTIFY_TYPE_SIGNOFF - - Sent when client signoff from SILC network. The server MUST - distribute this type to the local clients on the channel and - then send it to its primary router. The router or server - receiving the packet distributes this type to the local clients - on the channel and broadcast it to the network. This notify - MUST NOT be sent to the quitting client. - - Max Arguments: 2 - Arguments: (1) (2) - - The is the client which left SILC network. The - is free text string indicating the reason of the - signoff. - - -5 SILC_NOTIFY_TYPE_TOPIC_SET - - Sent when topic is set/changed on a channel. This type may be - sent only to the clients which are joined on the channel which - topic was just set or changed. The packet is destined to the - channel. - - Max Arguments: 2 - Arguments: (1) (2) - - The is the ID of the entity who set the topic. - It usually is Client ID but it can be Server ID and Channel ID - as well. - - -6 SILC_NOTIFY_TYPE_NICK_CHANGE - - Sent when client changes nick on a channel. The server MUST - distribute this type only to the local clients on the channel - and then send it to its primary router. The router or server - receiving the packet distributes this type to the local clients - on the channel and broadcast it to the network. This packet is - destined directly to the sent entity. This MUST be sent to those - clients that are joined on same channels as the client that - changed the nickname. This notify MUST NOT be sent multiple - times to the same recipient. This notify MUST be sent also to - the client that changed the nickname. - - Max Arguments: 3 - Arguments: (1) (2) - (3) - - The is the old ID of the client which changed - the nickname. The is the new ID generated by - the change of the nickname. The is the new nickname. - Note that it is possible to send this notify even if the - nickname has not changed, but client ID was changed. - - -7 SILC_NOTIFY_TYPE_CMODE_CHANGE - - Sent when channel mode has changed. This type MUST be sent only - to the clients which are joined on the channel which mode was - changed. This packet is destined to the channel. - - Max Arguments: 8 - Arguments: (1) (2) - (3) [] (4) <[hmac>] - (5) [] (6) [] - (7) [] (8) [] - - The is the ID (usually Client ID but it can be - Server ID as well when the router is enforcing channel mode - change) of the entity which changed the mode. The - is the new mode mask of the channel. The client can safely - ignore the argument since the SILC_PACKET_CHANNEL_KEY - packet will force the new channel key change anyway. The - argument is important since the client is responsible of setting - the new HMAC and the hmac key into use. The is - the passphrase of the channel, if it was now set. The argument is sent when the founder mode on the - channel was set. All routers and servers that receive the packet - MUST save the founder's public key so that the founder can - reclaim the channel founder rights back for the channel on any - server in the network. The argument is present when - the user limit was set or changed on the channel. - - The is an Argument List Payload and it is used - to add and/or remove channel public keys from the channel. Also, - when announcing channel information between servers and routers - during connecting phase this argument includes the list of channel - public keys. To add a public key to channel public key list the - SILC_CMODE_CHANNEL_AUTH mode is set and the argument type is 0x00, - and the argument is the public key. To remove a public key from - the channel public key list the argument type is 0x01, and the - argument is the public key to be removed. If the mode - SILC_CMODE_CHANNEL_AUTH is unset (and was set earlier) all public - keys are removed at once. Implementation MAY add and remove - multiple public keys at the same time by including multiple - arguments to the Argument List Payload where each - argument is one Public Key Payload. When is used - to announce information during server connecting phase the - argument type MUST be 0x03. See section 4.2.1 in [SILC1] for - more information. - - -8 SILC_NOTIFY_TYPE_CUMODE_CHANGE - - Sent when user mode on channel has changed. This type MUST be - sent only to the clients which are joined on the channel where - the target client is on. This packet is destined to the channel. - - Max Arguments: 4 - Arguments: (1) (2) - (3) (4) [] - - The is the ID (usually Client ID but it can be - Server ID as well when the router is enforcing user's mode - change) of the entity which changed the mode. The - is the new mode mask of the channel. The - is the client which mode was changed. The - is the public key of the channel founder and may be sent only - when first time setting the channel founder mode using the - SILC_COMMAND_CUMODE command, and when sending this notify. - - -9 SILC_NOTIFY_TYPE_MOTD - - Sent when Message of the Day (motd) is sent to a client. - - Max Arguments: 1 - Arguments: (1) - - The is the Message of the Day. This notify MAY be - ignored and is OPTIONAL. - - -10 SILC_NOTIFY_TYPE_CHANNEL_CHANGE - - Sent when channel's ID has changed for a reason or another. - This is sent by normal server to the client. This can also be - sent by router to other server to force the Channel ID change. - The Channel ID MUST be changed to use the new one. When sent - to clients, this type MUST be sent only to the clients which are - joined on the channel. This packet is destined to the sent - entity. - - Max Arguments: 2 - Arguments: (1) (2) - - The is the channel's old ID and the is the new one that MUST replace the old one. - Server which receives this from router MUST re-announce the - channel to the router by sending SILC_PACKET_NEW_CHANNEL packet - with the new Channel ID. - - -11 SILC_NOTIFY_TYPE_SERVER_SIGNOFF - - Sent when server quits SILC network. Those clients from this - server that are on channels must be removed from the channel. - This packet is destined to the sent entity. - - Max Arguments: 256 - Arguments: (1) (n) [] [...] - - The is the server's ID. The rest of the arguments - are the Client IDs of the clients which are coming from this - server and are thus quitting the SILC network also. If the - maximum number of arguments are reached another - SILC_NOTIFY_TYPE_SERVER_SIGNOFF notify packet MUST be sent. - When this notify packet is sent between routers the Client ID's - MAY be omitted. Server receiving the Client ID's in the payload - may use them directly to remove the client. - - -12 SILC_NOTIFY_TYPE_KICKED - - Sent when a client has been kicked from a channel. This MUST - also be sent to the client which was kicked from the channel. - The client which was kicked from the channel MUST be removed - from the channel. The client MUST also be removed from channel's - invite list if it is explicitly added in the list. This packet - is destined to the channel. The router or server receiving the - packet distributes this type to the local clients on the channel - and broadcast it to the network. - - Max Arguments: 3 - Arguments: (1) (2) [] - (3) - - The is the client which was kicked from the channel. - The kicker may have set the string to indicate the - reason for the kicking. The is the kicker. - - -13 SILC_NOTIFY_TYPE_KILLED - - Sent when a client has been killed from the network. This MUST - also be sent to the client which was killed from the network. - This notify MUST be sent to those clients which are joined on - same channels as the killed client. The client which was killed - MUST be removed from the network. This packet is destined - directly to the sent entity. The router or server receiving - the packet distributes this type to the local clients on the - channel and broadcast it to the network. The client MUST also - be removed from joined channels invite list if it is explicitly - added in the lists. This notify MUST NOT be sent multiple - times to same recipient. - - Max Arguments: 3 - Arguments: (1) (2) [] - (3) - - The is the client which was killed from the network. - The killer may have set the string to indicate the - reason for the killing. The is the killer, which - may be client but also router server. - - -14 SILC_NOTIFY_TYPE_UMODE_CHANGE - - Sent when user's mode in the SILC changes. This type is sent - only between routers as broadcast packet. - - Max Arguments: 2 - Arguments: (1) (2) - - The is the client which mode was changed. The - is the new mode mask. - - -15 SILC_NOTIFY_TYPE_BAN - - Sent when the ban list of the channel is changed. This notify - type is sent to local servers on the channel, but MUST NOT be - sent to clients on the channel. Router MUST broadcast this to - its primary router and to local servers on the channel. - - Max Arguments: 3 - Arguments: (1) (2) [] - (3) [] - - The is the channel which ban list was changed. - The is an argument of size of 1 byte where 0x00 means - adding a client to ban list, and 0x01 means deleting a client - from ban list. The indicates the information to be - added to or removed from the ban list. The format - format is defined in [SILC4] with SILC_COMMAND_BAN command. - When is used to announce information during server - connecting phase the argument type MUST be 0x03. See section - 4.2.1 in [SILC1] for more information. - - -16 SILC_NOTIFY_TYPE_ERROR - - Sent when an error occurs during processing some SILC procedure. - This is not used when error occurs during command processing, see - [SILC4] for more information about commands and command replies. - This type is sent directly to the sender of the packet whose - packet caused the error. See [SILC1] for definition when this - type can be sent. - - Max Arguments: 256 - Arguments: (1) (n) [...] - - The is the error type defined in [SILC4]. Note - that same types are also used with command replies to indicate - the status of a command. Both commands and this notify type - share same status types. Rest of the arguments are status type - dependent and are specified with those status types that can be - sent currently inside this notify type in [SILC4]. The is size of 1 byte. - - -17 SILC_NOTIFY_TYPE_WATCH - - Sent to indicate change in a watched user. Client can set - nicknames to be watched with SILC_COMMAND_WATCH command, and - receive notifications when they login to network, signoff from - the network or their user mode is changed. This notify type - is used to deliver these notifications. The notify type is - sent directly to the watching client. - - Max Arguments: 4 - Arguments: (1) (2) [] - (3) (4) [] - - The is the user's Client ID which is being watched, - and the is its nickname. If the client just - changed the nickname, then is the new nickname, but - the is the old client ID. The is the - user's current user mode. The can be same as the - Notify Payload's Notify Type, and is 16 bit MSB first order - value. If provided it may indicate the notify that occurred - for the client. If client logged in to the network the - MUST NOT be present. -.in 3 - -Notify types starting from 16384 are reserved for private notify -message types. - -Router server which receives SILC_NOTIFY_TYPE_SIGNOFF, -SILC_NOTIFY_TYPE_SERVER_SIGNOFF, SILC_NOTIFY_TYPE_KILLED, -SILC_NOTIFY_TYPE_NICK_CHANGE and SILC_NOTIFY_TYPE_UMODE_CHANGE -MUST check whether someone in the local cell is watching the nickname -the client has, and send the SILC_NOTIFY_TYPE_WATCH notify to the -watcher, unless the watched client in case has the user mode -SILC_UMODE_REJECT_WATCHING set. If the watcher client and the client -that was watched is same the notify SHOULD NOT be sent. - - -.ti 0 -2.3.8 Error Payload - -Error payload is sent upon error in protocol. Error may occur in -various conditions when server sends this packet. Client MUST NOT -send this payload but MUST be able to accept it. However, client -MAY ignore the contents of the packet as server is going to take -action on the error anyway. However, it is recommended that the -client takes error packet seriously. - - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| | -~ Error Message ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 14: Error Payload - - -.in 6 -o Error Message (variable length) - Human readable error - message. -.in 3 - - -.ti 0 -2.3.9 Channel Message Payload - -Channel Message Payload is used to send message to channels, a group -of users. These messages can only be sent if client has joined to -some channel. Even though this packet is very common in SILC it -is still special packet. Some special handling on sending and -reception of channel message is required. - -Padding MUST be applied into this payload since the payload is -encrypted separately from other parts of the packet with the -channel specific key. Hence the requirement of the padding. -The packet MUST be made multiple by eight (8) or by the block -size of the cipher, which ever is larger. - -The SILC header in this packet is encrypted with the session key -of the next receiver of the packet. Nothing else is encrypted -with that key. Thus, the actual packet and padding to be -encrypted with the session key is SILC Header plus padding to it. - -Receiver of the the channel message packet is able to determine -the channel the message is destined to by checking the Destination -ID from the SILC Packet header which tells the destination channel. -The original sender of the packet is also determined by checking -the source ID from the header which tells the client which sent -the message. The Destination ID MUST be Channel ID in the SILC -Packet header. - -This packet use generic Message Payload as Channel Message Payload. -See section 2.3.2.6 for generic Message Payload. - - -.ti 0 -2.3.10 Channel Key Payload - -All traffic in channels are protected by channel specific keys. -Channel Key Payload is used to distribute channel keys to all -clients on the particular channel. Channel keys are sent when -the channel is created, when new user joins to the channel and -whenever a user has left a channel. Server creates the new -channel key and distributes it to the clients by encrypting this -payload with the session key shared between the server and -the client. After that, client MUST start using the key received -in this payload to protect the traffic on the channel. - -The client which is joining to the channel receives its key in the -SILC_COMMAND_JOIN command reply message thus it is not necessary to -send this payload to the entity which sent the SILC_COMMAND_JOIN -command. - -Channel keys are cell specific thus every router in the cell have -to create a channel key and distribute it if any client in the -cell has joined to a channel. Channel traffic between cell's -are not encrypted using channel keys, they are encrypted using -normal session keys between two routers. Inside a cell, all -channel traffic is encrypted with the specified channel key. -Channel key SHOULD expire periodically, say, in one hour, in -which case new channel key is created and distributed. - -Note that, this packet is not used if SILC_CMODE_PRIVKEY mode is set -on channel. This means that channel uses channel private keys which -are not server generated. For this reason server cannot send this -packet as it does not know the key. - -The payload may only be sent with SILC_PACKET_CHANNEL_KEY packet. -It MUST NOT be sent in any other packet type. The following diagram -represents the Channel Key Payload. - - - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Channel ID Length | | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + -| | -~ Channel ID ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Cipher Name Length | | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + -| | -~ Cipher Name ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Channel Key Length | | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + -| | -~ Channel Key ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 15: Channel Key Payload - - - -.in 6 -o Channel ID Length (2 bytes) - Indicates the length of the - Channel ID field in the payload, not including any other - field. - -o Channel ID (variable length) - The Channel ID of the - channel. - -o Cipher Name Length (2 bytes) - Indicates the length of the - Cipher name field in the payload, not including any other - field. - -o Cipher Name (variable length) - Name of the cipher used - in the protection of channel traffic. This name is - initially decided by the creator of the channel but it - may change during the life time of the channel as well. - -o Channel Key Length (2 bytes) - Indicates the length of the - Channel Key field in the payload, not including any other - field. - -o Channel Key (variable length) - The actual channel key - material. -.in 3 - - -.ti 0 -2.3.11 Private Message Payload - -Private Message Payload is used to send private message between -two clients. The messages are sent only to the specified user -and no other user inside SILC network is able to see the message. - -The message can be protected by the session key established by the -SILC Key Exchange Protocol. However, it is also possible to agree -to use a private key to protect just the private messages. It is -for example possible to perform Key Agreement between two clients. -See section 2.3.20 Key Agreement Payload how to perform key -agreement. It is also possible to use static or pre-shared keys -to protect private messages. See the 2.3.12 Private Message Key -Payload and [SILC1] section 4.6 for detailed description for private -message key generation. - -If normal session key is used to protect the message, every server -between the sender client and the receiving client MUST decrypt the -packet and always re-encrypt it with the session key of the next -receiver of the packet. See section Client To Client in [SILC1]. - -When the private message key is used, and the Private Message Key -flag was set in the SILC Packet header no server or router en route -is able to decrypt or re-encrypt the packet. In this case only the -SILC Packet header is processed by the servers and routers en route. -Section Client To Client in [SILC1] gives example of this scheme. - -This packet use generic Message Payload as Private Message Payload. -See section 2.3.2.6 for generic Message Payload. - - -.ti 0 -2.3.12 Private Message Key Payload - -This payload is OPTIONAL and can be used to indicate that a static -or pre-shared key should be used in the private message communication -to protect the messages. The actual key material has to be sent -outside the SILC network, or it has to be a static or pre-shared key. -The sender of this packet is considered to be the initiator and the -receiver the responder when processing the raw key material as -described in the section 4.6 in [SILC1] and in the section 2.3 in -[SILC3]. - -Note that it is also possible to use static or pre-shared keys in -client implementations without sending this packet. Clients may -naturally agree to use a key without sending any kind of indication -to each other. The key may be for example a long-living static key -that the clients has agreed to use at all times. Note that it is -also possible to agree to use private message key by performing -a Key Agreement. See the section 2.3.20 Key Agreement Payload. - -This payload may only be sent by client to another client. Server -MUST NOT send this payload. After sending this payload and setting the -key into use this payload the sender of private messages MUST set the -Private Message Key flag into the SILC Packet Header. - -The payload may only be sent with SILC_PACKET_PRIVATE_MESSAGE_KEY -packet. It MUST NOT be sent in any other packet type. The following -diagram represents the Private Message Key Payload. - - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Cipher Name Length | | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + -| | -~ Cipher Name ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| HMAC Name Length | | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + -| | -~ HMAC Name ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 16: Private Message Key Payload - - - -.in 6 -o Cipher Name Length (2 bytes) - Indicates the length of the - Cipher Name field in the payload, not including any other - field. - -o Cipher Name (variable length) - Name of the cipher to use - in the private message encryption. If this field does not - exist then the default cipher of the SILC protocol is used. - See the [SILC1] for defined ciphers. - -o HMAC Name Length (2 bytes) - Indicates the length of the - HMAC Name field in the payload, not including any other - field. - -o HMAC Name (variable length) - Name of the HMAC to use - in the private message MAC computation. If this field does - not exist then the default HMAC of the SILC protocol is used. - See the [SILC1] for defined HMACs. -.in 3 - - -.ti 0 -2.3.13 Command Payload - -Command Payload is used to send SILC commands from client to server. -Also server MAY send commands to other servers. The following diagram -represents the Command Payload. - - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Payload Length | SILC Command | Arguments Num | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Command Identifier | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 17: Command Payload - - -.in 6 -o Payload Length (2 bytes) - Length of the entire command - payload including any command argument payloads associated - with this payload. - -o SILC Command (1 byte) - Indicates the SILC command. This MUST - be set to non-zero value. If zero (0) value is found in this - field the packet MUST be discarded. - -o Arguments Num (1 byte) - Indicates the number of arguments - associated with the command. If there are no arguments this - field is set to zero (0). The arguments MUST follow the - Command Payload. See section 2.3.2.2 for definition of the - Argument Payload. - -o Command Identifier (2 bytes) - Identifies this command at the - sender's end. The entity which replies to this command MUST - set the value found from this field into the Command Payload - used to send the reply to the sender. This way the sender - can identify which command reply belongs to which originally - sent command. What this field includes is implementation - issue but it is RECOMMENDED that wrapping counter value is - used in the field. -.in 3 - -See [SILC4] for detailed description of different SILC commands, -their arguments and their reply messages. - - -.ti 0 -2.3.14 Command Reply Payload - -Command Reply Payload is used to send replies to the commands. The -Command Reply Payload is identical to the Command Payload thus see -the 2.3.13 section for the payload specification. - -The entity which sends the reply packet MUST set the Command Identifier -field in the reply packet's Command Payload to the value it received -in the original command packet. - -See SILC Commands in [SILC4] for detailed description of different -SILC commands, their arguments and their reply messages. - - -.ti 0 -2.3.15 Connection Auth Request Payload - -Client MAY send this payload to server to request the authentication -method that must be used in authentication protocol. If client knows -this information beforehand this payload is not necessary to be sent. -Server performing authentication with another server MAY also send -this payload to request the authentication method. If the connecting -server already knows this information this payload is not necessary -to be sent. - -Server receiving this request SHOULD reply with same payload sending -the mandatory authentication method. Algorithms that may be required -to be used by the authentication method are the ones already -established by the SILC Key Exchange protocol. See section Key -Exchange Start Payload in [SILC3] for detailed information. - -The payload may only be sent with SILC_PACKET_CONNECTION_AUTH_REQUEST -packet. It MUST NOT be sent in any other packet type. The following -diagram represents the Connection Auth Request Payload. - - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Connection Type | Authentication Method | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 18: Connection Auth Request Payload - - -.in 6 -o Connection Type (2 bytes) - Indicates the type of the - connection. The following connection types are defined: - - - 1 Client connection - 2 Server connection - 3 Router connection - - If any other type is found in this field the packet MUST be - discarded and the authentication MUST be failed. - -o Authentication Method (2 bytes) - Indicates the authentication - method to be used in the authentication protocol. The following - authentication methods are defined: - - 0 NONE (mandatory) - 1 password (mandatory) - 2 public key (mandatory) - - If any other type is found in this field the packet MUST be - discarded and the authentication MUST be failed. If this - payload is sent as request to receive the mandatory - authentication method this field MUST be set to zero (0), - indicating that receiver should send the mandatory - authentication method. The receiver sending this payload - to the requesting party, MAY also set this field to zero (0) - to indicate that authentication is not required. In this - case authentication protocol still MUST be started but - server is most likely to respond with SILC_PACKET_SUCCESS - immediately. -.in 3 - - -.ti 0 -2.3.16 New ID Payload - -New ID Payload is a multipurpose payload. It is used to send newly -created ID's from clients and servers. When client connects to server -and registers itself to the server by sending SILC_PACKET_NEW_CLIENT -packet, server replies with this packet by sending the created ID for -the client. Server always creates the ID for the client. - -This payload is also used when server tells its router that new client -has registered to the SILC network. In this case the server sends -the Client ID of the client to the router. Similarly when router -distributes information to other routers about the client in the SILC -network this payload is used. - -Also, when server connects to router, router use this payload to inform -other routers about new server in the SILC network. However, every -server (or router) creates their own ID's thus the ID distributed by -this payload is not created by the distributor in this case. Servers -create their own ID's. Server registers itself to the network by -sending SILC_PACKET_NEW_SERVER to the router it connected to. The case -is same when router connects to another router. - -This payload MUST NOT be used to send information about new channels. -New channels are always distributed by sending the dedicated -SILC_PACKET_NEW_CHANNEL packet. Client MUST NOT send this payload. -Both client and server (and router) MAY receive this payload. - -The packet use generic ID Payload as New ID Payload. See section -2.3.2.1 for generic ID Payload. - - -.ti 0 -2.3.17 New Client Payload - -When client is connected to the server, keys has been exchanged and -connection has been authenticated, client MUST register itself to the -server. Client's first packet after key exchange and authentication -protocols MUST be SILC_PACKET_NEW_CLIENT. This payload tells server all -the relevant information about the connected user. Server creates a new -client ID for the client when received this payload and sends it to the -client in New ID Payload. - -This payload sends username and real name of the user on the remote host -which is connected to the SILC server with SILC client. The server -creates the client ID according the information sent in this payload. -The nickname of the user becomes the nickname sent in this payload. - -The payload may only be sent with SILC_PACKET_NEW_CLIENT packet. It -MUST NOT be sent in any other packet type. The following diagram -represents the New Client Payload. - - - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Username Length | | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + -| | -~ Username ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Real Name Length | | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + -| | -~ Real Name ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 19: New Client Payload - - -.in 6 -o Username Length (2 bytes) - Length of the Username field. - -o Username (variable length) - The username of the user on - the host where connecting to the SILC server. - -o Real Name Length (2 bytes) - Length of the Real Name field. - -o Real Name (variable length) - The real name of the user - on the host where connecting to the SILC server. -.in 3 - - -.ti 0 -2.3.18 New Server Payload - -This payload is sent by server when it has completed successfully both -key exchange and connection authentication protocols. The server -MUST register itself to the SILC Network by sending this payload. -The first packet after these key exchange and authentication protocols -is SILC_PACKET_NEW_SERVER packet. The payload includes the Server ID -of the server that it has created by itself. It also includes a -name of the server that is associated to the Server ID. - -The payload may only be sent with SILC_PACKET_NEW_SERVER packet. It -MUST NOT be sent in any other packet type. The following diagram -represents the New Server Payload. - - - - - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Server ID Length | | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + -| | -~ Server ID Data ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Server Name Length | | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + -| | -~ Server Name ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 20: New Server Payload - - -.in 6 -o Server ID Length (2 bytes) - Length of the Server ID Data - field. - -o Server ID Data (variable length) - The encoded Server ID - data. - -o Server Name Length (2 bytes) - Length of the server name - field. - -o Server Name (variable length) - The server name string. -.in 3 - - -.ti 0 -2.3.19 New Channel Payload - -Information about newly created channel is broadcasted to all routers -in the SILC network by sending this packet payload. Channels are -created by router of the cell. Server never creates channels unless -it is a standalone server and it does not have router connection, -in this case server acts as router. Normal server send JOIN command -to the router (after it has received JOIN command from client) which -then processes the command and creates the channel. Client MUST NOT -send this packet. Server MAY send this packet to a router when it is -announcing its existing channels to the router after it has connected -to the router. - -The packet use generic Channel Payload as New Channel Payload. See -section 2.3.2.3 for generic Channel Payload. The Mode Mask field in the -Channel Payload is the mode of the channel. - - -.ti 0 -2.3.20 Key Agreement Payload - -This payload is used by clients to request key negotiation between -another client in the SILC Network. The key agreement protocol used -is the SKE protocol. The result of the protocol, the secret key -material, can be used for example as private message key between the -two clients. This significantly adds security as the clients agree -about the key without any server interaction. The protocol is executed -peer to peer. The server and router MUST NOT send this payload. - -The sender MAY tell the receiver of this payload the hostname and the -port where the SKE protocol is running in the sender's end. The -receiver MAY then initiate the SKE negotiation with the sender. The -sender MAY also optionally not to include the hostname and the port -of its SKE protocol. In this case the receiver MAY reply to the -request by sending the same payload filled with the receiver's hostname -and the port where the SKE protocol is running. The sender MAY then -initiate the SKE negotiation with the receiver. - -This payload may be sent with SILC_PACKET_KEY_AGREEMENT and -SILC_PACKET_FTP packet types. It MUST NOT be sent in any other packet -types. The following diagram represents the Key Agreement Payload. - - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Hostname Length | | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + -| | -~ Hostname ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Port | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 21: Key Agreement Payload - - -.in 6 -o Hostname Length (2 bytes) - Indicates the length of the - Hostname field. - -o Hostname (variable length) - The hostname or IP address where - the SKE protocol is running, as UTF-8 encoded string. The sender - MAY fill this field when sending the payload. If the receiver - sends this payload as reply to the request it MUST fill this field. - -o Port (4 bytes) - The port where the SKE protocol is bound. - The sender MAY fill this field when sending the payload. If - the receiver sends this payload as reply to the request it - MUST fill this field. This is a 32 bit MSB first order value. -.in 3 - - -After the key material has been received from the SKE protocol it is -processed as the [SILC3] describes. If the key material is used as -channel private key then the Sending Encryption Key, as defined in -[SILC3] is used as the channel private key. Other key material must -be discarded. The [SILC1] in section 4.6 defines the way to use the -key material if it is intended to be used as private message keys. -Any other use for the key material is undefined. - - -.ti 0 -2.3.21 Resume Router Payload - -See the [SILC1] for Resume Router protocol where this payload is -used. The payload may only be sent with SILC_PACKET_RESUME_ROUTER -packet. It MUST NOT be sent in any other packet type. The following -diagram represents the Resume Router Payload. - - -.in 21 -.nf - 1 - 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Type | Session ID | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 22: Resume Router Payload - - -.in 6 -o Type (1 byte) - Indicates the type of the backup resume - protocol packet. The type values are defined in [SILC1]. - -o Session ID (1 bytes) - Indicates the session ID for the - backup resume protocol. The sender of the packet sets this - value and the receiver MUST set the same value in subsequent - reply packet. -.in 3 - - - - -.ti 0 -2.3.22 File Transfer Payload - -File Transfer Payload is used to perform file transfer protocol between -two entities in the network. The actual file transfer protocol is always -encapsulated inside the SILC Packet. The actual data stream is also sent -peer to peer outside SILC network. - -When an entity, usually a client wishes to perform file transfer protocol -with another client in the network, they perform Key Agreement protocol -as described in the section 2.3.20 Key Agreement Payload and in [SILC3], -inside File Transfer Payload. After the Key Agreement protocol has been -performed the subsequent packets in the data stream will be protected -using the new key material. The actual file transfer protocol is also -initialized in this stage. All file transfer protocol packets are always -encapsulated in the File Transfer Payload and protected with the -negotiated key material. - -The payload may only be sent with SILC_PACKET_FTP packet. It MUST NOT -be sent in any other packet type. The following diagram represents the -File Transfer Payload. - - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Type | | -+-+-+-+-+-+-+-+-+ + -| | -~ Data ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 23: File Transfer Payload - - -.in 6 -o Type (1 byte) - Indicates the type of the file transfer - protocol. The following file transfer protocols has been - defined: - - 1 Secure File Transfer Protocol (SFTP) (mandatory) - - If zero (0) value or any unsupported file transfer protocol - type is found in this field the packet MUST be discarded. - The currently mandatory file transfer protocol is SFTP. - The SFTP protocol is defined in [SFTP]. - -o Data (variable length) - Arbitrary file transfer data. The - contents and encoding of this field is dependent of the usage - of this payload and the type of the file transfer protocol. - When this payload is used to perform the Key Agreement - protocol, this field include the Key Agreement Payload, - as defined in the section 2.3.20 Key Agreement Payload. - When this payload is used to send the actual file transfer - protocol data, the encoding is defined in the corresponding - file transfer protocol. -.in 3 - - -.ti 0 -2.3.23 Resume Client Payload - -This payload is used by client to resume its detached session in the -SILC Network. A client is able to detach itself from the network by -sending SILC_COMMAND_DETACH command to its server. The network -connection to the client is lost but the client remains as valid -client in the network. The client is able to resume the session back -by sending this packet and including the old Client ID, and an -Authentication Payload [SILC1] which the server use to verify with -the detached client's public key. This also implies that the -mandatory authentication method is public key authentication. - -Server or router that receives this from the client also sends this, -without the Authentication Payload, to routers in the network so that -they know the detached client has resumed. Refer to the [SILC1] for -detailed description how the detaching and resuming procedure is -performed. - -The payload may only be sent with SILC_PACKET_RESUME CLIENT packet. It -MUST NOT be sent in any other packet type. The following diagram -represents the Resume Client Payload. - -.in 5 -.nf - 1 2 3 - 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 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| Client ID Length | | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + -| | -~ Client ID ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| | -~ Authentication Payload ~ -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.in 3 - -.ce -Figure 24: Resume Client Payload - - -.in 6 -o Client ID Length (1 byte) - The length of the Client ID - field not including any other field. - -o Client ID (variable length) - The detached client's Client - ID. The client that sends this payload must know the Client - ID. - -o Authentication Payload (variable length) - The authentication - payload that the server will verify with the detached client's - public key. If the server doesn't know the public key, it must - retrieve it for example with SILC_COMMAND_GETKEY command. -.in 3 - - - -.ti 0 -2.4 SILC ID Types - -ID's are used in the SILC network to associate different entities. -The following ID's has been defined to be used in the SILC network. - -.in 6 -0 No ID - - This is used when other ID type is available at the time. - -1 Server ID - - Server ID to associate servers. See the format of - this ID in [SILC1]. - -2 Client ID - - Client ID to associate clients. See the format of - this ID in [SILC1]. - -3 Channel ID - - Channel ID to associate channels. See the format of - this ID in [SILC1]. -.in 3 - -When encoding different IDs into the ID Payload, all fields are always -in MSB first order. The IP address, port, and/or the random number -are encoded in the MSB first order. - - -.ti 0 -2.5 Packet Encryption And Decryption - -SILC packets are encrypted almost entirely. Only the MAC at the end -of the packet is never encrypted. The SILC Packet header is the first -part of a packet to be encrypted and it is always encrypted with the -key of the next receiver of the packet. The data payload area of the -packet is always entirely encrypted and it is usually encrypted with -the next receiver's key. However, there are some special packet types -and packet payloads that require special encryption process. These -special cases are described in the next sections. First is described -the normal packet encryption process. - - - -.ti 0 -2.5.1 Normal Packet Encryption And Decryption - -Normal SILC packets are encrypted with the session key of the next -receiver of the packet. The entire SILC Packet header and the packet -data payload is is encrypted with the same key. Padding of the packet -is also encrypted always with the session key, also in special cases. -Computed MAC of the packet MUST NOT be encrypted. - -Decryption process in these cases are straightforward. The receiver -of the packet MUST first decrypt the SILC Packet header, or some parts -of it, usually first 16 bytes of it. Then the receiver checks the -packet type from the decrypted part of the header and can determine -how the rest of the packet must be decrypted. If the packet type is -any of the special cases described in the following sections the packet -decryption is special. If the packet type is not among those special -packet types rest of the packet can be decrypted with the same key. -At this point the receiver is also able to determine the length of the -packet. - -With out a doubt, this sort of decryption processing causes some -overhead to packet decryption, but never the less, is required. - -The MAC of the packet is also verified at this point. The MAC is -computed from the ciphertext of the packet so it can be verified -at this stage. The length of the packet need to be known to be able -to verify the MAC from the ciphertext so the first 16 bytes need to -be decrypted to determine the packet length. However, the MAC MUST -be verified from the entire ciphertext. - - -.ti 0 -2.5.2 Channel Message Encryption And Decryption - -Channel Messages (Channel Message Payload) are always encrypted with -the channel specific key. However, the SILC Packet header is not -encrypted with that key. As in normal case, the header is encrypted -with the key of the next receiver of the packet. Note that, in this -case the encrypted data area is not touched at all; it MUST NOT be -re-encrypted with the session key. - -Receiver of a channel message, who ever that is, is REQUIRED to decrypt -the SILC Packet header to be able to recognize the packet to be as -channel message. This is same procedure as for normal SILC packets. -As the receiver founds the packet to be channel message, rest of the -packet processing is special. Rest of the SILC Packet header is -decrypted with the same session key along with the padding of the -packet. After that the packet is protected with the channel specific -key and thus can be decrypted only if the receiver is the client on -the channel. See section 2.7 Packet Padding Generation for more -information about padding on special packets. - -If the receiver of the channel message is router which is routing the -message to another router then it MUST decrypt the Channel Message -payload too. Between routers (that is, between cells) channel messages -are protected with session keys shared between the routers. This -causes another special packet processing for channel messages. If -the channel message is received from another router then the entire -packet, including Channel Message payload, MUST be encrypted with the -session key shared between the routers. In this case the packet -decryption process is as with normal SILC packets. Hence, if the -router is sending channel message to another router the Channel -Message payload MUST have been decrypted and MUST be re-encrypted -with the session key shared between the another router. In this -case the packet encryption is as with any normal SILC packet. - -It must be noted that this is only when the channel messages are sent -from router to another router. In all other cases the channel -message encryption and decryption is as described before. This -different processing of channel messages with router to router -connection is because channel keys are cell specific. All cells have -their own channel keys thus the channel message traveling from one -cell to another MUST be protected as it would be any normal SILC -packet. - -If the SILC_CMODE_PRIVKEY channel mode has been set for the channel -then the router cannot decrypt the packet as it does not know the -private key. In this case the entire packet MUST be encrypted with -the session key and sent to the router. The router receiving the -packet MUST check the channel mode and decrypt the packet accordingly. - - -.ti 0 -2.5.3 Private Message Encryption And Decryption - -By default, private message in SILC are protected by session keys. -In this case the private message encryption and decryption process is -equivalent to normal packet encryption and decryption. - -However, private messages MAY be protected with private message key -which causes the packet to be special packet. The procedure in this -case is very much alike to channel packets. The actual private message -is encrypted with the private message key and other parts of the -packet is encrypted with the session key. See 2.7 Packet Padding -Generation for more information about padding on special packets. - -The difference from channel message processing is that server or router -en route never decrypts the actual private message, as it does not -have the key to do that. Thus, when sending packets between router -the processing is same as in any other case as well; the packet's header -and padding is protected by the session key and the data area is not -touched and is not re-encrypted. - -The true receiver of the private message is able to decrypt the private -message as it shares the key with the sender of the message. - - -.ti 0 -2.6 Packet MAC Generation - -Data integrity of a packet is protected by including a message -authentication code (MAC) at the end of the packet. The MAC is computed -from shared secret MAC key, that is established by the SILC Key Exchange -protocol, from packet sequence number, and from the encrypted packet -data. The MAC is always computed after packet is encrypted. This is -so called Encrypt-Then-MAC order; packet is first encrypted, then MAC -is computed from the encrypted data. - -The MAC is computed from entire packet. Every bit of data in the packet, -including SILC Packet Header is used in the MAC computing. This way -the entire packet becomes authenticated. - -Hence, packet's MAC generation is as follows: - - mac = MAC(key, sequence number | Encrypted SILC packet) - -The MAC key is negotiated during the SKE protocol. The sequence number -is a 32 bit MSB first value starting from zero for first packet and -increasing for subsequent packets, finally wrapping after 2^32 packets. -The value is never reset, not even after rekey has been performed. -However, rekey MUST be performed before the sequence number wraps -and repeats from zero. Note that the sequence number is incremented only -when MAC is computed for a packet. If packet is not encrypted and MAC is -not computed then the sequence number is not incremented. Hence, the -sequence number is zero for the very first encrypted packet. - -See [SILC1] for defined and allowed MAC algorithms. - - -.ti 0 -2.7 Packet Padding Generation - -Padding is needed in the packet because the packet is encrypted. It -always MUST be multiple by eight (8) or multiple by the block size -of the cipher, which ever is larger. The padding is always encrypted. - -For normal packets the padding is added after the SILC Packet Header -and between the Data Payload area. The padding for normal packets -may be calculated as follows: - -.in 6 -padding_length = 16 - (packet_length mod block_size) -if (padding_length < 8) - padding_length += block_size -.in 3 - -The `block_size' is the block size of the cipher. The maximum padding -length is 128 bytes, and minimum is 8 bytes. For example, packets that -include a passphrase or a password for authentication purposes SHOULD -pad the packet up to the maximum padding length. The maximum padding -is calculated as follows: - -.in 6 -padding_length = 128 - (packet_length mod block_size) -.in 3 - -For special packets the padding calculation is different as special -packets may be encrypted differently. In these cases the encrypted -data area MUST already be multiple by the block size thus in this case -the padding is calculated only for SILC Packet Header, not for any -other area of the packet. The same algorithm works in this case as -well, except that the `packet length' is now the SILC Packet Header -length. - -The padding MUST be random data, preferably, generated by -cryptographically strong random number generator for each packet -separately. - - -.ti 0 -2.8 Packet Compression - -SILC Packets MAY be compressed. In this case the data payload area -is compressed and all other areas of the packet MUST remain as they -are. After compression is performed for the data area, the length -field of Packet Header MUST be set to the compressed length of the -data. - -The compression MUST always be applied before encryption. When -the packet is received and decrypted the data area MUST be decompressed. -Note that the true sender of the packet MUST apply the compression and -the true receiver of the packet MUST apply the decompression. Any -server or router en route SHOULD NOT decompress the packet. - - -.ti 0 -2.9 Packet Sending - -The sender of the packet MUST assemble the SILC Packet Header with -correct values. It MUST set the Source ID of the header as its own -ID, unless it is forwarding the packet. It MUST also set the Destination -ID of the header to the true destination. If the destination is client -it will be Client ID, if it is server it will be Server ID and if it is -channel it will be Channel ID. - -If the sender wants to compress the packet it MUST apply the -compression now. Sender MUST also compute the padding as described -in above sections. Then sender MUST encrypt the packet as has been -described in above sections according whether the packet is normal -packet or special packet. Then sender MUST compute the MAC of the -packet. The computed MAC MUST NOT be encrypted. - - -.ti 0 -2.10 Packet Reception - -On packet reception the receiver MUST check that all fields in the -SILC Packet Header are valid. It MUST check the flags of the -header and act accordingly. It MUST also check the MAC of the packet -and if it is to be failed the packet MUST be discarded. Also if the -header of the packet includes any bad fields the packet MUST be -discarded. - -See above sections on the decryption process of the received packet. - -The receiver MUST also check that the ID's in the header are valid -ID's. Unsupported ID types or malformed ID's MUST cause packet -rejection. The padding on the reception is always ignored. - -The receiver MUST also check the packet type and start parsing the -packet according to the type. However, note the above sections on -special packet types and their parsing. - - -.ti 0 -2.11 Packet Routing - -Routers are the primary entities in the SILC network that takes care -of packet routing. However, normal servers routes packets as well, for -example, when they are routing channel message to the local clients. -Routing is quite simple as every packet tells the true origin and the -true destination of the packet. - -It is still RECOMMENDED for routers that has several routing connections -to create route cache for those destinations that has faster route than -the router's primary route. This information is available for the router -when other router connects to the router. The connecting party then -sends all of its locally connected clients, servers and channels. These -informations helps to create the route cache. Also, when new channels -are created to a cell its information is broadcasted to all routers -in the network. Channel ID's are based on router's ID thus it is easy -to create route cache based on these informations. If faster route for -destination does not exist in router's route cache the packet MUST be -routed to the primary route (default route). - -However, there are some issues when routing channel messages to group -of users. Routers are responsible of routing the channel message to -other routers, local servers and local clients as well. Routers MUST -send the channel message to only one router in the network, preferably -to the shortest route to reach the channel users. The message can be -routed into either upstream or downstream. After the message is sent -to a router in the network it MUST NOT be sent to any other router in -either same route or other route. The message MUST NOT be routed to -the router it came from. - -When routing for example private messages they should be routed to the -shortest route always to reach the destination client as fast as possible. - -For server which receives a packet to be routed to an entity that is -indirectly connected to the sender, the server MUST check whether that -particular packet type is allowed to be routed to that destination. Not -all packets may be sent by some odd entity to for example a local client, -or to some remote server or router, that is indirectly connected to the -sender. See section 2.3 SILC Packet Types and paragraph about indirectly -connected entities and sending packets to them. That section defines the -packets that may be sent to indirectly connected entities. When a server -or a router receives a packet that may be sent to indirectly connected -entity and it is destined to other entity except that server, it MUST -route it further either to shortest route or to the primary route to reach -that destination. - -Routers form a ring in the SILC network. However, routers may have other -direct connections to other routers in the network too. This can cause -interesting routing problems in the network. Since the network is a ring, -the packets usually should be routed into clock-wise direction, or if it -cannot be used then always counter clock-wise (primary route) direction. -Problems may arise when a faster direct route exists and router is routing -a channel message. Currently channel messages must be routed either -in upstream or downstream, they cannot be routed to other direct routes. -The SILC protocol should have a shortest path discovery protocol, and some -existing routing protocol, that can handle a ring network with other -direct routes inside the ring (so called hybrid ring-mesh topology), -MAY be defined to be used with the SILC protocol. Additional -specifications MAY be written on the subject to permeate this -specification. - - -.ti 0 -2.12 Packet Broadcasting - -SILC packets MAY be broadcasted in SILC network. However, only router -server may send or receive broadcast packets. Client and normal server -MUST NOT send broadcast packets and they MUST ignore broadcast packets -if they receive them. Broadcast packets are sent by setting Broadcast -flag to the SILC packet header. - -Broadcasting packets means that the packet is sent to all routers in -the SILC network, except to the router that sent the packet. The router -receiving broadcast packet MUST send the packet to its primary route. -The fact that SILC routers may have several router connections can -cause problems, such as race conditions inside the SILC network, if -care is not taken when broadcasting packets. Router MUST NOT send -the broadcast packet to any other route except to its primary route. - -If the primary route of the router is the original sender of the packet -the packet MUST NOT be sent to the primary route. This may happen -if router has several router connections and some other router uses -the router as its primary route. - -Routers use broadcast packets to broadcast for example information -about newly registered clients, servers, channels etc. so that all the -routers may keep these informations up to date. - - -.ti 0 -3 Security Considerations - -Security is central to the design of this protocol, and these security -considerations permeate the specification. Common security considerations -such as keeping private keys truly private and using adequate lengths for -symmetric and asymmetric keys must be followed in order to maintain the -security of this protocol. - - -.ti 0 -4 References - -[SILC1] Riikonen, P., "Secure Internet Live Conferencing (SILC), - Protocol Specification", Internet Draft, May 2002. - -[SILC3] Riikonen, P., "SILC Key Exchange and Authentication - Protocols", Internet Draft, May 2002. - -[SILC4] Riikonen, P., "SILC Commands", Internet Draft, May 2002. - -[IRC] Oikarinen, J., and Reed D., "Internet Relay Chat Protocol", - RFC 1459, May 1993. - -[IRC-ARCH] Kalt, C., "Internet Relay Chat: Architecture", RFC 2810, - April 2000. - -[IRC-CHAN] Kalt, C., "Internet Relay Chat: Channel Management", RFC - 2811, April 2000. - -[IRC-CLIENT] Kalt, C., "Internet Relay Chat: Client Protocol", RFC - 2812, April 2000. - -[IRC-SERVER] Kalt, C., "Internet Relay Chat: Server Protocol", RFC - 2813, April 2000. - -[SSH-TRANS] Ylonen, T., et al, "SSH Transport Layer Protocol", - Internet Draft. - -[PGP] Callas, J., et al, "OpenPGP Message Format", RFC 2440, - November 1998. - -[SPKI] Ellison C., et al, "SPKI Certificate Theory", RFC 2693, - September 1999. - -[PKIX-Part1] Housley, R., et al, "Internet X.509 Public Key - Infrastructure, Certificate and CRL Profile", RFC 2459, - January 1999. - -[Schneier] Schneier, B., "Applied Cryptography Second Edition", - John Wiley & Sons, New York, NY, 1996. - -[Menezes] Menezes, A., et al, "Handbook of Applied Cryptography", - CRC Press 1997. - -[OAKLEY] Orman, H., "The OAKLEY Key Determination Protocol", - RFC 2412, November 1998. - -[ISAKMP] Maughan D., et al, "Internet Security Association and - Key Management Protocol (ISAKMP)", RFC 2408, November - 1998. - -[IKE] Harkins D., and Carrel D., "The Internet Key Exchange - (IKE)", RFC 2409, November 1998. - -[HMAC] Krawczyk, H., "HMAC: Keyed-Hashing for Message - Authentication", RFC 2104, February 1997. - -[PKCS1] Kalinski, B., and Staddon, J., "PKCS #1 RSA Cryptography - Specifications, Version 2.0", RFC 2437, October 1998. - -[RFC2119] Bradner, S., "Key Words for use in RFCs to Indicate - Requirement Levels", BCP 14, RFC 2119, March 1997. - -[SFTP] Ylonen T., and Lehtinen S., "Secure Shell File Transfer - Protocol", Internet Draft, March 2001. - -[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO - 10646", RFC 3629, November 2003. - - -.ti 0 -5 Author's Address - -.nf -Pekka Riikonen -Snellmaninkatu 34 A 15 -70100 Kuopio -Finland - -EMail: priikone@iki.fi - - -.ti 0 -6 Full Copyright Statement - -Copyright (C) The Internet Society (2003). All Rights Reserved. - -This document and translations of it may be copied and furnished to -others, and derivative works that comment on or otherwise explain it -or assist in its implementation may be prepared, copied, published -and distributed, in whole or in part, without restriction of any -kind, provided that the above copyright notice and this paragraph are -included on all such copies and derivative works. However, this -document itself may not be modified in any way, such as by removing -the copyright notice or references to the Internet Society or other -Internet organizations, except as needed for the purpose of -developing Internet standards in which case the procedures for -copyrights defined in the Internet Standards process must be -followed, or as required to translate it into languages other than -English. - -The limited permissions granted above are perpetual and will not be -revoked by the Internet Society or its successors or assigns. - -This document and the information contained herein is provided on an -"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING -TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING -BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION -HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF -MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.