+
+
+
+
+
+
+Network Working Group P. Riikonen
+Internet-Draft
+draft-riikonen-silc-spec-00.txt 28 June 2000
+Expires: 28 Jan 2001
+
+
+ Secure Internet Live Conferencing (SILC),
+ Protocol Specification
+
+Status of this Memo
+
+ This document is an Internet-Draft. 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.''
+
+ To learn the current status of any Internet-Draft, please check the
+ ``1id-abstracts.txt'' listing contained in the Internet-Drafts
+ Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe),
+ munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or
+ ftp.isi.edu (US West Coast).
+
+ The distribution of this memo is unlimited.
+
+
+Abstract
+
+ This memo describes a Secure Internet Live Conferencing (SILC)
+ protocol which provides secure conferencing services over insecure
+ network channel. SILC is IRC [IRC] like protocol, however, it is
+ not equivalent to IRC and does not support IRC. Strong cryptographic
+ methods are used to protect SILC packets inside SILC network. Two
+ other Internet Drafts relates very closely to this memo; SILC Packet
+ Protocol [SILC2] and SILC Key Exchange and Authentication Protocols
+ [SILC3].
+
+
+
+
+
+
+
+
+
+
+Riikonen [Page 1]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+Table of Contents
+
+ 1 Introduction .................................................. 3
+ 2 SILC Concepts ................................................. 3
+ 2.1 SILC Network Topology ..................................... 4
+ 2.2 Communication Inside a Cell ............................... 5
+ 2.3 Communication in the Network .............................. 6
+ 2.4 Channel Communication ..................................... 7
+ 3 SILC Specification ............................................ 7
+ 3.1 Client .................................................... 7
+ 3.1.1 Client ID ........................................... 8
+ 3.2 Server .................................................... 8
+ 3.2.1 Server's Local ID List .............................. 9
+ 3.2.2 Server ID ........................................... 10
+ 3.2.3 SILC Server Ports ................................... 10
+ 3.3 Router .................................................... 11
+ 3.3.1 Router's Local ID List .............................. 11
+ 3.3.2 Router's Global ID List ............................. 12
+ 3.3.3 Router's Server ID .................................. 12
+ 3.4 Channels .................................................. 12
+ 3.4.1 Channel ID .......................................... 13
+ 3.5 Operators ................................................. 14
+ 3.6 SILC Commands ............................................. 14
+ 3.7 SILC Packets .............................................. 15
+ 3.8 Packet Encryption ......................................... 15
+ 3.8.1 Determination of the Source and the Destination ..... 16
+ 3.8.2 Client To Client .................................... 16
+ 3.8.3 Client To Channel ................................... 17
+ 3.8.4 Server To Server .................................... 18
+ 3.9 Key Exchange And Authentication ........................... 18
+ 3.10 Algorithms ............................................... 19
+ 3.10.1 Ciphers ............................................ 19
+ 3.10.2 Public Key Algorithms .............................. 20
+ 3.10.3 MAC Algorithms ..................................... 20
+ 3.10.4 Compression Algorithms ............................. 20
+ 3.11 SILC Public Key .......................................... 21
+ 4 SILC Procedures ............................................... 23
+ 4.1 Creating Client Connection ................................ 23
+ 4.2 Creating Server Connection ................................ 24
+ 4.3 Joining to a Channel ...................................... 25
+ 4.4 Channel Key Generation .................................... 26
+ 4.5 Private Message Sending and Reception ..................... 27
+ 4.6 Private Message Key Generation ............................ 27
+ 4.7 Channel Message Sending and Reception ..................... 28
+ 4.8 Session Key Regeneration .................................. 28
+ 4.9 Command Sending and Reception ............................. 29
+ 5 SILC Commands ................................................. 29
+ 5.1 SILC Commands Syntax ...................................... 29
+
+
+
+Riikonen [Page 2]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ 5.2 SILC Commands List ........................................ 31
+ 5.3 SILC Command Status Types ................................. 54
+ 5.3.1 SILC Command Status Payload ......................... 54
+ 5.3.2 SILC Command Status List ............................ 54
+ 6 Security Considerations ....................................... 58
+ 7 References .................................................... 59
+ 8 Author's Address .............................................. 60
+
+
+List of Figures
+
+ Figure 1: SILC Network Topology
+ Figure 2: Communication Inside cell
+ Figure 3: Communication Between Cells
+ Figure 4: SILC Public Key
+ Figure 5: SILC Command Status Payload
+
+
+1. Introduction
+
+ This document describes a Secure Internet Live Conferencing (SILC)
+ protocol which provides secure conferencing services over insecure
+ network channel. SILC is IRC [IRC] like protocol, however, it is
+ not equivalent to IRC and does not support IRC. Strong cryptographic
+ methods are used to protect SILC packets inside SILC network. Two
+ other Internet Drafts relates very closely to this memo; SILC Packet
+ Protocol [SILC2] and SILC Key Exchange and Authentication Protocols
+ [SILC3].
+
+ The protocol uses extensively packets as conferencing protocol
+ requires message and command sending. The SILC Packet Protocol is
+ described in [SILC2] and should be read to fully comprehend this
+ document and protocol. [SILC2] also describes the packet encryption
+ and decryption in detail.
+
+ The security of SILC protocol and for any security protocol for that
+ matter is based on strong and secure key exchange protocol. The SILC
+ Key Exchange protocol is described in [SILC3] along with connection
+ authentication protocol and should be read to fully comprehend this
+ document and protocol.
+
+ The SILC protocol has been developed to work on TCP/IP network
+ protocol, although it could be made to work on other network protocols
+ with only minor changes. However, it is recommended that TCP/IP
+ protocol is used under SILC protocol. Typical implementation would
+ be made in client-server model.
+
+
+
+
+
+Riikonen [Page 3]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+2. SILC Concepts
+
+ This section describes various SILC protocol concepts that forms the
+ actual protocol, and in the end, the actual SILC network. The mission
+ of the protocol is to deliver messages from clients to other clients
+ through routers and servers in secure manner. The messages may also
+ be delivered from one client to many clients forming a group, also
+ known as a channel.
+
+ This section does not focus to security issues, instead basic network
+ concepts are introduced to make the topology of the SILC network
+ clear.
+
+
+2.1 SILC Network Topology
+
+ SILC network is a cellular network as opposed to tree style network
+ topology. The rationale for this is to have servers that can perform
+ specific kind of tasks what other servers cannot perform. This leads
+ to two kinds of servers; normal SILC servers and SILC routers.
+ A difference between normal server and router server is that routers
+ knows everything about everything in the network. They also do the
+ actual routing of the messages to the correct receiver. Normal servers
+ knows only about local information and nothing about global information.
+ This makes the network faster as there are less servers that needs to
+ keep global information up to date at all time.
+
+ This, on the other hand, leads to cellular like network, where routers
+ are in the centrum on the cell and servers are connected to the router.
+ Following diagram represents SILC network topology.
+
+
+ ---- ---- ---- ---- ---- ----
+ | S8 | S5 | S4 | | S7 | S5 | S6 |
+ ----- ---- ----- ----- ---- -----
+ | S7 | S/R1 | S2 | --- | S8 | S/R2 | S4 |
+ ---- ------ ---- ---- ------ ----
+ | S6 | S3 | S1 | | S1 | S3 | S2 | ---- ----
+ ---- ---- ---- ---- ---- ---- | S3 | S1 |
+ Cell 1. \ Cell 2. | \____ ----- -----
+ | | | S4 | S/R4 |
+ ---- ---- ---- ---- ---- ---- ---- ------
+ | S7 | S4 | S2 | | S1 | S3 | S2 | | S2 | S5 |
+ ----- ---- ----- ----- ---- ----- ---- ----
+ | S6 | S/R3 | S1 | --- | S4 | S/R5 | S5 | Cell 4.
+ ---- ------ ---- ---- ------ ----
+ | S8 | S5 | S3 | | S6 | S7 | S8 | ... etc ...
+ ---- ---- ---- ---- ---- ----
+
+
+
+Riikonen [Page 4]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ Cell 3. Cell 5.
+
+ Figure 1: SILC Network Topology
+
+
+ A cell is formed when a server or servers connect to one router. In
+ SILC network normal server cannot directly connect to other normal
+ server. Normal server may only connect to SILC router which then
+ routes the messages to the other servers in the cell. Router servers
+ on the other hand may connect to other routers to form the actual SILC
+ network, as seen in above figure. However, router is also normal SILC
+ server; clients may connect to it the same way as to normal SILC
+ servers. Normal server also cannot have active connections to more
+ than one router. Normal server cannot be connected to two different
+ cells. Router servers, on the other hand, may have as many router to
+ router connections as needed.
+
+ There are many issues in this network topology that needs to be careful
+ about. Issues like the size of the cells, the number of the routers in
+ the SILC network and the capacity requirements of the routers. These
+ issues should be discussed in the Internet Community and additional
+ documents on the issue will be written.
+
+
+2.2 Communication Inside a Cell
+
+ It is always guaranteed that inside a cell message is delivered to the
+ recipient with at most two server hops. Client who is connected to
+ server in the cell and is talking on channel to other client connected
+ to other server in the same cell, will have its messages delivered from
+ its local server first to the router of the cell, and from the router
+ to the other server in the cell. Following diagram represents this
+ scenario.
+
+
+ 1 --- S1 S4 --- 5
+ S/R
+ 2 -- S2 S3
+ / |
+ 4 3
+
+
+ Figure 2: Communication Inside cell
+
+
+ Example: Client 1. connected to Server 1. message sent to
+ Client 4. connected to Server 2. travels from Server 1.
+ first to Router which routes the message to Server 2.
+
+
+
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+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ which then sends it to the Client 4. All the other
+ servers in the cell will not see the routed message.
+
+
+ If client is connected directly to the router, as router is also normal
+ SILC server, the messages inside the cell are always delivered only with
+ one server hop. If clients communicating with each other are connected
+ to the same server, no router interaction is needed. This is the optimal
+ situation of message delivery in the SILC network.
+
+
+2.3 Communication in the Network
+
+ If the message is destined to server that does not belong to local cell
+ the message is routed to the router server to which the destination
+ server belongs, if the local router is connected to destination router.
+ If there is no direct connection to the destination router, the local
+ router routes the message to its primary route. Following diagram
+ represents message sending between cells.
+
+
+ 1 --- S1 S4 --- 5 S2 --- 1
+ S/R - - - - - - - - S/R
+ 2 -- S2 S3 S1
+ / | \
+ 4 3 2
+
+ Cell 1. Cell 2.
+
+
+ Figure 3: Communication Between Cells
+
+
+ Example: Client 5. connected to Server 4. in Cell 1. message sent
+ to Client 2. connected to Server 1. in Cell 2. travels
+ from Server 4. to Router which routes the message to
+ Router in Cell 2, which then routes the message to
+ Server 1. All the other servers and routers in the
+ network will not see the routed message.
+
+
+ The optimal case of message delivery from client point of view is
+ when clients are connected directly to the routers and the messages
+ are delivered from one router to the other router.
+
+
+
+
+
+
+
+Riikonen [Page 6]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+2.4 Channel Communication
+
+ Messages may be sent to group of clients as well. Sending messages to
+ many clients works the same way as sending messages point to point, from
+ message delivery point of view. Security issues are another matter
+ which are not discussed in this section.
+
+ Router server handles the message routing to multiple recipients. If
+ any recipient is not in the same cell as the sender the messages are
+ routed further.
+
+ Server distributes the channel message to its local clients who are
+ joined to the channel. Also, router distributes the message to its
+ local clients on the channel.
+
+
+3. SILC Specification
+
+ This section describes the SILC protocol. However, [SILC2] and
+ [SILC3] describes other important protocols that are part of this SILC
+ specification and must be read.
+
+
+3.1 Client
+
+ A client is a piece of software connecting to SILC server. SILC client
+ cannot be SILC server. Purpose of clients is to provide the user
+ interface of the SILC services for end user. Clients are distinguished
+ from other clients by unique Client ID. Client ID is a 128 bit ID that
+ is used in the communication in the SILC network. The client ID is
+ based on the nickname selected by the user. User uses logical nicknames
+ in communication which are then mapped to the corresponding Client ID.
+ Client ID's are low level identifications and must not be seen by the
+ end user.
+
+ Clients provide other information about the end user as well. Information
+ such as the nickname of the user, username and the hostname of the end
+ user and user's real name. See section 3.2 Server for information of
+ the requirements of keeping this information.
+
+ The nickname selected by the user is not unique in the SILC network.
+ There can be 2^8 same nicknames for one IP address. As for comparison to
+ IRC [IRC] where nicknames are unique this is a fundamental difference
+ between SILC and IRC. This causes the server names to be used along
+ with the nicknames to identify specific users when sending messages.
+ This feature of SILC makes IRC style nickname-wars obsolete as no one
+ owns their nickname; there can always be someone else with the same
+ nickname. Another difference is that there are no limit of the length
+
+
+
+Riikonen [Page 7]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ of the nickname in the SILC.
+
+
+3.1.1 Client ID
+
+ Client ID is used to identify users in the SILC network. The Client ID
+ is unique to the extent that there can be 2^128 different Client ID's.
+ Collisions are not expected to happen. The Client ID is defined as
+ follows.
+
+ 128 bit Client ID based on IPv4 addresses:
+
+ 32 bit ServerID IP address (bits 1-32)
+ 8 bit Random number
+ 88 bit Truncated MD5 hash value of the nickname
+
+ o Server ID IP address - Indicates the server where this
+ client is coming from. The IP address hence equals the
+ server IP address where to the client has connected.
+
+ o Random number - Random number to further unify the
+ Client ID. This makes it possible to have 2^8 same
+ nicknames from the same server IP address.
+
+ o MD5 hash - MD5 hash value of the nickname is truncated
+ taking 88 bits from the start of the hash value. This
+ hash value is used to search the user's Client ID from
+ the ID lists.
+
+ Collisions could occur when more than 2^8 clients using same nickname
+ from the same server IP address is connected to the SILC network.
+ Server must be able to handle this situation by refusing to accept
+ anymore of that nickname.
+
+ Another possible collision may happen with the truncated hash value of
+ the nickname. It could be possible to have same truncated hash value for
+ two different nicknames. However, this is not expected to happen nor
+ cause any problems if it would occur. Nicknames are usually logical and
+ it is unlikely to have two distinct logical nicknames produce same
+ truncated hash value.
+
+
+3.2 Server
+
+ Servers are the most important parts of the SILC network. They form the
+ basis of the SILC, providing a point to which clients may connect to.
+ There are two kinds of servers in SILC; normal servers and router servers.
+ This section focuses on the normal server and router server is described
+
+
+
+Riikonen [Page 8]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ in the section 3.3 Router.
+
+ Normal servers may not directly connect to other normal server. Normal
+ servers may only directly connect to router server. If the message sent
+ by the client is destined outside the local server it is always sent to
+ the router server for further routing. Server may only have one active
+ connection to router on same port. Normal server may not connect to other
+ cell's router except in situations where its cell's router is unavailable.
+
+ Servers and routers in the SILC network are considered to be trusted.
+ With out a doubt, servers that are set to work on ports above 1023 are
+ not considered to be trusted. Also, the service provider acts important
+ role in the server's trustworthy.
+
+
+3.2.1 Server's Local ID List
+
+ Normal server keeps various information about the clients and their end
+ users connected to it. Every normal server must keep list of all locally
+ connected clients, Client ID's, nicknames, usernames and hostnames and
+ user's real name. Normal servers only keeps local information and it
+ does not keep any global information. Hence, normal servers knows only
+ about their locally connected clients. This makes servers efficient as
+ they don't have to worry about global clients. Server is also responsible
+ of creating the Client ID's for their clients.
+
+ Normal server also keeps information about locally created channels and
+ their Channel ID's.
+
+ Hence, local list for normal server includes:
+
+ server list - Router connection
+ o Server name
+ o Server IP address
+ o Server ID
+ o Sending key
+ o Receiving key
+ o Public key
+
+ client list - All clients in server
+ o Nickname
+ o Username@host
+ o Real name
+ o Client ID
+ o Sending key
+ o Receiving key
+
+
+
+
+
+Riikonen [Page 9]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ channel list - All channels in server
+ o Channel name
+ o Channel ID
+ o Client ID's on channel
+ o Client ID modes on channel
+ o Channel key
+
+
+
+3.2.2 Server ID
+
+ Servers are distinguished from other servers by unique 64 bit Server ID.
+ The Server ID is used in the SILC to route messages to correct servers.
+ Server ID's also provide information for Client ID's, see section 3.1.1
+ Client ID. Server ID is defined as follows.
+
+ 64 bit Server ID based on IPv4 addresses:
+
+ 32 bit IP address of the server
+ 16 bit Port
+ 16 bit Random number
+
+ o IP address of the server - This is the real IP address of
+ the server.
+
+ o Port - This is the port the server is binded to.
+
+ o Random number - This is used to further unify the Server ID.
+
+ Collisions are not expected to happen in any conditions. The Server ID
+ is always created by the server itself and server is resposible of
+ distributing it to the router.
+
+
+3.2.3 SILC Server Ports
+
+ SILC uses currently TCP port 334 on SILC network. However, this is not
+ official port assigned for SILC. Official port has been requested by
+ the IANA.
+
+ If there are needs to create new SILC networks in the future the port
+ numbers must be officially assigned by the IANA. Most convenience case
+ would be to assign port numbers upwards from 334.
+
+ Server on network above privileged ports (>1023) should not be trusted
+ as they could have been set up by untrusted party.
+
+
+
+
+
+Riikonen [Page 10]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+3.3 Router
+
+ Router server in SILC network is responsible for keeping the cell together
+ and routing messages to other servers and to other routers. Router server
+ is also a normal server thus clients may connect to it as it would be
+ just normal SILC server.
+
+ However, router servers has a lot of important tasks that normal servers
+ do not have. Router server knows everything about everything in the SILC.
+ They know all clients currently on SILC, all servers and routers and all
+ channels in SILC. Routers are the only servers in SILC that care about
+ global information and keeping them up to date at all time. And, this
+ is what they must do.
+
+
+3.3.1 Router's Local ID List
+
+ Router server as well must keep local list of connected clients and
+ locally created channels. However, this list is extended to include all
+ the informations of the entire cell, not just the server itself as for
+ normal servers.
+
+ However, on router this list is a lot smaller since routers do not keep
+ information about user's nickname, username and hostname and real name
+ since these are not needed by the router. Router keeps only information
+ that it needs.
+
+ Hence, local list for router includes:
+
+ server list - All servers in the cell
+ o Server name
+ o Server ID
+ o Router's Server ID
+ o Sending key
+ o Receiving key
+
+ client list - All clients in the cell
+ o Client ID
+
+ channel list - All channels in the cell
+ o Channel ID
+ o Client ID's on channel
+ o Client ID modes on channel
+ o Channel key
+
+
+ Note that locally connected clients and other information include all the
+ same information as defined in section section 3.2.1 Server's Local ID
+
+
+
+Riikonen [Page 11]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ List.
+
+
+3.3.2 Router's Global ID List
+
+ Router server must also keep global list. Normal servers do not have
+ global list as they know only about local information. Global list
+ includes all the clients on SILC, their Client ID's, all created channels
+ and their Channel ID's and all servers and routers on SILC and their
+ Server ID's. That is said, global list is for global information and the
+ list must not include the local information already on the router's local
+ list.
+
+ Note that the global list does not include information like nicknames,
+ usernames and hostnames or user's real names. Router does not keep
+ these informations as they are not needed by the router. This
+ information is available from the client's server which maybe queried
+ when needed.
+
+ Hence, global list includes:
+
+ server list - All servers in SILC
+ o Server name
+ o Server ID
+ o Router's Server ID
+
+ client list - All clients in SILC
+ o Client ID
+
+ channel list - All channels in SILC
+ o Channel ID
+ o Client ID's on channel
+ o Client ID modes on channel
+
+
+3.3.3 Router's Server ID
+
+ Router's Server ID's are equivalent to normal Server ID's. As routers
+ are normal servers as well same types of ID's applies for routers as well.
+ Thus, see section 3.2.2 Server ID. Server ID's for routers are always
+ created by the remote router where the router is connected to.
+
+
+3.4 Channels
+
+ A channel is a named group of one or more clients which will all receive
+ messages addressed to that channel. The channel is created when first
+ client requests JOIN command to the channel, and the channel ceases to
+
+
+
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+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ exist when the last client leaves it. When channel exists, any client
+ can reference it using the name of the channel.
+
+ Channel names are unique although the real uniqueness comes from 64 bit
+ Channel ID that unifies each channel. However, channel names are still
+ unique and no two global channels with same name may exist. Channel name
+ is a string which begins with `#' character. There is no limit on the
+ length of the channel name. Channel names may not contain any spaces
+ (` '), any non-printable ASCII characters, commas (`,') and wildcard
+ characters.
+
+ Channels can have operators that can administrate the channel and
+ operate all of its modes. Following operators on channel exist on SILC
+ network.
+
+ o Channel founder - When channel is created the joining client becomes
+ channel founder. Channel founder is channel operator with some more
+ privileges. Basically, channel founder can fully operate the channel
+ and all of its modes. The privileges are limited only to the particular
+ channel. There can be only one channel founder per channel. Channel
+ founder supersedes channel operator's privileges.
+
+ Channel founder privileges cannot be removed by any other operator on
+ channel. When channel founder leaves the channel there is no channel
+ founder on the channel. Channel founder also cannot be removed by
+ force from the channel.
+
+ o Channel operator - When client joins to channel that has not existed
+ previously it will become automatically channel operator (and channel
+ founder discussed above). Channel operator is able administrate the
+ channel, set some modes on channel, remove a badly behaving client from
+ the channel and promote other clients to become channel operator.
+ The privileges are limited only to the particular channel.
+
+ Normal channel user may be promoted (opped) to channel operator
+ gaining channel operator privileges. Channel founder or other channel
+ operator may also demote (deop) channel operator to normal channel
+ user.
+
+
+3.4.1 Channel ID
+
+ Channels are distinguished from other channels by unique Channel ID.
+ The Channel ID is a 64 bit ID and collisions are not expected to happen
+ in any conditions. Channel names are just for logical use of channels.
+ The Channel ID is created by the server where the channel is created.
+ The Channel ID is defined as follows.
+
+
+
+
+Riikonen [Page 13]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ 64 bit Channel ID based on IPv4 addresses:
+
+ 32 bit Router's Server ID IP address (bits 1-32)
+ 16 bit Router's Server ID port (bits 33-48)
+ 16 bit Random number
+
+ o Router's Server ID IP address - Indicates the IP address of
+ the router of the cell where this channel is created. This is
+ taken from the router's Server ID. This way SILC router knows
+ where this channel resides in the SILC network.
+
+ o Router's Server ID port - Indicates the port of the channel on
+ the server. This is taken from the router's Server ID.
+
+ o Random number - To further unify the Channel ID. This makes
+ sure that there are no collisions. This also means that
+ in a cell there can be 2^16 channels.
+
+
+3.5 Operators
+
+ Operators are normal users with extra privileges to their server or
+ router. Usually these people are SILC server and router administrators
+ that take care of their own server and clients on them. The purpose of
+ operators is to administrate the SILC server or router. However, even
+ an operator with highest privileges is not able to enter invite-only
+ channel, to gain access to the contents of a encrypted and authenticated
+ packets traveling in the SILC network or to gain channel operator
+ privileges on public channels without being promoted. They have the
+ same privileges as everyone else except they are able to administrate
+ their server or router.
+
+
+3.6 SILC Commands
+
+ Commands are very important part on SILC network especially for client
+ which uses commands to operate on the SILC network. Commands are used
+ to set nickname, join to channel, change modes and many other things.
+
+ Client usually sends the commands and server replies by sending a reply
+ packet to the command. Server may also send commands usually to serve
+ the original client's request. However, server may not send command
+ to client and there are some commands that server must not send.
+
+ Note that the command reply is usually sent only after client has sent
+ the command request but server is allowed to send command reply packet
+ to client even if client has not requested the command. Client may,
+ however, choose not to accept the command reply, but there are some
+
+
+
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+
+
+ command replies that the client should accept. Example of a such
+ command reply is reply to SILC_COMMAND_CMODE command that the server
+ uses to distribute the channel mode on all clients on the channel
+ when the mode has changed.
+
+ It is expected that some of the commands may be miss-used by clients
+ resulting various problems on the server side. Every implementation
+ should assure that commands may not be executed more than once, say,
+ in two (2) seconds. This should be sufficient to prevent the miss-use
+ of commands.
+
+ SILC commands are described in section 5 SILC Commands.
+
+
+3.7 SILC Packets
+
+ Packets are naturally the most important part of the protocol and the
+ packets are what actually makes the protocol. Packets in SILC network
+ are always encrypted using, usually, the shared secret session key
+ or some other key, for example, channel key, when encrypting channel
+ messages. The SILC Packet Protocol is a wide protocol and is described
+ in [SILC2]. This document does not define or describe details of
+ SILC packets.
+
+
+3.8 Packet Encryption
+
+ All packets passed in SILC network must be encrypted. This section
+ defines how packets must be encrypted in the SILC network. The detailed
+ description of the actual encryption process of the packets are
+ described in [SILC2].
+
+ Client and its server shares secret symmetric session key which is
+ established by the SILC Key Exchange Protocol, described in [SILC3].
+ Every packet sent from client to server, with exception of packets for
+ channels, are encrypted with this session key.
+
+ Channels has their own key that are shared by every client on the channel.
+ However, the channel keys are cell specific thus one cell does not know
+ the channel key of the other cell, even if that key is for same channel.
+ Channel key is also known by the routers and all servers that has clients
+ on the channel. However, channels may have channel private keys that
+ are entirely local setting for client. All clients on the channel must
+ know the channel private key before hand to be able to talk on the
+ channel. In this case, no server or router knows the key for channel.
+
+ Server shares secret symmetric session key with router which is
+ established by the SILC Key Exchange Protocol. Every packet passed from
+
+
+
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+
+
+ server to router, with exception of packets for channels, are encrypted
+ with the shared session key. Same way, router server shares secret
+ symmetric key with its primary route. However, every packet passed
+ from router to other router, including packets for channels, are
+ encrypted with the shared session key. Every router connection has
+ their own session keys.
+
+
+3.8.1 Determination of the Source and the Destination
+
+ The source and the destination of the packet needs to be determined
+ to be able to route the packets to correct receiver. This information
+ is available in the SILC Packet Header which is included in all packets
+ sent in SILC network. The SILC Packet Header is described in [SILC2].
+
+ The header is always encrypted with the session key who is next receiver
+ of the packet along the route. The receiver of the packet, for example
+ a router along the route, is able to determine the sender and the
+ destination of the packet by decrypting the SILC Packet Header and
+ checking the ID's attached to the header. The ID's in the header will
+ tell to where the packet needs to be sent and where it is coming from.
+
+ The header in the packet does not change during the routing of the
+ packet. The original sender, for example client, assembles the packet
+ and the packet header and server or router between the sender and the
+ receiver must not change the packet header.
+
+ Note that the packet and the packet header may be encrypted with
+ different keys. For example, packets to channels are encrypted with
+ the channel key, however, the header is encrypted with the session key
+ as described above. However, the header and the packet may be encrypted
+ with same key. This is case, for example, with command packets.
+
+
+3.8.2 Client To Client
+
+ Process of message delivery and encryption from client to another
+ client is as follows.
+
+ Example: Private message from client to another client on different
+ servers. Clients do not share private message delivery
+ keys; normal session keys are used.
+
+ o Client 1. sends encrypted packet to its server. The packet is
+ encrypted with the session key shared between client and its
+ server.
+
+ o Server determines the destination of the packet and decrypts
+
+
+
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+
+ the packet. Server encrypts the packet with session key shared
+ between the server and its router, and sends the packet to the
+ router.
+
+ o Router determines the destination of the packet and decrypts
+ the packet. Router encrypts the packet with session key
+ shared between the router and the destination server, and sends
+ the packet to the server.
+
+ o Server determines the client to which the packet is destined
+ to and decrypts the packet. Server encrypts the packet with
+ session key shared between the server and the destination client,
+ and sends the packet to the client.
+
+ o Client 2. decrypts the packet.
+
+
+ Example: Private message from client to another client on different
+ servers. Clients has established secret shared private
+ message delivery key with each other and that is used in
+ the message encryption.
+
+ o Client 1. sends encrypted packet to its server. The packet is
+ encrypted with the private message delivery key shared between
+ clients.
+
+ o Server determines the destination of the packet and sends the
+ packet to the router.
+
+ o Router determines the destination of the packet and sends the
+ packet to the server.
+
+ o Server determines the client to which the packet is destined
+ to and sends the packet to the client.
+
+ o Client 2. decrypts the packet with the secret shared key.
+
+
+ If clients share secret key with each other the private message
+ delivery is much simpler since servers and routers between the
+ clients do not need to decrypt and re-encrypt the packet.
+
+ The process for clients on same server is much simpler as there are
+ no need to send the packet to the router. The process for clients
+ on different cells is same as above except that the packet is routed
+ outside the cell. The router of the destination cell routes the
+ packet to the destination same way as described above.
+
+
+
+
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+
+
+3.8.3 Client To Channel
+
+ Process of message delivery from client on channel to all the clients
+ on the channel.
+
+ Example: Channel of four users; two on same server, other two on
+ different cells. Client sends message to the channel.
+
+ o Client 1. encrypts the packet with channel key and sends the
+ packet to its server.
+
+ o Server determines local clients on the channel and sends the
+ packet to the Client on the same server. Server then sends
+ the packet to its router for further routing.
+
+ o Router determines local clients on the channel, if found
+ sends packet to the local clients. Router determines global
+ clients on the channel and sends the packet to its primary
+ router or fastest route.
+
+ o (Other router(s) do the same thing and sends the packet to
+ the server(s))
+
+ o Server determines local clients on the channel and sends the
+ packet to the client.
+
+ o All clients receiving the packet decrypts the packet.
+
+
+3.8.4 Server To Server
+
+ Server to server packet delivery and encryption is described in above
+ examples. Router to router packet delivery is analogous to server to
+ server. However, some packets, such as channel packets, are processed
+ differently. These cases are described later in this document and
+ more in detail in [SILC2].
+
+
+3.9 Key Exchange And Authentication
+
+ Key exchange is done always when for example client connects to server
+ but also when server and router and router and router connects to each
+ other. The purpose of key exchange protocol is to provide secure key
+ material to be used in the communication. The key material is used to
+ derive various security parameters used to secure SILC packets. The
+ SILC Key Exchange protocol is described in detail in [SILC3].
+
+ Authentication is done after key exchange protocol has been successfully
+
+
+
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+
+
+ completed. The purpose of authentication is to authenticate for example
+ client connecting to the server. However, Usually clients are accepted
+ to connect to server without explicit authentication. Servers are
+ required use authentication protocol when connecting. The authentication
+ may be based on passphrase (pre-shared-secret) or public key. The
+ connection authentication protocol is described in detail in [SILC3].
+
+
+3.10 Algorithms
+
+ This section defines all the allowed algorithms that can be used in
+ the SILC protocol. This includes mandatory cipher, mandatory public
+ key algorithm and MAC algorithms.
+
+
+3.10.1 Ciphers
+
+ Cipher is the encryption algorithm that is used to protect the data
+ in the SILC packets. See [SILC2] of the actual encryption process and
+ definition of how it must be done. SILC has a mandatory algorithm that
+ must be supported in order to be compliant with this protocol.
+
+ Following ciphers are defined in SILC protocol:
+
+ blowfish-cbc Blowfish in CBC mode (mandatory)
+ twofish-cbc Twofish in CBC mode (optional)
+ rc6-cbc RC6 in CBC mode (optional)
+ rc5-cbc RC5 in CBC mode (optional)
+ mars-cbc Mars in CBC mode (optional)
+ none No encryption (optional)
+
+
+ All algorithms must use minimum of 128 bit key, by default. Several
+ algorithms, however, supports longer keys and it is recommended to use
+ longer keys if they are available.
+
+ Algorithm none does not perform any encryption process at all and
+ thus is not recommended to be used. It is recommended that no client
+ or server implementation would accept none algorithms except in special
+ debugging mode.
+
+ Additional ciphers may be defined to be used in SILC by using the
+ same name format as above.
+
+
+
+
+
+
+
+
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+
+
+3.10.2 Public Key Algorithms
+
+ Public keys are used in SILC to authenticate entities in SILC network
+ and to perform other tasks related to public key cryptography. The
+ public keys are also used in the SILC Key Exchange protocol [SILC3].
+
+ Following public key algorithms are defined in SILC protocol:
+
+ rsa RSA (mandatory)
+ dss DSS (optional)
+
+ Both of the algorithms are described in [Scheneir] and [Menezes].
+
+ Additional public key algorithms may be defined to be used in SILC.
+
+
+3.10.3 MAC Algorithms
+
+ Data integrity is protected by computing a message authentication code
+ (MAC) of the packet data. See [SILC2] for details how to compute the
+ MAC.
+
+ Following MAC algorithms are defined in SILC protocol:
+
+ hmac-sha1 HMAC-SHA1, length = 20 (mandatory)
+ hmac-md5 HMAC-MD5, length = 16 (optional)
+ none No MAC (optional)
+
+ The none MAC is not recommended to be used as the packet is not
+ authenticated when MAC is not computed. It is recommended that no
+ client or server would accept none MAC except in special debugging
+ mode.
+
+ The HMAC algorithm is described in [HMAC] and hash algorithms that
+ are used as part of the HMACs are described in [Scheneir] and in
+ [Menezes]
+
+ Additional MAC algorithms may be defined to be used in SILC.
+
+
+3.10.4 Compression Algorithms
+
+ SILC protocol supports compression that may be applied to unencrypted
+ data. It is recommended to use compression on slow links as it may
+ significantly speed up the data transmission. By default, SILC does not
+ use compression which is the mode that must be supported by all SILC
+ implementations.
+
+
+
+
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+
+
+ Following compression algorithms are defined:
+
+ none No compression (mandatory)
+ zlib GBU ZLIB (LZ77) compression (optional)
+
+ Additional compression algorithms may be defined to be used in SILC.
+
+
+3.11 SILC Public Key
+
+ This section defines the type and format of the SILC public key. All
+ implementations must support this public key type. See [SILC3] for
+ other optional public key and certificate types allowed in SILC
+ protocol. Public keys in SILC may be used to authenticate entities
+ and to perform other tasks related to public key cryptography.
+
+ The format of the SILC Public Key is as follows:
+
+
+ 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 |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Algorithm Name Length | |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
+ | |
+ ~ Algorithm Name ~
+ | |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Identifier Length | |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
+ | |
+ ~ Identifier ~
+ | |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | |
+ ~ Public Data ~
+ | |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+ Figure 4: SILC Public Key
+
+
+ o Public Key Length (4 bytes) - Indicates the full length
+ of the public key, not including this field.
+
+ o Algorithm Name Length (2 bytes) - Indicates the length
+
+
+
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+
+
+ of the Algorithm Length field, not including this field.
+
+ o Algorithm name (variable length) - Indicates the name
+ of the public key algorithm that the key is. See the
+ section 3.10.2 Public Key Algorithms for defined names.
+
+ o Identifier Length (2 bytes) - Indicates the length of
+ the Identifier field, not including this field.
+
+ o Identifier (variable length) - Indicates the identifier
+ of the public key. This data can be used to identify
+ the owner of the key. The identifier is of following
+ format:
+
+ UN User name
+ HN Host name or IP address
+ RN Real name
+ E EMail address
+ O Organization
+ C Country
+
+
+ Examples of an identifier:
+
+ `UN=priikone, HN=poseidon.pspt.fi, E=priikone@poseidon.pspt.fi'
+
+ `UN=sam, HN=dummy.fi, RN=Sammy Sam, O=Company XYZ, C=Finland'
+
+ At least user name (UN) and host name (HN) must be provided as
+ identifier. The fields are separated by commas (`,'). If
+ comma is in the identifier string it must be written as `\,',
+ for example, `O=Company XYZ\, Inc.'.
+
+ o Public Data (variable length) - Includes the actual
+ public data of the public key.
+
+ The format of this field for RSA algorithm is
+ as follows:
+
+ 4 bytes Length of e
+ variable length e
+ 4 bytes Length of n
+ variable length n
+
+
+ The format of this field for DSS algorithm is
+ as follows:
+
+
+
+
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+
+
+ 4 bytes Length of p
+ variable length p
+ 4 bytes Length of q
+ variable length q
+ 4 bytes Length of g
+ variable length g
+ 4 bytes Length of y
+ variable length y
+
+ The variable length fields are multiple precession
+ integers encoded as strings in both examples.
+
+ Other algorithms must define their own type of this
+ field if they are used.
+
+ All fields in the public key are in MSB (most significant byte first)
+ order.
+
+
+4 SILC Procedures
+
+ This section describes various SILC procedures such as how the
+ connections are created and registered, how channels are created and
+ so on. The section describes the procedures only generally as details
+ are described in [SILC2] and [SILC3].
+
+
+4.1 Creating Client Connection
+
+ This section descibres the procedure when client connects to SILC server.
+ When client connects to server the server must perform IP address lookup
+ and reverse IP address lookup to assure that the origin host really is
+ who it claims to be. Client, host, connecting to server must have
+ both valid IP address and fully qualified domain name (FQDN).
+
+ After that client and server performs SILC Key Exchange protocol which
+ will provide the key material used later in the communication. The
+ key exchange protocol must be completed successfully before the connection
+ registration may continue. The SILC Key Exchange protocol is described
+ in [SILC3].
+
+ Typical server implementation would keep a list of connections that it
+ allows to connect to the server. The implementation would check, for
+ example, the connecting client's IP address from the connection list
+ before the SILC Key Exchange protocol has been started. Reason for
+ this is that if the host is not allowed to connect to the server there
+ is no reason to perform a key exchange protocol.
+
+
+
+
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+
+
+ After successful key exchange protocol the client and server performs
+ connection authentication protocol. The purpose of the protocol is to
+ authenticate the client connecting to the server. Flexible
+ implementation could also accept the client to connect to the server
+ without explicit authentication. However, if authentication is
+ desired for a specific client it may be based on passphrase or
+ public key authentication. If authentication fails the connection
+ must be terminated. The connection authentication protocol is described
+ in [SILC3].
+
+ After successful key exchange and authentication protocol the client
+ registers itself by sending SILC_PACKET_NEW_CLIENT packet to the
+ server. This packet includes various information about the client
+ that the server uses to create the client. Server creates the client
+ and sends SILC_PACKET_NEW_ID to the client which includes the created
+ Client ID that the client must start using after that. After that
+ all SILC packets from the client must have the Client ID as the
+ Source ID in the SILC Packet Header, described in [SILC2].
+
+ Client must also get the server's Server ID that is to be used as
+ Destination ID in the SILC Packet Header when communicating with
+ the server (for example when sending commands to the server). The
+ ID may be resolved in two ways. Client can take the ID from an
+ previously received packet from server that must include the ID,
+ or to send SILC_COMMAND_INFO command and receive the Server ID as
+ command reply.
+
+ Server may choose not to use the information received in the
+ SILC_PACKET_NEW_CLIENT packet. For example, if public key or
+ certificate were used in the authentication, server may use those
+ informations rather than what it received from client. This is suitable
+ way to get the true information about client if it is available.
+
+ The nickname of client is initially set to the username sent in the
+ SILC_PACKET_NEW_CLIENT packet. User should set the nickname to more
+ suitable by sending SILC_COMMAND_NICK command. However, this is not
+ required as part of registration process.
+
+ Server must also distribute the information about newly registered
+ client to its router (or if the server is router, to all routers in
+ the SILC network). More information about this in [SILC2].
+
+
+4.2 Creating Server Connection
+
+ This section descibres the procedure when server connects to its
+ router (or when router connects to other router, the cases are
+ equivalent). The procedure is very much alike when client connects
+
+
+
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+
+
+ to the server thus it is not repeated here.
+
+ One difference is that server must perform connection authentication
+ protocol with proper authentication. Proper authentication is based
+ on passphrase or public key authentication.
+
+ After server and router has successfully performed the key exchange
+ and connection authentication protocol, the server register itself
+ to the router by sending SILC_PACKET_NEW_SERVER packet. This packet
+ includes the server's Server ID that it has created by itself and
+ other relevant information about the server.
+
+ After router has received the SILC_PACKET_NEW_SERVER packet it
+ distributes the information about newly registered server to all routers
+ in the SILC network. More information about this in [SILC2].
+
+ As client needed to resolve the destination ID this must be done by the
+ server that connected to the router, as well. The way to resolve it is
+ to get the ID from previously received packet. Server must also start
+ using its own Server ID as Source ID in SILC Packet Header and the
+ router's Server ID as Destination when communicating with the router.
+
+ If the server has already connected clients and locally created
+ channels the server must distribute these informations to the router.
+ The distribution is done by sending packet SILC_PACKET_NEW_CHANNEL.
+ See [SILC2] for more information on this.
+
+
+4.3 Joining to a Channel
+
+ This section describes the procedure when client joins to a channel.
+ Client may join to channel by sending command SILC_COMMAND_JOIN to the
+ server. If the receiver receiving join command is normal server the
+ server must check its local list whether this channel already exists
+ locally. This would indicate that some client connected to the server
+ has already joined to the channel. If this is case the client is
+ joined to the client, new channel key is created and information about
+ newly joined channel is sent to the router. The new channel key is
+ also distributed to the router and to all clients on the channel.
+
+ If the channel does not exist in the local list the command must be
+ sent to the router which will then perform the actual joining
+ procedure. When server receives the reply to the command from the
+ router it must be distributed to the client who sent the command
+ originally. Server will also receive the channel key from the server
+ that it must distribute to the client who originally requested the
+ join command. The server must also save the channel key.
+
+
+
+
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+
+
+ If the receiver of the join command is router it must first check its
+ local list whether anyone in the cell has already joined to the channel.
+ If this is the case the client is joined to the channel and reply is
+ sent to the client. If the command was sent by server the command reply
+ is sent to the server who sent it. Then the router must also create
+ new channel key and distribute it to all clients on the channel and
+ all servers that has clients on the channel.
+
+ If the channel does not exist on the router's local list it must
+ check the global list whether the channel exists at all. If it does
+ the client is joined to the channel as described previously. If
+ the channel does not exist the channel is created and the client
+ is joined to the channel. The channel key is also created and
+ distributed as previously described. The client joining to the created
+ channel is made automatically channel founder and both channel founder
+ and channel operator privileges is set for the client.
+
+ When the router joins the client to the channel it must send
+ information about newly joined client to all routers in the SILC
+ network. Also, if the channel was created in the process, information
+ about newly created channel must also be distributed to all routers.
+ The distribution of newly created channel is done by sending packet
+ SILC_PACKET_NEW_CHANNEL.
+
+ It is important to note that new channel key is created always when
+ new client joins to channel, whether the channel has existed previously
+ or not. This way the new client on the channel is not able to decrypt
+ any of the old traffic on the channel.
+
+ Client who receives the reply to the join command must start using
+ the received Channel ID in the channel message communication thereafter.
+ However, client must not start communicating on the channel before
+ it has received the packet SILC_PACKET_CHANNEL_KEY.
+
+ If client wants to know the other clients currently on the channel
+ the client must send SILC_COMMAND_NAMES command to receive a list of
+ channel users. Server implementation, however, may send command reply
+ packet to SILC_COMMAND_NAMES command after client has joined to the
+ channel even if the client has not sent the command.
+
+
+4.4 Channel Key Generation
+
+ Channel keys are created by router who creates the channel by taking
+ enough randomness from cryptographically strong random number generator.
+ The key is generated always when channel is created, when new client
+ joins a channel and after the key has expired. Key could expire for
+ example in an hour.
+
+
+
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+
+
+ The key must also be re-generated whenever some client leaves a channel.
+ In this case the key is created from scratch by taking enough randomness
+ from the random number generator. After that the key is distributed to
+ all clients on the channel. However, channel keys are cell specific thus
+ the key is created only on the cell where the client, who leaved the
+ channel, exists. While the server or router is creating the new channel
+ key, no other client may join to the channel. Messages that are sent
+ while creating the new key are still processed with the old key. After
+ server has sent the SILC_PACKET_CHANNEL_KEY packet must client start
+ using the new key. If server creates the new key the server must also
+ send the new key to its router. See [SILC2] on more information about
+ how channel messages must be encrypted and decrypted when router is
+ processing them.
+
+
+4.5 Private Message Sending and Reception
+
+ Private messages are sent point to point. Client explicitly destines
+ a private message to specific client that is delivered to only to that
+ client. No other client may receive the private message. The receiver
+ of the private message is destined in the SILC Packet Header as any
+ other packet as well.
+
+ If the sender of a private message does not know the receiver's Client
+ ID, it must resolve it from server. There are two ways to resolve the
+ client ID from server; it is recommended that client ipmlementations
+ send SILC_COMMAND_IDENTIFY command to receive the Client ID. Client
+ may also send SILC_COMMAND_WHOIS command to receive the Client ID.
+ If the sender has received earlier a private message from the receiver
+ it should have cached the Client ID from the SILC Packet Header.
+
+ Receiver of a private message should not explicitly trust the nickname
+ that it receives in the Private Message Payload, described in [SILC2].
+ Implementations could resolve the nickname from server, as described
+ previously, and compare the received Client ID and the SILC Packet
+ Header's Client ID. The nickname in the payload is merely provided
+ to be displayed for end user.
+
+ See [SILC2] for describtion of private message encryption and decryption
+ process.
+
+
+4.6 Private Message Key Generation
+
+ Private message may be protected by key generated by client. The key
+ may be generated and sent to the other client by sending packet
+ SILC_PACKET_PRIVATE_MESSAGE_KEY which travels through the network
+ and is secured by session keys. After that the private message key
+
+
+
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+
+
+ is used in the private message communication between those clients.
+ See more information about how this works technically in [SILC2].
+
+ Other choice is to entirely use keys that are not sent through
+ the SILC network at all. This significantly adds security. This key
+ would be pre-shared-key that is known by both of the clients. Both
+ agree about using the key and starts sending packets that indicate
+ that the private message is secured using private message key. This
+ is the technical aspect mentioned previously that is described
+ in [SILC2].
+
+ If the private message keys are not set to be used, which is the
+ case by default in SILC, the private messages are secured by using
+ normal session keys established by SILC Key Exchange protocol.
+
+
+4.7 Channel Message Sending and Reception
+
+ Channel messages are delivered to group of users. The group forms a
+ channel and all clients on the channel receives messages sent to the
+ channel.
+
+ Channel messages are destined to channel by specifying the Channel ID
+ as Destination ID in the SILC Packet Header. The server must then
+ distribute the message to all clients on the channel by sending the
+ channel message destined explicitly to a client on the channel.
+
+ See [SILC2] for describtion of channel message encryption and decryption
+ process.
+
+
+4.8 Session Key Regeneration
+
+ Session keys should be regenerated peridiocally, say, once in an hour.
+ The re-key process is started by sending SILC_PACKET_REKEY packet to
+ other end, to indicate that re-key must be performed.
+
+ If perfect forward secrecy (PFS) flag was selected in the SILC Key
+ Exchange protocol [SILC3] the re-key must cause new key exchange with
+ SKE protocol. In this case the protocol is secured with the old key
+ and the protocol results to new key material. See [SILC3] for more
+ information. After the SILC_PACKET_REKEY packet is sent the sender
+ will perform the SKE protocol.
+
+ If PFS flag was not set, which is the default case, then re-key is done
+ without executing SKE protocol. In this case, the new key is created by
+ hashing the old key with hash function selected earlier in the SKE
+ protocol. If the digest length of the hash function is too short for the
+
+
+
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+
+
+ key, then the key is distributed as described in section Processing the
+ Key Material in [SILC3]. After both parties has regenerated the session
+ key, both send SILC_PACKET_REKEY_DONE packet to each other. These packets
+ are still secured with the old key. After these packets, following
+ packets must be protected with the new key.
+
+
+4.9 Command Sending and Reception
+
+ Client usually sends the commands in the SILC network. In this case
+ the client simply sends the command packet to server and the server
+ processes it and replies with command reply packet.
+
+ However, if the server is not able to process the command, it is usually
+ sent to the server's router. This is case for example with commands such
+ as, SILC_COMMAND_JOIN and SILC_COMMAND_WHOIS commands. However, there
+ are other commands as well. For example, if client sends the WHOIS
+ command requesting specific information about some client the server must
+ send the WHOIS command to router so that all clients in SILC network
+ are searched. The router, on the other hand, sends the WHOIS command
+ to further to receive the exact information about the requested client.
+ The WHOIS command travels all the way to the server who owns the client
+ and it replies with command reply packet. Finally, the server who
+ sent the command receives the command reply and it must be able to
+ determine which client sent the original command. The server then
+ sends command reply to the client. Implementations should have some
+ kind of cache to handle, for example, WHOIS information. Servers
+ and routers along the route could all cache the information for faster
+ referencing in the future.
+
+ The commands sent by server may be sent hop by hop until someone is able
+ to process the command. However, it is preferred to destine the command
+ as precisely as it is possible. In this case, other routers en route
+ must route the command packet by checking the true sender and true
+ destination of the packet. However, servers and routers must not route
+ command reply packets to clients coming from other server. Client
+ must not accept command reply packet originated from anyone else but
+ from its own server.
+
+
+5 SILC Commands
+
+5.1 SILC Commands Syntax
+
+ This section briefly describes the syntax of the command notions
+ in this document. Every field in command is separated from each
+ other by whitespaces (` ') indicating that each field is independent
+ argument and each argument must have own Command Argument Payload.
+
+
+
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+
+
+ The number of maximum arguments are defined with each command
+ separately. The Command Argument Payload is described in [SILC2].
+
+ Every command defines specific number for each argument. Currently,
+ they are defined in ascending order; first argument has number one
+ (1), second has number two (2) and so on. This number is set into the
+ Argument Type field in the Command Argument Payload. This makes it
+ possible to send the arguments in free order as the number must be
+ used to identify the type of the argument. This makes is it also
+ possible to have multiple optional arguments in commands and in
+ command replies. The number of argument is marked in parentheses
+ before the actual argument.
+
+ Example: Arguments: (1) <nickname> (2) <username@host>
+
+
+ Every command replies with Status Payload. This payload tells the
+ sender of the command whether the command was completed succefully or
+ whether there was an error. If error occured the payload includes the
+ error type. In the next section the Status Payload is not described
+ as it is common to all commands and has been described here. Commands
+ may reply with other arguments as well. These arguments are command
+ specific and are described in the next section.
+
+ Example command:
+
+ EXAMPLE_COMMAND
+
+ Max Arguments: 3
+ Arguments: (1) <nickname>[@<server>] (2) <message>
+ (3) [<count>]
+
+ The command has maximum of 3 arguments. However, only first
+ and second arguments are mandatory.
+
+ First argument <nickname> is mandatory but may have optional
+ <nickname@server> format as well. Second argument is mandatory
+ <message> argument. Third argument is optional <count> argument.
+
+ The numbers in parentheses are the argument specific numbers
+ that specify the type of the argument in Command Argument Payload.
+ The receiver always knows that, say, argument number two (2) is
+ <message> argument, regardles of the ordering of the arguments in
+ the Command Payload.
+
+
+
+
+
+
+
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+
+
+ Reply messages to the command:
+
+ Max Arguments: 4
+ Arguments: (1) <Status Payload> (2) [<channel list>]
+ (3) <idle time> (4) [<away message>]
+
+ This command may reply with maximum of 4 arguments. However,
+ only the first and third arguments are mandatory. The numbers
+ in the parentheses have the same meaning as in the upper
+ command sending specification.
+
+ Every command reply with <Status Payload>, it is mandatory
+ argument for all command replies and for this reason it is not
+ described in the command reply descriptions.
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_ERR_TOO_MANY_TARGETS
+ SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
+ SILC_STATUS_ERR_NO_SUCH_NICK
+
+ Every command reply also defines set of status message that it
+ may return inside the <Status Payload>. All status messages
+ are defined in the section 5.3 SILC Command Status Types.
+
+
+5.2 SILC Commands List
+
+ This section lists all SILC commands, however, it is expected that a
+ implementation and especially client implementation has many more
+ commands that has only local affect. These commands are official
+ SILC commands that has both client and server sides and cannot be
+ characterized as local commands.
+
+ List of all defined commands in SILC follows.
+
+ 0 SILC_COMMAND_NONE
+
+ None. This is reserved command and must not be sent.
+
+
+ 2 SILC_COMMAND_WHOIS
+
+ Max Arguments: 2
+ Arguments: (1) <nickname>[@<server>] (2) [<count>]
+
+ Whois. Whois command is used to query various information about
+
+
+
+Riikonen [Page 31]
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+
+
+ specific user. The user maybe requested by their nickname and
+ server name. The query may find multiple matching users as
+ there are no unique nicknames in the SILC. The <count> option
+ maybe given to narrow down the number of accepted results. If
+ this is not defined there are no limit of accepted results.
+ The query may also be narrowed down by defining the server name
+ of the nickname.
+
+ To prevent miss-use of this service wildcards in the nickname
+ or in the servername are not permitted. It is not allowed
+ to request all users on some server. The WHOIS requests must
+ be based on specific nickname request.
+
+ The WHOIS request must be always forwarded to router by server
+ so that all users are searched. However, the server still must
+ search its locally connected clients. The server must send
+ this command to the server who owns the requested client. That
+ server must reply to the command.
+
+ Reply messages to the command:
+
+ Max Arguments: 7
+ Arguments: (1) <Status Payload> (2) <Client ID>
+ (3) <nickname>[@<server>] (4) <username@host>
+ (5) <real name> (6) [<channel list>]
+ (7) [<idle time>]
+
+ This command may reply with several command reply messages to
+ form a list of results. In this case the status payload will
+ include STATUS_LIST_START status in the first reply and
+ STATUS_LIST_END in the last reply to indicate the end of the
+ list. If there are only one reply the status is set to normal
+ STATUS_OK.
+
+ The command replies include the Client ID of the nickname,
+ nickname and servername, username and hostnamea and users real
+ name. Client should process these replies only after the last
+ reply has been received with the STATUS_LIST_END status. If the
+ <count> option were defined in the query there will be only
+ <count> many replies from the server.
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_LIST_START
+ SILC_STATUS_LIST_END
+ SILC_STATUS_ERR_NO_SUCH_NICK
+ SILC_STATUS_ERR_WILDCARDS
+
+
+
+Riikonen [Page 32]
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+
+
+ SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
+ SILC_STATUS_ERR_TOO_MANY_PARAMS
+
+
+ 3 SILC_COMMAND_WHOWAS
+
+ Max Arguments: 2
+ Arguments: (1) <nickname>[@<server>] (2) [<count>]
+
+ Whowas. This command is used to query history information about
+ specific user. The user maybe requested by their nickname and
+ server name. The query may find multiple matching users as there
+ are no unique nicknames in the SILC. The <count> option maybe
+ given to narrow down the number of accepted results. If this
+ is not defined there are no limit of accepted results. The query
+ may also be narrowed down by defining the server name of the
+ nickname.
+
+ To prevent miss-use of this service wildcards in the nickname
+ or in the servername are not permitted. The WHOWAS requests must
+ be based on specific nickname request.
+
+ The WHOWAS request must be always forwarded to router by server
+ so that all users are searched. However, the server still must
+ search its locally connected clients.
+
+ Reply messages to the command:
+
+ Max Arguments: 3
+ Arguments: (1) <Status Payload> (2) <nickname>[@<server>]
+ (3) <username@host>
+
+ This command may reply with several command reply messages to form
+ a list of results. In this case the status payload will include
+ STATUS_LIST_START status in the first reply and STATUS_LIST_END in
+ the last reply to indicate the end of the list. If there are only
+ one reply the status is set to normal STATUS_OK.
+
+ The command replies with nickname and username and hostname.
+ Every server must keep history for some period of time of its
+ locally connected clients.
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_LIST_START
+ SILC_STATUS_LIST_END
+ SILC_STATUS_ERR_NO_SUCH_NICK
+
+
+
+Riikonen [Page 33]
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+
+
+ SILC_STATUS_ERR_WILDCARDS
+ SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
+ SILC_STATUS_ERR_TOO_MANY_PARAMS
+
+
+ 4 SILC_COMMAND_IDENTIFY
+
+ Max Arguments: 2
+ Arguments: (1) <nickname>[@<server>] (2) [<count>]
+
+ Identify. Identify command is almost analogous to WHOIS command,
+ except that it does not return as much information. Only relevant
+ information such as Client ID is returned. This is usually used
+ to get the Client ID of a client used in the communication with
+ the client.
+
+ The query may find multiple matching users as there are no unique
+ nicknames in the SILC. The <count> option maybe given to narrow
+ down the number of accepted results. If this is not defined there
+ are no limit of accepted results. The query may also be narrowed
+ down by defining the server name of the nickname.
+
+ To prevent miss-use of this service wildcards in the nickname
+ or in the servername are not permitted. It is not allowed
+ to request all users on some server. The IDENTIFY requests must
+ be based on specific nickname request.
+
+ Implementations may not want to give interface access to this
+ commands as it is hardly a command that would be used a end user.
+ However, it must be implemented as it is used with private message
+ sending.
+
+ The IDENTIFY must be always forwarded to router by server so that
+ all users are searched. However, server must still search its
+ locally connected clients.
+
+ Reply messages to the command:
+
+ Max Arguments: 4
+ Arguments: (1) <Status Payload> (2) <Client ID>
+ (3) [<nickname>[@<server>]] (4) [<username@host>]
+
+ This command may reply with several command reply messages to form
+ a list of results. In this case the status payload will include
+ STATUS_LIST_START status in the first reply and STATUS_LIST_END in
+ the last reply to indicate the end of the list. If there are only
+ one reply the status is set to normal STATUS_OK.
+
+
+
+
+Riikonen [Page 34]
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+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ The command replies with Client ID of the nickname and if more
+ information is available it may reply with nickname and username
+ and hostname. If the <count> option were defined in the query
+ there will be only <count> many replies from the server.
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_LIST_START
+ SILC_STATUS_LIST_END
+ SILC_STATUS_ERR_NO_SUCH_NICK
+ SILC_STATUS_ERR_WILDCARDS
+ SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
+ SILC_STATUS_ERR_TOO_MANY_PARAMS
+
+
+ 5 SILC_COMMAND_NICK
+
+ Max Arguments: 1
+ Arguments: (1) <nickname>
+
+ Set/change nickname. This command is used to set nickname for
+ user. There is no limit of the length of the nickname in SILC.
+ Nickname must not include any spaces (` '), non-printable
+ characters, commas (`,') and any wildcard characters. Note:
+ nicknames in SILC are case-sensitive which must be taken into
+ account when searching clients by nickname.
+
+ Reply messages to the command:
+
+ Max Arguments: 2
+ Arguments: (1) <Status Payload> (2) <New ID Payload>
+
+ This command is replied always with New ID Payload that is
+ generated by the server every time user changes their nickname.
+ Client receiving this payload must start using the received
+ Client ID as its current valid Client ID. The New ID Payload
+ is described in [SILC2].
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_ERR_WILDCARDS
+ SILC_STATUS_ERR_NICKNAME_IN_USE
+ SILC_STATUS_ERR_BAD_NICKNAME
+ SILC_STATUS_ERR_NOT_REGISTERED
+ SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
+ SILC_STATUS_ERR_TOO_MANY_PARAMS
+
+
+
+Riikonen [Page 35]
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+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ 6 SILC_COMMAND_LIST
+
+ Max Arguments: 2
+ Arguments: (1) [<Channel ID>] [<server>]
+
+ The list command is used to list channels and their topics on
+ current server. If the <Channel ID> parameter is used, only the
+ status of that channel is displayed. Secret channels are not
+ listed at all. Private channels are listed with status indicating
+ that the channel is private.
+
+ If the <server> argument is specified the specified server's
+ channels are listed. In this case the command must be sent to
+ the server who owns the channel that was requested.
+
+ Reply messages to the command:
+
+ Max Arguments: 3
+ Arguments: (1) <Status Payload> (2) <channel>
+ (3) <topic>
+
+ This command may reply with several command reply messages to form
+ a list of results. In this case the status payload will include
+ STATUS_LIST_START status in the first reply and STATUS_LIST_END in
+ the last reply to indicate the end of the list. If there are only
+ one reply the status is set to normal STATUS_OK.
+
+ This command replies with channel name and the topic of the
+ channel. If the channel is private channel the <topic> includes
+ "*private*" string.
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_LIST_START
+ SILC_STATUS_LIST_END
+ SILC_STATUS_ERR_WILDCARDS
+ SILC_STATUS_ERR_NOT_REGISTERED
+ SILC_STATUS_ERR_TOO_MANY_PARAMS
+ SILC_STATUS_ERR_NO_SUCH_CHANNEL
+ SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
+ SILC_STATUS_ERR_NO_SUCH_SERVER
+
+
+
+
+
+
+
+
+
+Riikonen [Page 36]
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+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ 7 SILC_COMMAND_TOPIC
+
+ Max Arguments: 2
+ Arguments: (1) <Channel ID> (2) [<server>]]
+
+ This command is used to change or view the topic of a channel.
+ The topic for channel <Channel ID> is returned if there is no
+ <topic> given. If the <topic> parameter is present, the topic
+ for that channel will be changed, if the channel modes permit
+ this action.
+
+ Reply messages to the command:
+
+ Max Arguments: 2
+ Arguments: (1) <Status Payload> (2) [<topic>]
+
+ The command may reply with the topic of the channel if it is
+ set.
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_ERR_NOT_ON_CHANNEL
+ SILC_STATUS_ERR_WILDCARDS
+ SILC_STATUS_ERR_NOT_REGISTERED
+ SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
+ SILC_STATUS_ERR_NO_SUCH_CHANNEL
+ SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
+ SILC_STATUS_ERR_NO_CHANNEL_ID
+ SILC_STATUS_ERR_BAD_CHANNEL_ID
+ SILC_STATUS_ERR_TOO_MANY_PARAMS
+ SILC_STATUS_ERR_NO_CHANNEL_PRIV
+
+
+ 8 SILC_COMMAND_INVITE
+
+ Max Arguments: 2
+ Arguments: (1) <Client ID> (2) <channel>
+
+ This command is used to invite other clients to join to the
+ channel. There is no requirement that the channel the target
+ client is being invited to must exist or be a valid channel.
+ The <Client ID> argument is the target client's ID that is being
+ invited.
+
+ Reply messages to the command:
+
+
+
+
+
+Riikonen [Page 37]
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+
+
+ Max Arguments: 2
+ Arguments: (1) <Status Payload>
+
+ This command replies only with Status Payload.
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_ERR_NOT_ON_CHANNEL
+ SILC_STATUS_ERR_WILDCARDS
+ SILC_STATUS_ERR_NOT_REGISTERED
+ SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
+ SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
+ SILC_STATUS_ERR_TOO_MANY_PARAMS
+ SILC_STATUS_ERR_NO_RECIPIENT
+ SILC_STATUS_ERR_USER_ON_CHANNEL
+ SILC_STATUS_ERR_NO_CLIENT_ID
+
+
+ 9 SILC_COMMAND_QUIT
+
+ Max Arguments: 1
+ Arguments: (1) [<quit message>]
+
+ This command is used by client to end SILC session. The server
+ must close the connection to a client which sends this command.
+ if <quit message> is given it will be sent to other clients on
+ channel if the client is on channel when quitting.
+
+ Reply messages to the command:
+
+ This command does not reply anything.
+
+
+ 10 SILC_COMMAND_KILL
+
+ Max Arguments: 2
+ Arguments: (1) <Client ID> (2) [<comment>]
+
+ This command is used by SILC operators to remove a client from
+ SILC network. The removing has temporary effects and client may
+ reconnect to SILC network. The <Client ID> is the client to be
+ removed from SILC. The <comment> argument may be provided to
+ give to the removed client some information why it was removed
+ from the network.
+
+ Reply messages to the command:
+
+
+
+
+Riikonen [Page 38]
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+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ Max Arguments: 1
+ Arguments: (1) <Status Payload>
+
+ This command replies only with Status Payload.
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_ERR_WILDCARDS
+ SILC_STATUS_ERR_NOT_REGISTERED
+ SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
+ SILC_STATUS_ERR_TOO_MANY_PARAMS
+ SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
+ SILC_STATUS_ERR_NO_CLIENT_ID
+
+
+ 11 SILC_COMMAND_INFO
+
+ Max Arguments: 1
+ Arguments: (1) [<server>]
+
+ This command is used to fetch various information about a server.
+ If <server> argument is specified the command must be sent to
+ the requested server.
+
+ Reply messages to the command:
+
+ Max Arguments: 3
+ Arguments: (1) <Status Payload> (2) <Server ID>
+ (3) <string>
+
+ This command replies with the Server ID of the server and a
+ string which tells the information about the server.
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_ERR_WILDCARDS
+ SILC_STATUS_ERR_NOT_REGISTERED
+ SILC_STATUS_ERR_TOO_MANY_PARAMS
+ SILC_STATUS_ERR_NO_SUCH_SERVER_ID
+ SILC_STATUS_ERR_NO_SUCH_SERVER
+
+
+
+
+
+
+
+
+
+Riikonen [Page 39]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ 12 SILC_COMMAND_CONNECT
+
+ Max Arguments: 2
+ Arguments: (1) <Server ID>
+ (2) [<remote server/router>[:<port>]]
+
+ This command is used by operators to force a server to try to
+ establish a new connection to another router (if the connecting
+ server is normal server) or server (if the conneceting server is
+ router server). Operator may specify the server/router to be
+ connected by setting <remote server> argument.
+
+ Reply messages to the command:
+
+ Max Arguments: 1
+ Arguments: (1) <Status Payload>
+
+ This command replies only with Status Payload.
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_ERR_WILDCARDS
+ SILC_STATUS_ERR_NOT_REGISTERED
+ SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
+ SILC_STATUS_ERR_TOO_MANY_PARAMS
+ SILC_STATUS_ERR_NO_SUCH_SERVER_ID
+ SILC_STATUS_ERR_NO_SERVER_PRIV
+ SILC_STATUS_ERR_NO_ROUTER_PRIV
+
+
+ 13 SILC_COMMAND_PING
+
+ Max Arguments: 1
+ Arguments: (1) <Server ID>
+
+ This command is used by clients to test the communication
+ channel to its server if client suspects that the communication
+ is not working correctly. The <Server ID> is the ID of the
+ server the client is connected to.
+
+ Reply messages to the command:
+
+ Max Arguments: 1
+ Arguments: (1) <Status Payload>
+
+ This command replies only with Status Payload. Server returns
+ SILC_STATUS_OK in Status Payload if pinging was successful.
+
+
+
+Riikonen [Page 40]
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+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
+ SILC_STATUS_ERR_TOO_MANY_PARAMS
+ SILC_STATUS_ERR_NO_SUCH_SERVER_ID
+ SILC_STATUS_ERR_NOT_REGISTERED
+
+
+ 14 SILC_COMMAND_OPER
+
+ Max Arguments: 2
+ Arguments: (1) <username> (2) <authentication data>
+
+ This command is used by normal client to obtain server operator
+ privileges on some server or router. Note that router operator
+ has router privileges that supersedes the server operator
+ privileges and this does not obtain those privileges. Client
+ must use SILCOPER command to obtain router level privileges.
+
+ The <username> is the username set in the server configurations
+ as operator. The <authentication data> is the data that the
+ client is authenticated against. It may be passphrase prompted
+ for user on client's screen or it may be public key
+ authentication data (data signed with private key), or
+ certificate.
+
+ Reply messages to the command:
+
+ Max Arguments: 1
+ Arguments: (1) <Status Payload>
+
+ This command replies only with Status Payload.
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
+ SILC_STATUS_ERR_TOO_MANY_PARAMS
+ SILC_STATUS_ERR_NOT_REGISTERED
+ SILC_STATUS_ERR_BAD_PASSWORD
+ SILC_STATUS_ERR_AUTH_FAILED
+
+
+
+
+
+
+
+
+
+Riikonen [Page 41]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ 15 SILC_COMMAND_JOIN
+
+ Max Arguments: 3
+ Arguments: (1) <channel> (2) [<passphrase>]
+ (3) [<cipher>]
+
+ Join to channel/create new channel. This command is used to
+ join to a channel. If the channel does not exist the channel is
+ created on the server receiving the join request. The channel
+ may be protected with passphrase. If this is the case the
+ passphrase must be sent along the join command.
+
+ The name of the <channel> must not include any spaces (` '),
+ non-printable characters, commas (`,') or any wildcard characters.
+
+ Cipher to be used to secure the traffic on the channel may be
+ requested by sending the name of the requested <cipher>. This
+ is used only if the channel does not exist and is created. If
+ the channel already exists the cipher set previously for the
+ channel will be used to secure the traffic.
+
+ The server must check whether the user is allowed to join to
+ the requested channel. Various modes set to the channel affect
+ the ability of the user to join the channel. These conditions
+ are:
+
+ o The user must be invited to the channel if the channel
+ is invite-only channel.
+
+ o The Client ID/nickname/username/hostname must not match
+ any active bans.
+
+ o The correct passphrase must be provided if passphrase
+ is set to the channel.
+
+ o The user count limit, if set, must not be reached.
+
+ Reply messages to the command:
+
+ Max Arguments: 5
+ Arguments: (1) <Status Payload> (2) <channel>
+ (3) <Channel ID> (4) <channel mode mask>
+ (5) [<topic>]
+
+ This command replies with the channel name requested by the
+ client, channel ID of the channel and topic of the channel
+ if it exists. It also replies with the channel mode mask
+ which tells all the modes set on the channel. If the
+
+
+
+Riikonen [Page 42]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ channel is created the mode mask is zero (0).
+
+ Client must not start transmitting to the channel even after
+ server has replied to this command. Client is permitted to
+ start transmitting on channel after server has sent packet
+ SILC_PACKET_CHANNEL_KEY to the client.
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_ERR_WILDCARDS
+ SILC_STATUS_ERR_NOT_REGISTERED
+ SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
+ SILC_STATUS_ERR_TOO_MANY_PARAMS
+ SILC_STATUS_ERR_BAD_PASSWORD
+ SILC_STATUS_ERR_CHANNEL_IS_FULL
+ SILC_STATUS_ERR_NOT_INVITED
+ SILC_STATUS_ERR_BANNED_FROM_CHANNEL
+ SILC_STATUS_ERR_BAD_CHANNEL
+ SILC_STATUS_ERR_USER_ON_CHANNEL
+
+
+ 16 SILC_COMMAND_MOTD
+
+ Max Arguments: 1
+ Arguments: (1) <server>
+
+ This command is used to query the Message of the Day of a server.
+
+ Reply messages to the command:
+
+ Max Arguments: 2
+ Arguments: (1) <Status Payload> (2) [<motd>]
+
+ This command replies with the motd message if it exists.
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
+ SILC_STATUS_ERR_TOO_MANY_PARAMS
+ SILC_STATUS_ERR_NOT_REGISTERED
+ SILC_STATUS_ERR_NO_SUCH_SERVER
+
+
+
+
+
+
+
+
+Riikonen [Page 43]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ 17 SILC_COMMAND_UMODE
+
+ Max Arguments: 2
+ Arguments: (1) <Client ID> (2) <client mode mask>
+
+ This command is used by client to set/unset modes for itself.
+ However, there are some modes that the client may not set itself,
+ but they will be set by server. However, client may unset any
+ mode. Modes may be masked together ORing them thus having
+ several modes set. Client must keep its client mode mask
+ locally so that the mode setting/unsetting would work without
+ problems. Client may change only its own modes.
+
+ Following client modes are defined:
+
+ 0x0000 SILC_UMODE_NONE
+
+ No specific mode for client. This is the initial
+ setting when new client is created. The client is
+ normal client now.
+
+
+ 0x0001 SILC_UMODE_SERVER_OPERATOR
+
+ Marks the user as server operator. Client cannot
+ set this mode itself. Server sets this mode to the
+ client when client attains the server operator
+ privileges by SILC_COMMAND_OPER command. Client
+ may unset the mode itself.
+
+
+ 0x0002 SILC_UMODE_ROUTER_OPERATOR
+
+ Marks the user as router (SILC) operator. Client
+ cannot this mode itself. Router sets this mode to
+ the client when client attains the router operator
+ privileges by SILC_COMMAND_SILCOPER command. Client
+ may unset the mode itself.
+
+ Reply messages to the command:
+
+ Max Arguments: 2
+ Arguments: (1) <Status Payload> (2) <client mode mask>
+
+ This command replies with the changed client mode mask that
+ the client is required to keep locally.
+
+
+
+
+
+Riikonen [Page 44]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
+ SILC_STATUS_ERR_TOO_MANY_PARAMS
+ SILC_STATUS_ERR_NOT_REGISTERED
+ SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
+ SILC_STATUS_ERR_BAD_CLIENT_ID
+ SILC_STATUS_ERR_NOT_YOU
+ SILC_STATUS_ERR_UNKNOWN_MODE
+ SILC_STATUS_ERR_NO_RECIPIENT
+ SILC_STATUS_ERR_NO_CLIENT_ID
+
+
+ 18 SILC_COMMAND_CMODE
+
+ Max Arguments: 6
+ Arguments: (1) <Channel ID> (2) <channel mode mask>
+ (3) [<user limit>] (4) [<passphrase>]
+ (5) [<Client ID>] (6) [<cipher>[:<key len>]]
+
+ This command is used by client to set or change channel flags on
+ a channel. Channel has several modes that set various properties
+ of a channel. Modes may be masked together by ORing them thus
+ having several modes set. The <Channel ID> is the ID of the
+ target channel. The client changing channel mode must be on
+ the same channel and poses sufficient privileges to be able to
+ change the mode.
+
+ Following channel modes are defined:
+
+ 0x0000 SILC_CMODE_NONE
+
+ No specific mode on channel. This is the default when
+ channel is created. This means that channel is just plain
+ normal channel.
+
+
+ 0x0001 SILC_CMODE_PRIVATE
+
+ Channel is private channel. Private channels are shown
+ in the channel list listed with SILC_COMMAND_LIST command
+ with indicatioin that the channel is private. Also,
+ client on private channel will no be detected to be on
+ the channel as the channel is not shown in the client's
+ currently joined channel list. Channel founder and
+ channel operator may set/unset this mode.
+
+
+
+
+Riikonen [Page 45]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ Typical implementation would use [+|-]p on user interface
+ to set/unset this mode.
+
+
+ 0x0002 SILC_CMODE_SECRET
+
+ Channel is secret channel. Secret channels are not shown
+ in the list listed with SILC_COMMAND_LIST command. Secret
+ channels can be considered to be invisible channels.
+ Channel founder and channel operator may set/unset this
+ mode.
+
+ Typical implementation would use [+|-]s on user interface
+ to set/unset this mode.
+
+
+ 0x0004 SILC_CMODE_PRIVKEY
+
+ Channel uses private channel key to protect the traffic
+ on the channel. When this mode is set the client will be
+ responsible to set the key it wants to use to encrypt and
+ decrypt the traffic on channel. Server generated channel
+ keys are not used at all. This mode provides additional
+ security as clients on channel may agree to use private
+ channel key that even servers do not know. Naturally,
+ this requires that every client on the channel knows
+ the key before hand (it is considered to be pre-shared-
+ key). This specification does not define how the private
+ channel key is set as it is entirely local setting on
+ client end.
+
+ As it is local setting it is possible to have several
+ private channel keys on one channel. In this case several
+ clients can talk on same channel but only those clients
+ that share the key with the message sender will be able
+ to hear the talking. Client should not display those
+ message for the end user that it is not able to decrypt
+ when this mode is set.
+
+ Only channel founder may set/unset this mode. If this
+ mode is unset the server will distribute new channel
+ key to all clients on the channel which will be used
+ thereafter.
+
+ Typical implementation would use [+|-]k on user interface
+ to set/unset this mode.
+
+
+
+
+
+Riikonen [Page 46]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ 0x0008 SILC_CMODE_INVITE
+
+ Channel is invite only channel. Client may join to this
+ channel only if it is invited to the channel. Channel
+ founder and channel operator may set/unset this mode.
+
+ Typical implementation would use [+|-]i on user interface
+ to set/unset this mode.
+
+
+ 0x0010 SILC_CMODE_TOPIC
+
+ The topic of the channel may only be set by client that
+ is channel founder or channel operator. Normal clients
+ on channel will not be able to set topic when this mode
+ is set. Channel founder and channel operator may set/
+ unset this mode.
+
+ Typical implementation would use [+|-]t on user interface
+ to set/unset this mode.
+
+
+ 0x0020 SILC_CMODE_ULIMIT
+
+ User limit has been set to the channel. New clients
+ may not join to the channel when the limit set is
+ reached. Channel founder and channel operator may set/
+ unset the limit. The <user limit> argument is the
+ number of limited users.
+
+ Typical implementation would use [+|-]l on user interface
+ to set/unset this mode.
+
+
+ 0x0040 SILC_CMODE_PASSPHRASE
+
+ Passphrase has been set to the channel. Client may
+ join to the channel only if it is able to provide the
+ correct passphrase. Setting passphrases to channel
+ is entirely safe as all commands are protected in the
+ SILC network. Only channel founder may set/unset
+ the passphrase. The <passphrase> argument is the
+ set passphrase.
+
+ Typical implementation would use [+|-]a on user interface
+ to set/unset this mode.
+
+
+
+
+
+Riikonen [Page 47]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ 0x0080 SILC_CMODE_BAN
+
+ Ban mask has been set to the channel. The ban mask
+ may be used to ban specific clients to join the channel.
+ The <ban mask> argument is the set ban mask. When
+ unsetting a ban mask the mask must be provided as
+ argument. Channel founder and channel operator may
+ set/unset this mode. Channel founder may not be
+ added to the ban list.
+
+ Typical implementation would use [+|-]b on user interface
+ to set/unset this mode.
+
+
+ 0x0100 SILC_CMODE_OPERATOR
+
+ Sets channel operator privileges on the channel for a
+ client on the channel. The <Client ID> argument is the
+ target client on the channel. Channel founder and
+ channel operator may set/unset (promote/demote) this
+ mode.
+
+ Typical implementation would use [+|-]o on user interface
+ to set/unset this mode.
+
+
+ 0x0200 SILC_CMODE_CIPHER
+
+ Sets specific cipher to be used to protect channel
+ traffic. The <cipher> argument is the requested cipher.
+ When set or unset the server must re-generate new
+ channel key. If <key len> argument is specified with
+ <cipher> argument the new key is generated of <key len>
+ length.
+
+ Typical implementation would use [+|-]c on user interface
+ to set/unset this mode.
+
+
+ To make the mode system work, client must keep the channel mode
+ mask locally so that the mode setting and unsetting would work
+ without problems. The client receives the initial channel mode
+ mask when it joins to the channel. When the mode changes on
+ channel the server distributes the changed channel mode mask to
+ all clients on the channel by sending SILC_COMMAND_CMODE command
+ reply packet.
+
+
+
+
+
+Riikonen [Page 48]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ Reply messages to the command:
+
+ Max Arguments: 2
+ Arguments: (1) <Status Payload> (2) <channel mode mask>
+
+ This command replies with the changed channel mode mask that
+ client is required to keep locally. The same mask is also
+ sent to all clients on channel by sending additional command
+ reply to them.
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
+ SILC_STATUS_ERR_TOO_MANY_PARAMS
+ SILC_STATUS_ERR_NOT_REGISTERED
+ SILC_STATUS_ERR_NOT_ON_CHANNEL
+ SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
+ SILC_STATUS_ERR_BAD_CHANNEL_ID
+ SILC_STATUS_ERR_NO_CHANNEL_ID
+ SILC_STATUS_ERR_NO_CHANNEL_PRIV
+ SILC_STATUS_ERR_UNKNOWN_MODE
+ SILC_STATUS_ERR_NO_CLIENT_ID
+
+
+ 19 SILC_COMMAND_KICK
+
+ Max Arguments: 3
+ Arguments: (1) <channel> (2) <Client ID>
+ (3) [<comment>]
+
+ This command is used by channel operators to remove a client from
+ channel. The <channel> argument is the channel the client to be
+ removed is on currently. Note that the "kicker" must be on the same
+ channel. If <comment> is provided it will be sent to the removed
+ client.
+
+ Reply messages to the command:
+
+ Max Arguments: 1
+ Arguments: (1) <Status Payload>
+
+ This command replies only with Status Payload.
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
+
+
+
+Riikonen [Page 49]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ SILC_STATUS_ERR_TOO_MANY_PARAMS
+ SILC_STATUS_ERR_NOT_REGISTERED
+ SILC_STATUS_ERR_NO_SUCH_CHANNEL
+ SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
+ SILC_STATUS_ERR_NO_CHANNEL_PRIV
+ SILC_STATUS_ERR_NO_CLIENT_ID
+
+
+ 20 SILC_COMMAND_RESTART
+
+ Max Arguments: 0
+ Arguments: None
+
+ This command may only be used by server operator to force a
+ server to restart itself.
+
+ Reply messages to the command:
+
+ Max Arguments: 1
+ Arguments: (1) <Status Payload>
+
+ This command replies only with Status Payload.
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_ERR_NOT_REGISTERED
+ SILC_STATUS_ERR_NO_SERVER_PRIV
+
+
+ 21 SILC_COMMAND_CLOSE
+
+ Max Arguments: 1
+ Arguments: (1) <Server ID>
+
+ This command is used only by operator to close connection to a
+ remote site. The <Server ID> argument is the ID of the remote
+ site and must be valid.
+
+ Reply messages to the command:
+
+ Max Arguments: 1
+ Arguments: (1) <Status Payload>
+
+ This command replies only with Status Payload.
+
+
+
+
+
+
+Riikonen [Page 50]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
+ SILC_STATUS_ERR_TOO_MANY_PARAMS
+ SILC_STATUS_ERR_NOT_REGISTERED
+ SILC_STATUS_ERR_NO_SUCH_SERVER
+ SILC_STATUS_ERR_NO_SERVER_PRIV
+ SILC_STATUS_ERR_NO_SUCH_SERVER_ID
+
+
+ 22 SILC_COMMAND_DIE
+
+ Max Arguments: 0
+ Arguments: None
+
+ This command is used only by operator to shutdown the server.
+ All connections to the server will be closed and the server is
+ shutdown.
+
+ Reply messages to the command:
+
+ Max Arguments: 1
+ Arguments: (1) <Status Payload>
+
+ This command replies only with Status Payload.
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_ERR_NOT_REGISTERED
+ SILC_STATUS_ERR_NO_SERVER_PRIV
+
+
+ 23 SILC_COMMAND_SILCOPER
+
+ Max Arguments: 2
+ Arguments: (1) <username> (2) <authentication data>
+
+ This command is used by normal client to obtain router operator
+ privileges (also known as SILC operator) on some router. Note
+ that router operator has router privileges that supersedes the
+ server operator privileges.
+
+ The <username> is the username set in the server configurations
+ as operator. The <authentication data> is the data that the
+ client is authenticated against. It may be passphrase prompted
+ for user on client's screen or it may be public key
+
+
+
+Riikonen [Page 51]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ authentication data (data signed with private key), or
+ certificate.
+
+ Difference between router operator and server operator is that
+ router operator is able to handle cell level properties while
+ server operator (even on router server) is able to handle only
+ local properties, such as, local connections and normal server
+ administration.
+
+ Reply messages to the command:
+
+ Max Arguments: 1
+ Arguments: (1) <Status Payload>
+
+ This command replies only with Status Payload.
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
+ SILC_STATUS_ERR_TOO_MANY_PARAMS
+ SILC_STATUS_ERR_NOT_REGISTERED
+ SILC_STATUS_ERR_BAD_PASSWORD
+ SILC_STATUS_ERR_AUTH_FAILED
+
+
+ 24 SILC_COMMAND_LEAVE
+
+ Max Arguments: 1
+ Arguments: (1) <Channel ID>
+
+ This command is used by client to leave a channel the client is
+ joined to. After a client has leaved the channel the server
+ must create new key for the channel and distribute to all clients
+ still currently on the channel.
+
+ Reply messages to the command:
+
+ Max Arguments: 1
+ Arguments: (1) <Status Payload>
+
+ This command replies only with Status Payload.
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_ERR_NOT_REGISTERED
+ SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
+
+
+
+Riikonen [Page 52]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ SILC_STATUS_ERR_TOO_MANY_PARAMS
+ SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
+ SILC_STATUS_ERR_BAD_CHANNEL_ID
+ SILC_STATUS_ERR_NO_CHANNEL_ID
+
+
+ 25 SILC_COMMAND_NAMES
+
+ Max Arguments: 1
+ Arguments: (1) <Channel ID>
+
+ This command is used to list user names currently on the requested
+ channel; argument <Channel ID>. The server must resolve the
+ user names and send a comma (`,') separated list of user names
+ on the channel. Server or router may resolve the names by sending
+ SILC_COMMAND_WHOIS commands.
+
+ If the requested channel is a private or secret channel, this
+ command must not send the list of users, as private and secret
+ channels cannot be seen by outside. In this case the returned
+ name list may include a indication that the server could not
+ resolve the names of the users on the channel.
+
+ Reply messages to the command:
+
+ Max Arguments: 2
+ Arguments: (1) <Status Payload> (2) <name list>
+
+ This command replies with the comma separated list of users on
+ the channel.
+
+ Status messages:
+
+ SILC_STATUS_OK
+ SILC_STATUS_ERR_NOT_REGISTERED
+ SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
+ SILC_STATUS_ERR_TOO_MANY_PARAMS
+ SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
+ SILC_STATUS_ERR_BAD_CHANNEL_ID
+ SILC_STATUS_ERR_NO_CHANNEL_ID
+ SILC_STATUS_ERR_NOT_ON_CHANNEL
+
+
+ 26 - 254
+
+ Currently undefined commands.
+
+
+
+
+
+Riikonen [Page 53]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ 255 SILC_COMMAND_MAX
+
+ Reserved command. This must not be sent.
+
+
+5.3 SILC Command Status Types
+
+5.3.1 SILC Command Status Payload
+
+ Command Status Payload is sent in command reply messages to indicate
+ the status of the command. The payload is one of argument in the
+ command thus this is the data area in Command Argument Payload described
+ in [SILC2]. The payload is only 2 bytes of length. Following diagram
+ represents the Command Status Payload (field is always in MSB order).
+
+
+ 1
+ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Status Message |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+ Figure 5: SILC Command Status Payload
+
+
+ o Status Message (2 bytes) - Indicates the status message.
+ All Status messages are described in the next section.
+
+
+5.3.2 SILC Command Status List
+
+ Command Status messages are returned in the command reply messages
+ to indicate whether the command were executed without errors. If error
+ has occured the status tells which error occured. Status payload only
+ sends numeric reply about the status. Receiver of the payload must
+ convert the numeric values into human readable error messages. The
+ list of status messages below has an example human readable error
+ messages that client may display for the user.
+
+ List of all defined command status messages following.
+
+ Generic status messages:
+
+ 0 SILC_STATUS_OK
+
+ Ok status. Everything went Ok. The status payload maybe
+ safely ignored in this case.
+
+
+
+
+Riikonen [Page 54]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ 1 SILC_STATUS_LIST_START
+
+ Start of the list. There will be several command replies and
+ this reply is the start of the list.
+
+ 2 SILC_STATUS_LIST_END
+
+ End of the list. There were several command replies and this
+ reply is the last of the list. There won't be other replies
+ beloning to this list after this one.
+
+ 3 - 9
+
+ Currently undefined and has been reserved for the future.
+
+
+ Error status message:
+
+ 10 SILC_STATUS_ERR_NO_SUCH_NICK
+
+ "No such nickname". Requested nickname does not exist.
+
+ 11 SILC_STATUS_ERR_NO_SUCH_CHANNEL
+
+ "No such channel". Requested channel name does not exist.
+
+ 12 SILC_STATUS_ERR_NO_SUCH_SERVER
+
+ "No such server". Requested server name does not exist.
+
+ 13 SILC_STATUS_ERR_TOO_MANY_TARGETS
+
+ "Duplicate recipients. No message delivered". Message were
+ tried to be sent to recipient which has several occurrences in
+ the recipient list.
+
+ 14 SILC_STATUS_ERR_NO_RECIPIENT
+
+ "No recipient given". Command required recipient which was
+ not provided.
+
+ 15 SILC_STATUS_ERR_UNKNOWN_COMMAND
+
+ "Unknown command". Command sent to server is unknown by the
+ server.
+
+
+
+
+
+
+Riikonen [Page 55]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ 16 SILC_STATUS_ERR_WILDCARDS
+
+ "Wildcards cannot be used". Wildcards were provided but they
+ weren't permitted.
+
+ 17 SILC_STATUS_ERR_NO_CLIENT_ID
+
+ "No Client ID given". Client ID were expected as command
+ parameter but were not found.
+
+ 18 SILC_STATUS_ERR_NO_CHANNEL_ID
+
+ "No Channel ID given". Channel ID were expected as command
+ parameter but were not found.
+
+ 19 SILC_STATUS_ERR_BAD_CLIENT_ID
+
+ "Bad Client ID". Client ID provided were erroneous.
+
+ 20 SILC_STATUS_ERR_BAD_CHANNEL_ID
+
+ "Bad Channel ID". Channel ID provided were erroneous.
+
+ 21 SILC_STATUS_ERR_NO_SUCH_CLIENT_ID
+
+ "No such Client ID". Client ID provided does not exist.
+
+
+ 22 SILC_STATUS_ERR_NO_SUCH_CHANNEL_ID
+
+ "No such Channel ID". Channel ID provided does not exist.
+
+ 23 SILC_STATUS_ERR_NICKNAME_IN_USE
+
+ "Nickname already exists". Nickname created could not be
+ registered because number of same nicknames were already set to
+ maximum. This is not expected to happen in real life but is
+ possible to occur.
+
+ 24 SILC_STATUS_ERR_NOT_ON_CHANNEL
+
+ "You are not on that channel". The command were specified for
+ client user is not currently on.
+
+ 25 SILC_STATUS_ERR_USER_ON_CHANNEL
+
+ "User already on channel". User were invited on channel they
+ already are on.
+
+
+
+Riikonen [Page 56]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ 26 SILC_STATUS_ERR_NOT_REGISTERED
+
+ "You have not registered". User executed command that requires
+ the client to be registered on the server before it may be
+ executed.
+
+ 27 SILC_STATUS_ERR_NOT_ENOUGH_PARAMS
+
+ "Not enough parameters". Command requires more parameters
+ than provided.
+
+ 28 SILC_STATUS_ERR_TOO_MANY_PARAMS
+
+ "Too many parameters". Too many parameters were provided
+ for the command.
+
+ 29 SILC_STATUS_ERR_PERM_DENIED
+
+ "Your host is not among the privileged". The client tried to
+ register on server that does not allow this host to connect.
+
+ 30 SILC_STATUS_ERR_BANNED_FROM_SERVER
+
+ "You are banned from this server". The client tried to register
+ on server that has explicitly denied this host to connect.
+
+ 31 SILC_STATUS_ERR_BAD_PASSWORD
+
+ "Cannot join channel. Incorrect password". Password provided for
+ channel were not accepted.
+
+ 32 SILC_STATUS_ERR_CHANNEL_IS_FULL
+
+ "Cannot join channel. Channel is full". The channel is full
+ and client cannot be joined to it.
+
+ 33 SILC_STATUS_ERR_NOT_INVITED
+
+ "Cannot join channel. You have not been invited". The channel
+ is invite only channel and client has not been invited.
+
+ 34 SILC_STATUS_ERR_BANNED_FROM_CHANNEL
+
+ "Cannot join channel. You have been banned". The client has
+ been banned from the channel.
+
+
+
+
+
+
+Riikonen [Page 57]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+ 35 SILC_STATUS_ERR_UNKNOWN_MODE
+
+ "Unknown mode". Mode provided by the client were unknown to
+ the server.
+
+ 36 SILC_STATUS_ERR_NOT_YOU
+
+ "Cannot change mode for other users". User tried to change
+ someone else's mode.
+
+ 37 SILC_STATUS_ERR_NO_CHANNEL_PRIV
+
+ "Permission denied. You are not channel operator". Command may
+ be executed only by channel operator.
+
+ 38 SILC_STATUS_ERR_NO_SERVER_PRIV
+
+ "Permission denied. You are not server operator". Command may
+ be executed only by server operator.
+
+ 39 SILC_STATUS_ERR_NO_ROUTER_PRIV
+
+ "Permission denied. You are not SILC operator". Command may be
+ executed only by router (SILC) operator.
+
+ 40 SILC_STATUS_ERR_BAD_NICKNAME
+
+ "Bad nickname". Nickname requested contained illegal characters
+ or were malformed.
+
+ 41 SILC_STATUS_ERR_BAD_CHANNEL
+
+ "Bad channel name". Channel requested contained illegal characters
+ or were malformed.
+
+ 42 SILC_STATUS_ERR_AUTH_FAILED
+
+ "Authentication failed". The authentication data sent as
+ argument were wrong and thus authentication failed.
+
+
+6 Security Considerations
+
+ Security is central to the design of this protocol, and these security
+ considerations permeate the specification.
+
+
+
+
+
+
+Riikonen [Page 58]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+7 References
+
+ [SILC2] Riikonen, P., "SILC Packet Protocol", Internet Draft,
+ June 2000.
+
+ [SILC3] Riikonen, P., "SILC Key Exchange and Authentication
+ Protocols", Internet Draft, June 2000.
+
+ [IRC] Oikarinen, J., and Reed D., "Internet Relay Chat Protocol",
+ RFC 1459, May 1993.
+
+ [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 Exhange
+ (IKE)", RFC 2409, November 1998.
+
+ [HMAC] Krawczyk, H., "HMAC: Keyed-Hashing for Message
+ Authentication", RFC 2104, February 1997.
+
+
+
+
+
+
+
+
+
+Riikonen [Page 59]
+\f
+Internet Draft Secure Internet Live Conferencing 28 June 2000
+
+
+8 Author's Address
+
+ Pekka Riikonen
+ Kasarmikatu 11 A4
+ 70110 Kuopio
+ Finland
+
+ EMail: priikone@poseidon.pspt.fi
+
+
+
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+Riikonen [Page 60]
+\f
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projects / runtime.git / commitdiff