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Network Working Group P. Riikonen
Internet-Draft
-draft-riikonen-silc-ke-auth-09.txt XXX
-Expires: XXX
+draft-riikonen-silc-ke-auth-09.txt 15 January 2007
+Expires: 15 July 2007
.in 3
The second protocol, SILC Connection Authentication protocol provides
user level authentication used when creating connections in SILC
-network. The protocol is transparent to the authentication data
-which means that it can be used to authenticate the connection with, for
-example, passphrase (pre-shared secret) or public key (and certificate)
-based on digital signatures.
+network. The protocol supports passphrase (pre-shared secret)
+authentication and public key (and certificate) authentication based
+on digital signatures.
2 SILC Key Exchange Protocol .................................... 3
2.1 Key Exchange Payloads ..................................... 4
2.1.1 Key Exchange Start Payload .......................... 4
- 2.1.2 Key Exchange Payload ................................ 8
+ 2.1.2 Key Exchange Payload ................................ 9
2.2 Key Exchange Procedure .................................... 11
- 2.3 Processing the Key Material ............................... 12
- 2.4 SILC Key Exchange Groups .................................. 14
- 2.4.1 diffie-hellman-group1 ............................... 14
+ 2.3 Processing the Key Material ............................... 13
+ 2.4 SILC Key Exchange Groups .................................. 15
+ 2.4.1 diffie-hellman-group1 ............................... 15
2.4.2 diffie-hellman-group2 ............................... 15
- 2.4.3 diffie-hellman-group3 ............................... 15
+ 2.4.3 diffie-hellman-group3 ............................... 16
2.5 Key Exchange Status Types ................................. 16
-3 SILC Connection Authentication Protocol ....................... 17
- 3.1 Connection Auth Payload ................................... 18
- 3.2 Connection Authentication Types ........................... 19
- 3.2.1 Passphrase Authentication ........................... 19
- 3.2.2 Public Key Authentication ........................... 20
+3 SILC Connection Authentication Protocol ....................... 18
+ 3.1 Connection Auth Payload ................................... 19
+ 3.2 Connection Authentication Types ........................... 20
+ 3.2.1 Passphrase Authentication ........................... 20
+ 3.2.2 Public Key Authentication ........................... 21
3.3 Connection Authentication Status Types .................... 21
-4 Security Considerations ....................................... 21
-5 References .................................................... 21
+4 Security Considerations ....................................... 22
+5 References .................................................... 22
6 Author's Address .............................................. 23
-7 Full Copyright Statement ...................................... 23
+7 Full Copyright Statement ...................................... 24
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The second protocol, SILC Connection Authentication protocol provides
user level authentication used when creating connections in SILC
-network. The protocol is transparent to the authentication data which
-means that it can be used to authenticate the connection with, for example,
-passphrase (pre-shared secret) or public key (and certificate) based
+network. The protocol supports passphrase (pre-shared secret)
+authentication and public key (and certificate) authentication based
on digital signatures.
The basis of secure SILC session requires strong and secure key exchange
packets, SILC Packet Header, described in [SILC2], is at the beginning
of all packets sent in during this protocol. All the fields in the
following payloads are in MSB (most significant byte first) order.
-Following descriptions of these payloads.
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however without this flag UDP connection cannot be
used. The flag MAY also be used in TCP connection.
+ When using with UDP/IP implementations SHOULD use
+ anti-replay methods where an anti-replay window
+ defines what packets are replays. An example of
+ anti-window protocol is in [RFC2406] Section 3.4.2
+ with example source code in [RFC2401] Appendix C.
+ While [RFC2401] and [RFC2406] does not relate to SILC,
+ the anti-replay method used is applicable in SILC.
+
PFS 0x02
Perfect Forward Secrecy (PFS) to be used in the
server, or server is connecting to a router the Mutual Authentication
flag MAY be omitted. However, if the connection authentication protocol
for the connecting entity is not based on digital signatures (it is
-based on pre-shared key) then the Mutual Authentication flag SHOULD be
-enabled. This way the connecting entity has to provide proof of
-possession of the private key for the public key it will provide in
-this protocol.
+based on pre-shared key or there is no authentication) then the Mutual
+Authentication flag SHOULD be enabled. This way the connecting entity
+has to provide proof of possession of the private key for the public key
+it will provide in this protocol.
When performing re-key with PFS selected this is the only payload that
is sent in the SKE protocol. The Key Exchange Start Payload MUST NOT
o Public Key (or certificate) (variable length) - The
public key or certificate of the party. This public key
- is used to verify the digital signature. The public key
+ may be used to verify the digital signature. The public key
or certificate in this field is encoded in the manner as
defined in their respective definitions; see previous field.
is not desired. The public key authentication works by sending a
digital signature as authentication data to the other end, say, server.
The server MUST then verify the signature by the public key of the sender,
-which the server has received earlier in SKE protocol.
+which the server has received earlier in SKE protocol, or which the
+server has cached locally at some previous time.
The signature is computed using the private key of the sender by signing
the HASH value provided by the SKE protocol previously, and the Key
5 References
[SILC1] Riikonen, P., "Secure Internet Live Conferencing (SILC),
- Protocol Specification", Internet Draft, June 2003.
+ Protocol Specification", Internet Draft, January 2007.
[SILC2] Riikonen, P., "SILC Packet Protocol", Internet Draft,
- June 2003.
+ January 2007.
-[SILC4] Riikonen, P., "SILC Commands", Internet Draft, June 2003.
+[SILC4] Riikonen, P., "SILC Commands", Internet Draft, January 2007.
[IRC] Oikarinen, J., and Reed D., "Internet Relay Chat Protocol",
RFC 1459, May 1993.
[RFC2279] Yergeau, F., "UTF-8, a transformation format of ISO
10646", RFC 2279, January 1998.
+[RFC2401] Kent, S., et al, "Security Architecture for the Internet
+ Protocol", RFC 2401, November 1998.
+
+[RFC2406] Kent, S., et al, "Security Architecture for the Internet
+ Protocol", RFC 2406, November 1998.
+
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6 Author's Address
.nf
Pekka Riikonen
-Snellmaninkatu 34 A 15
-70100 Kuopio
+Helsinki
Finland
EMail: priikone@iki.fi
projects / crypto.git / blobdiff