Configuring Ciphers

The algorithm(s) used for session encryption can be chosen in the sshd2_config file:

Ciphers             aes128-cbc,3des-cbc

The system will attempt to use the different encryption ciphers in the sequence specified on the line. Currently supported cipher names are the following:

aes128-cbc
aes192-cbc
aes256-cbc
3des-cbc
arcfour
blowfish-cbc
cast128-cbc
twofish-cbc
twofish128-cbc
twofish192-cbc
twofish256-cbc
cast128-12-cbc@ssh.com
des-cbc@ssh.com
seed-cbc@ssh.com
rijndael-cbc@ssh.com

Special values for this option are the following:

Any: allows all the ciphers including none
AnyStd: allows only the ciphers mentioned in IETF-SecSh draft and none The standard ciphers are aes128-cbc, 3des-cbc, twofish128-cbc, cast128-cbc, twofish-cbc, blowfish-cbc, idea-cbc, aes192-cbc, aes256-cbc, twofish192-cbc, twofish256-cbc, and arcfour.
none: no encryption, connection will be in plaintext
AnyCipher: allows any available cipher apart from the non-encrypting cipher mode none
AnyStdCipher: the same as AnyCipher, but includes only those ciphers mentioned in IETF-SecSh- draft (excluding none).

The default ciphers are:

aes128-cbc
aes192-cbc
aes256-cbc
3des-cbc