[Contents] [Index]

About This Document >>     Installing SSH Tectia Server for IBM z/OS >>     Using SSH Tectia Server for IBM z/OS >>     Configuring the Server >>         Configuration Files >>         Subconfigurations >>         Ciphers and MACs         Compression         Configuring Root Logins         Restricting User Logins         Subsystems         Auditing >>         Securing the Server >>         Default sshd2_config Configuration File         Default ssh_certd_config Configuration File     Configuring the Client >>     Authentication >>     Troubleshooting SSH Tectia Server for IBM z/OS >>     Examples of Use >>     Man Pages >>     Log Messages >>

Ciphers and MACs

The algorithm(s) used for symmetric session encryption can be chosen in the sshd2_config and ssh2_config files:

Ciphers aes128

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

• 3des-cbc
• aes128-cbc
• aes192-cbc
• aes256-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 cipher values including none
• AnyStd: allows only standard ciphers and none
• none: forbids any use of encryption
• 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). This is the default value.

The MAC (Message Authentication Code) algorithm(s) used for data integrity verification can be selected in the sshd2_config and ssh2_config files:

MACs hmac-sha1,hmac-md5

The system will attempt to use the different HMAC algorithms in the sequence they are specified on the line. Supported MAC names are the following:

• hmac-md5
• hmac-md5-96
• hmac-sha1
• hmac-sha1-96
• hmac-sha256@ssh.com
• hmac-sha256-96@ssh.com

Special values for this option are the following:

• Any: allows all the MAC values including none
• AnyStd: allows only standard MACs and none
• none: forbids any use of MACs
• AnyMac: allows any available MAC apart from none
• AnyStdMac: the same as AnyMac, but includes only those MACs mentioned in IETF-SecSh-draft (excluding none). This is the default value.

Both cipher and MAC can also be defined using command-line arguments with ssh2 and scp2:

$ scp2 -c twofish -m hmac-md5 foobar user@remote:./tmp  

Note: Algorithm names are case-sensitive.