ssl_server_ciphers

Specifies the cipher suites used by the server; each suite in the list is separated by a colon (:). This parameter must follow the OpenSSL cipher string syntax. 

ssl_server_ciphers = cipherSuites

For example, you can enable the cipher suites for security level 2 with the following setting: 

ssl_server_ciphers = @SECLEVEL=2

See Specify Cipher Suites for more information about the cipher suites available in EMS and the syntax for specifying them in this parameter.