Go to Network > User VPN > SSL VPN > General.
Click Advanced Settings.
Select the Encryption algorithm:
The Digital Encryption Standard (DES) is a 64-bit block algorithm that uses a 56-bit key. The Advanced Encryption Standard (AES) is a private key algorithm supporting key lengths from 128 to 256 bits and variable-length blocks of data.
AES 128 CBC—A 128-bit block Cipher Block Chaining (CBC) algorithm that uses a 128-bit key.
AES 192 CBC—A 192-bit block Cipher Block Chaining (CBC) algorithm that uses a 192-bit key.
AES 256 CBC—a 256-bit block Cipher Block Chaining (CBC) algorithm that uses a 256-bit key.
3DES—Triple-DES, in which plain text is encrypted three times by three keys.
BF-CDC—a 64-bit block unpatented, keyed, symmetric Cipher Block Chaining (CBC) algorithm by Blowfish
Select the Authentication algorithm:
MD5—Message Digest (version 5) hash algorithm (on one-way hash function) developed by RSA Data Security, which is intended for digital signature applications, where a large file must be compressed in a secure manner before being encrypted with a private key/public key algorithm.
SHA1—Secure Hash Algorithm 1, which produces a 160-bit message digest. The large message digest provides security against brute-force collision and inversion attacks.
Select the key size:
Set the Key lifetime options in hours (1-24). Maximum allowable hours is 24.
Check the Enable compress traffic check box to allow SSL VPN traffic to be transparently compressed and uncompressed.
Check the Enable debug mode check box to show additional debugging information SSL VPN logs.