To specify encryption algorithms (ciphers)
In the Administrator, connect to the server, then click the Server tab. SFTP should be enabled.
In the left pane, click the Site you want to configure.
In the right pane, click the SFTP Settings tab.
In the Use encryption algorithms list, select any or all encryption methods:
aes128 - Advanced Encryption Standard (AES) block cipher using 128-bit keys.
aes256 - Advanced Encryption Standard (AES) block cipher using 256-bit keys.
ARCFOUR - Arcfour is intended to be compatible with the RC4 cipher trademarked by RSA Data Security, makers of the famous OpenPGP program. It uses a 128-bit key and provides good security.
cbc - Cipher Block Chaining is an encryption technique used with block ciphers where the previous encrypted block is used as a basis for encrypting the next block, so that every block has to be in the correct order to be decrypted properly.
CAST128 - This cipher is the CAST block cipher using 128-bit keys.
Triple DES (3DES) - This algorithm uses a 24-bit triple key to encrypt data 3 times. The 24-bit key is split into 3 8-bit segments and each is used for encryption. Triple DES is fast, but not as strong as the other algorithms.
Blowfish - The Blowfish algorithm is a public-domain block cipher method using a 128-bit key. Blowfish was intended to be a replacement for 3DES. It provides good security.
Twofish - Twofish is an improved version of Blowfish. It provides the strongest security available in the Server and should protect your data in most transfers. Secure FTP Server recognizes Twofish encryption using 128- and 256-bit keys.
Click OK. The Server tries each selected algorithm with the client until one is agreed upon.