When encrypting, MOVEit Central uses the symmetric encryption algorithm associated with public key of the first recipient. (Prior to version 3.4, the algorithm was specified as part of the Process task element; during an upgrade to MOVEit Central 3.4, these preferences are copied to the recipient key settings.) The "Edit" button allows you to choose which algorithm should be used for this public key.
The choices are:
Default - Use the default preferred algorithm specified in the PGP public key itself. All of the other choices cause MOVEit Central to explicitly override this algorithm.
3DES - Triple DES: three rounds of the well-known 56-bit 1977-vintage DES algorithm.
AES128 - 128-bit AES. AES is the Advanced Encryption Standard approved by the US National Institute of Standards and Technology in 2001.
AES192 - 192-bit AES.
AES256 - 256-bit AES.
CAST5 - 128-bit CAST5, an algorithm rarely used outside the context of PGP.
IDEA - 128-bit IDEA, an algorithm rarely used outside the context of PGP because it is proprietary.
TWOFISH - a free 1999-vintage algorithm similar in security to AES, and designed by a team of well-known cryptographers, including Bruce Schneier.
All of these algorithms are considered secure, though AES256 and TWOFISH may have an edge over the others. Your choice will probably be made on the basis of compatibility with the recipient's software. "Default" is probably the safest choice.
