Files are decrypted in MOVEit Automation by using Process steps that refer to built-in script "PGP Decrypt". This script does not require any parameters.
Configuring the Process
To decrypt a file, you must have a private key corresponding to the public key that was used to encrypt the file. MOVEit Automation will automatically search for a matching key in your PGP keyring. If there is no matching key, the process will fail with an appropriate error message.