I'm trying to a cascading cipher encryption algorithm to encrypt a textfile via mcrypt. I'm essentially trying to emulate the behavior of TrueCrypt, where it can cascade two or three different cipher algorithms when encryption data.
From this website I see that cascading encryption algorithms are a feature of mcrypt.
Three ciphers in a cascade [15, 16] operating in XTS mode (see the section Modes of Operation). Each 128-bit block is first encrypted with Serpent (256-bit key) in XTS mode, then with Twofish (256-bit key) in XTS mode, and finally with AES (256-bit key) in XTS mode. Each of the cascaded ciphers uses its own key. All encryption keys are mutually independent (note that header keys are independent too, even though they are derived from a single password – see the section Header Key Derivation, Salt, and Iteration Count). See above for information on the individual cascaded ciphers.
However, the command line mcrypt provided from the sourceforge page doesn't seem to have a switch for cascading ciphers.
Is this cascading encryption algorithm option only available through the mcrypt library rather than the command line utility? Furthermore, will encrypting the encrypted file with a new cipher (but same password) be cryptographically the same as the cascading ciphers algorithms?
As a side note: the main reason I'm trying to use mcrypt over TrueCrypt is because TrueCrypt has a 64 character limit on the password length. If there is another open source utility without this password length limit, please let me know.
I'm aware that GnuGP doesn't have a 64 character limit, but I'm not sure if it supports cascading cipher algorithms.