Crypt::des_ede3 implements des-ede3 encryption. this is triple-des encryption where an encrypt operation is encrypt-decrypt-encrypt, and decrypt is decrypt-encrypt-decrypt. this implementation uses crypt::des to do its dirty des work, and simply provides a wrapper around that module: setting up the individual des ciphers, initializing the keys, and performing the encryption/decryption steps.

you're probably best off not using this module directly, as the encrypt and decrypt methods expect 8-octet blocks. you might want to use the module in conjunction with crypt::cbc, for example. this would be des-ede3-cbc, or triple-des in outer cbc mode.