The basic scenario I'm looking at is encrypting some data using a password-derived key (using PBKDF2 with sane salt sizes and iteration counts). I am not sure if what I'm doing is sound practice or just pointless overengineering and wanted to get a sanity check.
My inclination is to use the PBKDF2 output as a key encryption key, rather than using it to directly key the cipher (with the key used for the cipher itself being created by a good PRNG). For some reason the idea of using it directly makes me nervous, but not in a way I can articulate, leading me to suspect I'm worried over nothing. So, assuming using it as a KEK makes sense: At first I thought to use XOR to combine the two keys, but realized that could lead to related key attacks (by just flipping bits in the field containing the encrypted key). That is probably not a problem with good algorithms, but, then again, why take the chance; so I was thinking instead using NIST's AES-wrap (or perhaps a less weirdly designed variant of it that uses HMAC for integrity checking and AES in CBC mode for confidentiality). Am I thinking about this far harder than I should? -Jack --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to [EMAIL PROTECTED]