Maybe I'm missing something here. If I am, please bonk me. Here's a simple method for knowing that some data you received is encrypted: 1. Require a specific method (we'll use PGP in this example). 2. When a message comes in, check for a PGP format message. If you really wanted to get fancy, you could parse the PGP header a bit to make sure the data was really encrypted. It's true that this isn't "cryptographic" in the sense of testing the ciphertext itself, but it should work for the practical goal of enforcing a "must be encrypted" rule. ---------------------------------------------------------------------- Jeff Licquia (lame .sig, huh?) | Finger for PGP 2.6 public key jalicqui@prairienet.org | Me? Speak for whom? You've got licquia@cei.com (work) | to be kidding!