There's no way which can't be spoofed by a determined opponent willing to send truly weird looking messages (as I demonstrated in an earler post), but that's not the point. I suggest that you just look for ascii-armouring - ie, long (>50 byte) printable character strings without embedded spaces. If the majority of the body has this format, then call it encrypted. And/or look for the standard tag strings for smime or pgp encrypted text, if you're worried about unencrypted but uuencoded naughty pictures being sent. You can't catch everything, but you can do reasonable due diligence to stop spammers and filter out non-contrived unencrypted content. Peter Trei

---------- From: Tom Vogt[SMTP:tom@ricardo.de] Sent: Wednesday, October 04, 2000 4:36 AM To: Trei, Peter Cc: Multiple recipients of list Subject: Re: Anonymous Remailers cpunk

"Trei, Peter" wrote:

...

I would like to suggest that a remailer could eliminate nearly all it's problems by only sending out encrypted mails - that is, if after removing the encryption that was applied using it's own private key, it finds that the result is plaintext, it simply drops the message.

I like that idea. so much that I might start a remailer with these properties, in order to test it out.

single question left: what is a reliable way to see whether or not a text is plain or cipher?