Gmane — Gmane Address Obfuscation
Not So Hard Encryption
While a real encryption algorithm is used, it will probably be possible to find the encryption key over time, since the number of encrypted/unencrypted pairs will be somewhat huge after a while. That’s not the point — the point is simply to make it somewhat harder for address gathering robots to get to the mail addresses.
If every entity that provided email addresses did this, I think spam would dry up quite quickly.
After all, encryption, even strong commerce-quality encryption, has been about making it harder, while not impossible, to get at some information. In the case of email, this scheme seems robust enough.