alt.anonymous.messages-to-mail.
A program which downloads articles from alt.anonymous.messages, tries to decrypt all of them with the keys accessible on the current keychain, and remails the ones which succeed to the current user, for reading with any sensible e-mail software.
Requirements.
slrn, zsh, sendmail-compatible local mail delivery, gpg.
Ideas.
Symmetric encryption, passphrase-protected keys read from gpg-agent.
INSTALL.
git clone https://github.com/qybta/a.a.m-mail ~/aam;
crontab =(crontab -l;echo '*/271 * * * * ~/aam/check-mail');
Read the source for more information. It isn't much.
Anonymity.
alt.anonymous.messages unfortunately doesn't provide a very large anonymity set, but this is augmented some by using Tor for retrieving the messages. For nation states to deanonymize Tor users without any prior suspicion is currently hard, but not impossible. If you're under suspicion, as is well-known, you're basically fucked using only Tor. Deanonymizing a.a.m users without getting the secret key should be impossible, at least until "they" can crack/procure the keys.
On the server side, assuming non-adversarial news-server, you can hide in the anonymity set of other usenet users by using a random and well used server, and paying in some anonymous manner if it costs you, of course. With adversarial news-server "they" can easily distinguish you from others by seeing which articles you download, so it's hardly worth hiding the timing information. Downloading a fixed somewhat large number at a random time would be preferable, but I couldn't do that to a free news-server.
On the receiving side, this becomes a question of information security. Full disk encryption, fascist firewalls, updated software and few running services for a reduced attack surface, is a must. Don't even think about web-browsing. For added security, use a second computer for the attempted decryption, preferably one that hasn't been connected to the internet.