Gmane's web interface has gone down, which broke a link to a ring signature specification that I wrote in 2014 as a proposed extension to OpenPGP. If you are looking for it, here's an archived copy. I've put this on indefinite hold, but I think it can still be useful if implemented. However, I am hoping that a more modern protocol, like Saltpack, will come to replace the aging OpenPGP (which is under revision). At the moment, if you want two-party designated-verifier encrypted messages using only OpenPGP, I suggest wrapping messages in symmetric encryption with a mutually-authenticated shared secret key before encrypting (asymmetrically) for the recipient.
I have taken down all my servers as I no longer have time to maintain them. They will not reappear and the subdomains will never be reused.
I maintain two servers that provide a few public services; you may freely use these services.
220.127.116.11) is in Strasbourg, France, and runs:
18.104.22.168) is in St. Louis, MO, and is currently down from hard drive failure.