What is Throw-KeyIDs?

When GPG encrypts a message it includes the Key ID of the key used. This way when the message is decrypted, GPG looks for the Key ID so it knows which key to use for the decryption process. However, GPG has a feature that allows it to encrypt the message without including the Key ID. It's called throw-keyids. The point is to hide which key encrypted the message. It's an additional security measure used occasionally to foil attackers. In order for GPG to decrypt the message it tries each secret key on the users keyring until the correct key succeeds in deccrypting the message. We have an experimental type of nymserver, currently, that uses this tactic. If you see the reference to throw-keyids then you are using this new type of nymserver.