What is metadata?

What methods or mechanisms exist to securely encrypt messaging metadata?

• A method used so that an electronic message still reaches the targeted recipient but the message metadata (such as sender, subject, date, etc.) can only be viewed by the recipient (and no provider in between).

• Answer:

  Since the Metadata is there to tell the system where to send the message, you can only avoid it by sending the message somewhere where anyone can pick it up (but only the intended recipient can decrypt it). This may sound strange and silly (since you're sharing a secret message with the entire world), but such a system actually exists: Mixmaster remailers in conjunction with Usenet. To send a message, you encrypt it so only the correct recipient can decrypt it. Then you use a chain of remailers to anonymously transport the message to a Mail2News gateway to forward it into a newsgroup like (nomen est omen...) Alt.Anonymous.Messages All the recipient has to do is download all messages (that have come in since he last checked), and look for a message that either matches criteria you both agreed with beforehand, or that he can decrypt (trying to decrypt all downloaded messages). This way, nobody can tell who the sender sent the message to (all you see is an encrypted mail to a Remailer), and nobody can tell which message was for this particular recipient (he downloads all messages, regardless of whether he can decrypt them).