Talking about encrypting metadata doesn't really make a whole bunch of sense - at least not by itself. The metadata is, more or less, who you're sending the thi

Talking about encrypting metadata doesn't really make a whole bunch of sense - at least not by itself. The metadata is, more or less, who you're sending the thing to. It's like saying you encrypted the address on an envelope - you know? The postman's not going to take that anywhere if it's got gibberish printed on the front of the envelope. If I'm your ISP, then I can read who you're sending it too right off of your packets, and if that information's not there, then I can't send the packets on - the message doesn't go anywhere. You can, perhaps, obfuscate it with onion routing - provided a significant percentage of the network hasn't been compromised - but .... Well, I don't think Onion routing is really secure in the long-term because: A ) ISPs taken as a group will have a look-down/shoot-down sort of perspective on the whole thing. If I know who you talk to and all the people who you talk to talk to (and so on) then I can follow you through the system fairly easily. You can insert dummy packets to try to obfuscate the message but - 1. I don't think Tor or any of the other mainstream progs currently do that. It's a bandwidth-expensive move. 2. Anything that contacts a person of interest can be prioritised for and even with some low level obfuscation in place, you'll appear on a list of a few tens or hundreds of people who might have sent something to them, which can then be combined with other data, (i.e. you still give up a great many bits of information even if you attempt to obfuscate at a low level.) B ) I think that it probably makes sense as a cost exercise for nation states to become significant parts of the network which will give them a decent chance of having the entire message chain through to your endpoint. I think you really need the system to pass on messages through the endpoint with a semi-random number of jumps to make things worthwhile and for the person you're sending to to be part of that network and pass on regular coms for a significant time before anyone tries to contact them with something non-regular. Someone asked me on here, a while back, how many terrorists I wanted to talk to. And it really is that sort of problem, I think.