I'm going with fundamentally flawed. Or perhaps more exactly, a solution for a non-problem.
Things PGP can do:
- Hide the contents of a message. But not the fact of a message nor who it's to. And it's only as hidden as a key that your recipient has to keep secret indefinitely.
- Permanently be incriminating, since the message can be as easily opened a decade from now.
- Prove you're you. Which is great for incriminating you. Also the proof is only good if your secret key is still secret, which probably isn't the case if you've been arrested. At that point, it's good for convincing people it's you when it's really the FBI.
- Authenticate keys through a trust mechanism so sparsely populated that unless you're actually in a spy cell, the chances of having a valid trust path from A to B is astronomically small.
- Distribute keys through what is really only slightly more sophisticated than a world-writable Dropbox.
Add one more thing: stop the NSA per the Snowden leaks. Everything else in the leaks failed that test. Using a solution strong against the strongest attacker is worthwhile to people wondering how good various solutions really are.
Far as a decade from now, that's probably all you need given the statute of limitations.
Statute of limitations isn't a blank slate that means if you can get away with something for n years you're off scott free.
I'm not googling this type of query at work, but typically as more information about a crime becomes available to law enforcement, the statute of limitations is reset. So if you're buying something illicit and securing communications with PGP, and the SOL is 5 years, if LE doesn't get the contents of that communication for 4 years, they still have 5 years to decide what to do with it.
All SOL means is that LE can't sit on incriminating information about you indefinitely and pursue charges decades in the future for minor crimes.
1) Key rotation can solve the second part of this.
2) Key rotation solves this, but you lose the ability to read old messages yourself. If you don't have the keys anymore you can't view the message.
3) This isn't unique to PGP? Or do you have an alternative? Because plaintext is infinitely less secure in this regard.
4) Depends how you determine trust of a user. In an ideal world you'd be correct. But I trust the person I've known for nearly 6 years is them when I signed their key, though we've never met IRL. Very possible it isn't them but is also astronomically slim of a chance.
Key rotation makes the WoT even more complicated and less trustworthy. That's a big problem.
Proving you're you is great if you're, say, Canonical distributing package updates to Ubuntu, where the adversary is malware distributors.
But where your adversary is eg: the FBI, then it promotes a false sense of assurance, because it's actually really easy to spoof someone if you can arrest them and force them to give the key password.
> - Prove you're you. Which is great for incriminating you. Also the proof is only good if your secret key is still secret, which probably isn't the case if you've been arrested. At that point, it's good for convincing people it's you when it's really the FBI.
So, best practice: publish your private signing key publically if you ever get arrested?
Things PGP can do:
- Hide the contents of a message. But not the fact of a message nor who it's to. And it's only as hidden as a key that your recipient has to keep secret indefinitely.
- Permanently be incriminating, since the message can be as easily opened a decade from now.
- Prove you're you. Which is great for incriminating you. Also the proof is only good if your secret key is still secret, which probably isn't the case if you've been arrested. At that point, it's good for convincing people it's you when it's really the FBI.
- Authenticate keys through a trust mechanism so sparsely populated that unless you're actually in a spy cell, the chances of having a valid trust path from A to B is astronomically small.
- Distribute keys through what is really only slightly more sophisticated than a world-writable Dropbox.