One thing on the horizon that will fundamental change the nature of computing and security is quantum computing. Google (arguably) has one, and it’s not crazy to think the NSA has an even better one. Given that a quantum computer could possibly crack all existing encryption methods, and cracking Bitcoin’s or Ethereum’s encryption would mean an attacker could determine your private key and get access to your wallet, this poses the natural question: could the NSA crack Bitcoin or Ethereum right now if they wanted to?
The answer is that they possibly could, but they definitely won’t. The reason is that you would never blow the lid off of your quantum computer project for such small peanuts. As Andreas Antonopoulos puts it, “The last thing they’re going to use that on is Bitcoin, because the moment you use it on Bitcoin and you announce to the world we have quantum cryptography that can build elliptic curves, guess what happens?” Your rivals try to implement quantum resistance. “You just blew all of your advancements in that technology.”
There is historical precedent for this. In WW2, British Intelligence cracked the Enigma machine, allowing them to decode German communications. They started becoming aware of German movements, including imminent attacks on vulnerable targets. However, they could not act on every bit of intelligence without alerting the Germans that they had cracked the Enigma machine. Ultimately, boats were sunk and people died because British Intelligence had to keep their discovery secret.
If you’re still paranoid, I recommend generating a new address every time you do a transaction in tokens on the blockchain and don’t leave any tokens left over when you’re done. An attacker can only attack addresses that are known by the network (i.e., has been involved in a transaction), and by the time your address is known you will have already sent all the tokens out of it. This method should let you sleep at night until the underlying protocol is updated to be quantum resistant.