A few things:
-this looks like more marketing than substance, to me. prosecutors send out shitloads of these subpoenas all the time (see eg here
https://transparency.fb.com/data/government-data-requests/) and I strongly suspect this was just a junior (or old) person who doesn't know what Signal is and sent a routine subpoena. They require next to no approvals. In other words, this isn't a coordinated attempt by DOJ to get Signal to start publishing records.
-Ultimately this issue isn't that big of a deal to law enforcement. In 99% of cases they can just get the defendant's cell phone and look at his unencrypted messages in the Signal and Whatsapp applications directly.
-I think in theory if a lot of platforms start doing end to end encryption globally, then things could get a little more interesting. But as far as I know for a lot of tech stacks (like ones more complex than simple messaging) that's difficult to do.
-Ultimately this issue isn't that big of a deal to law enforcement. In 99% of cases they can just get the defendant's cell phone and look at his unencrypted messages in the Signal and Whatsapp applications directly.
-I think in theory if a lot of platforms start doing end to end encryption globally, then things could get a little more interesting. But as far as I know for a lot of tech stacks (like ones more complex than simple messaging) that's difficult to do.