Say for the sake of argument that the US government decided to ban all encryption in communications. Since modern encryption makes a message practically indistinguishable from random noise, would sending random noise also be banned? If not, and since there's no practical way to tell them apart, how could this be enforced?

  • Of course not. Encryption relates to communication, not random noise. Commented Feb 14, 2016 at 18:23
  • Encrypted communication and random noise are indistinguishable (at least in my scenario, in real life it may not be, see Dawn's answer for that). Since an eavesdropping government would not be able to tell the two apart, would sending random noise over the internet be banned? If not, how would they even tell that I'm using encryption? (assuming that there's no headers in the communication that gives it away)
    – Daffy
    Commented Feb 14, 2016 at 20:08
  • How can one sensibly answer a question about what a nonexistent hypothetical law would or would not do? A legislature could draft this law in such a way that it clearly would forbid transmitting random noise. It could draft it in such a way that it clearly would not. It could draft it in a way that was ambiguous, and then if there was ever an attempt to enforce it against random noise, a court would have to rule on the interpretation. I think this is really in "angels on the head of a pin" territory. Commented Feb 14, 2016 at 22:29
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    @nate I thought I gave a sensible answer. The main issue this brings up is evidentiary, not statutory. The question only makes sense if the hypothetical statute allows random noise but prohibits encryption, thus making the distinction matter.
    – user3851
    Commented Feb 14, 2016 at 22:43
  • You are also forgetting the target of this hypothetical legislation. They're not nearly as concerned about the single programmer who cobbles together an unbreakable one-time pad for fun and doesn't distribute it. They're going after the person who makes the software for everyone, so that mass surveillance remains usable and signals intelligence keeps working relatively smoothly. They don't want apple or microsoft making unbreakable phones; they care much less about small-time holes in signals intelligence. (They still care, but it's not as important.)
    – Tom
    Commented Feb 15, 2016 at 12:06

1 Answer 1


It isn't true that modern encryption necessarily makes messages indistinguishable from random noise.

However, let's assume that this is true, for the sake of your question.

It depends on how the statute is written, but a reasonable one would not make it a crime to send random noise.

It could be enforced by proving that you did the encryption, and then sent what you encrypted across a communication channel. They could have undercover operatives waiting to be sent encrypted material. The encryption system that a user chooses to use might not be as secure as advertised (making it very easy to distinguish from noise if you know its weakness).

If all the government had was access to the communication channel and listened there, then you're right, it would be hard to prove and enforce, but they have access to more than that.

  • It's important to note that "indistinguishable" has a very precise meaning in cryptography.
    – forest
    Commented May 10, 2019 at 1:43

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