[ars]

What about asking companies to voluntarily limit their encryption to bit depths that are crackable with huge resources, but to avoid anything stronger than that? Then you don't even need a backdoor.

This means government can't do it in bulk, and it would out of the reach of an ordinary individual, but it would still be possible.

[bitxbitxbitcoin]

Then in five or ten years the computing resources needed to crack that encryption would be available at the corner store.

[ars]

So adjust the encryption level as time goes on. Don't make the policy the number of bits, rather set the amount of computation needed.