[glitchc]

Shared secret keys may work, with one key shard in the hands of the user themselves. That way a court order may compel the user to give up the key shard, but no govt. agency or other authority can unilaterally access the device.

[rossng]

Then the shard _is_ the secret key. The court has no more power to compel you to give it up than any other secret key. I'm not sure what you're proposing here.

[glitchc]

Not true. The shard alone is insufficient to unlock the secret. But to your point, the scheme could be designed in an n of m fashion. The simplest scheme is comprised of three shards: 1) You 2) Org 3) Govt. (ideally DoJ)

Any two can be used in concert to unlock the secret. You and the Org combine shards to access account. You or Org can be compelled by Govt. to reveal shard, through a warrant. The third shard is held at the DoJ, and also requires a warrant.