> The only defense against surveillance of communication channels is to make it technically impossible.

The UK has key disclosure requirements in RIPA. There's a 2 year prison sentence (5 years if it's a national security or child indecency case).

Key disclosure: https://www.legislation.gov.uk/ukpga/2000/23/part/III

Failure to comply with a notice: https://www.legislation.gov.uk/ukpga/2000/23/section/53