@neil thanks!

Oh, this is bad.

"if it is shown that that person was in possession of a key to any protected information at any time before the time of the giving of the section 49 notice, that person shall be taken for the purposes of those proceedings to have continued to be in possession of that key at all subsequent times"

Prison up to 5 years if you forgot the passphrase at any time, unless you can prove that you did forget it. Guilty unless you somehow prove your own forgetfulness?