The "I do not recall" answer in high profile trials is so common that it's essentially become a meme. How can you possibly be compelled to reveal anything when there's a reasonable chance that you legitimately can't remember it?
In particular, I don’t remember the pin or password to some devices and accounts. They are shapes, on the pin-pad or keyboard. There are enough alternative ways of logging in (the apple face thingy, yubikey, you could hypothetically have devices setting up arbitrarily complex interlocking login processes) that I suspect the court would just define what they want, rather than how they want you to do it.
I could be wrong though, no actual experience here with the legal system at all.