Do note that 42bits is way too low for a secure password. You should be targeting something over 77 bits [0], so you would need to combine 2 passphrases. Sound pretty hard to remember to me :P
Shameless plug: I made a secure* passphrase and password generator in Python [1]
It depends entirely on your security requirements, but all in all, in broad definitions, 42 bits is not enough. Maybe if key rotation happens fast enough, faster than expected brute force, then, maybe? Again, all up to definitions and context.
Let's not forget that this "passphrase generator" is mostly a joke :D