This is a good test to see whether LastPass stick to Kerckhoff's principle: "a cryptosystem should still be secure even if everything, except the secret key, is known"

Bitcoin works this way. Keep your private key secure and everything else is open

Nothing is safe

To my understanding, they only keep encrypted copies of your password. as long as they don't have your password they can't access your data even if they had it.

KeepPass is opensource so if they stole the code the joke is on the hacker :) Unless i am missing something