how it's encrypted

your browser does all the encrypting. the server stores ciphertext and hashes, nothing it could read.

the chain

your password and three answers form a chain of keys. each key comes from the one before, so question 2 stays sealed until answer 1 is right.

step	made from	the server keeps
root key	argon2id of your password, 64 mib, 3 passes	nothing
login proof	the root key	a hash
each question	sealed with the key before it: the root key for question 1, then answer 1's key, then answer 2's	ciphertext
each answer's key	argon2id of the key before it plus your answer	nothing
each answer's proof	that answer's key	a hash
vault key	random, wrapped by answer 3's key	the wrapped key
each item	aes-256-gcm with the vault key	ciphertext

keeping things current

every item has a version, listed in an encrypted index. when you unlock, your browser checks both. old copies, swapped files, deleted things coming back, or a rolled-back vault all get caught and flagged.

no cheap keys

your browser refuses key settings weaker than argon2id with 64 mib and 3 passes, whatever the server asks for.