This is a demo of Recauth (recall-based authentication method) which can be used
for primary vault (password manager) to be a part of the efforts to make
password-less authentication.
There are possession (inc. passkeys), inherence, and memorizing used in infosec, possession can't
be used for vault 'cause losing it means losing all. Inherence can be copied or
used while consciousless (eg. sleeping) and can't be for primary vault too. The only
factor is memorizing is possible in this case, but remembering complex password is
not favoured modernly. Using recall-based method is a good try to be passwordless.
This idea was used in the early Internet for account recovery. The idea is each user has
a sequence of security questions to answer, the vault combines the answers and make
a hash password or key. Answers are case-insensitive, and spaces are collapsed, to avoid
exact memorizing which is hard in humans. After auth, a short PIN is used to avoid answering again.