Methods and systems for storing secret information in a digital vault
include obtaining from a user answers to a number of different questions,
and identifying which subsets or combinations of the questions for which
correct answers later provided by an entity will enable that entity to
gain access to the secret information in the vault. The number of
questions in each combination is less than the total number of questions,
and at least one subset has at least two questions. For each subset, a
corresponding string of answers is generated, the string is hashed, and
the resulting hash value is combined with the digital secret. This hides
the digital secret, which is then stored in the vault. Methods and
systems for registering authentication material include storing a hashed
string of answers for each combination, generating "multiple
authenticators."