METHOD AND SYSTEM FOR SECURELY STORING DATA USING A SECRET SHARING SCHEME

摘要

A method of securely storing a target number is provided based on the Chinese-Remainder Theorem, A set of n congruence pairs of numbers are generated, wherein a target number (a secret) can be uniquely derived from any t out of the n pairs. In one aspect the divisors are pre-selected such that any randomly selected n integers from the sequence are a valid Asmuth-Bloom sequence for any access structure (t, n) where 1t≤n≤N. In another aspect, means are provided for prestoring members of a Mignotte or Asmuth-Bloom sequence of N divisors in a look-up table from which n divisors can be selected. In this way a flexible access structure is supported. CRT secret shares for a selected access structure can be generated without having to perform the laborious process of calculating Mignotte sequences for each secret and access structure. Storage required to store the secret shares is also reduced by storing and retrieving congruence pairs in the form of an index and a remainder.