Secret sharing method and system

摘要

In a secret sharing process based on an improved threshold scheme, secret data is shared as shared data parts equal to or greater than a threshold value in number such that the secret data cannot be reconstructed from shared data parts less than the threshold value in number. Each of the shared data pieces is created essentially from a different combination of the secret data pieces and the data pieces for secret sharing computation. The secret sharing process allows an algorithm desired by the user to be freely incorporated, and can prevent the secret data to be easily reconstructed even when more shared data parts than the threshold value are acquired by a third party.

主权项

1. A secret sharing method in which secret data is shared as shared data parts equal to or greater than a threshold value in number such that the secret data cannot be reconstructed from shared data parts less than the threshold value in number, comprising:
deriving secret data pieces from secret data stored in a storage; generating a plurality of groups being equal to or greater than the threshold value in number, one of the groups having at least parts of unpublished data pieces, and another one of the groups having at least parts of secret data pieces derived from the secret data stored in a storage; creating, by a processor, a plurality of shared data parts, each of which having shared data pieces, at least parts of the shared data pieces are created by combining at least parts of the unpublished data pieces and at least parts of the secret data pieces; and combining the created shared data pieces into a plurality of shared data parts, including first shared data parts and second shared data parts, equal to or greater than the threshold value in number; wherein at least parts of the shared data pieces combined into the first shared data parts are created based on combinations of at least parts of the unpublished data pieces and at least parts of the secret data pieces, and at least parts of the shared data pieces combined into the second shared data parts are created based on other combinations of at least parts of the unpublished data pieces and at least parts of the secret data pieces, which are different from the combinations of at least parts of the unpublished data pieces and at least parts of the secret data pieces that were used to create the first shared data parts.