Threshold digital signature method and system having forward security

Abstract

The invention belongs to the technical field of information safety, which relates to a signature problem of numerical information, in particular to a numerical information method and a system thereof which can increase the difficulty of stealing a signature key for opponents and can lighten the influence of signature key leakage. The signature method adds a threshold mechanism and a sub-secret replacing mechanism through applying a Shamir secret sharing technology and a multiaspect security computing technology. The threshold mechanism enhances the security of the signature key, and can play the action of right dispersedness. The sub-secret replacing mechanism realizes the front safety of the signature key, namely even if obtaining the signature key of the current time bucket, the opponents also can not forge a legalized signature belonging to the previous time bucket through the key so that the validity of original signatures is protected, and the loss of key leakage is reduced. In addition, the signature method also comprises a member adding mechanism which enhances the security and the application range of the scheme.

Description

Technical field [0001] The present invention belongs to the field of information security technology, and relates to the problem of signing digital information. More specifically, it relates to a digital signature method and system that can increase the difficulty of an adversary in stealing a signature key and can reduce the impact of signature key leakage. Background technique [0002] The concept of forward security signature was introduced by Anderson in 1997 to solve some of the shortcomings of common digital signatures: once the secret key is lost (or stolen), all the signatures previously generated by this key become invalid. In order to reduce such losses, Anderson proposed to divide the validity period of the key into periods. At the end of each period, the signer obtains a new secret key for the next period from the secret key of the current period in a one-way mode, and Safely delete secret keys that are no longer used. The public key remains unchanged throughout the l...

AI Technical Summary

Problems solved by technology

[0002] The concept of forward security signature was introduced by Anderson in 1997, which solves some defects of common digital signatures: once the secret key is lost (or stolen), all previous signatures generated by this key become invalid

In 2001, Abdalla and Miner proposed a forward-safe threshold digital signature, but the signature key and verification key of the scheme are relatively long

) However, if the square root of U is not known, then is difficult to calculate

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