Revocable Concurrent Signatures
Yinliang Zhao · Xi'an Jiaotong Daxue xuebao · 2009
Aiming at the problem of fair exchange of digital signatures,a scheme of revocable concurrent signatures is proposed.In the step of signing,the signer chooses a piece of special information named keystone.The one-way function is then used to compute the keystone footprint,and then the encryption of the signer's public key is obtained by raising the keystone footprint to the power of his secret key.The keystone footprints are computed once more from the released keystones after the exchange of signatures,and each signer's public key is raised to the power of the keystone footprint.Then the identities of signers are recognized by comparing the results with the encryptions of the public keys produced in the step of signing,and the ambiguity of signatures can be revoked.Compared with traditional concurrent signatures schemes,the proposed scheme can avoid various attacks.Moreover,when a pair of revocable concurrent signatures is produced,only one keystone is required so that exchange protocols are simplified.It has been verified in a concrete construction that the proposed scheme is secure in the random oracle model under the decisional Diffie-Hellman assumption and the discrete logarithms assumption.