Cryptographic devices and methods for generating and verifying linearly homomorphic structure-preserving signatures

摘要

Generation of linearly homomorphic structure-preserving signature à on a vector by computing, in a processor (120), using a signing key sk = Ç i �¢ ³ i �¢ ´ i i = 1 n , signature elements (z, r, u) by calculating z = ˆ� i = 1 n M i - Ç i , r = , ˆ� i = 1 n M i - ³ i , u = ˆ� i = 1 n M i - ´ i , and outputting the signature a comprising the signature elements (z, r, u). The signature is verified by verifying, in a processor (220) that and that (z,r,u) satisfy the equalities and determing that the signature has been successfully verified in case the verifications are successful and that the signature has not been successfully verified otherwise. Also provided are a fully-fledged scheme and a context-hiding scheme.