Patent ID: 6072874
Filing Date: 2000-06-06
Classification: H04L

Abstract:
A signing apparatus used for signing by a user on usage information of a source provided in a format made to be available by the use of key information, comprising:means for generating said usage information which is to be signed;means for performing a first computation by utilizing said key information which has been encrypted and said usage information;means for performing a second computation by utilizing a private key of said user and a result of said first computation;means for performing a third computation by utilizing a result of said second computation, and thereby generating said key information which has been decrypted and a result of said computation performed on said usage information by utilizing said private key of said user; andmeans for making said source available by utilizing said decrypted key information, wherein said means for performing the first computation assumes the product of two large prime numbers to be a modulus, the two large prime numbers not being known to said user and, using said modulus, generates a first diagonal matrix having said encrypted key information and said usage information as components, and produces a second matrix from said first matrix, said second matrix being a different representation of said first matrix using an arbitrary basis.