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SIGNATURE VALIDITY TERM EXTENSION DEVICE, SIGNATURE VALIDITY TERM VERIFYING DEVICE, SIGNATURE VALIDITY TERM EXTENSION SYSTEM, SIGNATURE VALIDITY TERM EXTENSION METHOD, AND RECORDING MEDIUM RECORDED WITH SIGNATURE VALIDITY TERM EXTENSION PROGRAM
SIGNATURE VALIDITY TERM EXTENSION DEVICE, SIGNATURE VALIDITY TERM VERIFYING DEVICE, SIGNATURE VALIDITY TERM EXTENSION SYSTEM, SIGNATURE VALIDITY TERM EXTENSION METHOD, AND RECORDING MEDIUM RECORDED WITH SIGNATURE VALIDITY TERM EXTENSION PROGRAM
PROBLEM TO BE SOLVED: To shorten the total of the time needed to verify a prolongation signature by decreasing the total of the data size of the extension signature when the terms of validity of multiple signatures are extended at the same time.;SOLUTION: Pieces of initial input data (104) having terms of validity respectively are obtained and primary generated data (105A) are generated from the obtained initial input data; and a server signature (105D) as a digital signature having a term of validity later than any of the terms of validity of the pieces of input initial data is generated and output data (105) including the primary generated data, server signature, and validity term information on the server signature are generated.;COPYRIGHT: (C)2002,JPO
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