Encryption manner and decoding manner, with the encryption device, the decoding device, the crypto equipment, and

摘要

PROBLEM TO BE SOLVED: To achieve an encryption multi-address calling even when a KEM-DEM hybrid encryption is used.;SOLUTION: An apparatus at a transmission side generates a common session key (r) to be used commonly between apparatuses for conducting the multi-address calling, records the common session key (r), encrypts the common session key (r) using a secret key a_i each apparatus of the multi-address calling, encrypts a plain sentence (m) using the common session key (r), and transmits a set of the secret key e_i encrypted toward a receiving side, an encrypted common encryption key y_i, and an encryption sentence (c). The apparatus at the receiving side decodes the encrypted common session key y_i using the secret key a_i, records the common session key (r), and obtains the plain sentence (m) by decoding the encryption sentence (c) using the common session key (r). In the multi-address callings after the second time, the apparatus at the transmission side encrypts the plain sentence (m) using the recorded common session key (r), and decodes the encryption sentence (c) using the common session key (r) recorded by the apparatus at the receiving side.;COPYRIGHT: (C)2006,JPO&NCIPI