BROADCAST COMMUNICATION ENCRYPTING METHOD, INFORMATION ENCRYPTING METHOD, INFORMATION DECRYPTING METHOD, APPARATUSES THEREFOR, PROGRAMS THEREFOR, AND RECORIDNG MEDIA THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide high security, to deal with information of a communication target even if the information is streaming data with high-efficiency communication quantity and computational complexity, and to divert a device of the standard specification.;SOLUTION: The present invention relates to a broadcast communication encrypting method for encrypting information and transmitting the encrypted information to a plurality of transmission destinations, wherein a public key pk_i and an encryption function KE of a transmission destination are used to generate a private key a_i and an encrypted private key e_i (8, S56), a common key R is generated (54, S57), the common key R and the private key a_i are exclusively ORed, the common key R is encrypted (94, S80), the common key R is used to generate a mask M equal with a bit length of information (m) to be communicated (1322, S62), the mask M and the information (m) are exclusively ORed, the information (m) is encrypted (1324, S84), the common key R and encrypted information c' are used to generate an identifier Tag of the encrypted information c' with PKA security (1326, S64), and the encrypted information c' and the identifier Tag are coupled.;COPYRIGHT: (C)2008,JPO&INPIT