FACSIMILE EQUIPMENT AND FACSIMILE COMMUNICATION SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a compound machine in which even when key information (common key) commonly held by a transmission side and a reception side leaks, the content of cryptographic communication is not decodable only by the common key.SOLUTION: A compound machine (transmission side) 1 includes: an operation part; a storage part 12 for storing a common key which is the same as that of a compound machine (reception side) 2; a transmission data generation part 15 for generating message data; a cryptographic key generation part 16 for selecting one or more types of signals as a cipher generation use signal from among signals transmitted/received to and from the compound machine (reception side) 2, and for generating a cryptographic key by using the common key and the signal value of the cipher generation use signal; an encryption part 17 for encrypting the message data by using the generated cryptographic key to generate encrypted data; and a communication part 13 for transmitting the encrypted data and information for decryption including information indicating the type of the cipher generation use signal to the compound machine (reception side) 2.SELECTED DRAWING: Figure 3