ENCRYPTION COMMUNICATION SYSTEM, COMMUNICATION DEVICE, KEY DISTRIBUTION DEVICE, ENCRYPTION COMMUNICATION METHOD

摘要

Provided are an encryption communication system, a communication device, a key distribution device, and an encryption communication method with which a common key can be safely shared as required with an anonymous communication party that is not predetermined, without the common key being shared in advance. The encryption communication system comprises a first communication device and a second communication device that stores a master key which is an encryption key. The encryption communication system is characterized in that the first communication device has: a common key storage means that stores a key pair comprising a first key which is a common key used for communication with the second communication device, and a second key with which the first key is encrypted by means of the master key possessed by the second communication device; and a common key transmission means that transmits the second key to the second communication device. The encryption communication system is also characterized in that the second communication device has a common key acquisition means that receives the second key and decrypts the received second key by means of the master key to acquire the first key.