An encryption device, a decrypting device, a secret key generation device, a copyright protection system and a cipher communication device including: a CRL memory unit memorizing a CRL, a device key ring memory unit memorizing a specific device key KD_A in every IC card used in a decrypting device, a content key memory unit memorizing a content key Kc, which is a secret key for decrypting content, and a hashing function processing unit calculating a hashing value of the CRL memorized in the CRL memory unit. The devices further including an Ex-OR unit carrying out an exclusive OR between the hashing value and the device key KD_A memorized in the device key ring memory unit, and an Enc unit encrypting the content key Kc memorized in the content key memory unit using an output value of an Ex-OR unit.