Cryptographic communication terminal, cryptographic communication center apparatus, cryptographic communication system, and storage medium

A computer readable medium storing a program for implementing:

• a control section for designating an encrypted cryptographic algorithm and an encrypted encryption/decryption key to be used in cryptographic communication based on identification information;
• a cryptographic algorithm storage section for storing not less than one type of cryptographic algorithm used for cryptographic communication in encrypted form, and outputting the encrypted cryptographic algorithm designated by the control section;
• a key information storage section for storing and outputting the encrypted encryption/decryption key designated by the control section to be used for cryptographic communication and an encrypted key used for decrypting the encrypted cryptographic algorithm;
• a key information decryption section for decrypting the encrypted encryption/decryption key used for cryptographic communication and the encrypted key used for decrypting the encrypted cryptographic algorithm to create an encryption/decryption key used for cryptographic communication and an decryption key used for decrypting the encrypted cryptographic algorithm;
• a cryptographic algorithm decryption section for decrypting the encrypted cryptographic algorithm to generate a cryptographic algorithm by using the decryption key for decrypting the encrypted cryptographic algorithm;
• and
• an encryption/decryption section for encrypting/decrypting communication messages by using the cryptographic algorithm and the encryption/decryption key.

A cryptographic communication center apparatus, comprising:

• at least one cryptographic communication terminal , the terminal including:
• a control section for designating an encrypted cryptographic algorithm and an encrypted encryption/decryption key to be used in cryptographic communication based on identification information;
• a cryptographic algorithm storage section for storing not less than one type of cryptographic algorithm used for cryptographic communication in encrypted form, and outputting the encrypted cryptographic algorithm designated by the control section;
• a key information storage section for storing and outputting the encrypted encryption/decryption key designated by the control section to be used for cryptographic communication and an encrypted key used for decrypting the encrypted cryptographic algorithm;
• a key information decryption section for decrypting the encrypted encryption/decryption key used for cryptographic communication and the encrypted key used for decrypting the encrypted cryptographic algorithm to create an encryption/decryption key used for cryptographic communication and a decryption key used for decrypting the encrypted cryptographic algorithm;
• a cryptographic algorithm decryption section for decrypting the encrypted cryptographic algorithm to generate a cryptographic algorithm by using the decryption key for decrypting the encrypted cryptographic algorithm;
• and
• an encryption/decryption section for encrypting/decrypting communication messages by using the cryptographic algorithm and the encryption/decryption key,
• wherein when the algorithm decryption key is requested from a partner of the cryptographic communication center apparatus, said apparatus inputs the corresponding algorithm decryption key as information to be transmitted to the partner to said encryption/decryption section.