A Cryptographic Key Distribution Mechanism Using Double Encryption for Secret Communications

Cryptographic key distribution is one of the important problems when a conventional cipher is used for secret communications. Key distribution methods can be categorized as those using a conventional cipher system and those using a public key system. In key distribution methods using a conventional cipher system, the key encryption key should be sent secretly by manual operation. In key distribution methods using a public key system, no manual operation is necessary. This paper proposes a key distribution method (mechanism) which has the same functions as key distribution methods using a public key system. The proposed method is called a double encryption key distribution method and uses modular exponential computation in GF(p), where p is a prime. The authentication scheme for the key distribution method is shown. The advantages of the proposed key distribution method are as follows. Functions, performance and security are almost equal to main key distribution methods using a public key system. Additionally, since each node can generate and delete the encryption and decryption keys for the modular exponential function in each key distribution, it is unnecessary for each node to keep the keys.