An improved Kerberos protocol based on fast RSA algorithm

Kerberos is a widely-adopted network authentication protocol, which provides secure authentication service based on the reliable third-party. By exploiting a shared key, Kerberos ensures the confidentiality and integrity for a session. Kerberos, an authentication protocol based on symmetric cryptography system, has some inherent security flaws, such as undeniability, difficulty in key exchange, inability to fulfill digital signature and authentication. After an analysis of its security flaws, the paper improves Kerberos by applying fast RSA algorithm, more specifically, using Montgomery algorithm to count modular exponentiation of large numbers, and adopting the Chinese Remainder Theorem when using private key to calculate fast RSA algorithm. Thus, the improved Kerberos is more efficient and secure in use. In addition, compared with the original one, the improved protocol has amelioration and improvement in more than one performance, including key storage, clock synchronization, password guess and non-repudiation of the notes. Consequently, its authentication process is safe, authentic and reliable.