A New Secure Hash Dynamic Structure Algorithm (SHDSA) for Public Key Digital Signature Schemes

This paper presents a new secure hash algorithm based on dynamic structure algorithm called Secure Hash Dynamic Structure Algorithm (SHDSA). It uses a famous secure hash algorithm (SHA) given by the National Institute of Standards and Technology (NIST). All NIST SHA have fixed structure, fixed constant and fixed output length. The goal of the new Advanced Encryption Standard (AES) is to offer, at its three cryptovariable size, 128, 192 and 256 bits of security, is the need for companion hash algorithms which provide similar levels of enhanced security. The basic design of SHDSA is to have variable output length of 128,192 and 256 bits, variable number of compression functions (single, double), variable number of iterations in each compression function and variable compression function structure. With this dynamic structure, it can provide many choices for practical applications with different level of security. The SHDSA has been designed to satisfy the dynamic structure algorithm with different level of enhanced security and to resist the advanced SHA attacks. The security analysis of the SHDSA is compared to the old SHA given by the NIST and it gives more security and excellent results as shown in our discussion. In this paper, the digital signature standard algorithm (DSSA) which is given by the NIST has been modified using the proposed SHDSA. The SHDSA can be used in many applications suclh as, public key cryptosystems, digital signature, digital signcryption, message authentication code and random number generators.