Sattar J. Aboud

An Efficient RSA Public Key Encryption Scheme

In this paper, we propose an efficient RSA public key encryption scheme, which is improved version of original RSA scheme. The proposed RSA encryption scheme is based on linear group over the ring of integer mod a composite modulus n which is the product of two distinct prime numbers. In the proposed scheme the original message and the encrypted message are h x h square matrices with entities in zn indicated via l(h, zn) . Since the original RSA Scheme is a block cipher in which the original message and cipher message are integer in the interval [0, n -1] for some integer modulus n. Therefore, in this paper, we generalize RSA encryption scheme in order to be implemented in the general linear group on the ring of integer mod n. Furthermore, the suggested encryption scheme has no restriction in encryption and decryption order and is claimed to be efficient, scalable and dynamic.

Efficient Threshold Signature Scheme

In this paper, we introduce a new threshold signature RSA-typed scheme. The proposed scheme has the characteristics of un-forgeable and robustness in random oracle model. Also, signature generation and verification is entirely non-interactive. In addition, the length of the entity signature participate is restricted by a steady times of the length of the RSA signature modulus. Also, the signing process of the proposed scheme is more efficient in terms of time complexity and interaction.

Secure Undeniable Threshold Proxy Signature Scheme

the threshold proxy signature scheme allows the original signer to delegate a signature authority to the proxy group to cooperatively sign message on behalf of an original signer. In this paper, we propose a new scheme which includes the features and benefits of the RSA scheme. Also, we will evaluate the security of undeniable threshold proxy signature scheme with known signers. We find that the existing threshold proxy scheme is insecure against the original signer forgery. In this paper, we show the cryptanalysis of an existed scheme. Additional, we propose the secure, undeniable and known signers threshold proxy signature scheme which answers the drawback of an existed scheme. We also demonstrate that a threshold proxy signature suffers from a conspiracy of an original signer and a secret share dealer, that the scheme is commonly forgeable, and cannot offer undeniable. We claim that the proposed scheme offers the undeniable characteristic.