RAM-RSA and RBM-RSA: A New Fast Hybrid RSA Variants

Since the development of RSA in 1977, many RSA variants are developed. The objectives behind these variants are either to improve RSA decryption time, to accelerate RSA encryption time or to rebalance RSA encryption and decryption time. The Mprime RSA variant is a well known variant that improve standard RSA decryption time, while Rebalanced RSA-CRT variant lowered decryption time. Later, the Rebalanced RSA-CRT Scheme A and Scheme B variants are developed to improve encryption cost in Rebalanced RSA-CRT variant.

The Rprime RSA variant was proposed in 2002, as a hybrid variant that use the key generation algorithm of Rebalanced RSA (modified for k primes) together with the decryption algorithm of Mprime RSA in order to further improve decryption time.

In this paper, we combine the achievements of Mprime variant and RSA Rebalanced Scheme A and Scheme B variants to develop two RSA variants that improve both the encryption and decryption time. We call these variants RAM-RSA (Rebalanced Scheme A with Mprime) and RBM-RSA (Rebalanced Scheme B with Mprime).

The experimental tests show that; for decryption RAM-RSA and RBM-RSA are respectively 3.4 and 2.8 times faster than Rprime RSA, and for encryption they are respectively 4.5 and 5.8 times faster than Rprime RSA.