S-DES: An Efficient & Secure DES Variant

In this paper, we propose an efficient and secure variant of DES (S-DES), which strikes a good balance between performance and security level when compared to 3DES. S-DES is based on the same round function of DES, however, we introduce different modifications to overcome the weaknesses of the original DES such as the extended Feistel Network (FN) instead of the FN. The main advantage of the proposed scheme is that it benefits from the cryptographic characteristics of DES substitution and diffusion primitives. However, the size of the secret key is extended to 112 bits and the data block is set to 128 bits, which provides better resistance against the attacks that plagued DES. Moreover, the proposed internal scheme of S-DES allows for a parallel implementation, which reduces the response latency. Finally, the main idea of this paper is not to provide a better alternative to the existing standard (AES), but to provide an efficient candidate solution from the well-optimized DES cipher.