A Systematic Method for Tackling Data Encryption Standard Vulnerabilities

Abstract

Data Encryption Standard (DES) is a broadly used symmetric-key algorithm for ciphering digital data. However, there are several vulnerabilities related to this technique, including key distribution, namely, the key must be securely passed between the associated parties, and susceptibility, that is, the DES is defenceless against brute force and cryptanalysis attacks upon the key and the message, respectively. This paper attempts to tackle the first vulnerability by using the Diffie-Hellman protocol, as it enables the parties to interchange unshared secret. In addition, the second vulnerability is alleviated through: (1) performing the Columnar Transposition Cipher on the message before DES, (2) replacing the classical shifting process of the key with a type of shifter called Barrel. These improvements are vital for safeguarding against breaches and sophisticated attacks. The findings of conducted experiments have revealed that the proposed method satisfies the key and plaintext avalanche with a 50% output bit flipped in the ciphertext, and the average time required to crack passwords handled by the enhanced DES is more than that for classical DES. Therefore, the proposed method of this paper has raised the security requirements of DES.