Bit level symmetric key cryptography using genetic algorithm

Abstract

Symmetric key encryption is known to produce the same cipher text from the same set of plain text and key, each time the encryption process is carried out. Here the authors have developed a technique in which different cipher texts will be generated for the same set of plain text and key each time the plain text is encrypted. The different generated cipher texts can be decrypted using the same user key. This is done by using genetic algorithm. Genetic algorithm has been used to generate an intermediate key which is unique each time the algorithm is executed. This intermediate key combined with a first level cipher text generates the second level cipher text. In the later stage the intermediate key is embedded with the second level cipher text using the user given key to produce the third and final cipher text. The process of embedding is done by using a completely new algorithm. The technique introduced may be implemented to encrypt any kind of confidential data. After encryption the size of the original file will change. The hackers or intruders will not be able to apply the standard attacks such as brute force attack, known plain text attack, differential attack or statistical attack. Without having any knowledge of the key, decryption of the text will not be possible. The present method has been tested on various known plain texts and the results show quite satisfactory.