A Highly Secure Secret Key Encryption Methodology Using Dual Permutation

This paper describes a novel secret key cryptography algorithm where a dual encryption methodology has been incorporated. The first level is a block level encryption, where the original text message is divided into several fixed sizeblocks. An initial permutation has been applied on that n number of block sets and by using a secret key, a particular sequence of blockshas been chosen. The second level is a bit level encryption, where the same permutation has been applied within each block and a particular bit sequence within a block has been chosen.XOR and bit shifting are some intermediate operation has been applied for security purpose.Asecret key is being prepared by storing the block level as well as the bit level random values.The block size of this proposed method is 16bits. The main key advantage of the proposed method is that by using this bit level and block level encryption the securityis increasedof the algorithm in a higher semantic level.