Symmetric key cryptosystem using combined cryptographic algorithms - Generalized modified Vernam Cipher method, MSA method and NJJSAA method: TTJSA algorithm

In the present paper the authors have introduced a new combined cryptographic method called TTJSA. Nath et al. have already developed some symmetric key methods. In the present work the authors have used two methods MSA and NJJSAA which were developed by Nath et al. and have developed a new algorithm, generalized modified Vernam Cipher Method. The above three methods are applied in random order on any given plain text for a number of times to get the ultimate cipher text file. In the present work, authors modified the standard Vernam Cipher Method for all characters (ASCII code 0-255) with randomized keypad, and have also introduced a feedback mechanism. The method has been closely monitored on different known plain text and it was found that this method is almost unbreakable. The present method allows multiple encryption/decryption. The present method is an extremely secure block cipher method and it can be applied to encrypt data in Defense system, Banking sector, mobile network etc. The advantage of the present method is that one can apply this method on top of any other standard algorithm such as DES, AES or RSA. The method is suitable to encrypt any type of file.