Asoke Nath

Bio: Asoke Nath is an academic researcher from St. Xavier's College-Autonomous, Mumbai. The author has contributed to research in topics: Encryption & Multiple encryption. The author has an hindex of 19, co-authored 99 publications receiving 1049 citations. Previous affiliations of Asoke Nath include National Chiao Tung University & Indian Association for the Cultivation of Science.

Symmetric Key Cryptography Using Random Key Generator.

Abstract: In the present work we have introduced a new symmetric key cryptographic method for encrypting as well as decrypting any file such as binary file, text file or any other file. In our method we have modified the idea of Play fair method into a new platform where we can encrypt or decrypt any file. We have introduced a new randomization method for generating the randomized key matrix to encrypt plain text file and to decrypt cipher text file. We have also introduced a new algorithm for encrypting the plain text multiple times. Our method is totally dependent on the random text_key which is to be supplied by the user. The maximum length of the text_key can be of 16 characters long and it may contain any character(ASCII code 0 to 255). We have developed an algorithm to calculate the randomization number and the encryption number from the given text_key. The size of the encryption key matrix is 16x16 and the total number of matrices can be formed from 16 x 16 is 256! which is quite large and hence if someone applies the brute force method then he/she has to give trail for 256! times which is quite absurd. Moreover the multiple encryption method makes the system further secured. We propose that our method could be appropriate in sensor network where the massive computation is not possible but the security of data is important at the same time.

A New Symmetric Key Cryptography Algorithm Using Extended MSA Method: DJSA Symmetric Key Algorithm

Abstract: In the present work the authors introduced a new symmetric key cryptographic method for encryption as well as decryption of any file such as binary file, text file or any other file. Nath et. al. (1) developed an algorithm called MSA for encryption and decryption of any file using a random key square matrix containing 256 elements. The weak point of MSA algorithm is that if someone applies the brute force method then he has to give a trial for factorial 256 to find the actual key matrix. Now in the modern world this number of trial runs may not be impossible for the hacker. To get rid of this problem here the authors suggest a better algorithm than MSA. In the present method the authors considered the size of the key matrix to be 65536 and in each cell we store 2 characters pattern instead of 1 character unlike MSA method. If someone wants to give a brute force method to find our actual key then one has to give a trial for factorial 65536 runs! Theoretically this is an intractable problem. Moreover the authors have also introduced multiple encryptions here to make the system more secured. This method will be suitable in any business house, government sectors, communication network, defense network system, sensor networks etc. In the present work the authors have introduced a square key matrix of size 256 by 256 where in each cell there are all possible 2-lettered words (ASCII code 0-255). The total number of words possible is 65536. The key matrix is then randomized using the method proposed by Nath et. al(1). The user has to enter some secret text-key. The maximum length of the text key should be 16 characters long. To calculate the randomization number and the number of encryption to be done is calculated from the text-key using a method proposed by Nath et.al(1). The present method will be most suitable for encryption of a file whose size is less than or equal to 2MB. If the file size is very big then we suggest choosing small encryption number to speed up the system.

Advanced Steganography Algorithm using Encrypted secret message

Abstract: In the present work the authors have introduced a new method for hiding any encrypted secret message inside a cover file. For encrypting secret message the authors have used new algorithm proposed by Nath et al(1). For hiding secret message we have used a method proposed by Nath et al(2). In MSA(1) method we have modified the idea of Play fair method into a new platform where we can encrypt or decrypt any file. We have introduced a new randomization method for generating the randomized key matrix to encrypt plain text file and to decrypt cipher text file. We have also introduced a new algorithm for encrypting the plain text multiple times. Our method is totally dependent on the random text_key which is to be supplied by the user. The maximum length of the text_key can be of 16 characters long and it may contain any character(ASCII code 0 to 255). We have developed an algorithm to calculate the randomization number and the encryption number from the given text_key. The size of the encryption key matrix is 16x16 and the total number of matrices can be formed from 16 x 16 is 256! which is quite large and hence if someone applies the brute force method then he/she has to give trail for 256! times which is quite absurd. Moreover the multiple encryption method makes the system further secured. For hiding secret message in the cover file we have inserted the 8 bits of each character of encrypted message file in 8 consecutive bytes of the cover file. We have introduced password for hiding data in the cover file. We propose that our new method could be most appropriate for hiding any file in any standard cover file such as image, audio, video files. Because the hidden message is encrypted hence it will be almost impossible for the intruder to unhide the actual secret message from the embedded cover file. This method may be the most secured method in digital water marking.

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

Abstract: 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.

Fuzzy hierarchical analysis

Abstract: We present a new method of finding the fuzzy weights in fuzzy hierarchical analysis which is the direct fuzzification of the original method used by Saaty (1980) in the analytic hierarchy process. We test our new procedure in two cases where there are formulas for the crisp weights. An example is presented where there are five criteria and three alternatives.

Evaluation of Services Using a Fuzzy Analytic Hierarchy Process

Abstract: This paper proposes a new approach for tackling the uncertainty and imprecision of the service evaluation process. Identifying suitable service offers, evaluating the offers and choosing the best alternatives are activities that set the scene for the consequent stages in negotiations and influence in a unique manner the following deliberations. The pre-negotiation problem in negotiations over services is regarded as decision-making under uncertainty, based on multiple criteria of quantitative and qualitative nature, where the imprecise decision-maker’s judgements are represented as fuzzy numbers. A new fuzzy modification of the analytic hierarchy process is applied as an evaluation technique. The proposed fuzzy prioritisation method uses fuzzy pairwise comparison judgements rather than exact numerical values of the comparison ratios and transforms the initial fuzzy prioritisation problem into a non-linear program. Unlike the known fuzzy prioritisation techniques, the proposed method derives crisp weights from consistent and inconsistent fuzzy comparison matrices, which eliminates the need of additional aggregation and ranking procedures. A detailed numerical example, illustrating the application of our approach to service evaluation is given.

Fuzzy numbers: an overview

Abstract: This paper is an overview of past and present works dealing with fuzzy numbers and their operations A fuzzy number (more generally a fuzzy quantity) is a fuzzy set in the real line Particular cases include usual real numbers and intervals Usual operations on the real line canonically extend to operations between fuzzy quantities, thus extending the usual interval (or error) analysis to many-valued quantities What is obtained is a counterpart of random variable calculus, but where, contrary to the latter case, errors never compensate Many results pertaining to mathematical properties as well as calculation methods are now available and are summed up in the paper The dual theory — “optimistic” operations on fuzzy numbers, ie, with maximal error compensation — is also outlined; its interest lies in providing tools for solving fuzzy number equations Lastly, the problem of comparing fuzzy numbers is considered The paper includes some historical background, as well as an extensive bibliography of applications to mathematics and engineering