Ravindra Kumar Singh

Performance Analysis of RC6, Twofish and Rijndael Block Cipher Algorithms

In this paper, Performance analysis of RC6, Twofish and Rijndael block cipher algorithms have been done on the basis of execution time and resource utilization. CPU utilization and memory utilization both are considered for determining resource utilization. These algorithms are parameterized algorithm and were designed to meet the requirements of the Advanced Encryption Standard (AES) competition and selected among five finalists of that competition. These three algorithms have a variable block size and a variable key size in their structure and encrypt four w-bits at a time. Allowable choices for w are 16 bits, 32 bits, and 64 bits. Twofish and Rijndael have same structure for encryption and decryption while RC6 have different. RC6, Twofish and Rijndael have 20, 16 and 10 rounds respectively. Performances of these three algorithms have been evaluated on key size of 128-bits, 192-bit and 256-bit in this paper. General Terms Cryptography, Block cipher, Symmetric encryption, RC6, Twofish, Rijndael

3D - Playfair cipher with additional bitwise operation

3D-Playfair cipher is multiple letter encryption cipher. In this, trigraphs of plaintext are treated as single units and converted into corresponding cipher text trigraphs. 3D-Playfair Ciphers originates due to the limitations in classical Playfair as it supports only alphabets and may not support two alphabets at the same time. It also eliminates the fact that a diagram and its reverse will encrypt in a similar fashion. 3D-Playfair cipher supports all 26 alphabets, 10 digits and 28 special characters. The theme of research is to furnish security to data which contains alphabets numerals and special characters during transmission thats why additional bitwise operations are introduced and applied on the cipher text of 3D-Playfair cipher with a random key. Linear Feedback Shift Register is a good candidate for generation of random sequences and is selected for generating random keys for bitwise operations to offer better security to cipher text before transmission over the internet. Here X-OR or X-NOR operations are taken into consideration for the bitwise operations based on the key.

Bi-directional pixel-value differencing approach for RGB color image

A two layer data hiding method for RGB color image has been proposed in this paper. It is an enhancement of Wu and Tsais method (PVD) and J. K. Mandals method (Color Image Steganography Based on Pixel Value Differencing in Spatial Domain). J. K. Mandals method will be referred as “Color PVD” in this research paper. Proposed method is relatively secure and efficient in term of data hiding capability and quality of stego image. Caesar cipher is considered to play the role of security wall for this approach. Difference of pixel pairs (non overlapping consecutive pixels in the cover image) drives the data hiding capacity of this method. Two layer data hiding and LZW compression technique are also involved to enlarge the data hiding capability of this method. In second layer of data hiding, left pixel of the pixel pair is considered as right pixel and viceversa to improve the stego image quality. Stego image in this technique is totally indistinguishable from the original image by the human eye and it is secure against the RS detection attack. Beside this it also avoids falling of boundary problem of the pixels.

3D(4 X 4 X 4) - Playfair Cipher

The theme of this research is to provide security for the data that contains alphabets numerals and special characters during its transmission. However because of the drawbacks inherent in the classical Playfair cipher which adversely affects the security, this research proposed 3D-Playfair Cipher (4 X 4 X 4 Playfair cipher) which works on trigraph rather than using digraph which eliminates the fact that a diagram and its reverse will encrypt in a similar fashion. 3D-Playfair cipher supports all 26 alphabets {AZ}, 10 digits {0-9} and 28 special characters { ! “ #

6 X 6 Playfair Cipher using LFSR based Unique Random Number Generator

% & ‘ ( ) * + , - . / : ; ? @ [ \ ] ^ _ | } which eliminate the limitation of classical Playfair in which “i” and “j” both character cannot appear at the same time. 3D-Playfair enhances the security by increasing complexity. Various types of cryptography attacks have been taken under consideration for original Playfair cipher but not vulnerable for this proposed cipher.

A hybrid approach of image steganography

Playfair cipher is the well-known multiple letter encryption cipher. Here the digraphs in the plaintext are treated as single units and converted into corresponding cipher text digraphs. However because of the drawbacks inherent in the 5 X 5 Playfair cipher which adversely affects the security we proposed a 6 X 6 Playfair cipher and then coupled it with Linear Feedback Shift Register based Unique Random Number Generator [1]. 6 X 6 Playfair cipher supports all 26 alphabets (A-Z) and 10 digits (09) which eliminate the limitation of 5 X 5 Playfair in which “i” and “j” both character could not appear at the same time [2, 3]. LFSR not only enhances the security up to a considerable level by generating random sequences but also provides a much faster rate of encryption and decryption [1], that’s why LFSR based Unique Random Number Generator is chosen for the consideration. This paper deals in with the security issues of the new proposed system. Various types of cryptography attacks have been taken under consideration for original Playfair cipher but not vulnerable for this proposed cipher. KeywordsPlayfair cipher, Random number, LFSR, Polyalphabetic cipher

Bi-directional Pixel-Value Differencing Approach for Steganography

A hybrid approach of cryptography, data compression and steganography has been proposed in this paper. Motivation behind this research is to provide a smart image steganographic technique which must be capable enough to provide better quality stego-image with a high data hiding capability. Proposed approach is a LSB based approach and inspired with the invention of H. B. Kekre in the field of image steganography. Maximum data hiding capability of proposed approach will be evaluated from kekres algorithm. Proposed approach hides data in the upper LSB bit only when its adjacent LSB bit of all the pixel have conceived a bit of secret data for better quality of the stego-image. LZW compression scheme is used to optimize the size of secret data, it will enable a personal to hide approx 2 times more data in a cover-image. This approach is secure against the RS detection attack and its stego-image is totally indistinguishable from the original image (cover-image) by the human eye.

Performance Analysis of RC5, Blowfish and DES Block Cipher Algorithms

A hybrid image steganographic approach has been proposed in this paper to enlarge the data hiding capability of cover image as well as to improve the quality of stego image. This research is a hybrid combination of cryptography, steganography and data compression. The basic building block of this approach is Wu and Tsai’s method (PVD), LZW compression scheme, Vernam cipher and gray code. In this approach, chunks of the secret data are embedded by altering the pixel values of the consecutive pixels in the cover image according to their hiding capacity. The hiding capacity of the two consecutive pixels depends on their difference value, which is calculated by pixel-value differencing technique (PVD). Two layer data hiding is the key feature of this approach that’s why it is called a Bi-Directional approach. Two layer data hiding approach improves the data hiding capacity and quality of stego image as well. In second layer data hiding we consider left pixel of the pixel pair as the right pixel and vive-versa. It improves the quality of stego image. In this technique stego image is totally indistinguishable from the original image by the human eye. It is also secure against the RS detection attack.