Development of an Improved Playfair Cryptosystem Using Rhotrix.
Abstract
is one of the best-known ciphers but it is limited to aspects such as space, numbers, and other printable
. The existing technique is based on the use of a 5 × 5 matrix. This algorithm can only allow the text that contains uppercase alphabets only. But many algorithms have been proposed which allow extension of playfair to 6 × 6 matrix, 8 × 8 matrix and 7 × 4 matrix.
This dissertation deals with some of the limitations such as lowercase, numbers, white space and repetition of alphabet in pairs. Proposed modification uses rhotrix which is a new paradigm of matrix theory for rectangular arrays.
This work proposes an improved key matrix formation of the playfair cipher.
The order of the rhotrix will be set to 6 to make it compatible with the [n×(n-1)] mode of rhotrix representation which supports all 26 alphabets in both upper case letters (a-z) as well as lower case letters (a-z), ten digits (0-9), special characters and the extended special characters.
Experimental result produced better Playfair cipher to incorporate randomness and to eliminate the chances of being attacked by frequency testing of character occurrence over an existing 11 × 11 matrix. The system was developed in java because of platform independence and availability.
Introduction
Background of the Study
The security of data transmission is an important problem in communication networks. A communication system is reliable as long as it maintains the integrity, availability, and privacy of data. Data integrity is the protection of data from unauthorized modification, resistance to penetration, and undetected modification.
Therefore, it is important to secure a cryptosystem that provides encryption and decryption to the data. To achieve a secure cryptosystem, Cryptology is essential. Cryptology is the study of cryptography and crypt analysis. is the study of information hiding and verification.
It includes the protocols, algorithms and strategies to securely and consistently prevent or delay unauthorized access to sensitive information and enable verifiability of every component in a communication (Saini and Mandal, 2015).
Cryptanalysis is the art of ‘attacking’ cryptosystems in order to ‘crack’ them or at least discover their weaknesses (Stallings, 2011).
When cryptanalysis reveals weaknesses in cryptosystems, cryptographers create more secure cryptosystems. Conversely, as cryptosystems become stronger, cryptanalysts try to discover more powerful methods of attacking them. Thus, cryptography and cryptanalysis are complementary.
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