%0 Journal Article %T Proposal of a New Block Cipher reasonably Non-Vulnerable against Cryptanalytic Attacks %A Abhijit Chowdhury %A Angshu Kumar Sinha %A Saurabh Dutta %J International Journal of Computer Science Issues %D 2012 %I IJCSI Press %X This paper proposes a new block cipher termed as "Modular Arithmetic based Block Cipher with Varying Key-Spaces (MABCVK)" that uses private key-spaces of varying lengths to encrypt data files. There is a simple but intelligent use of theory of modular arithmetic in the scheme of the cipher. Based on observed implementation of the proposed cipher on a set of real data files of several types, all results are tabulated and analyzed. The schematic strength of the cipher and the freedom of using a long key-space expectedly can make it reasonably non-vulnerable against possible cryptanalytic attacks. As a part of the future scope of the work, it is also intended to formulate and implement an enhanced scheme that will use a carrier image to have a secure transmission of the private key. %K Cryptography %K Modular Arithmetic %K Carrier Image %K Data Security %K IJCSI %U http://www.ijcsi.org/papers/IJCSI-9-1-1-370-373.pdf