Journal of Network and Information Security

Abdulkadir H. Disina ¹, Zahraddeen A. Pindar ¹, Sapiee Bin Hj. Jamel ¹

Affiliations
1 Department of Information Security, UniversitiTun Hussein Onn Malaysia, Batu Pahat, MY

Abstract

Cryptography is the art of encoding messages into an unreadable form from a sender and re-transforming back to its readable form at the receiver end. This is an enhanced Caesar cipher against frequency analysis using bidirectional shift. This algorithm encrypts message bit by bit or character by character (stream cipher) and uses one key ideology (symmetric key cipher), the sender encrypts the message before transmitting and the receiver decrypts upon receiving using the same key as the one used for the encryption. It shifts the plain text characters to different direction which eliminates repetition of characters in the cipher text. Previous versions of Caesar cipher hadonly 26 English alphabets to be encrypted, which the attacker knew that there were only 26 choices to choose from, to determine the plain text. And when the alphabet of the same type are encrypted, they will have the same symbol representing each, which gives hint to attacker on how to break it by using frequency cryptanalysis. The enhanced method (Enhanced Caesar cipher) has 95 characters as digital messages as against 26 alphabets. Based on this method, the sender will transposition the bits in the message according to their sequence arrangement (odd and even position) to shift the characters in the odd position to the left and characters in the even position to the right side, based on the key given by the user, as the key to both shifts. Shifting the plain text to different directions mitigates the problem of repetition which the previous version suffers from. To make decryption more difficult, each character will switch position with the next to randomize their arrangement. The cipher was successfully developed and working accurately. It was developed on java platform using java eclipse IDE and NETBEANS IDE 7. 1. 2. It has successfully passed all the tests and proven its accuracy obtaining the result of 100% repetition free. Thus, the proposed method is highly resistant to frequency analysis. This provides more security than the earlier versions and it serves as an option to be integrated with other algorithms to strengthen the security.

Keywords

Caesar Cipher, Cryptography, Repetition Exclusion, Encryption, Decryption, Shift, Switch, Symmetric-Key Cipher, Key Generation.

Full Text

     

Zahraddeen A. Pindar ¹, Sapiee Jamel ¹, Abdulkadir H. Disina ¹

Affiliations
1 Department of Information Security, UniversitiTun Hussein Onn Malaysia, Batu Pahat, MY

Abstract

The advent of check digit methods has aided the detection of errors while computing data into an information system. Prominent check digit methods such as Universal Product Code (UPC), International Standard Book Number (ISBN-10), Luhn and Verhoeff check digit methods are widely used in detecting errors. This research will focus on the current UPC method as it is used widely around the world. The current UPC method does not effectively detect all types of errors. Thus, failure to detect errors can lead to undesired consequences like purchasing a wrong item or letting perpetrators to get away with their crimes. This paper examines the limitations of the UPC check digit method and proposes the idea of a double check digit method which produces two check digits. The proposed method is an enhancement of the current UPC modulus 10 check digit method. A comparative test was conducted to compare the ability of the proposed method and the current UPC method in detecting errors. However, results have shown that the proposed method has an average of 95.75 accuracy of detecting all tested errors as compared to the current UPC which detects 65% of tested errors respectively. Thus, the proposed method is more efficient than the current UPC check digit method in detecting errors.

Keywords

Double Check Digit, Interdependence, Errors.

Full Text