Secure transmission of authenticated messages using new encoding scheme and Steganography

• Authors: Kalavathi Alla;G. Gowri Shankar;G. Bala Subrahmanyam
• Venue: Proceedings of the Second International Conference on Computational Science, Engineering and Information Technology
• Year: 2012

The demand for effective information security schemes is increasing day by day, with the exponential growth and use of Internet. Cryptography and Steganography are two popular techniques which are to be used for effective secret communications. In this paper, we propose a new encoding scheme to covert the secret text into cipher text. The proposed encoding scheme treats every 16 message characters as a single unit where each character is encoded in 7 bit binary and then it coverts each unit to 14 ASCII characters of length 8 bits. This encoding scheme converts the message block into cipher text. Hash code is calculated on the original message at the transmission side. Sender generates 3 different keys from the calculated hash code. Key 1 tracks the original position of alphabets and digits alternatively. Key 2 can be obtained by separating the first 10 alphabets retrieved from hash code and add the remaining alphabets at the end of separated digits. Key 3 is the reverse of key 2. Now hide the separated 10 alphabets from hash code (in generating key 2) in an image using least significant bit steganography. Cipher text, stego image and the two keys are transmitted to the end user. Upon receiving the data receiver applies the reverse procedure and can check the authenticity of the document. The proposed method is very efficient in generating cipher text and also in verifying the authenticity of the message. Instead of simply transmitting the hash code, the proposed methods protects the cryptographic checksum value in two different keys and in a stego image.