Reliable block based cryptosystem: Combination of Merkle-Hellman and RSA for secured image transmission

In the recent years, internet multimedia has made life easy and at the same time added complexity in terms of security. Robust and secured transmission strategy for high-quality image is considered a great challenge. However majority of image encryption techniques do not consider reliability during transmission and this issue is considered a problem that should be handled by an efficient cryptosystem. Apart from above mentioned the design of the system should fulfill extremes of Scalability, Usability and accountability of digital data. Valuable multimedia content such as digital images, however is vulnerable to unauthorized access while in storage and during transmission over a network. As the computers are more and more integrated via the network the distribution of digital media is becoming faster. For effective protection of intellectual properties like security, integrity, confidentiality of the organization´s data is an important issue. In this paper a new approach to encrypt the image using the concept of Merkle - Hellman Knapsack Cryptosystem and RSA for better reliability is being proposed. Experimental results show that the proposed approach based on block replacement code algorithm reduces the number of encrypted blocks drastically.