A Novel Approach for Compression of Encrypted Grayscale Images Using Huffman Coding

Currently information security is becoming more important in data storage and transmission. Images are broadly used in several processes. Therefore, the protection of image data from unauthorized access is essential. Image encryption plays a major role in the field of information hiding. The objective of this paper is to provide an efficient coding technique for compress the encrypted gray scale images without any loss. This is made possible by using Huffman coding. This paper uses resolution-progressive compression (RPC) technique to achieve better result. RPC compresses an encrypted image progressively in resolution, such that the decoder can observe a low-resolution version of the image, study local statistics based on it, and use the statistics to decode the next resolution level. The experimental results show that the method used in this paper for compression gives good result.