Implementation and Performance Evaluation of Asymmetrical Encryption Scheme for Lossless Compressed Grayscale Images

The employment of compression and encryption methods enables the transmission of images across a communication link with less bandwidth consumption and resistance against differential assaults. In this study, the gray scale images are compressed using the Huffman lossless compression approach. Each pixel is given a unique prefix code with a configurable length in this. The frequency of occurrence of characters has an inverse relationship with prefix code length. Asymmetrical RSA encryption is used to encrypt compressed images. In the RSA encryption technique, the encryption key is kept in the open as opposed to the decryption key, which is kept private. Analysis of the compression parameters, together with correlation coefficient and entropy analysis, is used to convey the effectiveness of suggested techniques. Five 512 × 512 grayscale test images are used as text images and to verify the results.