Novel Encryption method for Grayscale Halftone Images using Random numbers
D. Manjula, C. Vijaya · 2014
Cryptography is derived from the Greek words kryptos, hidden, and graphein, write or hidden writing''. It is a means of transforming data in a way that renders it unreadable by anyone except the intended recipient. Visual cryptography (invented by Naor & Shamir in 1994) is a method for securely encrypting messages in such a way that the recipient won't need a computer to decrypt them. It is the technique that divide the secret image into n multiple shares. Each share constitutes some information and when k shares out of n stack together the secret will reveal. However less than k shares do not work. In this paper a novel encryption method is used for gray scale halftone images using random numbers. The size of the retrieved image is same as the size of input secret image. Extra security is added by introducing keys, which are same at both encryption and decryption. This leads to no degradation in image quality as desired in certain image processing applications.