A stable image steganography: a novel approach based on modified RSA algorithm and 2–4 least significant bit (LSB) technique

Abstract

Nowadays, due to the rapid technological growth of information technology billions of data transferred through the network around the world in a fraction of seconds. To protect the transferred information from unauthorized access, security mechanism is required. At this point, significant role is performed by a technology called information security. So, to provide security, various techniques have been evolved such as cryptography, steganography and digital watermarking. Cryptography converts the message into scrambled format whereas in steganography the secret message is buried in the digital media. In this paper, both cryptography and steganography is combined to safeguard the information. First, the message is encrypted with the help of revised RSA algorithm to convert the message into secret message. Second, the cover image is segmented into edge and non-edge pixels using Canny edge detection technique and then N1(two) and N2 (four) bits of the secret messages are buried into the edge and non-edge pixel areas using LSB technique. Finally, the essential parameters like N1, N2 and the length values are implanted into the last four pixels of the cover-image to obtain the stego-image. At the recipient side, the hidden data are extracted from the stego-image after extracting N1, N2 and length information. Then, the extracted secret data is decrypted using revised RSA algorithm. Modified RSA algorithm improves the security by using two pairs of keys. At last, the various performance metrics parameters such as entropy, MSE, peak signal to noise ratio and histogram are measured. It is observed that the proposed system attains improved efficiency, security and imperceptibility properties of information hiding from the results.