IMAGE STEGANOGRAPHY USING 4LSB

Abstract

This technology proposes a lossless, a reversible, and a combined knowledge concealing schemes for
ciphertext pictures encrypted by public key cryptosystems with probabilistic and holomorphic properties. Within the
lossless theme, the ciphertext pixels square measure replaced with new values to insert the extra knowledge into many
LSB-planes of ciphertext pixels by multiple layer wet paper secret writing. Then, the embedded knowledge is directly
extracted from the encrypted domain and also the knowledge embedding operation doesn't have an effect on the
cryptography of original plaintext image. Within the reversible theme, a pre-processing is developed to contract the
image bar chart before image cryptography, so the modification on encrypted pictures for knowledge embedding won't
cause any constituent oversaturation in plaintext domain. Though a small distortion is introduced, the embedded
knowledge is extracted and also the original image is recovered from the directly decrypted image. As a result of the
compatibility between the lossless and reversible schemes, the info embedding operations within the 2 manners is at
the same time executed in associate degree encoded image. With the combined technique, a receiver could extract a
region of embedded knowledge before cryptography, and extract another part of embedded knowledge and recover the
initial plaintext image when cryptography.