Abstract: Using data hiding technique one can send the information to the accurate user without noticing to third person. Data can be hidden using different cover Medias, like video, audio, images or text. As an Internet based communications of images have increased, encryption of images has become very important way to protect images especially on the Internet. This work proposes a new scheme for hiding data in encrypted image with LSB substitution. It consists of image encryption, data embedding and data-extraction/image-recovery phases. A content owner encrypts the original image using an encryption key. A data-hider changes the least significant bits of the encrypted image using a data-hiding key to create a sparse space to accommodate some additional data. At the receiver side, the data that is embedded in the created space can be easily retrieved from the encrypted image using the data-hiding key. Since the data embedding only affects the LSB, a decryption with the encryption key can result in an image similar to the original version. When using both of the encryption and data-hiding keys, the embedded additional data can be successfully extracted and the original image can be perfectly recovered.
Keywords: Data hiding, data extraction, image encryption, reversible data hiding