Data Hiding Method Using Adaptive Pixel Pair Matching

Data Hiding or Steganography has been an important communicated network since people started communicating in writing. The main aim in steganography is to hide a secret message within cover media in such a way that an observer cannot detect the presence of contents of the hidden message. Cover images are original images without secret data and after embedding secret data they are called as stego images. Steganography and cryptography are counter parts in digital security the obvious advantage of steganography over Cryptography is that messages do not attract attention to themselves, to messengers, or to recipients. The progress in steganography has also led to many serious problems such as hacking, compression, reformate, etc. Steganography finds its role in attempt to address these growing concerns. We know that, with the use of steganographic techniques, it is possible to hide secret information within images, Audio and video files which is statistically undetectable. This paper proposes a new data embedding technique which uses two pixel sequentially one after another which is kwon as pixel pair matching (PPM) technique. The basic idea of PPM is to use the values of pixel pair as a reference coordinate, and search a coordinate in the neighbourhood set of this pixel pair according to a given message digit. The two pixel is then replaced by the searched coordinate to store the digit. The APPM method offers lower distortion than DE by providing more compact neighbourhood sets and allowing embedded digits in any notational system.