SECURE COMMUNICATION USING ADAPTIVE PIXEL PAIR MATCHING EMBEDDING METHOD AND NYMBLE SYSTEM

ABSTRACT A secure communication using adaptive pixel pair matching (APPM) embedding method and nymble system is proposed. The data to be secured is made hidden using APPM method and then saved from where only authorised entities can access the file. The basic idea of pixel pair matching (PPM) is to use the values of pixel pair as a reference coordinate, and then search a coordinate in the neighbourhood set of the reference coordinate according to a given message digit. The pixel pair is then swapped by the searched coordinate to conceal the digit. The two data-hiding methods proposed recently based on PPM are Exploiting modification direction (EMD) and diamond encoding (DE). Diamond encoding is the extension of EMD whereas the APPM method is the extension of DE. The proposed method offers lower distortion than DE and other steganographic methods, by providing more compact neighbourhood sets and allowing embedded digits in any notational system. To provide more security to the hidden data, we present Nymble, a system in which servers can blacklist misbehaving users in the network, thereby blocking users without compromising their anonymity. Thus the proposed system ensures that the data to be communicated is more secure Key words:Adaptive pixel pair matching (APPM), diamond encoding (DE), exploiting modification direction (EMD), least significant bit (LSB), optimal pixel adjustment process (OPAP), pixel pair matching (PPM), Nymble, Anonymous blacklisting, privacy