On Security of Compressed Gray Scale Image Using Joint Encryption and Data Hiding
Amit Phadikar, Santi P. Maity · Information Security Journal A Global Perspective · 2011
This paper proposes a novel scheme that integrates quality access control and tracking of illicit distribution of digital image(s) in a single platform. The goal is achieved by (1) modulating some of the valuable Discrete Cosine Transform (DCT) coefficients of the compressed data followed by (2) embedding a binary watermark (fingerprint) as tracking information using Quantization Index Modulation (QIM). The data modulation process serves the purpose of access control so that an unauthorized user is unable to enjoy proper visual quality. On the other hand, embedded watermark tracks illicit distribution. The coefficients to be modulated are selected pseudo randomly using a secret key (K). Before embedding, the watermark is encoded by applying convolution coding that reliably identifies colluder(s) involved in time varying (intelligent) collusion operation. Simulation results have shown the validity of the above claims without affecting compatibility with standard JPEG coding scheme.