Surmounting the Effects of Lossy Compression on Steganography

Abstract

Steganographic techniques can be used to hide data within digital images with little or no visible change in the perceived appearance of the image and can be exploited to export sensitive information. Since images are frequently compressed for storage or transmission, effective steganography must employ coding techniques to counter the errors caused by lossy compression algorithms. The Joint Photographic Expert Group (JPEG) compression algorithm, while producing only a small amount of visual distortion, introduces a relatively large number of errors in the bitmap data. It is shown that, despite errors caused by compression, information can be steganographically encoded into pixel data so that it is recoverable after JPEG processing, though not with perfect accuracy. 1. Introduction Two techniques are available to those wishing to transmit secrets using unprotected communications media. One is cryptography, where the secret is scrambled and can be reconstituted only by the holder of a...