EXTRACTING ATTACK TO LSB STEGANOGRAPHY OF JPEG IMAGES

摘要

The "extracting attack" on steganography is a kind of steganalysis, the purpose of which is to extract the hidden message or recover the stego-key. In this paper we discuss how to recover the key of LSB JPEG steganographic schemes such as "JP hide and seek". In fact, extracting attack can be treated as a special kind of cryptanalysis, and we solve this problem by using both traditional steganalysis and traditional cryptanalysis. Our approach is to build a set as a measure, and this measure have some advantage of accordant probability with the correct key, so the correlation attack of cryptanalysis can be used to identify the stegokey. Experiments show that the search speed is 6400-8000 keys per second. This speed would allow us to search through all numerical passwords of length up to 16 bit keys in about 8 seconds.