Стеганография — Stego (Jpeg)


Стеганография — это когда идет передача секретных сообщений, и когда сам факт передачи тщательно скрывается. Это наука развивалась параллельно с криптографией, а зачастую вместе с ней. Для скрытой передачи сообщений как правило нужен «контейнер», алгоритм внедрения и детектор. Контейнером может служить практически любая информация или материал. Вариантов контейнеров может быть множество: фото, видео, звук, текст. Основная задача стеганографии внедрить сообщение так чтобы было невозможно выявить признаки передачи информации в контейнере, при этом может использоваться сжатие и шифрование исходного текста.

JPHIDE and JPSEEK are programs which allow you to hide a file in a jpeg visual image. There are lots of versions of similar programs available on the internet but JPHIDE and JPSEEK are rather special. The design objective was not simply to hide a file but rather to do this in such a way that it is impossible to prove that the host file contains a hidden file. Given a typical visual image, a low insertion rate (under 5%) and the absence of the original file, it is not possible to conclude with any worthwhile certainty that the host file contains inserted data. As the insertion percentage increases the statistical nature of the jpeg coefficients differs from «normal» to the extent that it raises suspicion. Above 15% the effects begin to become visible to the naked eye. Of course some images are much better than others when used a host file — plenty of fine detail is good. A cloudless blue sky over a snow covered ski paradise is bad. A waterfall in a forest is probably ideal.

It is also available as a Windows and DOS version ready to run. This is not because I am a Windows/DOS fan but rather that the products need to reach a wider audience. My main concern over Windows/DOS is not that they are making a few people very very rich but rather that the source code is not available for scrutiny and there may well be built in trojan horses. Be that as it may they are a fact of life and in any case it was fun learning visual C++.


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