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DissidentX a Steganography Tool From Bittorrent Creator

Bram Cohen, better known for bringing us the BitTorrent protocol, much maligned as public opinion more often than not associates it with piracy, has developed DissidentX a steganographic tool.

“Stenography is the art and science of encoding hidden messages in such a way that no one, apart from the sender and intended recipient, suspects the existence of the message. It is a form of security through obscurity.”

We are seeing it’s use for both good, such as DissidentX that aims at providing political dissidents a way to communicate covertly, and bad such as obfuscation in malware samples, the Alureon Trojan comes to mind.

A simplified example would be a steganographically modified image, that appears perfectly normal, but upon closer inspection has a few random pixels that are of a different color.

To the untrained eye, these pixels could be static, maybe a bit of file corruption, when in fact they are a hidden message.

Traditional steganographic techniques tend not to be very stealthy and can be detected.

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Bram Cohen

Brams new tool takes steganography to a whole new level and hopes to make the fact there’s a secret message even more difficult to detect.

It uses a new form of steganography that leverages cryptographic hashes to make detection more difficult. One example of the many new techniques it uses is the absence of text in a seed document can be used as part of the steganographic process.

This makes collaborating on the creation of an innocent looking document a possible covert channel! “I took that last paragraph out, I didn’t like it… Wink, Wink.”

DissidentX also allows for multiple messages to be encoded in the same document, providing a defense against “rubber hose decryption” my favorite kind! This is where the secret is extracted by force, with torture or by beating the recipient with a rubber hose, hence the name.

It’s interesting to see tools such as steganography, tools typically used to evade surveillance and repressive regimes making a resurgence.


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