Bittorrent developer builds tool that hides message in random file

Bram Cohen, the software developer who pioneered the bittorrent protocol, has developed a new steganography tool called DissidentX. According to Cohen, DissidentX makes it significantly more difficult to detect deliberate manipulations in files.

In steganography, information is hidden in apparently harmless objects. This encryption method can be used, for example, to hide a message in an image. The tool Cohen is working on uses a method where a message can be hidden in any type of file. The bittorrent creator therefore mainly calls DissidentX a framework where the emphasis is on hiding the message as well as possible, he says in an interview with Forbes.

DissidentX uses a method where the recipient can retrieve the data that is hidden by generating a hash of the parent file. This hash contains the message, which can then be decrypted with the recipient’s key. According to Cohen, DissidentX also manages to hide the data to be hidden in a file through unpredictable patterns, which further complicates detection. In addition, it is possible to hide different messages for different recipients, while the tool also contains additional mechanisms to reduce detection of the use of steganography.

Just like with TrueCrypt, for example, it is possible with DissidentX to apply different encryption layers. This creates a mechanism of ‘credible refutability’, whereby a person, for example, gives up key A, while another invisible encrypted container requires key B.

Cohen says he started DissidentX after Haystack, another steganography tool, was found to be unsafe. The software was used by political dissidents in Iran, among others. Cohen believes that if his DissidentX software is further developed, it can be used by human rights organizations, for example, to communicate securely via the Tor network.