Polish scientists hope steganography could help beat authoritarian Web censorship
Now, that’s an idea I like (via iRevolution): sneaking secret messages in Web traffic to beat down the censors in authoritarian countries! The smart folks at the Institute of Telecommunications in Warsaw, Poland have been experimenting with steganography (the art of hiding a secret message in an open medium) to help us think about new ...
Now, that's an idea I like (via iRevolution): sneaking secret messages in Web traffic to beat down the censors in authoritarian countries! The smart folks at the Institute of Telecommunications in Warsaw, Poland have been experimenting with steganography (the art of hiding a secret message in an open medium) to help us think about new tools to bypass censorship restrictions:
Now, that’s an idea I like (via iRevolution): sneaking secret messages in Web traffic to beat down the censors in authoritarian countries! The smart folks at the Institute of Telecommunications in Warsaw, Poland have been experimenting with steganography (the art of hiding a secret message in an open medium) to help us think about new tools to bypass censorship restrictions:
Wojciech Mazurczyk, along with Krzysztof Szczypiorski and Milosz Smolarczyk, have already worked out how to sneak messages into internet phone calls, and now the Warsaw team have turned their attention to the internet’s transmission control protocol (TCP).
Web, file transfer, email and peer-to-peer networks all use TCP, which ensures that data packets are received securely by making the sender wait until the receiver returns a "got it" message. If no such acknowledgement arrives (on average 1 in 1000 packets gets lost or corrupted), the sender’s computer sends the packet again. This scheme is known as TCP’s retransmission mechanism – and it can be bent to the steganographer’s whim, says Mazurczyk.
Their system, dubbed retransmission steganography (RSTEG), relies on sender and receiver using software that deliberately asks for retransmission even when email data packets are received successfully. "The receiver intentionally signals that a loss has occurred. The sender then retransmits the packet but with some secret data inserted in it," he says in a preliminary research paper (www.arxiv.org/abs/0905.0363). So the message is hidden among the teeming network traffic.
Could a careful eavesdropper spot that RSTEG is being used because the first sent packet is different from the one containing the secret message? As long as the system is not over-used, apparently not, because if a packet is corrupted the original packet and the retransmitted one will differ from each other anyway, masking the use of RSTEG.
Any other interesting and fresh examples of how steganography or even steganography-like tricks could be used to beat the censors? Most of you will be familiar with the Einstein Blackboard Writing Generator, but is there anything more recent out there?
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