Secret Storage Hides Encrypted Data In Plain Sight

April 28, 2011 – 6:57 AM

A new data storage technique provides security, as well as plausible deniability. Whereas encrypted data can be easily spotted–if not necessarily decrypted, without obtaining the decryption keys from the device owner–the new technique disguises stored data as random disk fragmentation. When implemented correctly, a digital forensic investigator might not even know that secret information was stored on the drive.

The new technique was first detailed in “Designing a cluster-based covert channel to evade disk investigation and forensics,” a recent paper written by researchers from the University of Southern California at Los Angeles and the National University of Science and Technology (NUST) in Islamabad, Pakistan.

“There could be a number of potential uses for this technology, but the main strength of our technique lies in its ability to conceal information in cases where encryption cannot be used–e.g., where the presence of encrypted data would appear suspicious and may be deemed an unacceptable risk to the communicating parties,” said report co-author Fauzan Mirza, a communication systems engineering professor at NUST, in an email interview. “The obvious application of these techniques would be among people or organizations that need to protect information against powerful–well-resourced–adversaries, such as spies, terrorists, whistleblowers, political groups, etc.”

This type of covert channel could also have enterprise security applications, such as creating a covert password safe. Likewise, “it could also be used to implement a software copy protection mechanism or information tracking/watermarking mechanism,” or even as part of a data leakage protection mechanism, said Mirza. “We did not go into these applications, since–as academics–we wanted to bring to light the simplicity and novelty of the idea, rather than dwell on the applications. We left that part to the readers.”


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