The researchers, from the University of Southern California in Los Angeles and the National University of Science and Technology in Islamabad, Pakistan, say that with this approach they can store sensitive information on a cluster-based filesystem.
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"Under the proposed approach, a covert channel is used to encode the sensitive information by modifying the fragmentation patterns in the cluster distribution of an existing file," says the paper, 'Designing a cluster-based covert channel to evade disk investigation and forensics'.
The paper further adds that as opposed to existing schemes, the proposed covert channel does not require storage of any additional information on the filesystem.
As per the paper a capacity of up to 24 bits/cluster can be achieved on a half-empty disk.