Abstract
Steganographic protocols enables one to “embed” covert messages into inconspicuous data over a
public communication channel in such a way that no one, aside from the sender and the intended receiver
can even detect the presence of the secret message. In this paper, we provide a new provably-secure,
private-key steganographic encryption protocol. We prove the security of our protocol in the complexity-
theoretic framework where security is quantified as the advantage (compared to a random guess) that
the adversary has in distinguishing between innocent covertext and stegotext that embeds a message of
his choice. The fundamental building block of our steganographic encryption protocol is a “one-time
stegosystem” that allows two parties to transmit messages of length at most that of the shared key with
information-theoretic security guarantees. The employment of a pseudorandom generator (PRG) permits
secure transmission of longer messages in the same way that such a generator allows the use of one-time
pad encryption for messages longer than the key in symmetric encryption. In this paper, we initiate
the study of employing randomness extractors in a steganographic protocol construction to embed secret
messages over the channel. To the best of our knowledge this is the first time randomness extractors have been applied in steganography
Original language | English |
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Publication status | Published - 2009 |