Cryptology ePrint Archive: Report 2004/246

Upper and Lower Bounds on Black-Box Steganography

Nenad Dedic and Gene Itkis and Leonid Reyzin and Scott Russell

Abstract: We study the limitations of steganography when the sender is not using any properties of the underlying channel beyond its entropy and the ability to sample from it. On the negative side, we show that the number of samples the sender must obtain from the channel is exponential in the rate of the stegosystem. On the positive side, we present the first secret-key stegosystem that essentially matches this lower bound regardless of the entropy of the underlying channel. Furthermore, for high-entropy channels, we present the first secret-key stegosystem that matches this lower bound statelessly (i.e., without requiring synchronized state between sender and receiver).

Category / Keywords: steganography, covert communication, rejection sampling, lower bound, pseudorandomnness, information hiding, huge random objects

Date: received 22 Sep 2004, last revised 4 Jun 2008

Contact author: reyzin at cs bu edu

Available format(s): Postscript (PS) | Compressed Postscript (PS.GZ) | PDF | BibTeX Citation

Note: This paper incorporates and supersedes report 2003/093. Extended abstract of this paper appears at TCC 2005. This is the full version, to appear in the Journal of Cryptology (Feb. 29 2008 revision clarifies the lowerbound proof and makes other, minor, changes; Jun 4 2008 revision corrects typos).

Version: 20080604:204822 (All versions of this report)

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