Journal of Cryptology

, Volume 27, Issue 1, pp 23-44

First online:

A One-Time Stegosystem and Applications to Efficient Covert Communication

  • Aggelos KiayiasAffiliated withDepartment of Computer Science and Engineering, University of Connecticut
  • , Yona RaekowAffiliated withFraunhofer Institute for Algorithms and Scientific Computing
  • , Alexander RussellAffiliated withDepartment of Computer Science and Engineering, University of Connecticut
  • , Narasimha ShashidharAffiliated withDepartment of Computer Science, Sam Houston State University Email author 

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We present the first information-theoretic steganographic protocol with an asymptotically optimal ratio of key length to message length that operates on arbitrary covertext distributions with constant min-entropy. Our results are also applicable to the computational setting: our stegosystem can be composed over a pseudorandom generator to send longer messages in a computationally secure fashion. In this respect our scheme offers a significant improvement in terms of the number of pseudorandom bits generated by the two parties in comparison to previous results known in the computational setting. Central to our approach for improving the overhead for general distributions is the use of combinatorial constructions that have been found to be useful in other contexts for derandomization: almost t-wise independent function families.

Key words

Information hiding Steganography Data hiding Steganalysis Covert communication