Predictable Rain? Steganalysis of Public-key Steganography Using Wet Paper Codes

Carnein Matthias, Schöttle Pascal, Böhme Rainer


Abstract
Symmetric steganographic communication requires a secret stego-key pre-shared between the communicating parties. Public-key steganography (PKS) overcomes this inconvenience. In this case, the steganographic security is based solely on the underlying asymmetric encryption function. This implies that the embedding positions are either public or hidden by clever coding, for instance using Wet Paper Codes (WPC), but with public code parameters. We show that using WPC with efficient encoding algorithms may leak information which can facilitate an attack. The public parameters allow an attacker to predict among the possible embedding positions the ones most likely used for embedding. This approach is independent of the embedding operation. We demonstrate it for the case of least significant bit (LSB) replacement and present two new variants of Weighted Stego-Image (WS) steganalysis specifically tailored to detect PKS using efficient WPC. Experiments show that our WS variants can detect PKS with higher accuracy than known methods, especially for low embedding rates. The attack is applicable even if a hybrid stegosystem is constructed and public-key cryptography is only used to encapsulate a secret stego-key.

Keywords
public-key steganography, weighted stego-image steganalysis, wet paper codes



Publication type
Conference Paper

Peer reviewed
Yes

Publication status
Published

Year
2014

Conference
ACM Workshop on Information Hiding and Multimedia Security (IHMMSec '14)

Venue
Salzburg, Austria

Book title
Proceedings of the 2nd ACM Workshop on Information Hiding and Multimedia Security (IH & MMSec '14)

Editor
Unterweger, Andreas; Uhl, Andreas; Katzenbeisser, Stefan; Kwitt, Roland; Piva, Alessandro

Start page
97

End page
108

Publisher
ACM

Place
New York, NY, USA

Language
English

ISBN
978-1-4503-2647-6

DOI