The Realizations of Steganography in Encrypted Domain

TL;DR

This paper introduces steganography in encrypted domains (SIED) for secure secret communication within ciphertexts, analyzing various application modes, security levels, and practical schemes based on reversible data hiding techniques.

Contribution

It proposes a novel SIED framework, classifies application modes, defines security standards, and presents four practical schemes with different security levels.

Findings

Four application modes of SIED are classified.

Four security levels for SIED are defined.

Four practical SIED schemes are developed and analyzed.

Abstract

With the popularization and application of privacy protection technologies in cloud service and social network, ciphertext has been gradually becoming a common platform for public to exchange data. Under the cover of such a plat-form, we propose steganography in encrypted domain (SIED) in this paper to re-alize a novel method to realize secret communication Based on Simmons' model of prisoners' problems, we discuss the application scenarios of SIED. According to the different accesses to the encryption key and decryption key for secret mes-sage sender or receiver, the application modes of SIED are classified into four modes. To analyze the security requirments of SIED, four levels of steganalysis attacks are introduced based on the prior knowledge about the steganography system that the attacker is assumed to obtain in advance. Four levels of security standards of SIED are defined correspondingly. Based on the existing reversible data hiding techniques, we give four schemes of SIED as practical instances with different security levels. By analyzing the embedding and extraction characteris-tics of each instance, their SIED modes, application frameworks and security lev-els are discussed in detail.