Multimedia Security 2

7Data Hiding in the Encrypted Domain

Pauline PUTEAUX and William PUECH

LIRMM, Université de Montpellier, CNRS, France

In recent years, the development of cloud computing has meant that more and more users are uploading their personal data to remote servers. However, this can result in major security breaches that pose a constant risk in terms of confidentiality, authentication and integrity. To mitigate these problems, multimedia data may be encrypted prior to transmission and storage. In this chapter, we focus on the problem of processing this encrypted multimedia data, specifically on data hiding in the encrypted domain.

7.1. Introduction: processing multimedia data in the encrypted domain

For security reasons, more and more digital data are encrypted before being transferred or archived. During the transmission or archiving process, these data often need to be analyzed or processed directly in the encrypted domain, without knowing its original, clear content (Erkin et al. 2007). Figure 7.1 shows some of the main applications for multimedia data processing in the encrypted domain: sharing visual secrecy between multiple people; data hiding in encrypted multimedia data (so that the person inserting or extracting data does not have access to its original content); recompression of crypto-compressed images or videos (for secure transmission over low-speed networks); indexing and searching for multimedia content in encrypted databases; and the correction of noisy encrypted images. ...