Reversible Data Hiding for Encrypted Images

This article explores a technique called "Reversible Data Hiding" used for encrypting images. Reversible data hiding is a method of embedding data within digital media while maintaining the ability to completely restore the original content without quality degradation. This technique finds applications in various domains including personal privacy protection and digital copyright management. From an implementation perspective, reversible data hiding typically employs algorithms like difference expansion or histogram shifting, where specific pixel values are modified to accommodate hidden data while preserving recovery information. It's important to note that while reversible data hiding can conceal data effectively, it doesn't constitute full encryption since the embedded data can be detected and extracted with proper authorization. The implementation often involves key functions for data embedding and extraction, where the embedding process modifies pixel values in predetermined patterns and the extraction algorithm reverses these modifications. Therefore, when employing reversible data hiding, careful consideration must be given to the trade-offs between privacy requirements and security levels, ensuring appropriate authentication mechanisms are in place for data access.