Encryption-enhanced reversible watermarking for medical images via prediction and RC4 encryption

Abstract

Watermarking and encryption are complementary tools for information security. We propose a combined encryption and reversible watermarking scheme which has the advantages of both encryption and watermarking for medical images. The method uses Sachnev et.al's prediction and sorting scheme for watermark embedding which is the best in watermarking literature with a modification to improve the embedding capacity slightly. The encryption is done using RC4algorithm which is a stream cipher capable of processing variable sized blocks. Watermarking will protect the ownership identity and everything it is supposed to but encryption will be highly desirable in the case of medical images to ensure authenticity of the same.

An Image Watermarking Method Using Discrete Tchebichef Transform and Singular Value Decomposition Based on Chaos Embedding

“…On the security side, in various watermarking studies previously proposed encryption techniques on the watermark before being embedded. Watermarks can be encrypted by a variety of methods, from the simplest only with XOR operations, then to DES, RC4, or AES [19][20][21], and currently the most popular is the scramble technique based chaotic-map [22,23]. Scramble technique is more suitable for encrypting multimedia data such as images because it is resistant to differential and statistical attacks, as well as minimizing the possibility of over computing due to the complexity of calculations [24,25].…”