A Joint Encryption/Watermarking System for Verifying the Reliability of Medical Images

Dalel Bouslimi (1) , Gouenou Coatrieux (1) , Michel Cozic (2) , Christian Roux (1)

1 LaTIM - Laboratoire de Traitement de l'Information Medicale
2 Medecom

In this paper, we propose a joint Encryption/Watermarking (E/W) system for the purpose of protecting medical images. This system is based on an approach which combines a substitutive watermarking algorithm, the quantization index modulation (QIM), with an encryption algorithm: a stream cipher algorithm (e.g. the RC4) or a block cipher algorithm (e.g. the AES in CBC mode of operation). Our objective is to give access to the outcomes of the image integrity and of its origin even though the image is stored encrypted. If watermarking and encryption are conducted jointly at the protection stage, watermark extraction and decryption can be applied independently. The security analysis of our scheme and experimental results achieved on 8 bit depth ultrasound images as well as on 16 bit encoded PET images demonstrate the capability of our system to securely make available security attributes in both spatial and encrypted domains while minimizing image distortion. Furthermore, by making use of the AES block cipher in CBC mode, the proposed system is compliant with or transparent to the DICOM standard.

Mots clés: Block Cipher; Encryption; Medical Image; Security; Quantization Index modulation; Stream Cipher; Watermarking

Dalel Bouslimi, Gouenou Coatrieux, Michel Cozic, Christian Roux. A Joint Encryption/Watermarking System for Verifying the Reliability of Medical Images. IEEE Transactions on Information Technology in Biomedicine, 2012, 16 (5), pp.891-899. ⟨hal-00948429⟩