VLSI ARCHITECTURE OF AN INVISIBLE WATERMARKING UNIT FOR A BIOMETRIC-BASED SECURITY SYSTEM IN A DIGITAL CAMERA Saraju P. Mohanty O. B. Adamo Elias Kougianos Email: smohanty@cse.unt.edu Email: oba0002@unt.edu Email: eliask@unt.edu Computer Science and Engineering Computer Science and Engineering Electrical Engineering Technology University of North Texas, TX 76203. Univ of North Texas, TX 76203. Univ of North Texas, TX 76203. Abstract— Due to the need for increased border security, we present a novel system in the form of a digital camera that embeds biometric data into an image. The embedding process is performed using an invisible watermarking algorithm that allows for verification of the image as well as the identity of the carrier. This paper presents an area efficient and high performance VLSI architecture implementing the invisible watermarking algorithm towards the development of the camera. I. I NTRODUCTION In order to improve document and border security, it is proposed to include biometric data such as fingerprints, sig- natures, etc., in the electronic passport [1]. The key objectives of the passport are to identify the owner, authenticate the document, and copyright the passport. However, there are continuous risks of unauthorized access and modification to the data contained within the passport. We propose that an effective solution to combating unauthorized access such as “skimming” and “eavesdropping” is the judicious use of watermarking [2] and encryption [3]. We have introduced the concept of a secure digital camera (SDC) that has both watermarking and encryption capabilities in [2]. In this paper we present a novel architecture of an invisible watermarking unit which will be integrated in our previous SDC work. We employed the use of parallelism and resource-sharing to meet the timing and area constraints. The FPGA prototype version of the proposed architecture is estimated to be operating at 256MHz . Earlier in [4] a software based biometric system were presented and cameras, such as the PhotoPC 3000Z/800Z, with watermarking capabilities were commercially produced (but discontinued.) II. SECURE BIOMETRIC DATA PROCESSING IN OUR SDC The passport image is watermarked with biometric data during the “enrollment process” as shown in Fig. 1. When an individual applies for a passport or ID card, our proposed SDC is used to invisibly watermark the individual’s binary biometric data into the applicant’s image captured by it. The “verification process” is needed during the authentica- tion of the individual’s identity and picture. At the checkpoint, the image is acquired by scanning the passport and the encrypted compound biometric data is extracted from the acquired image and decrypted using the original key that was earlier stored in a secure external storage, as shown Fig. 2. The biometric data is then authenticated with the biometric data of the passport’s owner through invisible watermarking. Fingerprint Iris Signature key Invisible Watermark Visible Watermark MUX Encrypted Binary image Barcode AES Host Image Host Image AES Serial Number of camera Compound Biometric Image Mixer Converter A/D Lens person Image stored in passport secure channel Fig. 1. The Enrollment Process Encrypted Biometric Data Invisble Watermark Extraction External Storage (Encrypted Host Image/ Key) Decryption Mixer Comparator From passport Biometric Data Mixed Image From Passport Host Image Biometric Data From passport owner 1 or 0 for verification Fig. 2. The Verification Process III. SECURE I NVISIBLE WATERMARKING ALGORITHM As presented in Fig. 3, the algorithm inserts a binary image as a watermark into the host image (passport photo). The watermark is inserted in the perceptually significant compo- nents so that the watermarked image is robust with respect to common attacks. After the preprocessing phase, the host image I is divided into 8 × 8 blocks and the DCT (discrete cosine transform) of each block is calculated. For the insertion phase, the DC component c 00 and the three low frequency components c 00 , c 10 , and c 11 are considered for insertion. The watermark (biometric image) is partitioned to the same number of blocks as the host image (passport photo) with a block size of 2 × 2. If the watermark’s binary value in block k is w ij (k) the insertion process is carried out as, ∀i, j, and k [5], c ′ ij (k)=  c ij (k)(1 + α ij ) if w ij (k)=1, c ij (k)(1 - α ij ) if w ij (k)=0. A value of 0.1 is used for α ac and 0.02 for α dc . IV. OUR PROPOSED VLSI ARCHITECTURE The architecture of the invisible watermarking chip consists of 3 distinct modules: insertion module, extraction module, and controller module. The structures of the extraction and insertion modules are very similar, so due to lack of space we will present the insertion module only. The insertion module performs the watermarking insertion process. The architecture of this module is shown Fig. 4(a),