Robust Image Encryption Scheme for Biometric Finger Print Images using Bit Planes, DWT & Cubic Map

Abstract

UIDAI employs biometric finger print system to generate omnipresent identity card for Indian citizens. Biometric finger print images are therefore accepted by all Banks and Government offices to established identity of the person. Furthermore lots of private organizations employ biometric finger print system to record attendance and personal information of its employees. Consequently these biometric finger print images are stored and transmitted widely enhancing risk of misusing user personal information and cybercrimes. In this paper, robust image encryption scheme for biometric finger print images is proposed through bit planes; cubic map and DWT. The complete encryption or decryption process can be decomposed into three methods. Firstly each 8-bit biometric image is separated into 8 bit planes corresponding to each bit. Secondly DWT is applied that further encrypts the image in frequency domain by manipulating LL subbands through cubic map. Finally inverse DWT (IDWT) converts each image into spatial domain which is synthesis to from a single 8-bit encrypted image. The robustness of the proposed encryption scheme is measured through entropy, correlation coefficient, number of pixel change rate (NPCR) and unified average change intensity (UACI). Furthermore the proposed encryption scheme is also tested successfully for compression and noise attacks.