Abstract
We propose an asymmetric cryptosystem based on optical scanning cryptography (OSC) and elliptic curve cryptography (ECC) algorithm. In the encryption stage of OSC, an object is encrypted to cosine and sine holograms by two pupil functions calculated via ECC algorithm from sender’s biometric image, which is sender’s private key. With the ECC algorithm, these holograms are encrypted to ciphertext, which is sent to the receiver. In the stage of decryption, the encrypted holograms can be decrypted by receiver’s biometric private key which is different from the sender’s private key. The approach is an asymmetric cryptosystem which solves the problem of the management and dispatch of keys in OSC and has more security strength than the conventional OSC. The feasibility of the proposed method has been convincingly verified by numerical and experiment results.
Introduction
Optical image encryption has attracted much attention in recent years because of its inherent capability of high parallelism and multidimensional freedoms (amplitude, phase and polarization). Since Refrégiér and Javidi first proposed the double random phase encoding (DRPE) technique1, researchers have introduced many extended optical encryption methods such as a series of optical transforms2,3,4,5, digital holography6,7,8, joint transform correlator9,10,11 and ghost imaging12,13,14, etc. Furthermore, optical scanning cryptography (OSC)15,16,17,18,19 envisioned by Poon has become a prospective technology. Different from that of other CCD-based hologram acquisition systems, it can capture the hologram of a physical object with a fast scanning mechanism along with single-pixel recording. Indeed, some encryption systems have been proposed based on OSC. Yan et al. obtained experimental results of encryption using fingerprint keys18. Furthermore, they first demonstrated optical cryptography of 3-D object images in an incoherent optical system with biometric keys19