A Novel Elliptic Curve Cryptography Based Approach of Re-watermarking for Cheque Truncation System

Abstract

Cheque Truncation System (CTS) is a technique of preventing tangible movement of cheque by substituting it with a digital image, with an aim for secure and faster clearance. For the first time re-watermarking is applied for authenticating transactions in CTS. Methodology for the proposed approach splits the host image (I_h) into two layers (L). In L₁ cheque details are fused with two image color channels to form a composite message (C_m). Secure hash algorithm (SHA-512) is applied to C_m to generate a unique message digest (M_d). Elliptic Curve Digital Signature Algorithm (ECDSA) is applied to M_d to create a digital signature. The signature is embedded by exploiting Human Visual System (HVS) color channel sensitivity in equally parted mode. In L₂, joint secret is established to form key using Elliptic Curve Diffie Hellman Protocol (ECDHP). Advanced Encryption Standard (AES) is applied to user details intricate in the transaction. Encrypted contents are then inserted in L₂ by applying Discrete Cosine Transform (DCT). Experimental results state solution to integrity concerns by using ECDSA with SHA-512, reaction to security issues by AES and the response to key distribution problem by ECDHP. An effective semi-blind CTS is perceived with PSNR between 59-60 dB.

Keywords:

• Advanced Encryption Standard
• Cheque Truncation System
• Discrete Cosine Transform
• Elliptic Curve Diffie Hellman Protocol
• Elliptic Curve Digital Signature Algorithm
• Re-watermarking