A NEW SEMI-FRAGILE IMAGE AUTHENTICATION FRAMEWORK COMBINING ECC AND PKI INFRASTRUCTURES
Qibin Sun, Shih-Fu Chang, Kurato Maeno and Masayuki Suto
This paper presents a new semi-fragile framework aiming at extending public key signature scheme from message level to content level. The content signing procedure includes signature generation and watermark embedding while the content authentication procedure includes watermark extraction and signature verification. One main unique contribution is the novel use of error correction coding (ECC) to address the incidental distortions caused by some acceptable manipulations such as lossy compression. Another unique feature is integration of PKI security infrastructure and the hashing mechanism to achieve security and short signatures/watermarks. In the signing procedure, block-based invariant features are extracted from the image content and then encoded by ECC to obtain their corresponding parity check bits (PCB). All PCBs are then embedded back into image as watermarks for the purpose of authentication and locating content alteration. In addition, codewords are concatenated, hashed and finally signed by content owners private key to generate a global cryptographic signature. The authentication procedure is the inverse procedure of signing except using content owners public key for signature verification. After describing the proposed algorithm in details, an implementation example is given by combining our system with invariant features explored in earlier systems.
Keywords digital signature, watermark, authentication, integrity protection, PKI, error correction coding