Tamper-Localization Watermarking with Systematic Error Correcting Code

This paper presents an authentication watermarking method which can localize the tampering regions in fine granularity. Unlike the previous block-wise tampering-localization watermarking methods which embed authentication messages including the image index, block index and block hash, the present scheme encodes the block hash with a systematic error correcting code and then merely embeds the parity symbols into the blocks. At the verification stage, each block hash can be recovered with the embedded parity symbols if the number of tampered blocks is within a threshold value. Since the total size of parity symbols is much smaller than the total size of block hashes, the present paper reduces the size of the authentication message greatly and hence increases the localizing granularity or security strength.