A new public-key authentication watermarking for binary document images resistant to parity attacks

An authentication watermarking technique (AWT) inserts some hidden data into an image in order to detect any accidental or malicious image alteration. Recent papers have proposed some cryptography-based AWTs for binary and halftone images, but none of them seems to be well-suited for public-key authentication of binary document images. Many of the previous public-key AWTs for binary images can be assaulted by "parity attacks." This paper proposes a new AWT for binary document images that can detect any modification of the watermarked document, even a single pixel flipping. Moreover, both its secretand public-key versions are completely immune against parity attacks. Document images watermarked by the proposed technique present high visual quality, without salt-and-pepper noise.