An arithmetic based on the shape of dots for halftone

To solve the defects which called interference fringes (in printing it is called moiré) in printed image that caused easily in halftoning to achieve information hiding. An arithmetic was given that based on the shape of halftone dots which use MQAM(Multiple Quadrature the Amplitude Modulation) to complete information hiding in halftoning. This method not only can solve the moiré problems effectively and optimize the printed image quality, but the information hiding capacity can also be greatly improved. The moiré can be eliminated by using a pseudo-random scrambling method to encrypt the plaintext information, that the ciphertext can be represented by different shape of dots.