id="p0005">A multiple-image fusion and watermarking using interference is proposed.
id="p0010">The encrypted images are fused with gray cover image to get watermarked image.
id="p0015">The secret color images are protected by encrypted images as well as cover image.
id="p0020">Each user has an identity key and two phase-only keys as three decryption keys.
id="p0025">Numerical simulations demonstrate and validate the feasibility of the proposed method.