Abstract:As the phase truncation encryption algorithm can not resist the problem of information leakage, this paper proposes an encryption algorithm of phase truncation Fresnel transform and random amplitude mask in order to resist information disclosure. Firstly, the original image is divided into three separate color channels in the Fresnel transform after adding random amplitude mask channel, and then the four channels were Fresnel diffraction truncation. The algorithm not only improves the relevance between the secret key and the ciphertext also eliminates the risk of information leakage through the cascade process. Through simulation experiment and result analysis, this algorithm not only has good robustness against the error distance parameter, the noise of the cipher, the pollution of the block, the leakage of the cipher and the different attack,but also solves the problem of information leakage.