title: Comment on "Optical image encryption with Hartley transforms".
abstract: We numerically demonstrate that the image encryption algorithm with intensity random filtering in the Hartley domain proposed in a recent Letter by Chen and Zhao [Opt. Lett.31, 3438 (2006)] has the problem of low security. Original image information can be visually revealed only by an inverse Hartley transform without any decryption key.
authors.affiliation: Harbin Institute of Technology, Department of Physics, Harbin, China.
authors.forename: Zhengjun
authors.initials: Z
authors.lastname: Liu
authors.forename: Shutian
authors.initials: S
authors.lastname: Liu