A method of and an apparatus for verifying authenticity of a target authentication device comprising a reference pattern having a characteristic frequency and a security pattern, the security pattern comprises an embedded security device that is coded with phase modulation information. The method comprises extracting frequency domain data from an image of the target authentication device to facilitate verification of authenticity of the target authentication device. The method provides a very effective end expedient mechanism for verifying authenticity of a moire or moire like authentication device to combat counterfeiting.