Variable Order Weighted Unitary Transforms Encryption Algorithm Of Image

In this paper, we establish a new kind of the weighted unitary transformationoperator, that is, the variable order weighted unitary transforms. And then we providean optical image encryption method—the variable order weighted unitary transformsencryption algorithm. This transform keeps the mathematical properties of theweighted unitary transforms, that is, the continuity, the linear character, theinterchangeability and the unitarity. And these properties provide the theoretical basisfor the encryption system. Compared with the recent encryption method, this methoduses the order as the secret key and the selection scope of all the parameters can beexpanded from the real number filed to the real vector space. This method hasimportant theoretical significance in the field of optical information security andinformation processing, without increasing the computational complexity. The paperalso analyses the security features from the properties of the method itself and theability to resist the outside crack from. That is, losing part of the cipher or sufferingfrom noise pollution, the system can still restore the original image. On the other hand,the mathematical properties lead to the diversity of the decryption process. It ensuresthe safety and the statistical property of the encryption system.The method we researched combines with the random phase encoding,comparing with the double random phase encoding, it reduces the complexity. Inevery integral process of the encryption method, it produces different random phasematrixes and because of the randomness of the matrix, every cipher is the relativeindependent. Then from the angle of the probability and the statistic, even if stealingpart of the relative secret keys, the eavesdropper cannot guess the other secret keys, sohe cannot restore the original image. These all can add the difficulty of decipher, so asto improve the security of the system.