| In the era of information explosion,the information security is becoming a important and challageing task with the rapid development of internet and communication devices.Many researchers figured out that the inherent character of the propagatin of light,including its parallism,the simulanteous modulation of its phase and its amplitude and etc,made the optical image encrypion become a promising tool for information security due to its parallism and its high dimension.Many acticles about optical image encryption(OIE)have been published in recent years,but OIE still needs many effects to be studied deeply and to be applied optically in prctiacl application.From OIE merged,much attention is focued on double random phase encryption(DRPE).Although DRPE has the advantages,such as the simple process of encryption and decryption,and the high decryption quality,DRPE has disadvantages too.The light is in the form of complex matrix with amplitude part and phase part,which results in large amount of storage and difficulty in recroding.To solve the problem,Chen introduced coherent diffraction imaging into OIE,in which recording several intensity images as cipertexts is sufficent for decoding high-quality decrypted image.The intensity images are conventient for storage and transmittacne,furtherly,the number of cipertexts is increased and the space of encryption keys is enlarged so that the security of this system is enhanced significantly.First of all,we introduce the basic theory of optical diffraction and OIE.Then,we give a detailed description and simulation about a diffraction encryption system based on 3 ciphertexts captured from three distances.Secondly,we described a system using just one ciphertext with some redundant information,which saved the burden of storage and transmittance.Finally,we figured out the weakness of the above mentioned systems,and proposed a novel and improved system.We give a detailed description,and make simulation to verify its effectiveness. |
PDF Full Text Request