Asymmetric image optical encryption under spatially incoherent illumination

In this paper new method of asymmetric optical encryption is presented. It is based on the double encryption using spatially incoherent illumination: to obtain a ciphertext a plaintext is encoded twice, first time by sender, second time-by recipient. This way no exchange of encryption keys is required. Two variants of this method were analyzed: one in which both encryption procedures are implemented optically and another one in which the first operation is done optically and the second one-numerically. Both variants were numerically simulated and the latter one was implemented optically. Results of numerical and optical experiments demonstrate high quality of decrypted images (decoding error 0.19), thus confirming usability of proposed method.