title: Optical hierarchical authentication based on interference and hash function.
abstract: We propose a method to achieve the purpose of hierarchical authentication on the basis of two beams' interference and the one-way hash function. For this security protection system, only if the "phase key" and the password-controlled "phase lock" of a user are verified simultaneously can one obtain a permission to visit the confidential resources of the system. Moreover, this scheme can not only check the legality of the users but also verify their identity levels so as to grant them corresponding hierarchical access permissions. The authentication process is straightforward; the phase key and the password-controlled phase lock of one user are loading on two spatial light modulators in advance, by which two coherent beams are modulated and then interfere with each other at the output plane leading to an output image. By comparing the output image with all the standard certification images in the database, the system can thus verify the user's identity. However, the system designing process involves an iterative modified phase retrieval algorithm. For an authorized user, a phase lock is first created based on a "digital fingerprint," which is the result of a hash function on a preselected user password. The corresponding phase key can then be determined by use of the phase lock and a designated standard certification image. Theoretical analysis and computer simulations both validate the effectiveness of our method.
authors.affiliation: College of Optoelectronic Engineering, Key Laboratory of Optoelectronics Devices and Systems, Education Ministry of China, Shenzhen University, Shenzhen, China.
authors.forename: Wenqi
authors.initials: W
authors.lastname: He
authors.forename: Xiang
authors.initials: X
authors.lastname: Peng
authors.forename: Xiangfeng
authors.initials: X
authors.lastname: Meng
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Liu