一种基于双光束干涉的分级身份认证方法

提出一种基于双光束干涉的分级身份认证方法. 本方法通过同时验证用户的"口令"和"相位钥"以实现对用户身份的双重安全认证. 它不仅可以判断某个用户是否合法, 还能鉴别出其相应的身份级别, 从而确定并授予其相应的系统访问权限. 认证过程的核心功能组件是一个基于干涉的光学装置, 用户"口令" 控制的"相位锁" 和用户携带的"相位钥" 被分别加载至此装置中的两个空间光调制器(spatial light modulator, SLM), 两束相干光分别经过这两个SLMs的调制后, 在输出面得到一幅干涉图, 它被传送至计算机并与系统数据库中的"认证图像" 进行匹配, 以完成身份的鉴别. 系统的设计则是一个逆向的迭代求解问题, 本文根据事先给定的某个用户的身份级别(对应着某个认证图像)和随机给定的 "相位锁", 利用一种修正的相位恢复算法确定出其对应的"相位钥". 理论分析和仿真实验都证明了此方案是可行而有效的. 关键词： 干涉 傅里叶光学 相位恢复 身份认证

Multi-level authentication based on two-beam interference

A method of multi-level authentication based on two-beam interference is proposed. By verifying the "password" and "phase key" of one user simultaneously, the system can thus achieve the two-factor authentication on the user's identity. This scheme can not only check the legality of one user, but also verify his identity level as an authorized user and then grant the user the corresponding permissions to access the system resources. While operating the authentication process, which largely depends on an optical setup based on interference, a "phase key" and a password-controlled "phase lock" are firstly loaded on two spatial light modulators (SLMs), separately. Then two coherent beams are respectively, modulated by the two SLMs and then interfere with each other, leading to an interference pattern in the output plane. It is recorded and transmitted to the computer to finish the last step of the authentication process: comparing the interference pattern with the standard verification images in the database of the system to verify whether it is an authorized user. When it turns to the system designing process for a user, which involves an iterative algorithm to acquire an estimated solution of an inverse problem, we need to determine the "phase key" according to a modified phase retrieval iterative algorithm under the condition of an arbitrarily given "phase lock" and a previously determined identity level (corresponding to a certain standard verification image). The theoretical analysis and simulation experiments both validate the feasibility and effectiveness of the proposed scheme.