一种图像hash算法的实现.doc

一种图像Hash算法的实现

摘要：随着图像处理技术的发展，人们对数字图像内容的更改和编辑变得非常容易，且不留痕迹，用眼睛很难判定其真实性。当数字图像中包含有政治、军事、商业、监控、个人、及医疗等敏感的或重要的信息时，必须有相关的技术对其进行认证。面向认证的图像Hash是图像认证的一种主要的技术手段。近年来受到了广泛的重视并出现了多种图象Hash算法。其中Fridrich等人提出的一种鲁棒的图象Hash算法被认为是经典的图象Hash算法之一。
面向认证的图像Hash主要包括以下三个性能指标：1) 稳健性，2) 脆弱性， 3) 安全性，其是图像Hash的核心性能指标。为了更深入的研究面向认证的Hash算法的性能，需要实现一些经典的算法。本论文深入地了解Fridrich所提出的算法，并实现了该算法。在实现的过程中重点解决了阈值的选取问题，使图象Hash值中的0，1个数尽可能相同。

关键词：图像认证 图像安全 密钥保护 Hash函数

Image identify based on Hash function
Abstract: With the development of the technology of the processing of image, it is easy for people to change and edit the image and that is invisible to eyes. If the content of the image involved the some critical information such as politician, military, business and medical treatment, We need a kind of technology to identify the picture. Hash function which can identify the image is a major way. There are a lot of Hash functions in recent years. One of them which was offered by Fridrich with robust is widely recognized as a classical arithmetic..
  There are three major indexes of the Hash function : (1)stability (2) frangibility (3)safety. We need to realize some classical arithmetic in order to study the Hash function for image further. This theory analysis the Fridich’s Hash function, and realize the Hash. During the process, how to calculate a threshold so as to the number of the 1 and 0 are approximately equal.