一种可撤销的指纹模板保护方案

A Cancelable Fingerprint Template Protection Scheme

在指纹识别系统中,当用户的指纹模板被攻击者获取时,用户的隐私和安全就可能遭到威胁,因此,保护指纹特征模板已成为一个关键环节。尽管许多指纹模板保护方法已经被提出,但是要设计一个同时满足多样性、可撤销性、不可逆性和高性能的方案仍具有一定的挑战性。文章提出一种可撤销的指纹模板保护方案,将原始指纹细节点信息经过不可逆变换生成可撤销的比特串模板,其主要思想是:任选一个细节点作为基准点,与周围其他所有细节点进行两两比较,得到相对距离和方向场角度差;然后,将其量化并映射到一个定义的二维极坐标网格中;按照一定顺序读取网格单元中的数据,得到一个一维比特串模板。当比特串模板泄露时,通过改变用户口令PIN生成新的比特串模板,达到可撤销的目的。由于变换过程是不可逆的,所以即使攻击者获得比特串模板也不能恢复出原始指纹特征信息,保护了用户的隐私。在实验中,用指纹数据库FVC2004 DB1和FVC2004 DB2对文中方法与S.Wang提出的方法分别进行测试,实验结果显示,文章提出方法的性能优于S.Wang提出的方法,并且具有更高的安全性。

In a tmgerprlnt authentication system, the user＇s privacy and security would be threatened when attacker obtain user＇s fingerprint template, therefore, the fingerprint template protection has become a key link.Although many fingerprint template protection methods have been proposed, it is still a challenging task to devise a scheme which satisfies both diversity, revocable, irreversible and high-performance. This paper proposes a cancelable fingerprint template protection scheme which generates a revocable bit-string template from a set of minutiae points. The main idea is to choose a minutiae point as reference point, comparing with all other minutiae points to get relative distance and direction Angle, then, mapping the minutiae into a 2 dimensional polar grid which consist of small cells and finding out which cells include minutiae. Changing the user＇s password to generate new bit- string template when the bit-string template has been revealed. Because of the transformation process is irreversible, so the attacker can＇t restore the original fingerprint information by bit-string template.This method could protect the privacy of users. In the experiments,testing this method and S.Wang＇s method which has been presented by the FVC2004 DB 1 and FVC2004 DB 1 database, the experimental results showed that the proposed method is superior and higher security than S. Wang＇s method.