Shinji Hirata

Cancelable Biometrics with Perfect Secrecy for Correlation-Based Matching

In this paper, we propose a novel method of Cancelable Biometrics for correlation-based matching. The biometric image is transformed by Number Theoretic Transform (Fourier-like transform over a finite field), and then the transformed data is masked with a random filter. By applying a particular kind of masking technique, the correlation between the registered image and the input matching image can be computed in masked domain (i.e., encrypted domain) without knowing the original images. And we proved theoretically that in our proposed method the masked version does not leak any information of the original image, in other words, our proposed method has perfect secrecy. Additionally, we applied our proposed method to finger-vein pattern verification and experimentally obtained very high verification performance.

Parameter management schemes for cancelable biometrics

Protecting biometric information is a critical issue in biometric systems, since physical characteristics such as fingerprints, irises, face and vein patterns, cannot be changed or revoked like passwords. To address this issue, an authentication scheme called cancelable biometrics has been studied, in which the biometric features are transformed by a kind of encryption or one-way function and matched without restoring the original features. The transformation function is determined by a user-specific parameter, which plays a similar roll as an encryption key. To secure biometric features using the cancelable biometrics, the parameters have to be managed properly. In this paper, we review several naive schemes for parameter management and point out that they reduce the usability of authentication systems. Then we propose a novel parameter management scheme based on server-side parameter management and authentication protocols using one-time parameters and one-time templates. Our scheme makes it possible to realize a cancelable biometric authentication system with high usability and security.

Secure ID management for social security and tax number system

The Japanese government will adopt the Social Security and Tax Number System. The system is beneficial, but it is necessary to consider how to prevent abuse of the system. To prevent any abuse of the system, we developed a secure device which manages IDs such as Social Security and Tax Number. This secure device safely manages IDs, and can increase efficiency of audit. In this paper, we evaluate the Japanese Social Security and Tax Number System by fault-tree analysis and summarise the proposed ID-management device.