Recently biometric authentication systems have become open and large scale thus leading to its widespread use. However, no systematic study has been done with regards to the safety of such systems. On the other hand, cancelable biometrics, the intentional distortion of biometric characteristics to protect sensitive data in biometric authentication systems, has been widely studied. Many methods have been proposed for cancelable biometrics technology, but the security criterion in such is indefinite. In this paper, we consider cancelable biometric techniques from the perspective of the safety of the system. We also verify the effect of the security precaution of the liveness detection techniques using Fault Tree Analysis, a risk evaluation method about data protection and spoofing prevention techniques.