Micro nail authentication is an authentication mechanism that uses a minute part of the fingernail surface. Using a fingernail that grows over time, the right to be forgotten is satisfied because the biometric information is short-lived. The viability of micro nail authentication was proven with a prototype system in previous studies. However, there are several issues with the prototype system, particularly pertaining to problems with authentication accuracy and convenience. Therefore, this paper aims to improve the feasibility of the prototype system. First, the authors explain how using a nail surface for micro biometric authentication ensures the right to be forgotten. Subsequently, the authors provide details of an improved system that solves the problems present in the previous research. Finally, experiments conducted using the improved system are described, and its feasibility and speed are evaluated.