Proposal of a Transformation Method for Iris Codes in Iris Scanning Verification
Hiroki Ota · IEICE Transactions on Fundamentals of Electronics Communications and Computer Sciences · 2005
In this paper, we propose a transformation function for a user's raw data, an iris in scanning verification on the server, since the code requires to be hidden from even a server administrator. We then show that the user can be properly authenticated on the server, even though the code is transformed by the proposed function. reason is that the function has a characteristic, The (normalized) Hamming distances between the enrolled codes and the verified codes are conserved before and after the computation of the that is, the normalized Hamming distance in this scheme is equal to that in the existing scheme. We also show that the transformed code is sufficiently secure to hide the original code, even if a stronger attack model is supposed than the previously described model. That can be explained from the following two reasons. One reason is that nonlinear function, which consists of the three-dimensional rotation about the x-axis and the y-axis with the code lengthened bit by bit, and the cyclic shift, does not enable an attacker to conjecture the code. other reason is that the success probabilities for the exhaustive search attack concerning the code in the supposed attack models are lower than those of the previously proposed methods and are negligible.