Of the unique biological characteristics people have--fingerprints, the retina, and DNA--fingerprints are the most convenient. Moreover, there is already a theoretical foundation, and it is internationally standardized and interchangeable information.
在指紋、視網膜、DNA 等人身特徵中，只有指紋最方便，且已有理論根據，是國際標準化的可交換資訊。