問68
頻出度★★★
生体認証の仕組みとして, 静脈パターンを利用するものはどれか。
平成23年度 特別試験 ITパスポート試験 問68
This question's explanation and your answers so far.
解説
問 68
Incorrectア
Face authentication converts shape features on the surface of the face into numbers and matches them: the outline of the face, the positional relationship of the eyes, nose, and mouth, and the spacing between each part, all taken from a facial image captured by a camera. What it uses is, in the end, the visible features that appear on the body surface, not the vein pattern inside the body. It is convenient in that a camera alone can authenticate a person without contact or restraint, and footage from security cameras can be used, but it has the weakness that accuracy easily drops under the influence of lighting conditions, facial expressions, makeup, aging, masks, and the like. It does not use veins, so it is wrong.
Incorrectイ
Iris authentication photographs and matches the complex wrinkle pattern that appears on the iris, the doughnut-shaped membrane around the pupil of the eyeball. The iris pattern is complete shortly after birth and then hardly changes for a lifetime; it also differs between the left and right eyes and varies greatly between individuals, so it ranks among the more accurate forms of biometric authentication. However, what it reads is the pattern of the iris, not blood vessels. Note that retina authentication, which uses the blood vessel pattern of the retina at the back of the eye, is a biometric method that does use blood vessels of the eye, but it is a different method from iris authentication and is also different from the palm vein pattern in this question. Since iris authentication is not a mechanism that uses vein patterns, it is wrong.
Incorrectウ
Voiceprint authentication matches a person using the voiceprint obtained by frequency analysis of speech that the person utters — that is, the frequency components of the voice and how they change over time. It is convenient because only a microphone is needed and it can even be used to verify identity over a telephone line, but it has problems: it is vulnerable to changes in the voice caused by a cold or physical condition, to surrounding noise, and to impersonation by playing back a recorded voice. What it uses is speech, a physical and behavioral characteristic, not the pattern of veins running inside the body, so it is wrong.
- エ
正解 The correct answer is エ. Palm authentication is a biometric authentication method that reads the vein pattern of the palm to verify that a person is who they claim to be. When near-infrared light is shone on the palm, the reduced hemoglobin in the blood flowing through the veins absorbs that near-infrared light, so only the parts where veins run appear as black lines. This branching shape of the blood vessels is captured as an image and compared with a pattern registered in advance, which decides whether the person is the registered individual. Vein patterns differ from one person to another and hardly change after adulthood, so they can be used stably as a clue for authentication. The biggest characteristic of vein authentication is that the feature it uses is inside the body. It leaves no trace on objects that are touched, as a fingerprint does, and it cannot be photographed from outside, as a face can, so it is hard for another person to steal and copy, giving it high resistance to forgery. Because it is not information on the body surface, it is also less affected by surface changes such as dry hands, small cuts, or dirt, and it can be made contactless — the user simply holds a hand over the device — which makes it easy to handle from a hygiene standpoint as well. Thanks to these advantages, it is used for identity verification at bank ATMs and for entry and exit control at data centers, laboratories, and similar facilities. Finger vein authentication is another method that uses the same vein patterns, and both count as a “mechanism that uses vein patterns” in the sense of this question. Among the choices, only エ uses the veins inside the body, so the correct answer is エ.
ここがポイント
- Learn which physical feature each representative biometric method uses — vein patterns are used by palm vein authentication and finger vein authentication; the ridge pattern of a finger is used by fingerprint authentication; the wrinkle pattern of the iris of the eye is used by iris authentication (different from retina authentication, which uses the blood vessels at the back of the eye); the shape of the face surface is used by face authentication; and the frequency characteristics of the voice are used by voiceprint authentication. Be able to state the one-to-one match between each method and the feature it reads.
- Why vein authentication is highly regarded — veins are information inside the body, so they leave no trace and are hard to observe or copy from outside, which gives high resistance to forgery, and the method is also little affected by changes in the surface condition of the hand such as dirt, dryness, or small cuts. In addition, biometric authentication in general shares one common idea: the false acceptance rate (FAR), which is wrongly accepting another person, and the false rejection rate (FRR), which is wrongly rejecting the right person, are in a trade-off relationship, so the decision threshold is adjusted according to the intended use.
用語