In this blog post, we will examine how effectively smartphone fingerprint and iris recognition technologies protect personal information, and analyze the limitations and security issues of biometric technology.
With the advancement of the internet and the widespread adoption of smartphones, the importance of personal information has grown more than ever before. Mobile devices such as smartphones store sensitive information, including personal photos, messages, and financial data, making their protection a matter directly linked not only to personal privacy but also to financial security. Consequently, security systems designed to protect this critical personal information from crimes such as identity theft and financial fraud continue to evolve. Moving beyond simple password-based methods, biometric recognition—which identifies individuals using their biological characteristics or behavioral patterns—is gradually becoming a part of our daily lives.
Among these biometric systems, the oldest and most widely adopted is the fingerprint recognition system. Fingerprints consist of ridges—the raised parts formed by sweat glands in the dermis protruding through the epidermis in a specific pattern—and valleys—the indented parts. Because fingerprints are unique to each individual and remain unchanged throughout a person’s life unless the dermis is damaged, fingerprint recognition has long been a universally used biometric method. In particular, it has a very long history of use by law enforcement agencies as a means of identifying criminals. These fingerprint recognition systems identify individuals by matching registered fingerprints with those being queried through a fingerprint input device; during the fingerprint input process, differences in light intensity and electrical charge arise depending on the ridges and valleys.
There are various methods for distinguishing fingerprints based on these differences, with the most common being optical fingerprint recognition and capacitive sensor-based fingerprint recognition. The method that distinguishes fingerprints based on the intensity of reflected light is called optical fingerprint recognition. While the optical method was initially used primarily in large-scale facilities, recent improvements in its performance have led to its application in a wide range of fields. Capacitive fingerprint recognition utilizes the electrical conductivity of the skin. It verifies identity by detecting changes in electrical charge based on the shape of the ridges that come into contact with the input device when a finger is placed on it. While optical fingerprint recognition offers high accuracy, its disadvantages include large device size and high cost. Optical fingerprint recognition devices are primarily used in corporate time-and-attendance systems and banks. Capacitive fingerprint recognition devices have the advantages of being compact, inexpensive, and easy to mass-produce. However, they have the disadvantage that the internal silicon chip (semiconductor) can be damaged by static electricity upon contact. Recently, however, this drawback has been overcome by coating the chip surface to improve stability. Touch ID, the fingerprint recognition system introduced by Apple, is also a capacitive fingerprint recognition system. In addition to these two methods, there are thin-film systems that use sensors in the form of very thin films, and pyroelectric fingerprint recognition systems that detect changes in temperature. As such, fingerprint recognition technology is evolving in various forms and becoming deeply embedded in our daily lives.
Another emerging biometric technology is iris recognition. The iris is a doughnut-shaped membrane surrounding the pupil that regulates the amount of light entering the eye by contracting and relaxing. The iris forms around 18 months after birth and remains unchanged for a lifetime. The iris contains two muscles—the iris sphincter and the iris dilator—that control contraction and relaxation; the intricate patterns on the iris sphincter are unique to each individual. An infrared camera, which does not reflect light, captures an image of the entire eye, extracts only the iris portion, and then analyzes that area in detail.
The principle of iris recognition is to digitize the iris’s unique pattern. Once the acquired iris data is stored and registered, it is compared with the data of the iris being scanned to verify identity.
The iris has approximately 250 distinguishing points, far more than the roughly 40 found in fingerprints, making it significantly more reliable than fingerprints in terms of error rates and security. While the error rate for traditional fingerprint recognition is 1 in 10,000, the error rate for iris recognition is 1 in 1 million when using one eye and 1 in 1 trillion when using both eyes. Furthermore, because fingerprints are exposed on the skin’s surface, they can be damaged by manual labor or contaminated with foreign substances, making identification difficult. As someone who tends to have sweaty hands, I often experience the inconvenience of difficulties with fingerprint recognition. Furthermore, while fingerprint recognition requires direct finger contact, iris recognition is a contactless method, offering the advantages of fewer usage restrictions and greater hygiene. Thanks to these benefits, iris recognition is gaining prominence; for example, smartphones released by Samsung Electronics and Apple are equipped with iris recognition technology. In the future, iris recognition technology is expected to be applied to more products and services to enhance security.
In addition, other biometric technologies are continuously being developed. One such method is brainwave recognition, which verifies identity by analyzing the brain’s response to specific words or images; this technology holds the potential to lead the future of biometrics. Furthermore, vein recognition—a technique that identifies individuals by recognizing the vascular patterns in their fingers or wrists—is also gaining attention. Efforts to identify individuals using various physical characteristics are underway worldwide, and as technology advances, security systems are becoming increasingly sophisticated. In the future, these biometric technologies will become even more deeply integrated into our daily lives, setting new standards for security.
