DefinitionIn biometric systems, the goal of liveness testing is to determine if the biometric being captured is an actual measurement from the authorized, live person who is present at the time of capture. While fingerprint systems may have an excellent performance and improve security, previous studies have shown it is not difficult to make molds of latent fingerprints left by legitimate users and to create fake fingers made from Play-Doh, gelatin, and silicon materials to fool a variety of fingerprint scanners, termed spoofing. Liveness detection reduces the risk of spoofing by requiring a liveness signature, in addition to matched biometric information. Methods can be divided into hardware and software categories. Hardware methods include measurements like pulse oximetry, electrocardiogram, or odor, while software-based measurements use additional processing of the biometric information itself to isolate liveness signatures like perspiration and deformation. While liveness algorithm makes spoofing more difficult, they need to be considered as components of a biometric system, which bring with it performance characteristics along with factors such as ease of use, collectability, universality, spoof-ability, permanence, and in some cases, even uniqueness. No system is perfect in its ability to prevent spoof attacks. However, liveness algorithms can reduce this vulnerability to minimize the risk of spoofing.Fingerprints are graphical ridge-valley patterns from human fingers. Fingerprint recognition is a widely used and efficient technique for biometric authentication. While fingerprint systems may have excellent performance and improve security, previous studies have shown it is not difficult to make molds of latent fingerprints left by legitimate users and to create fake fingers made from Play-Doh, gelatin, and silicon materials to fool a variety of fingerprint scanners [1,2]. The most famous of which is the work by Matsumoto and colleagues. In the reports, two different techniques were used to create a mold. The first technique directly used a subject's finger to create the mold in free molding plastic, whereas the second technique involved making a mold from a latent fingerprint image. Casts were made of gelatin material and termed "gummy fingers." Verification rates of gummy fingers ranged from 68 to 100 %. For method of creating a cast from residual fingerprints, all fingerprint systems were able to enroll the spoof finger and verify more than 67 % of the attempts. Similar results have been obtained on subsequent studies with various materials including silicon, clay, and Play-Doh [1, 2] and on one study which looked at cadaver fingers [2].