If an identification process using a biometric system detects a 100% match between a presented template and a stored template, the interpretation of this result is suspected tampering. A biometric system is a system that uses physical or behavioral characteristics of a person to verify their identity, such as fingerprint, iris, voice, or face. A biometric system compares the presented template, which is the biometric data captured from the person at the time of identification, with the stored template, which is the biometric data enrolled and stored in the system database. A biometric system usually does not produce a 100% match, as there are always some variations or errors in the biometric data due to environmental, physiological, or technical factors. A biometric system uses a threshold or a tolerance level to determine whether the match is acceptable or not. A 100% match is very unlikely and suspicious, as it may indicate that someone has tampered with the biometric system or the biometric data, such as by copying, modifying, or spoofing the stored template or the presented template12 References: CISSP All-in-One Exam Guide, Eighth Edition, Chapter 5: Identity and Access Management, p. 267; Official (ISC)2 CISSP CBK Reference, Fifth Edition, Domain 5: Identity and Access Management, p. 647.