Abstract
Reliable identi¬cation is the need of the modern networked society to grant access to di erent resources to genuine personnel. The lacunae of traditional identi¬cation systems paved the way to -nd alternatives. As an alternative, biometrics, which is the science of establishing human identity, based on the physical or behavioral characteristics o er several advantages. A number of biometric characteristics have been identi¬ed and tested during recent decades. This paper provides an in-depth analysis of the existing biometric systems along with their advantages and limitations. Besides, we also discuss soft biometrics and multi-modal biometric systems in detail and identify the scenarios and metrics which play pivotal role in the successful implementation and accuracy of biometrics technology. For comparative analysis of biometrics modalities, we identify two di erent sets of features and provide a qualitative comparison of di erent modalities.