The capability to identify individuals and to associate personal attributes (e.g., name, nationality, etc.) with an individual has been crucial to the fabric of human society. Humans typically use body characteristics such as face, voice, and gait along with other contextual information (e.g., location and clothing) to recognize one another. The set of attributes associated with a person constitutes their personal identityIdentity. In the early days of civilization, people lived in small communities where individuals could easily recognize each other. However, an explosion in population growth accompanied by increased mobility in modern society has necessitated the development of sophisticated identity management systems that can efficiently record and maintain personal identities of individuals.