Identity theft is a growing concern in the digital era. As per the US Federal Trade Commission, millions of people got victimized in each year . Traditional authentication methods such as passwords and identity documents are not sufficient to combat ID theft or ensure security. Such representations of identity can easily be forgotten, lost, guessed, stolen, or shared. On the contrary, biometric systems recognize individuals based on their anatomical traits (e.g., fingerprint, face, palm print, iris, and voice) or behavioral traits (e.g., signature, gait). As such traits are physically linked to the user, biometric recognition is a natural and more reliable mechanism for ensuring that only legitimate or authorized users are able to enter a facility, access a computer system, or cross international borders. Biometric systems also offer unique advantages such as deterrence against repudiation and the ability to detect whether an individual has multiple identity cards (e.g., passports) under different names. Thus, biometric systems impart higher levels of security when appropriately integrated into applications requiring user authentication. In this paper, an attempt has been made to secure the biometric data using sudoku puzzle. © Springer India 2015.