Abstract: A system and method for affixing a signature using biometric authentication, is described herein. The system is configured for registering a user by receiving a set of biometric samples of the user, processing the set of biometric samples to compute a Secret-Key (S1) corresponding to the user, generating a Unique-Number (N1) using a random number generation algorithm, applying a Function (F1) to the Secret-Key (S1) and the Unique-Number (N1), to compute a Public-Key (P1), receiving a document signing request from an application. Once the user is registered, the system is configured to receive a biometric sample from the user in real-time and compute the Secret-Key (S2) for authenticating the user. Once the user is authenticated, the system may capture the user's approval to affix the user's signature to the document and transmit the user's signature to the application upon successful authentication of the user.