PIN (Personal Identification Numbers), passwords, smart cards and digital certificates are some of the means employed for user authentication in various electronic commerce applications. However, these means do not really identify a person, but only knowledge of some data or belonging of some determined object. This paper introduces the notion of Biometric Signature: a new approach to integrate biometrics with PKI (Public Key Infrastructure) using biometric based signature key generation. This is based on iris recognition, which is secure, efficacious, fast, convenient, non-invasive and correctly identifies the maker of the transaction. It also compares integration of iris templates with two existing and widely used digital signature algorithms, RSA and DSA (Digital Signature Algorithm) for biometric signatures and discusses the problems associated with them individually. Speed of both is measured and compared with the help of JAVA implementation for both approaches.