If a smartcard provides security functions such as electronic signature creation, valuables such as electronic money and/or sensitive data such as medical data, then the smartcard has to verify that it is used by the legitimate cardholder. For this purpose, the user has usually to present a PIN. Since smartcards become more and more powerful, it is feasible to implement on-card matching algorithms allowing to perform a biometric user verification in the smartcard. 1 Legal Background for Electronic Signatures and Signer Verification In 1999, the EU has published the “EU Directive 1999/93/EC of the European Parliament and the council of 13 December 1999 on a Community framework for electronic signatures [1]”. In this Directive, the use of “Secure Signature Creation Devices (SSCD)” for the creation of Qualified Electronic Signatures is described. The most important instance of such an SSCD is a smartcard which is able to compute an electronic signature using the Signature Creation...