This invention provides for progressive processing of biometric samples to
facilitate verification of an authorized user. The initial processing is
performed by a security token. Due to storage space and processing power
limitations, excessive false rejections may occur. To overcome this
shortfall, the biometric sample is routed to a stateless server, which
has significantly greater processing power and data enhancement
capabilities. The stateless server receives, processes and returns the
biometric sample to the security token for another attempt at
verification using the enhanced biometric sample. In a second embodiment
of the invention, a second failure of the security token to verify the
enhanced biometric sample sends either the enhanced or raw biometric
sample to a stateful server. The stateful server again processes the
biometric sample and performs a one to many search of a biometric
database. The biometric database contains the master set of enrolled
biometric templates associated with all authorized users. Signals
generated by the stateful server are used by the security token to allow
or deny access to a resource or function. In both embodiments of the
invention, the heuristics remain with the security token.