1. A method for authenticating a user, comprising the steps of: acquiring an image of an original fingerprint of the user at a local authentication device, and identifying minutiae points on the original fingerprint image where a ridge in the fingerprint joins another ridge or a ridge ends, and the combination of any three minutiae points forms a triangle, with triangles being proportional regardless of possible differences in scale of two fingerprints being compared, and the local authentication device determining a reference triangle of three minutiae points in the original fingerprint; the local authentication device transmitting data relating to the reference triangle of minutiae points in the original fingerprint to a plurality of remote authentication devices, each remote authentication device performing a validation function upon the original fingerprint image utilizing data related to the reference triangle to determine if it has a stored candidate fingerprint in memory having a triangle matching the reference triangle, and if so the remote authentication device sends back to the local authentication device data on two of the minutiae points of the reference triangle to form a reference side, and also sends data on a third new minutiae point, not related to the first reference triangle, in the stored candidate fingerprint; when data on the third new minutiae point is received by the local authentication device, the local authentication device can determine the stored candidate fingerprint not to be a match if the original fingerprint does not have the third new minutiae point, and if the third new minutiae point is validated, the local authentication device sends a fourth new minutiae point to the remote device, and each successive validation transaction results in an additional minutiae point being sent between the local authenticating device and the remote authentication device until the authentication method determines a match.