1. A method of authenticating a signature, comprising the steps of: sampling a signature and storing data representative of the signature; converting said data to high dimension vectors using a recursive sampling process; feeding the high dimension vectors to an unsupervised neural network and performing a high order principal component extraction process on the high dimension vectors by cumulative orthonormalization, thereby identifying clusters of high dimension points; and analyzing the clusters of high dimension points to determine, based on previously stored information, the authenticity of the signature.