System and method for generation and use of asymmetric crypto-keys each having a public portion and multiple private portions

A system for authenticating network users, the system operable in multiple modes, comprising:

• a plurality of user network stations, each representing a user, and each associated with an asymmetric crypto-key having a public/private key pair, with the private key of each public/private key pair having one of a first number of private key portions and a second number of private key portions, the second number of private key portions being greater than the first number of private key portions;
• and
• at least one sponsor network station representing a sponsor and configured to (i) receive a plurality of authentication requests from the plurality of user network stations, (ii) determine the identity of the user represented by the user station from which each of the plurality of authentication requests is received, (iii) select one of at least a first mode of operation and a second mode of operation based upon the determined identity of the represented user, and (iv) if the first mode of operation is selected, sign the authentication request received from the applicable user network station using one portion of the private key of an asymmetric crypto-key associated with the applicable user station, wherein the private key has the first number of private key portions, and if the second mode of operation is selected, sign the authentication request received from the applicable user network station using one portion of the private key of an asymmetric crypto-key associated with the applicable user station, wherein the private key has the second number of private key portions.