A method of authenticating a network client to a relying party computer via a computer server comprises the computer server receiving a transaction code from a token manager via a first communications channel. The network client is configured to communicate with a token manager which is configured to communicate with a hardware token interfaced therewith. The network client is also configured to communicate with the relying party computer and the computer server. The computer server also receives a transaction pointer from the relying party computer via a second communications channel that is distinct from the first communications channel. Preferably, the transaction pointer is unpredictable by the computer server. The computer server transmits an authorization signal to the relying party computer in accordance with a correlation between the transaction code and the transaction pointer. The authorization signal facilitates authentication of the network client to the relying party computer.