Network resource access control methods and systems using transactional artifacts

A method for allowing access to access controlled network resources, the method comprising:

• receiving, with a first device associated with a service provider, a credential generated by a second device associated with a user;
• generating, with the first device, a verifier by processing a first device artifact based on a transactional history between the first device and the second device as observed by the first device;
• initiating, with the first device, a transaction process in response to a transaction request by the second device;
• comparing the credential and the verifier to determine whether to permit the transaction process;
• and
• allowing access to the access controlled network resources if the comparing indicates the credential and the verifier are based on a same transactional history, and
• wherein the credential is based in part on a second device artifact maintained by the second device and processed by the second device based on a transactional history between the first device and the second device as observed by the second device, and
• wherein the second device artifact is modified by the second device subsequent to a previous transaction between the user and the service provider before the credential is received by the first device for authentication during the transaction process.