An authentication system for electronic transactions occurring over a computerized network is provided that includes: (a) a transaction authentication system interface operatively coupled to the computerized network for receiving proposed transactions information over the computerized network; and (b) a transaction authentication tool, operatively coupled to the transaction authentication system interface, where the tool includes: an automated anti-fraud analysis component for analyzing transactions information from a plurality of proposed transactions and automatically rejecting a first subset of proposed transactions according to automatic rejection criteria and automatically assigning a second subset of transactions for additional review; and an automated acceptance component for analyzing the second subset of transactions and accepting a third subset of transactions from the second subset based upon automatic accepting criteria.