This study developed an Integrated Authentication System for Internet-Based Financial Transactions by integrating multiple authentication factors for Internet banking. It formulated the model, simulated the proposed model and evaluated the performance of the model. This was with a view of preventing Internet banking fraud, which mitigated against users. Three factors of entity authentication policies in four levels were integrated. The technique is characterized by the use of unique factors of authentication at different points in a transaction process. The model was transformed into an algorithm and simulated with MATLAB. A set of passwords, challenge questions, token codes and iris images were obtained to serve as input data to the simulated model. Performance comparison of the proposed model with an existing model was carried out using False Acceptance Rate (FAR) and False Rejection Rate (FRR) as metrics. This study concluded by substantially strengthening the overall securityof Internet-based bank transactions. This could be effective in protecting sensitive customers' information by significantly reducing the rate of Internet banking fraud.