Based on the registering idea of IRR (internet routing registry), the concept of Prefix Policy is proposed,and a new Internet registry mechanism, E-IRR, is presented. E-IRR offers an efficient and defensive method toprevent hijacked routes. In E-IRR, every participant declares its prefix policies, and makes use of the others’registered prefix policies to validate BGP routes. Measures are designed to guarantee the validity of prefix policies,and evaluate its capabilities of security and performance. The major benefits of the method are the balance itreaches between the capability of preventing prefix hijacks and the security mechanism’s requirements of practicaldeployment, the facts that the method lends itself to stepwise deployment and needs not any BGP extension for security. These properties, not shared by alternative approaches, make it an attractive and viable solution to theprefix hijacking problem.