In the online retrieving valuable information in special databases, it is important to protect the privacy of users preventing the server from knowing the information what the users retrieve. The problem was not solved until the privacy information retrieval (PIR) schemes were presented. A PIR scheme allows a user to retrieve a date item from online database while hiding the index of the data item from the database server. However, retrieving valuable information is another problem needs to be solved. Most transactions are completed by credit card through delivering its number and membership in the internet to the server. Then the server will know the privacy of users. It will become a challenge to private information retrieval (PIR) schemes considering the e-payment need.

In this paper, we propose a new PIR scheme, which use a secure coprocessor (SC), with e-payment scheme for protecting the privacy of customers in querying valuable information. The scheme will not reveal personal information or buying information of customers in the internet environment, it can really protect the customers? privacy. Comparing with previous PIR schemes, the scheme, combined with e-payment scheme in retrieving valuable information in special database, is more practical than previous PIR schemes in the internet applications because of considering e-payment need.