Microsoft Corp. and Arcot Systems Inc. announced Tuesday an agreement to integrate Microsoft’s .Net Passport online authentication system with Arcot’s TransFort payment authentication software for credit cards.

The combination of TransFort with Microsoft’s Passport authentication and single sign-on service would make it easier for customers to use their credit cards to make online purchases, the companies said in a statement.

Representatives from Microsoft and Arcot Systems could not immediately be reached for comment.

Arcot Systems, of Santa Clara, Calif., makes online payment systems for banks and merchants that issue credit cards from Visa International Inc. and MasterCard International Inc. as well as providing the software used by Visa for its own Verified by Visa program, according to Arcot’s Web site.

Passport stores a user’s individual financial information, in turn allowing the user to make online purchases on a variety of Passport-approved Web sites with a single password. When coupled with TransFort, banks authenticating Visa or MasterCard credit cards would only require Passport users to type in their user name and password once to shop online, the companies said.

Since Passport’s launch last year, Microsoft has come under sustained criticism regarding the level of control Passport gives the Redmond, Wash., software giant over personal information including credit card information, full name, address, gender and date of birth.