This error could be exploited when users are doing transactions using credit card or mobile devices such as phones.
For at least two policies, the entire transaction, using a credit card, can be completed on the Internet.
It is used in some databases to safely handle transactions, using timestamps.
In the majority of cases, transactions using these cards will be verified by the customer entering a PIN.
Microsoft has hinted that it may charge a fee for every transaction using its system, though the details have not been announced.
Visa pays a fee to Microsoft for every transaction using certain Microsoft software.
Several members of Congress say they will closely scrutinize transactions using "purchase cards," government-paid credit cards subject to past abuse.
The accountant can then find out from the client the nature of any uncoded transactions using one of BankLink's electronic reports including an online service.
The number of transactions using the American Express card has increased over last year, but the company won't say by how much.
The four Chicago and New York exchanges plan to develop electronic audit trail systems to record transactions using hand-held terminals.