A transaction authorization system allows a customer to authorize transactions relating to at least one account associated with an institution. Data storage means enable access to customer identification data, a customer's remote communication device (RCD), and security identifier data associating the account with the identification data. Communication means receive an authorization request, referenced to the security identifier data, relating to the transaction and enable communication with the customer via the RCD to authorize a transaction or to indicate that a transaction is fraudulent. Data processing means identify the customer and RCD using the identification data and determine if the transaction is authorized, or has been indicated as being fraudulent, and if the transaction is fraudulent, to determine the type of fraud. The communication means provide an indication, referenced to the security identifier data, to the institution of whether the transaction is authorized.