Authorization system using partial card numbers

An authorization system includes a database, and at least one computer server in communication with the database. The database includes a plurality of database records, each including an account number and an associated card number. Each card number has fewer digits than the associated account number. The server is configured to receive, from a communications terminal, a request message that initiates a transaction with the server. The server is configured to request an authentication credential from the terminal, and in the database locate the card number that matches the received authentication credential and locate the account number that is associated with the located card number. The server is configured to request authorization of a test transaction using the account number, receive an authorization response confirming authorization of the test transaction, and authorize the initiated transaction in response to the authorization response. The test transaction is different from the initiated transaction.