Secure networked transaction system

1. A method of approving a transaction between a customer and a merchant, the method comprising:

receiving, by a verification computing system, a verification request for a transaction from a merchant device, the verification request comprising first data indicating a first portion of payment account information;

transmitting, by the verification computing system, a first verification string to the merchant device;

receiving, by the verification computing system, second data indicating a second portion of payment account information from a customer device;

determining a payment account number based at least on the first portion and the second portion of payment account information;

initiating approval of the transaction using the payment account number; and

upon determining that the transaction is approved, transmitting, by the verification computing system, a second verification string to the customer device, wherein the transaction is verified and/or completed by the merchant device in response to the merchant device receiving the second verification string from the customer device and the merchant device matching the first and the second verification strings.

2. The method of claim 1 , wherein the first data comprises at least part of a debit card account number and the second data comprises at least part of a PIN number associated with the debit card account number.

3. The method of claim 1 , wherein the first data comprises at least part of a credit card account number and the second data comprises at least part of a card security code associated with the credit card account number.

4. The method of claim 1 , further comprising:

transmitting a transaction identifier to the merchant device; and

receiving a copy of the transaction identifier from the customer device.

5. The method of claim 1 , wherein initiating approval of the transaction using the payment account number comprises:

transmitting the payment account number to a gateway device of a debit and/or credit card processing network; and

receiving an indicator of approval from the gateway device.

6. A system for approving a transaction between a customer and a merchant, the system comprising:

a computer readable medium; and

one or more processors configured to cause one or more computing devices to:

receive a verification request for a transaction from a merchant device, the verification request comprising first data indicating a first portion of payment account information;

initiate storage of the first data in the computer readable medium;

transmit a first verification string to the merchant device;

receive second data indicating a second portion of payment account information from a customer device;

initiate storage of the second data in the computer readable medium;

determine a payment account number based at least on the first portion and the second portion of payment account information;

initiate approval of the transaction using the payment account number; and

upon determining that the transaction is approved, transmit a second verification string to the customer device, wherein the transaction is verified and/or completed by the merchant device in response to the merchant device receiving the second verification string from the customer device and the merchant device matching the first and the second verification strings.

7. The system of claim 6 , wherein the first data comprises at least part of a debit card account number and the second data comprises at least part of a PIN number associated with the debit card account number.

8. The system of claim 6 , wherein the first data comprises at least part of a credit card account number and the second data comprises at least part of a card security code associated with the credit card account number.

9. The system of claim 6 , wherein initiating approval of the transaction using the payment account number comprises:

transmitting the payment account number to a gateway device of a debit and/or credit card processing network; and

receiving an indicator of approval from the gateway device.

10. A tangible computer readable storage medium having computer-executable instructions stored thereon, the computer-executable instructions readable by a computing system comprising one or more computing devices, wherein the computer-executable instructions are executable on the computing system in order to cause the computing system to perform operations comprising:

receiving a verification request for a transaction from a merchant device, the verification request comprising first data indicating a first portion of payment account information;

storing the first data in a computer readable medium;

transmitting a first verification string to the merchant device;

receiving second data indicating a second portion of payment account information from a customer device;

storing the second data in a computer readable medium;

determining a payment account number based at least on the first portion and the second portion of payment account information;

initiating approval of the transaction using the payment account number; and

upon determining that the transaction is approved, transmitting a second verification string to the customer device, wherein the transaction is verified and/or completed by the merchant device in response to the merchant device receiving the second verification string from the customer device and the merchant device matching the first and the second verification strings.

11. The tangible computer readable storage medium of claim 10 , wherein initiating approval of the transaction using the payment account number comprises:

transmitting the payment account number to a gateway device of a debit and/or credit card processing network; and

receiving an indicator of approval from the gateway device.

12. The tangible computer readable storage medium of claim 10 , wherein the operations further comprise:

transmitting a transaction identifier to the merchant device; and

receiving a copy of the transaction identifier from the customer device.