Message storage and transfer system

1. An apparatus for storing and transferring content, the apparatus comprising:

an interface configured to send and receive messages through a communications medium, the interface including a first cryptographic function for protecting messages being sent, and a second cryptographic function for verifying received messages;

a memory storing at least a current content, a respective unique identifier of the storage media, and a log of content transfers; and

a controller operatively coupled to the interface and the memory, the controller operating under control of instruction code to execute a Transfer-In process to record a transfer of message content to a storage media, and to execute a Transfer-Out process to record a transfer of message content from the storage media:

wherein the Transfer-In process comprises steps of:

receiving, via the interface, a content transfer message including at least a message content to be transferred;

determining, using the second cryptographic function, a validity of the received content transfer message;

determining, using the log, whether the received content transfer message is likely a duplicate;

responsive to determination that the received content transfer message is valid and is likely not a duplicate, increasing the current content by the message content to be transferred and recording information of the content transfer in the log; and

responsive to determination that either the received content transfer message is invalid or is likely a duplicate, discarding the content transfer message; and

wherein the Transfer-Out process comprises steps of:

receiving, via the interface, a content transfer request message including at least a message content to be transferred;

determining whether the current content is equal to or greater than the message content to be transferred, and generating an error message responsive to determination that the current content is not equal to or greater than the message content to be transferred, and otherwise generating a content transfer message including the message content to be transferred, decreasing the current content by the message content amount to be transferred; recording information of the content transfer in the log, and using the first cryptographic function to protect the generated content transfer message; and

wherein the information recorded in the log comprises a digest of each transfer message and each transfer request message contains a challenge word, and wherein detecting a likely duplicate transfer request message comprises:

for each content transfer process completed by the controller, storing the challenge word contained in the respective transfer request message, as part of the information of the content transfer stored in the log; and

upon receipt of a new transfer request message, comparing the respective challenge word contained in the new transfer request message to challenge words already stored in the log.

2. The apparatus as claimed in claim 1 , wherein each storage media comprises any one of:

a physical storage media; and

a virtual storage media instantiated and maintained by a server.

3. The apparatus as claimed in claim 1 , wherein the communications medium comprises any one or more of:

a network;

a communications device connected to the network and connected to a respective storage media via the interface, the communications device hosting the storage media for communications through the network; and

a direct link between the storage media and a terminal or another storage media.

4. The apparatus as claimed in claim 3 , wherein the network is the internet.

5. The apparatus as claimed in claim 3 , wherein the communications device is selected from the list comprising Personal Data Assistants (PDAs); cell phones, hand-held computers and lap-top computers.

6. The apparatus as claimed in claim 3 , wherein the direct link is a wireless link.

7. The apparatus as claimed in claim 3 , wherein the terminal is selected from the list comprising merchant's point-of-sale devices, self-service kiosks and “touch-and-go” terminals.

8. The apparatus as claimed in claim 1 , wherein the first cryptographic function comprises applying a digital signature to the message being sent, and wherein the second cryptographic function comprises determining a validity of a digital signature included in a received message.

9. The apparatus as claimed in claim 1 , wherein the digest comprises a hash of the respective transfer message.

10. The apparatus as claimed in claim 1 , further comprising a display operatively connected to the controller, such that the controller can display information including the current content.

11. The apparatus as claimed in claim 10 , wherein the display is a touch-screen for receiving user input.

12. The apparatus as claimed in claim 10 , further comprising at least one button for receiving user input.

13. The apparatus as claimed in claim 10 , wherein the transfer-out process comprises comparing the message content to be transferred to a user-input content, and generating the transfer message only if the message content to be transferred matches the user-input content.

14. The apparatus as claimed in claim 10 , wherein the received transfer request message includes a message content to be transferred having a null value, and wherein the transfer-out process comprises generating the transfer message using the user-input content as the message content to be transferred.

15. An electronic content exchange system comprising:

a communications channel; and

at least two apparatuses, each apparatus comprising:

an interface configured to send and receive messages through a communications medium, the interface including a first cryptographic function for protecting messages being sent, and a second cryptographic function for verifying received messages;

a memory storing at least a current content, a respective unique identifier of storage media, and a log of content transfers; and

a controller operatively coupled to the interface and the memory, the controller operating under control of instruction code to execute a Transfer-In process to record a transfer of message content to the storage media, and to execute a Transfer-Out process to record a transfer of message content from the storage media:

wherein the Transfer-In process comprises steps of:

receiving, via the interface, a content transfer message including at least a message content to be transferred;

determining, using the second cryptographic function, a validity of the received content transfer message;

determining, using the log, whether the received content transfer message is likely a duplicate;

responsive to determination that the received content transfer message is valid and is likely not a duplicate, increasing the current content by the message content to be transferred and recording information of the content transfer in the log; and

responsive to determination that either the received content transfer message is invalid or is likely a duplicate, discarding the content transfer message; and

wherein the Transfer-Out process comprises steps of:

receiving, via the interface, a content transfer request message including at least a message content to be transferred;

determining whether the current content is equal to or greater than the message content to be transferred, and generating an error message responsive to determination that the current content is not equal to or greater than the message content to be transferred, and otherwise generating a content transfer message including the message content to be transferred, decreasing the current content by the message content amount to be transferred; recording information of the content transfer in the log, and using the first cryptographic function to protect the generated content transfer message; and

wherein the information recorded in the log comprises a digest of each transfer message and each transfer request message contains a challenge word, and wherein detecting a likely duplicate transfer request message comprises:

for each content transfer process completed by the controller, storing the challenge word contained in the respective transfer request message, as part of the information of the content transfer stored in the log; and

upon receipt of a new transfer request message, comparing the respective challenge word contained in the new transfer request message to challenge words already stored in the log.