Smart card purchasing transactions using wireless telecommunications network

A method of processing a purchase of an item from a merchant server computer by a user over a wireless telecommunications network using a mobile telephone handset equipped with a subscriber identification module (SIM), said method comprising:

• receiving, by a payment server computer associated with said merchant server computer, a draw request message over said telecommunications network through the handset from said SIM of said handset, wherein said draw request message includes a purchase amount for said item and an identifier of a smart card that is in communication with said handset via a card reader interface and said draw request is formulated by said SIM;
• generating, by said payment server computer, a cryptographic signature S2 using a first cryptographic key shared between said smart card and an issuer of said smart card;
• sending a debit message, by said payment server computer, to said smart card, wherein said debit message includes said cryptographic signature S2 and an approval to debit said smart card by said purchase amount;
• generating, by said smart card, a cryptographic signature S3 using a second cryptographic key shared between said smart card and said issuer of said smart card, said cryptographic signature S3 uniquely identifying said smart card;
• receiving, by said payment server computer, a debit result message from said smart card that includes a cryptographic signature S3;
• verifying, by said payment server computer, said cryptographic signature S3 from said smart card using said second shared cryptographic key, wherein verification of said signature S3 indicates that said signature S2 has been verified by said smart card and that a stored-value application of said smart card has been debited by said purchase amount;
• and
• sending, by said payment server computer, a confirmation message to said merchant server computer indicating that said smart card has been debited by said purchase amount, whereby said merchant server computer releases said item to said user.

A purchasing system for purchasing an item for a user, said purchasing system comprising:

• a wireless telecommunications network for providing communication between entities;
• a mobile telephone handset in communication with said telecommunications network, said handset including a card reader for communicating with said smart card, a subscriber identification module (SIM), and an input interface;
• a smart card that is in communication with said handset via a card reader interface, said smart card including a stored value, a cryptographic key shared with an issuer of said smart card, wherein said smart card is programmed to verify a first cryptographic signature S2 and to generate a second cryptographic signature S3;
• a merchant server computer programmed to generate a purchase instruction message intended for said SIM, said purchase instruction message including a purchase amount of said item and a merchant identifier;
• and
• a payment server computer programmed to receive a draw request message formulated by said SIM from said SIM through the handset, to generate a debit message intended for said smart card that includes said first cryptographic signature S2, to verify said second cryptographic signature S3, and to generate a confirmation of payment by said smart card for said merchant server computer, whereby said item is purchased over said wireless telecommunications network and is released to said user associated with said smart card.