Value transfer system

• US 5,778,067 A
• Filed: 06/17/1996
• Issued: 07/07/1998
• Est. Priority Date: 04/12/1990
• Status: Expired due to Term

• Current Assignee: Mondex International Ltd. (MasterCard Incorporated)
• Original Assignee: Mondex International Ltd. (MasterCard Incorporated)
• Inventors: Jones, Timothy Lloyd, Higgins, Graham Robert L.
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US08/664,907
• Time in Patent Office: 750 Days
• Field of Search: 380/4, 380/9, 380/21, 380/23, 380/24, 380/25, 380/49, 380/50, 380/29, 380/30, 235/379, 235/380, 705/35, 705/39, 705/40, 705/41, 705/42, 705/43, 705/44
• US Class Current: 705/65
• CPC Class Codes: G06Q 20/02 involving a neutral party, e.g. certification authority, notary or trusted third party [TTP]
• CPC Class Codes: G06Q 20/06 Private payment circuits, e.g. involving electronic currency used among participants of a common payment scheme
• CPC Class Codes: G06Q 20/10 specially adapted for electronic funds transfer [EFT] systems; specially adapted for home banking systems
• CPC Class Codes: G06Q 20/105 involving programming of a portable memory device, e.g. IC cards, "electronic purses"
• CPC Class Codes: G06Q 20/204 comprising interface for record bearing medium or carrier for electronic funds transfer or payment credit
• CPC Class Codes: G06Q 20/341 Active cards, i.e. cards including their own processing means, e.g. including an IC or chip
• CPC Class Codes: G06Q 20/367 involving electronic purses or money safes
• CPC Class Codes: G06Q 20/3676 Balancing accounts
• CPC Class Codes: G06Q 20/3829 involving key management
• CPC Class Codes: G06Q 20/401 Transaction verification
• CPC Class Codes: G06Q 20/40975 using encryption therefor
• CPC Class Codes: G07F 7/1008 Active credit-cards provided with means to personalise their use, e.g. with PIN-introduction/comparison system

Abstract

A value transfer system which allows value to be transferred between electronic purses comprises computer which controls the loading of purses with value and the redemption of value from purses, a special bulk purse or purses and a value meter securely linked thereto which registers the total net value issued to the bulk purse or purses. Draw-down of value and redemption of value transactions are effected with the bulk purses.

Claims

1. A value transfer system, said system comprising:

a computer system;

a plurality of electronic purses;

at least one exchange device whereby said purses communicate with each other to transfer value in transactions which are off-line from the computer system; and

a cryptographic key system under which communication between purses is effected, each purse storing one or more cryptographic keys and including a microprocessor, wherein, in a transaction between a first purse having a microprocessor of a first computing power and a second purse having a microprocessor of a second computing power, said first power being superior to said second power, the microprocessors are programmed to send to the first purse a secret key of the second purse.

2. A value transfer system as claimed in claim 1 in which the first purse stores its own unique public/secret key pair in the cryptographic system, and wherein said step of sending to the first purse a secret key of the second purse is preceded by the step of sending to the second purse the public key of the first purse, and wherein the secret key of the second purse is encrypted using the public key of the first purse prior to being sent to the first purse.

3. A value transfer system as claimed in claim 2 wherein the transaction includes the subsequent steps of encrypting, in said first purse, a transaction message using the secret key of said second purse and sending the encrypted message to the second purse.

4. A value transfer system as claimed in claim 3 in which the second purse stores its own unique public/secret key pair in the cryptographic system, said transaction including the step of decrypting, in said second purse, the transaction message using the public key of the second purse.

5. A value transfer system as claimed in claim 3 in which the secret key of the second purse takes the form of an encryption key for a symmetrical cryptographic system, said transaction including the step of decrypting in said second purse, the transaction message using the encryption key.

6. A value transfer system as claimed in claim 1 wherein the transaction includes the subsequent steps of encrypting, in said first purse, a transaction message using the secret key of said second purse and sending the encrypted message to the second purse.

7. A value transfer system as claimed in claim 6 in which the second purse stores its own unique public/secret key pair in the cryptographic system, said transaction including the step of decrypting, in said second purse, the transaction message using the public key of the second purse.

8. A value transfer system as claimed in claim 6 in which the secret key of the second purse takes the form of an encryption key for a symmetrical cryptographic system, said transaction including the step of decrypting in said second purse, the transaction message using the encryption key.