Electronic cash controlled by non-homomorphic signatures

• US 20020073318A1
• Filed: 12/11/2000
• Published: 06/13/2002
• Est. Priority Date: 12/11/2000
• Status: Active Grant

• Current Assignee: PayPal, Inc. (PayPal Holdings, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Gennaro, Rosario, Tresser, Charles
• Granted Patent: US 7,640,432 B2
• Time in Patent Office: Days
• US Class Current: 713/176
• 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 20/085 involving remote charge determination or related payment systems
• CPC Class Codes: G06Q 20/367 involving electronic purses or money safes
• CPC Class Codes: G06Q 20/3674 involving authentication
• CPC Class Codes: G06Q 20/3821 Electronic credentials
• CPC Class Codes: G06Q 20/3829 involving key management
• CPC Class Codes: G06Q 20/401 Transaction verification

Abstract

A method and system for establishing and managing digital cash. This method is to emit and circulate secure electronic cash that allows to use non-homomorphic signature schemes, and avoids having to use blind signature techniques. With one specific embodiment, the method provides anonymous digital cash, and comprises the steps of providing an entity with a secure coprocessor, a user establishing a secure channel to a program running on said coprocessor, and the user sending a coin to be digitally signed to the coprocessor.

Claims

1. A method of providing anonymous digital cash, said method comprising:

providing an entity with a secure co-processor;

a user establishing a secure channel to a program running on said coprocessor; and

the user sending a coin to be digitally signed to the coprocessor using any secure digital signature algorithm.

2. A method according to claim 1, further comprising the steps of:

the processor providing a signature to authenticate;

the user using said coin for payment to a merchant; and

the merchant returning the signed coin to the entity for credit to an account of the merchant.

3. A method of creating and managing electronic cash, comprising the steps:

a customer communicating to a secure cryptography generator an encryption scheme and a cash amount;

establishing a unit representing the cash amount;

signing the unit;

using the secure cryptography generator to encrypt the signed unit using the encryption scheme;

storing in a database the encrypted signed unit and a value for the unit;

transmitting the encrypted signed unit to the customer;

the customer decrypting the encrypted signed unit to obtain the signed unit; and

using the signed unit as a payment.

4. A method according to claim 3, further including the steps of:

establishing an expiration date for the unit; and

storing the expiration date in the database.

5. A method according to claim 3, wherein the signing step includes the step of using the secure cryptography generator to sign the unit.

6. A method according to claim 3, wherein the signing step includes the step of signing the unit with a non-homomorphic signature.

7. A system for creating and managing electronic cash, comprising the steps:

a secure cryptography generator, including means for receiving an encryption scheme and a cash amount from a customer;

means for establishing a unit representing the cash amount;

means for signing the unit;

wherein the secure cryptography generator encrypt the signed unit using the encryption scheme;

a database for storing the encrypted signed unit and a value for the unit;

means for transmitting the encrypted signed unit to the customer; and

means for the customer to decrypt the encrypted signed unit to obtain the signed unit, wherein the customer is able to use the signed unit as a payment.

8. A system according to claim 7, further including means for establishing an expiration date for the unit, and wherein

the expiration date is stored in the database.

9. A system according to claim 7, wherein the secure cryptography generator includes means for signing the unit.

10. A system according to claim 7, wherein the means for signing includes means for signing the unit with a non-homomorphic signature.

11. A program storage device readable by machine, tangibly embodying a program of instructions executable by the machine to perform method steps for creating and managing electronic cash, said method steps comprising:

using a secure cryptography generator to receive from a customer an encryption scheme and a cash amount;

establishing a unit representing the cash amount;

signing the unit;

using the secure cryptography generator to encrypt the signed unit using the encryption scheme;

storing in a database the encrypted signed unit and a value for the unit;

transmitting the encrypted signed unit to the customer;

decrypting the encrypted signed unit to obtain the signed unit; and

using the signed unit as a payment.

12. A program storage device according to claim 11, wherein said method steps further include the steps of:

establishing an expiration date for the unit; and

storing the expiration date in the database.

13. A program storage device according to claim 11, wherein the signing step includes the step of using the secure cryptography generator to sign the unit.

14. A program storage device according to claim 13, wherein the signing step includes the step of signing the unit with a non-homomorphic signature.