Zero-knowledge interaction processing system and method

Patent metadata

Field	Value
Publication number	US-2023208643-A1
Application number	US-202117560701-A
Country	US
Kind code	A1
Filing date	Dec 23, 2021
Priority date	Dec 23, 2021
Publication date	Jun 29, 2023
Grant date	—

Abstract

A user device generates an initiate interaction request message comprising a state commitment. The user device provides the initiate interaction request message to a first server computer, which creates a verify state request message comprising an interaction index, an interaction index commitment, and a first commitment signature formed from the state commitment and the interaction index commitment. The user device receives the verify state request message, then generates a modified verify state request message comprising a user device public key, the state commitment, the interaction index commitment, and the first commitment signature. The user device provides the modified verify state request message to a second server computer. The second server computer verifies the state commitment, verifies the first commitment signature, and creates a second commitment signature formed from the state commitment and the interaction index commitment. The user device receives a verify state response message comprising the second commitment signature.

First claim

What is claimed is:

1 . A method comprising:
generating, by a user device, an initiate interaction request message comprising a state commitment; providing, by the user device, the initiate interaction request message to a first server computer, wherein the first server computer creates a verify state request message comprising an interaction index, an interaction index commitment, and a first commitment signature formed from the state commitment and the interaction index commitment; receiving, by the user device, the verify state request message from the first server computer; generating, by the user device, a modified verify state request message comprising a user device public key, the state commitment, the interaction index commitment, and the first commitment signature; providing, by the user device, the modified verify state request message to a second server computer, wherein the second server computer verifies the state commitment, verifies the first commitment signature, and creates a second commitment signature formed from the state commitment and the interaction index commitment; and receiving, by the user device, a verify state response message comprising the second commitment signature from the second server computer.

2 . The method of claim 1 further comprising:
generating, by the user device, an amount commitment based on an amount maintained by the user device:
generating, by the user device, a partial new state based on the user device public key, a new serial number, a new first random value, a new second random value, a new balance amount;
generating, by the user device, a new identifier commitment based on the user device public key and the new serial number;
generating, by the user device, a balance commitment based on the new balance amount;
generating, by the user device, a zero-knowledge proof using at least the interaction index, the state commitment, the amount commitment, the new identifier commitment, and the balance commitment;
generating, by the user device, an interaction request message comprising the interaction index, the state commitment, the amount commitment, the new identifier commitment, the balance commitment, the second commitment signature, and the zero-knowledge proof;
providing, by the user device, the interaction request message to the first server computer, wherein the first server computer evaluates the elements of the interaction request message and generates an interaction completed message, based on the evaluation, comprising a third commitment signature formed from the interaction index and the amount commitment, a fourth commitment signature formed from the new identifier commitment and the balance commitment, and a fifth commitment signature formed from the state commitment and the fourth commitment signature; and
receiving, by the user device, the interaction completed message from the first server computer,

3. The method of claim 2 further comprising:
after receiving the interaction completed message, generating, by the user device, a state update request message comprising the user device public key, the fourth commitment signature, and the fifth commitment signature; and
providing, by the user device, the state update request message to the second server computer, wherein the second server computer verifies the fourth commitment signature and the fifth commitment signature, and stores the fourth commitment signature.

4 . The method of claim 2 further comprising:
generating, by the user device, an interaction submitted notification message comprising the interaction index, the amount, and the third commitment signature; and
providing, by the user device, the interaction submitted notification message to a receiving device.

5 . The method of claim 2 , wherein generating the new partial state further comprises:
obtaining, by the user device, a current state comprising a serial number, the user device public key, a balance amount, a first random value, a second random value, and a state signature; generating, by the user device, the new serial number by incrementing a serial number of the current state by a predetermined amount; determining, by the user device, the new first random value and the new second random value; and determining, by the user device, the new balance amount based on the balance amount and the amount.

6 . The method of claim 1 , wherein the user device is a second user device, wherein the method is an interaction reception method that further comprises:
prior to generating the initiate interaction request message, receiving, by the user device, an interaction submitted notification message from a first user device, wherein the interaction submitted notification message comprises the interaction index, an amount, and a third commitment signature.

7 . The method of claim 6 , wherein the first server computer is an interaction validation computer and the second server computer is a state attestation computer, and the user device is a mobile phone.

8 . The method of claim 1 , wherein the first server computer is an interaction validation computer and the second server computer is a state attestation computer.

9 . The method of claim 1 further comprising:
generating, by the user device, the state commitment using a state signature and a random value chosen from a first random value and a second random value.

10 . The method of claim 9 , wherein the first random value, the second random value, and the state signature are included in a state stored by the user device.

11 . A user device comprising:
a processor; and a computer-readable medium coupled to the processor, the computer-readable medium comprising code executable by the processor for implementing a method comprising:
generating an initiate interaction request message comprising a state commitment;
providing the initiate interaction request message to a first server computer, wherein the first server computer creates an verify state request message comprising an interaction index, an interaction index commitment, and a first commitment signature formed from the state commitment and the interaction index commitment;
receiving the verify state request message from the first server computer;
generating a modified verify state request message comprising a user device public key, the state commitment, the interaction index commitment, and the first commitment signature;
providing the modified verify state request message to a second server computer, wherein the second server computer verifies the state commitment, verifies the first commitment signature, and creates a second commitment signature formed from the state commitment and the interaction index commitment; and
receiving a verify state response message comprising the second commitment signature from the second server computer

12 . The user device of claim 11 , wherein prior to generating the interaction request message, the method further comprises:
enrolling the user device in an interaction processing system comprising the first server computer and the second server computer.

13 . The user device of claim 12 , wherein enrolling in the interaction processing system further comprises:
generating an identifier commitment based on the user device public key, a serial number, and a first random value; generating a balance commitment based on a balance amount and a second random value; generating an enrollment proof based on the identifier commitment, the balance commitment, the user device public key, the balance amount, the first random value, and the second random value; generating an enrollment request

Assignees

• Visa Int Service Ass

Inventors

• Watson Gaven James
• Wagner Kim
• Badrinarayanan Saikrishna
• Raghuraman Srinivasan

Classifications

• H04L9/3247

  involving digital signatures · CPC title

• H04L9/3218 Primary

  using proof of knowledge, e.g. Fiat-Shamir, GQ, Schnorr, ornon-interactive zero-knowledge proofs · CPC title

• H04L63/0407

  wherein the identity of one or more communicating identities is hidden (cryptographic mechanisms or cryptographic arrangements for anonymous credentials or for identity based cryptographic systems H04L9/00) · CPC title

• H04L2209/56

  Financial cryptography, e.g. electronic payment or e-cash · CPC title

• H04L2209/42

  Anonymization, e.g. involving pseudonyms · CPC title