Method and system for enabling traceable privacy-maintaining multi-hop offline transactions in digital currencies

Patent metadata

Field	Value
Publication number	US-11900367-B2
Application number	US-202117550596-A
Country	US
Kind code	B2
Filing date	Dec 14, 2021
Priority date	Dec 14, 2021
Publication date	Feb 13, 2024
Grant date	Feb 13, 2024

Abstract

A method for processing offline cryptocurrency transfers includes: receiving, by a receiver of a computing device, a first transfer message, wherein the first transfer message is cryptographically signed using a first private key of a first key pair; validating, by a processor of the computing device, the cryptographic signature of the first transfer message using a first public key of the first key pair; storing, in a memory of the computing device, the validated first transfer message; receiving, by an input device of the computing device, a transfer instruction, the transfer instruction including at least a communication address; and electronically transmitting, by a transmitter of the computing device, the validated first transfer message to an external device based on at least the communication address.

First claim

What is claimed is:

1. A method for processing offline cryptocurrency transfers, comprising:
storing, in a computing device, a blockchain wallet having access to an amount of cryptographic currency on a blockchain associated with a blockchain network;
storing, in a secure element of the computing device, a first public key of a first key pair;
communicating, by the computing device, with a blockchain node in the blockchain network, to request a cryptographically signed issuing transfer message;
receiving, by a receiver of the computing device, from the blockchain node in the blockchain network, a first transfer message that is cryptographically signed by the blockchain node using a first private key of the first key pair and is associated with a transfer of cryptographic currency to the computing device that has already been published to the blockchain associated with the blockchain network;
validating, by a processor of the computing device, the cryptographic signature of the first transfer message using the first public key of the first key pair stored in the secure element of the computing device, wherein said validation ensures that the transfer message will be honored by the blockchain network after an offline transaction is made;
storing, in a memory of the computing device, the validated first transfer message;
receiving, by an input device of the computing device, a transfer instruction, the transfer instruction including at least a communication address;
generating, by the processor of the computing device, a data container by wrapping the first validated first transfer message with a second transfer message; and
electronically transmitting, by a transmitter of the computing device, the data container to an external device based on at least the communication address.

2. The method of claim 1 , further comprising:
generating, by the processor of the computing device, the second transfer message, wherein the second transfer message includes at least a payment amount, a destination reference, and a reference to the first transfer message.

3. The method of claim 2 , wherein the destination reference and payment amount are included in the received transfer instruction.

4. The method of claim 2 , wherein the destination reference is a second public key of a second key pair.

5. The method of claim 4 , further comprising:
receiving, by the receiver of the computing device, the second public key from the external device.

6. The method of claim 2 , further comprising:
cryptographically signing, by the processor of the computing device, the generated second transfer message using a second private key of a second key pair.

7. The method of claim 1 , wherein the memory is the Secure Element.

8. The method of claim 1 , wherein the memory is inaccessible by a user of the computing device.

9. A system for processing offline cryptocurrency transfers, comprising:
a blockchain network;
an external device; and
a computing device including
a memory storing a blockchain wallet having access to an amount of cryptographic currency on a blockchain associated with the blockchain network,
a secure element storing a first public key of a first key pair,
a transmitter communicating with a blockchain node in the blockchain network to request a cryptographically signed issuing transfer message,
a receiver receiving, from the blockchain node in the blockchain network, a first transfer message that is cryptographically signed by the blockchain node using a first private key of the first key pair and is associated with a transfer of cryptographic currency to the computing device that has already been published to the blockchain associated with the blockchain network,
a processor validating the cryptographic signature of the first transfer message using the first public key of the first key pair stored in the secure element of the computing device, wherein said validation ensures that the transfer message will be honored by the blockchain network after an offline transaction is made, and
an input device, wherein
the memory further stores the validated first transfer message,
the input device a transfer instruction, the transfer instruction including at least a communication address,
the processor generates a data container by wrapping the first validated first transfer message with a second transfer message, and
the transmitter electronically transmits the data container to an external device based on at least the communication address.

10. The system of claim 9 , wherein the processor of the computing device generates the second transfer message, wherein the second transfer message includes at least a payment amount, a destination reference, and a reference to the first transfer message.

11. The system of claim 10 , wherein the destination reference and payment amount are included in the received transfer instruction.

12. The system of claim 10 , wherein the destination reference is a second public key of a second key pair.

13. The system of claim 12 , wherein the receiver of the computing device receives the second public key from the external device.

14. The system of claim 10 , wherein the processor of the computing device cryptographically signs the generated second transfer message using a second private key of a second key pair.

15. The system of claim 9 , wherein the memory is the Secure Element.

16. The system of claim 9 , wherein the memory is inaccessible by a user of the computing device.

17. The method of claim 1 , wherein the data container is a payment message.

18. The system of claim 9 , wherein the data container is a payment message.

Assignees

• Mastercard International Inc

Inventors

• Higgins Stephen

Classifications

• H04L9/50

  using hash chains, e.g. blockchains or hash trees · CPC title

• H04L9/3247

  involving digital signatures · CPC title

• H04L9/0819

  Key transport or distribution, i.e. key establishment techniques where one party creates or otherwise obtains a secret value, and securely transfers it to the other(s) (network architectures or network communication protocols for key distribution in a packet data network H04L63/062) · CPC title

• G06Q20/38215

  Use of certificates or encrypted proofs of transaction rights · CPC title

• G06Q20/409

  Device specific authentication in transaction processing · CPC title