Blockchain-based transaction method and apparatus, and remitter device

Patent metadata

Field	Value
Publication number	US-11032077-B2
Application number	US-202017079362-A
Country	US
Kind code	B2
Filing date	Oct 23, 2020
Priority date	Sep 20, 2018
Publication date	Jun 8, 2021
Grant date	Jun 8, 2021

Abstract

Implementations of the present specification provide a blockchain-based transaction method and apparatus, and a remitter device. The method includes: calculating a transaction amount commitment, a first commitment random number ciphertext, a first transaction amount ciphertext, a second commitment random number ciphertext, and a second transaction amount ciphertext; and submitting transaction data to the blockchain, the transaction data including the transaction amount commitment, the first commitment random number ciphertext, the first transaction amount ciphertext, the second commitment random number ciphertext, and the second transaction amount ciphertext, for the transaction amount commitment, the first commitment random number ciphertext, and the first transaction amount ciphertext to be recorded into a remitter account, and the transaction amount commitment, the second commitment random number ciphertext, and the second transaction amount ciphertext to be recorded into a remittee account.

First claim

What is claimed is:

1. A blockchain-based transaction method, comprising:
calculating a transaction amount commitment based on a commitment random number and a transaction amount involving a remitter account and a remitter account with respect to a blockchain;
obtaining a first commitment random number ciphertext and a first transaction amount ciphertext by encrypting the commitment random number and the transaction amount separately based on a homomorphic encryption public key of the remitter account using a homomorphic encryption algorithm;
obtaining a second commitment random number ciphertext and a second transaction amount ciphertext by encrypting the commitment random number and the transaction amount separately based on a homomorphic encryption public key of the remittee account using the homomorphic encryption algorithm; and
submitting transaction data to the blockchain, the transaction data including the transaction amount commitment, the first commitment random number ciphertext, the first transaction amount ciphertext, the second commitment random number ciphertext, and the second transaction amount ciphertext, for the transaction amount commitment, the first commitment random number ciphertext, and the first transaction amount ciphertext to be recorded into the remitter account, and the transaction amount commitment, the second commitment random number ciphertext, and the second transaction amount ciphertext to be recorded into the remittee account.

2. The method according to claim 1 , wherein the remitter account registers a remitter balance commitment, a remitter random number ciphertext, and a remitter balance ciphertext in the blockchain; the remitter balance commitment is calculated based on a remitter random number and a remitter balance; the remitter random number ciphertext is calculated based on the remitter random number by using the homomorphic encryption algorithm; the remitter balance ciphertext is calculated based on the remitter balance by using the homomorphic encryption algorithm; and
wherein the remittee account registers a remittee balance commitment, a remittee random number ciphertext, and a remittee balance ciphertext in the blockchain; the remittee balance commitment is calculated based on a remittee random number and a remittee balance; the remittee random number ciphertext is calculated based on the remittee random number by using the homomorphic encryption algorithm; the remittee balance ciphertext is calculated based on the remittee balance by using the homomorphic encryption algorithm.

3. The method according to claim 2 , wherein the transaction amount commitment, the first transaction amount ciphertext, and the first commitment random number ciphertext are recorded into the remitter account by:
updating the remitter balance commitment based on the transaction amount commitment, updating the remitter random number ciphertext based on the first commitment random number ciphertext, and updating the remitter balance ciphertext based on the first transaction amount ciphertext; and
 wherein the transaction amount commitment, the second transaction amount ciphertext, and the second commitment random number ciphertext are recorded into the remittee account by:
updating the remittee balance commitment based on the transaction amount commitment, updating the remittee random number ciphertext based on the second commitment random number ciphertext, and updating the remittee balance ciphertext based on the second transaction amount ciphertext.

4. The method according to claim 3 , wherein an updated remitter balance commitment is a quotient of the remitter balance commitment and the transaction amount commitment; an updated remitter random number ciphertext is a quotient of the remitter random number ciphertext and the first commitment random number ciphertext; and an updated remitter balance ciphertext is a quotient of the remitter balance ciphertext and the first transaction amount ciphertext; and
wherein an updated remittee balance commitment is a product of the remittee balance commitment and the transaction amount commitment; an updated remittee random number ciphertext is a product of the remittee random number ciphertext and the second commitment random number ciphertext; and an updated remittee balance ciphertext is a product of the remittee balance ciphertext and the second transaction amount ciphertext.

5. The method according to claim 1 , wherein the obtaining the first commitment random number ciphertext and the first transaction amount ciphertext includes:
obtaining the first commitment random number ciphertext by encrypting the commitment random number based on a first encryption random number and the homomorphic encryption public key of the remitter account using the homomorphic encryption algorithm; and
obtaining the first transaction amount ciphertext by encrypting the transaction amount based on a second encryption random number and the homomorphic encryption public key of the remitter account using the homomorphic encryption algorithm.

6. The method according to claim 1 , wherein the obtaining the second commitment random number ciphertext and the second transaction amount ciphertext includes:
obtaining the second commitment random number ciphertext by encrypting the commitment random number based on a third encryption random number and the homomorphic encryption public key of the remittee account using the homomorphic encryption algorithm; and
obtaining the second transaction amount ciphertext by encrypting the transaction amount based on a fourth encryption random number and the homomorphic encryption public key of the remittee account using the homomorphic encryption algorithm.

7. The method according to claim 1 , comprising:
before the submitting the transaction data to the blockchain,
generating a first zero-knowledge proof, the first zero-knowledge proof configured to verify that the transaction amount is not less than 0;
wherein the transaction data includes the first zero-knowledge proof.

8. The method according to claim 1 , comprising:
before the submitting the transaction data to the blockchain,
generating a second zero-knowledge proof, the second zero-knowledge proof configured to verify that the transaction amount is not greater than the remitter balance;
wherein the transaction data includes the second zero-knowledge proof.

9. The method according to claim 1 , comprising:
before the submitting the transaction data to the blockchain,
generating a third zero-knowledge proof, the third zero-knowledge proof configured to verify that the commitment random number for calculating the transaction amount commitment is consistent with the commitment random number for calculating the second commitment random number ciphertext, and verify that the transaction amount for calculating the transaction amount commitment is consistent with the transaction amount for calculating the second transaction amount ciphertext;
wherein the transaction data includes the third zero-knowledge proof.

10. The method according to claim 1 , comprising:
before the submitting the transaction data to the blockchain,
obtaining signature data by signing the transaction data using a signature private key of the remitter account;
wherein the transaction data includes the signature data.

11. The method according to claim 1 , wherein the calculating the transaction amount commitment based on the commitment random number and the transaction amount includes:
obtaining a first transaction amount commitment based on a first commitment random number and the transaction amount, and obtaining a second transaction amount commitment based on a second commitment

Assignees

• Advanced New Technologies Co Ltd

Inventors

• Ma Baoli
• Zhang Wenbin

Classifications

• H04L9/50

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

• H04L63/123

  received data contents, e.g. message integrity · CPC title

• H04L2209/42

  Anonymization, e.g. involving pseudonyms · CPC title

• H04L9/008

  involving homomorphic encryption · CPC title

• H04L2209/56

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