System and method for information protection

Patent metadata

Field	Value
Publication number	US-11277389-B2
Application number	US-201816342605-A
Country	US
Kind code	B2
Filing date	Nov 27, 2018
Priority date	Nov 27, 2018
Publication date	Mar 15, 2022
Grant date	Mar 15, 2022

Abstract

A computer-implemented method comprises: committing a transaction amount of a transaction with a commitment scheme to obtain a transaction commitment value, the commitment scheme comprising at least a transaction blinding factor; generating a first key of a symmetric key pair; encrypting a combination of the transaction blinding factor and the transaction amount t with the first key; and transmitting the transaction commitment value T and the encrypted combination to a recipient node associated with a recipient of the transaction for the recipient node to verify the transaction. The first key is a symmetrical key generated with Diffie-Hellman (DH) key exchange protocol that can be used to encrypt/decrypt the random numbers and the plaintext balances, thus providing convenient management. The method provides a robust privacy protection for transaction amounts, asset values, and blinding factors in commitment schemes.

First claim

The invention claimed is:

1. A computer-implemented method for information protection, comprising:
obtaining a first combination of a transaction blinding factor r_t and a transaction amount t encrypted with a first key of a symmetric key pair, a second combination of a change blinding factor r_y and a change y encrypted with another key generated based on a private key SK_A and a public key PK_A of a sender of a transaction, and obtaining a transaction commitment value T and a change commitment value Y, wherein: the change y indicates an excess over the transaction amount t, the transaction amount t is committed with a commitment scheme by a sender node associated with the sender to obtain the transaction commitment value T, the change y is committed with the commitment scheme to obtain the change commitment value Y, the commitment scheme comprising at least the transaction blinding factor r_t;
generating a second key of the symmetric key pair;
decrypting the obtained first combination with the second key generated by a recipient node associated with a recipient of the transaction to obtain the transaction blinding factor r_t and the transaction amount t; and
verifying the transaction based at least on the transaction commitment value T, the transaction blinding factor r_t, and the transaction amount t.

2. The method of claim 1 , wherein:
generating the second key of the symmetric key pair comprises generating the second key of the symmetric key pair based on a private key SK_B of the recipient and the public key PK_A of the sender under Diffie-Hellman (DH) key exchange protocol; and
the commitment scheme comprises a Pedersen commitment based at least on the transaction blinding factor r_t and with the transaction amount t being a committed value.

3. The method of claim 1 , wherein:
the first key is generated by the sender node based on the private key SK_A of the sender of the transaction and a public key PK_B of the recipient of the transaction.

4. The method of claim 1 , wherein:
the first combination of the transaction blinding factor r_t and the transaction amount t comprises a concatenation of the transaction blinding factor r_t and the transaction amount t.

5. The method of claim 1 , wherein verifying the transaction based at least on the transaction commitment value T, the transaction blinding factor r_t, and the transaction amount t comprises:
in response to determining that the transaction commitment value T does not match the commitment scheme of the transaction amount t based on the transaction blinding factor r_t, rejecting the transaction; and
in response to determining that the transaction commitment value T matches the commitment scheme of the transaction amount t based on the transaction blinding factor r_t, approving the transaction by signing the transaction to generate a recipient signature SIGB to return to the sender node associated with the sender.

6. The method of claim 5 , further comprising:
transmitting the recipient signature SIGB to the sender node for the sender node to:
verify the recipient signature SIGB;
in response to successfully verifying the recipient signature SIGB, approve the transaction by signing the transaction with the private key SK_A of the sender to generate a sender signature SIGA, and submit information of the transaction to one or more nodes in a blockchain network for the one or more nodes to verify the transaction; and
in response to not successfully verifying the recipient signature SIGB, reject the transaction.

7. The method of claim 6 , wherein the information of the transaction comprises:
the first combination of the transaction blinding factor r_t and the transaction amount t encrypted with the first key of the symmetric key pair, the second combination of the change blinding factor r_y and the change y encrypted with the key generated based on the private key SK_A and the public key PK_A of the sender, the transaction commitment value T, the change commitment value Y committing the change y of the transaction with the commitment scheme, the sender signature SIGA, and the recipient signature SIGB.

8. A non-transitory computer-readable storage medium storing instructions to be executed by one or more processors to cause the one or more processors to perform operations comprising:
obtaining a first combination of a transaction blinding factor r_t and a transaction amount t encrypted with a first key of a symmetric key pair, a second combination of a change blinding factor r_y and a change y encrypted with another key generated based on a private key SK_A and a public key PK_A of a sender of a transaction, and obtaining a transaction commitment value T and a change commitment value Y, wherein: the change y indicates an excess over the transaction amount t, the transaction amount t is committed with a commitment scheme by a sender node associated with the sender to obtain the transaction commitment value T, the change y is committed with the commitment scheme obtain the change commitment value Y, the commitment scheme comprising at least the transaction blinding factor r_t;
generating a second key of the symmetric key pair;
decrypting the obtained first combination with the second key generated by a recipient node associated with a recipient of the transaction to obtain the transaction blinding factor r_t and the transaction amount t; and
verifying the transaction based at least on the transaction commitment value T, the transaction blinding factor r_t, and the transaction amount t.

9. The storage medium of claim 8 , wherein:
generating the second key of the symmetric key pair comprises generating the second key of the symmetric key pair based on a private key SK_B of the recipient and the public key PK_A of the sender under Diffie-Hellman (DH) key exchange protocol; and
the commitment scheme comprises a Pedersen commitment based at least on the transaction blinding factor r_t and with the transaction amount t being a committed value.

10. The storage medium of claim 8 , wherein:
the first key is generated by the sender node based on the private key SK_A of the sender of the transaction and a public key PK_B of the recipient of the transaction.

11. The storage medium of claim 8 , wherein:
the first combination of the transaction blinding factor r_t and the transaction amount t comprises a concatenation of the transaction blinding factor r_t and the transaction amount t.

12. The storage medium of claim 8 , wherein verifying the transaction based at least on the transaction commitment value T, the transaction blinding factor r_t, and the transaction amount t comprises:
in response to determining that the transaction commitment value T does not match the commitment scheme of the transaction amount t based on the transaction blinding factor r_t, rejecting the transaction; and
in response to determining that the transaction commitment value T matches the commitment scheme of the transaction amount t based on the transaction blinding factor r_t, approving the transaction by signing the transaction to generate a recipient signature SIGB to return to the sender node associated with the sender.

13. The storage medium of claim 12 , wherein the operations further comprise:
transmitting the recipient signature SIGB to the sender node for the sender node to:
verify the recipient signature SIGB;
in response to successfully verifying the recipient signature SIGB, approve the transaction by signing the transaction with the private key SK_A of the sender to generate a sender signature SIGA, and submit information of the transaction to one or more nodes in a blockchain network for the one

Assignees

• Advanced New Technologies Co Ltd

Inventors

• Ma Baoli
• Zhang Wenbin
• Ma Huanyu
• Liu Zheng
• Cui Jiahui

Classifications

• H04L9/50

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

• H04L2209/04

  Masking or blinding · CPC title

• H04L2209/56

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

• H04L2209/046

  of operations, operands or results of the operations · CPC title

• H04L9/3247

  involving digital signatures · CPC title