# US 10,873,449 B2 · Key data processing method and apparatus, and server

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- Number: US 10,873,449 B2
- Document ID: US10873449B2
- Status: Granted
- Kind: B2
- Application number: 16/113,722
- Filed: 2018-08-27
- Published: 2020-04-30
- Granted: 2020-12-22
- Earliest claimed: 2017-08-28
- Assignees: Advanced New Technologies Co., Ltd.
- Applicants: Advanced New Technologies Co., Ltd.
- Inventors: Hao Wu
- Web page: https://patentgrep.com/patent/US10873449B2

## CPC

- H04L 9/0819: {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)}
- G06F 9/30029: {Logical and Boolean instructions, e.g. XOR, NOT}
- G06Q 20/367: {involving electronic purses or money safes}
- G06Q 20/3829: {involving key management}
- H04L 9/0637: {Modes of operation, e.g. cipher block chaining [CBC], electronic codebook [ECB] or Galois/counter mode [GCM]}
- H04L 9/083: {involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP]}
- H04L 9/085: {Secret sharing or secret splitting, e.g. threshold schemes}
- H04L 9/0869: {involving random numbers or seeds}
- H04L 9/14: using a plurality of keys or algorithms
- H04L 9/50: {using hash chains, e.g. blockchains or hash trees}
- H04L 2209/24: Key scheduling, i.e. generating round keys or sub-keys for block encryption
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- G06Q: INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR

## Abstract

A parent cryptographic key associated with a blockchain object is obtained. A number of parties (N) to share control over the blockchain object is obtained. N child cryptographic keys are generated based on the parent cryptographic key by applying a predetermined algorithm to the parent cryptographic key, wherein N is an integer greater than or equal to 2, and wherein the N child cryptographic keys are collectively configured to enable reconstruction of the parent cryptographic key.

## Claims

### Claim 1

A computer-implemented method for managing shared ownership in a block chain network, the method comprising:
obtaining a parent cryptographic key associated with a blockchain object and one or more assets owned by a number of parties; and
responsive to detecting a change in the one or more assets or a change in the number of parties that own the one or more assets,
generating N child cryptographic keys CX based on the parent cryptographic key by applying a predetermined algorithm to the parent cryptographic key, wherein N is an integer greater than or equal to 2 and corresponds to a current number of parties that own the one or more assets;
wherein applying the predetermined algorithm comprises
generating N−1 random numbers Ri, wherein i is an integer between 1 and N−1 and Ri is a non-negative integer, determining a prime number P greater than at least one of a value S of the parent cryptographic key or the random numbers Ri, wherein the random numbers Ri range from 0 to P−1, and
generating the N child cryptographic keys CX by performing a modulo operation on P using a summation of the value S and one or more terms that include Ri multiplied by a value from 1 to N to obtain the child cryptographic keys CX, wherein the one or more terms depend on the current number of parties N, and
wherein the N child cryptographic keys CX are collectively configured to enable reconstruction of the parent cryptographic key.

### Claim 2 (depends on 1)

The computer-implemented method of claim 1, further comprising:
transmitting the N child cryptographic keys to corresponding parties; and
deleting the parent cryptographic key.

### Claim 3 (depends on 1)

The computer-implemented method of claim 1, wherein applying the predetermined algorithm comprises:
calculating the child cryptographic keys CX according to the following equation:
CX=P mod(S+Σm=1N-1RmXm).

### Claim 4 (depends on 1)

The computer-implemented method of claim 1, wherein applying the predetermined algorithm to the parent cryptographic key comprises:
modifying the parent cryptographic key based on a randomly generated character string.

### Claim 5 (depends on 1)

The computer-implemented method of claim 1, further comprising:
receiving a plurality of cryptographic keys;
determining that a number of received plurality of cryptographic keys is equal to the number of parties sharing control over the blockchain object; and
in response to determining that a number of received plurality of cryptographic keys is equal to the number of parties sharing control over the blockchain object, reconstructing the parent cryptographic key by applying a reconstruction algorithm to the received plurality of cryptographic keys.

### Claim 6

A non-transitory, computer-readable medium storing one or more instructions executable by a computer system to perform operations comprising:
obtaining a parent cryptographic key associated with a blockchain object and one or more assets owned by a number of parties; and
responsive to detecting a change in the one or more assets or a change in the number of parties that own the one or more assets,
generating N child cryptographic keys CX based on the parent cryptographic key by applying a predetermined algorithm to the parent cryptographic key, wherein N is an integer greater than or equal to 2 and corresponds to a current number of parties that own the one or more assets;
wherein applying the predetermined algorithm comprises
generating N−1 random numbers Ri, wherein i is an integer between 1 and N−1 and Ri is a non-negative integer, determining a prime number P greater than at least one of a value S of the parent cryptographic key or the random numbers Ri, wherein the random numbers Ri range from 0 to P−1, and
generating the N child cryptographic keys CX by performing a modulo operation on P using a summation of the value S and one or more terms that include Ri multiplied by a value from 1 to N to obtain the child cryptographic keys CX, wherein the one or more terms depend on the current number of parties N, and
wherein the N child cryptographic keys CX are collectively configured to enable reconstruction of the parent cryptographic key.

### Claim 7 (depends on 6)

The non-transitory, computer-readable medium of claim 6, wherein the operations further comprise:
transmitting the N child cryptographic keys to corresponding parties; and
deleting the parent cryptographic key.

### Claim 8 (depends on 6)

The non-transitory, computer-readable medium of claim 6, wherein applying the predetermined algorithm comprises:
calculating the child cryptographic keys CX according to the following equation:
CX=P mod(S+Σm=1N-1RmXm).

### Claim 9 (depends on 6)

The non-transitory, computer-readable medium of claim 6, wherein applying the predetermined algorithm to the parent cryptographic key comprises:
modifying the parent cryptographic key based on a randomly generated character string.

### Claim 10 (depends on 6)

The non-transitory, computer-readable medium of claim 6, wherein the operations further comprise:
receiving a plurality of cryptographic keys;
determining that a number of received plurality of cryptographic keys is equal to the number of parties sharing control over the blockchain object; and
in response to determining that a number of received plurality of cryptographic keys is equal to the number of parties sharing control over the blockchain object, reconstructing the parent cryptographic key by applying a reconstruction algorithm to the received plurality of cryptographic keys.

### Claim 11

A computer-implemented system, comprising:
one or more computers; and
one or more computer memory devices interoperably coupled with the one or more computers and having tangible, non-transitory, machine-readable media storing one or more instructions that, when executed by the one or more computers, perform one or more operations comprising:
obtaining a parent cryptographic key associated with a blockchain object and one or more assets owned by a number of parties; and
responsive to detecting a change in the one or more assets or a change in the number of parties that own the one or more assets,
generating N child cryptographic keys CX based on the parent cryptographic key by applying a predetermined algorithm to the parent cryptographic key, wherein N is an integer greater than or equal to 2 and corresponds to a current number of parties that own the one or more assets:
wherein applying the predetermined algorithm comprises
generating N−1 random numbers Ri, wherein i is an integer between 1 and N−1 and Ri is a non-negative integer, determining a prime number P greater than at least one of a value S of the parent cryptographic key or the random numbers Ri, wherein the random numbers Ri range from 0 to P−1, and
generating the N child cryptographic keys CX by performing a modulo operation on P using a summation of the value S and one or more terms that include Ri multiplied by a value from 1 to N to obtain the child cryptographic keys CX, wherein the one or more terms depend on the current number of parties N, and
wherein the N child cryptographic keys CX are collectively configured to enable reconstruction of the parent cryptographic key.

### Claim 12 (depends on 11)

The computer-implemented system of claim 11, wherein the operations further comprise:
transmitting the N child cryptographic keys to corresponding parties; and
deleting the parent cryptographic key.

### Claim 13 (depends on 11)

The computer-implemented system of claim 11, wherein applying the predetermined algorithm comprises:
calculating the child cryptographic keys CX according to the following equation:
CX=P mod(S+Σm=1N-1RmXm).

### Claim 14 (depends on 11)

The computer-implemented system of claim 11, wherein applying the predetermined algorithm to the parent cryptographic key comprises:
modifying the parent cryptographic key based on a randomly generated character string.