IP Library Granted Patent US 12,470,374
Granted Patent B2
US 12,470,374 · App. 18/533,103 · Granted Nov 11, 2025

Controlled cryptographic private key release

Inventors: John Fletcher (Cambridge, GB); Thomas Trevethan (London, GB)
Assignee: NCHAIN LICENSING AG
H04L9/085H04L9/30H04L9/3213H04L9/3247
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Quick Facts
Patent No.
US 12,470,374
App. No.
18/533,103
Granted
Nov 11, 2025
Kind
B2
Abstract

Techniques are presented to instantiate an event chain with a first block, wherein the first block is timestamped with an instantiation time; monitor for an event associated with a monitoring request; signal to other nodes in a plurality of nodes based on the monitoring by providing a commitment to a plurality of nodes in the plurality of nodes, wherein based on occurrence of the event providing either a dummy signal or an indicator comprising an encryption private key share held by the node, wherein the commitment is provided to the other nodes in the plurality of nodes; monitor for commitments from the other nodes in the plurality of nodes, wherein each commitment comprises a dummy signal or an encryption key share; process the commitments received from the other nodes to obtain an encryption private key share; and identify the encryption private key based on the analysis of the commitments.

Claims (27)

1 . A computer-implemented method of identifying an encryption private key, the method implemented by a node in a plurality of nodes, the method comprising:

instantiating an event chain with a first block, wherein the first block is timestamped with an instantiation time;

monitoring for an event associated with a monitoring request;

signalling to other nodes in a plurality of nodes based on the monitoring by providing a commitment to a plurality of nodes in the plurality of nodes, wherein based on occurrence of the event providing either a dummy signal or an indicator comprising an encryption private key share held by the node, wherein the commitment is provided to the other nodes in the plurality of nodes;

monitoring for commitments from the other nodes in the plurality of nodes, wherein each commitment comprises a dummy signal or an encryption key share;

processing the commitments received from the other nodes to obtain an encryption private key share; and

identifying the encryption private key based on the analysis of the commitments.

2 . The computer-implemented method of claim 1 , wherein an event chain comprises a temporary blockchain.

3 . The computer-implemented method of claim 2 , wherein the event chain is a proof-of-stake blockchain mined by the plurality of nodes that each have stakes encumbered with a group-stake public key.

4 . The computer-implemented method of claim 1 , wherein the blocks of the event chain are generated at an interval specified in the monitoring request.

5 . The computer-implemented method of claim 4 , wherein the interval is selected to be less than a latency the requester indicates for the key release following the event.

6 . The computer-implemented method of claim 1 , wherein the monitoring for the event comprises monitoring of a network server.

7 . The computer-implemented method of claim 1 , wherein the dummy signal is of the same length as the encryption private key share.

8 . The computer-implemented method of claim 1 , wherein the dummy signal is randomly generated by the node.

9 . The computer-implemented method of claim 1 , wherein the commitment further comprises a group-stake public key share for the respective node.

10 . The computer-implemented method of claim 1 , wherein the commitment is signed based on a group-stake private key share held by the node performing the method.

11 . The computer-implemented method of claim 1 , wherein the commitment is provided in a block on the event chain.

12 . The computer-implemented method of claim 11 , wherein each block is time stamped.

13 . The computer-implemented method of claim 1 , wherein the encryption private key is reconstructed based on the encryption private key shares obtained from the other nodes.

14 . The computer-implemented method of claim 13 , wherein the encryption private key is reconstructed in accordance with a threshold key construction scheme.

15 . A non-transitory computer-readable storage medium comprising computer-executable instructions that, when executed, configure a processor to execute operations:

instantiating an event chain with a first block, wherein the first block is timestamped with an instantiation time;

monitoring for an event associated with a monitoring request;

signalling to other nodes in a plurality of nodes based on the monitoring by providing a commitment to a plurality of nodes in the plurality of nodes, wherein based on occurrence of the event providing either a dummy signal or an indicator comprising an encryption private key share held by the node, wherein the commitment is provided to the other nodes in the plurality of nodes;

monitoring for commitments from the other nodes in the plurality of nodes, wherein each commitment comprises a dummy signal or an encryption key share;

processing the commitments received from the other nodes to obtain an encryption private key share; and

identifying the encryption private key based on the analysis of the commitments.

Assignments (2)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Dec 31, 2023
From: FLETCHER, JOHN; TREVETHAN, THOMAS
To: NCHAIN HOLDINGS LTD.
Reel/Frame 065986/0972 →
CHANGE OF NAME Recorded Dec 31, 2023
From: NCHAIN HOLDINGS LTD
To: NCHAIN LICENSING AG
Reel/Frame 066160/0138 →
Priority Claims (1)
GB 1710176 · Jun 26, 2017 · national
Continuity (3)
Continuation 17738895 · May 6, 2022
Continuation 16626294
Related Publication 20240113868A1 · Apr 4, 2024
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