US 12,445,277 B2
Threshold key exchange
Michaella Pettit, London (GB)
Assigned to nChain Licensing AG, Zug (CH)
Appl. No. 18/275,372
Filed by nChain Licensing AG, Zug (CH)
PCT Filed Jan. 5, 2022, PCT No. PCT/EP2022/050116
§ 371(c)(1), (2) Date Aug. 1, 2023,
PCT Pub. No. WO2022/167163, PCT Pub. Date Aug. 11, 2022.
Claims priority of application No. 2101590 (GB), filed on Feb. 5, 2021.
Prior Publication US 2024/0097894 A1, Mar. 21, 2024
Int. Cl. H04L 9/08 (2006.01)
CPC H04L 9/0861 (2013.01) [H04L 9/0825 (2013.01); H04L 9/085 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A computer-implemented method of generating a shared cryptographic key based on at least one shared secret, wherein each participant belonging to a first group has a respective share of a first secret, the first secret having a first threshold number and a corresponding first public key, wherein a second coordinator has a second public key corresponding to a second secret, and wherein the method is performed by a first coordinator of the first group and comprises:
obtaining, from at least the first threshold number of participants of the first group, respective shares of the shared cryptographic key, where each respective share of the shared cryptographic key is based on i) a respective zeroth order coefficient of a respective private polynomial used to calculate the respective share of the first secret, and ii) the second public key; and
generating the shared cryptographic key based on the obtained respective shares of the cryptographic key, wherein the second coordinator is configured to generate the same shared cryptographic key.