Patent ID: 11936774
Assignee: NCHAIN LICENSING AG
Field: Digital communication (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A computer-implemented method of determining, at a first node (C), a common secret (CS) that is common with the first node (C) and a second node (S), wherein the first node (C) is associated with a first asymmetric cryptography pair of a cryptography system common to the first node and the second node and having a homomorphic property, the first asymmetric cryptography pair having a first node master private key (V1C) and a first node master public key (P1C), and the second node (S) is associated with a second asymmetric cryptography pair of the cryptography system, the second asymmetric cryptography pair having a second node master private key (V1S) and a second node master public key (P1S), the method comprises:
determining a first node second private key (V2C) based on at least the first node master private key (V1C) and a deterministic key (DK), wherein the deterministic key is common to the first node and second node;
determining a second node second public key (P2S) based on at least the second node master public key (P1S) and the deterministic key (DK); and
determining the common secret (CS) based on the first node second private key (V2C) and the second node second public key (P2S),
wherein the same common secret (S) can be determined at the second node (S) based on a first node second public key (P2C) and a second node second private key (V2S), wherein:
the first node second public key (P2C) is based on at least the first node master public key (P1C) and the deterministic key (DK); and
the second node second private key (V2S) is based on at least the second node master private key (V1S) and the deterministic key (DK).