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

Claim 23:
24. A system for determining a common secret between a 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), and the system comprising:
a first processing device, associated with the first node (C), configured to:
determine 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 the second node;
determine a second node second public key (P2S) based on at least the second node master public key (P1S) and the deterministic key (DK); and
determine 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 can be determined by a second processing device, associated with the second node (S), configured to:
determine a first node second public key (P2C) based on at least the first node master public key (P1C) and the deterministic key (DK);
determine a second node second private key (V2S) based on at least the second node master private key (V1S) and the deterministic key (DK); and
determine the common secret based on the first node second public key (P2C) and a second node second private key (V2S).