Patent attributes
At least one proof transaction for recording on a blockchain comprises at least an s-part for an Elliptic Curve Digital Signature Algorithm, ECDSA, signature. The s-part is computed from a set of signature components, each provided by a participant of a signing subset of a set of keyshare participants. Each of keyshare participant holds an ephemeral keyshare of an unknown ephemeral key, and each of the signing components is provided by the participant of the signing subset based on their ephemeral keyshare. The at least one proof transaction indicates an r-challenge of at least one challenge transaction, and a node of a blockchain network applies signature verification to: (i) the s-part of the at least one proof transaction, and (ii) one of: (iia) an r-part of the r-challenge, (iib) an r-part of the at least one proof transaction, and in that event checks that that r-part satisfies the r-challenge.
