Cross-chain messaging and message validation

A cross-chain messaging mechanism in a first subchain comprising:

• a network interface;
• a processor coupled to the network interface;
• and
• a memory coupled to the processor comprising a public-key-share list and instructions executable by the processor to:
• receive a first message from a first subchain at a second subchain via the network interface, wherein the second subchain comprises a public-key-share list of the first subchain, wherein the first message comprises a threshold signature of the first subchain that indicates the first message is approved by a consensus of a plurality of member nodes of the first subchain according to a pre-agreed-upon consensus protocol know to both the first subchain and the second subchain;
• determine if the message is valid based on validation criteria, comprising (1) determining if the first message is valid based on the public-key-share list, and (2) determining if the first message is valid based on the threshold signature included in the first message, including validating the threshold signature is validated by a group key derived from a plurality of key shares of the public-key-share list of the first subchain stored in the second subchain according to the pre-agreed-upon consensus protocol known to the first subchain and the second subchain;
• and
• respond to the message being concluded valid by executing a transaction based on the message.

A method comprising:

• receiving a message at a first subchain from a second subchain, wherein the first subchain comprises a public-key-share list of the second subchain, wherein the message comprises a threshold signature of the second subchain that indicates the message is approved by a consensus of member nodes of the second subchain according to a pre-agreed-upon consensus protocol know to both the first subchain and the second subchain;
• determining if the message satisfies at least a first validation criterion and a second validation criterion based on the public-key-share list, including determining if the message is valid based on the threshold signature included in the message, including validating the threshold message includes a group public key derived from a plurality of key shares of the public-key-share list of the second subchain according to a pre-agreed-upon consensus protocol known to both the first subchain and the second subchain;
• and
• responsive to the first validation criterion and the second validation criterion being satisfied:
• executing a transaction in the first subchain based on the message.

A method comprising:

• receiving a first message from a first subchain at a smart contract of a second subchain, wherein the smart contract of the second subchain comprises a public-key-share list of the first subchain;
• determining if the first message is valid based on the public-key-share list;
• executing a transaction based on the first message responsive to the first message being determined valid;
• and
• producing a threshold number of signature shares from a signature share comprising m or more signature shares, wherein executing the transaction based on the first message comprises:
• generating a response message within the second subchain;
• aggregating the threshold number of signature shares within the response message from a plurality of nodes of the second subchain;
• and responsive to the threshold number of signature shares being aggregated within the response message:
• generating a threshold signature;
• adding the threshold signature to the response message;
• and
• transmitting the response message to the first subchain.