Abstract: A computer-implemented method of generating a secondary transaction identifier of a target transaction which enables a querying user to determine whether the target transaction comprises a candidate data field. The method comprises identifying a set of data fields of the target transaction, each data field comprising respective data of the transaction; and generating a transaction hash tree. Each data field is hashed to generate a respective one of a plurality of leaf hashes of the transaction hash tree. The root hash of the transaction hash tree comprises the secondary transaction identifier.

Abstract: Methods and devices for propagating blocks in a blockchain network. At a mining node, while hashing a first block header of a first candidate block, the mining node sends, to other mining nodes, a first message specifying transactions and their order in a first ordered set of transactions contained in the first candidate block. The mining also receives a second message specifying transactions and their order in a second ordered set of transactions contained in a second candidate block being mined by a second mining node. If the mining node succeeds in mining the candidate block it notifies other mining nodes by providing them with a coinbase transaction, hash value, and timestamp. If another mining node is successful, then the mining node receives information from the other mining node from which, in conjunction with the second message, it can assemble the second candidate block and validate it.