Abstract: A computer-implemented method for generating a challenge blockchain transaction, wherein the challenge blockchain transaction is associated with a puzzle and a proof criterion, wherein the puzzle is satisfied by a puzzle solution, and wherein the proof criterion is satisfied by a proof, the method comprising: generating a first locking script of the challenge blockchain transaction which, when executed with a first unlocking script of a solution blockchain transaction comprising a candidate puzzle solution, a public key, a candidate proof, and a signature generated for the solution blockchain transaction is configured to: verify that the candidate puzzle solution satisfies the puzzle; verify that the signature is valid for the public key; and verify that the candidate proof satisfies the proof criterion, wherein the proof criterion requires that the candidate proof is derived from the candidate puzzle solution and the public key; and making the challenge blockchain transaction available to one or more nodes o

Abstract: A computer-implemented method for generating a puzzle blockchain transaction. A first locking script of the puzzle blockchain transaction is provided, the first locking script corresponding to a first unspent transaction output and comprising a hash value derived from a target solution of a time-lock puzzle, and a set of puzzle parameters of the time-lock puzzle. The target solution is computed using a set of secret puzzle parameters. The time-lock puzzle is solvable using the set of puzzle parameter in a time equal to or greater than a minimum solving time. The set of puzzle parameters does not comprise the secret puzzle parameters. The locking script is configured to, when executed with a first unlocking script of a solution blockchain transaction, verify a candidate solution, computed using the set of puzzle parameters, provided in the first unlocking script of the solution blockchain transaction based on the hash value.

Abstract: A computer implemented method for time-locking a blockchain transaction. The method comprises computing a solution to a time-lock puzzle using a set of secret puzzle parameters. The time-lock puzzle is solvable using a set of puzzle parameter in a time equal to or greater than a minimum solving time. The set of puzzle parameters does not comprise the secret puzzle parameters. The method further comprises generating a transaction encryption key K, encrypting the blockchain transaction using the encryption key K, and encrypting the transaction encryption key K using the solution to the time-lock puzzle.