Abstract: A computer-implemented method of implementing a token protocol using a blockchain, wherein the method is performed by a first party and comprises: obtaining a first blockchain transaction, the first blockchain transaction comprising a first output comprising a first locking script, the first locking script comprising token data; constructing a Merkle tree based on the first locking script, wherein the token data is divided across one or more leaves of the Merkle tree; generating a first signature based on a first message comprising a Merkle root of the Merkle tree; and making the first signature available for inclusion in a second output of the first blockchain transaction.

Abstract: A computer-implemented method of redacting data of a blockchain transaction, wherein the method comprises: obtaining a first blockchain transaction, the first blockchain transaction comprising one or more respective scripts comprising respective target data to be redacted; for at least one of the one or more respective scripts, constructing a respective Merkle tree based on the respective script, wherein the respective target data is divided across one or more of the respective leaves of the respective Merkle tree, and generating a redacted version of the first blockchain transaction by replacing the at least one respective script with a respective Merkle root of the respective Merkle tree.

Abstract: A computer implemented method of providing proof of an ordered sequence of events, the method performed on a computing device and comprising: receiving a transaction; creating a further transaction to be sent to a further computing device; obtaining proof data associated with the further transaction that provides proof to the further computing device that the further transaction is linked to an initial transaction in a transaction chain comprising the transaction, wherein the initial transaction relates to an initial event in the ordered sequence of events, and the proof data comprises: (i) a proof; (ii) an identifier of the transaction; and (iii) a unique identifier of the initial transaction; and sending the further transaction and the proof data to the further computing device.

Abstract: A method for blocking sensitive data in a message, the method performed on a computing device and comprising: creating a copy of said message; generating at least one zero knowledge proof, the generating of each of said at least one zero knowledge proof comprising: obtaining a mask bit string which identifies locations of at least one sensitive bit in bits of said copy; computing a public bit string by modifying said bits of said copy by assigning the at least one sensitive bit with a predetermined value; determining a secret bit string which includes said at least one sensitive bit and satisfies a requirement that said bits of said copy are equal to an output of a bitwise logical calculation using the public bit string, the mask bit string and the secret bit string; hashing the copy of said message or a portion thereof to generate an output hash value; and generating a zero knowledge proof using the public bit string, the mask bit string, the output hash value, the secret bit string; removing each of said at

Abstract: Systems and methods for validating information of a user by registering a user private identifier to a registry may generate a user public key and a user private key, the keys together forming a user cryptographic public/private key pair, generate generating a nonce value using a cryptographic random generator, generate the user public identifier, wherein the user public identifier is a hash value generated by applying a cryptographic hash function to: the user public key, the nonce value, and at least one identity trait that the user has previously registered with the registry, sign the user public identifier with the user private key to obtain a signed user public identifier, generate a zero knowledge proof of the at least one identity trait; and transmit to the registry computer system: the user public identifier, the signed user public identifier, the user public key, and the zero knowledge proof.