nChain Holdings Limited

A method of encrypting data is disclosed. The method comprises determining, at a first node associated with a first public-private key pair of a cryptography system having a first private key (V A ) and a first public key (P A ), a common secret (S 1 ) common with the first node and a second node, wherein the second node is associated with a second public-private key pair of the cryptography system having a second private key (V B ) and a second public key (P B ). The common secret is determined on the basis of the first private key and the second public key, and the properties of the cryptography system are such that the common secret can be determined on the basis of the second private key and the first public key. An encryption key, based on the common secret, is determined for encryption of data (M), and the data is encrypted on the basis of the encryption key, wherein the step of encrypting data includes an exclusive or (XOR) operation.

A method of encrypting data at an electronic device where the electronic device is associated with a key device. Each device is associated with an asymmetric cryptography pair, each pair including a first private key and a first public key. Respective second private and public keys may be determined based on the first private key, first public key and a deterministic key. A secret may be determined based on the second private and public keys. The data at the electronic device may be encrypted using the determined secret or an encryption key that is based on the secret. Information indicative of the deterministic key may be sent to the key device where the information may be stored.

There may be provided a computer-implemented method. It may be implemented at least in part using a blockchain network such as, for example, the Bitcoin network. The computer-implemented method includes: i) encrypting a plaintext message to a cryptographic public key in accordance with an identity-based encryption scheme using at least a congress public key to generate an encrypted message, wherein the congress public key is associated with members of a congress, respective members of the congress having access to private key shares usable in a threshold decryption scheme in which at least a threshold of private key shares are sufficient to derive a decryption key through the combination of partial contributions to the decryption key on behalf of the congress; ii) generating, using at least a cryptographic private key corresponding to the cryptographic public key, a digital signature over a first set of instructions to perform cryptographic operations upon an occurrence of an event; and iii) broadcasting one or more transactions to a proof-of-work blockchain network, the one or more transactions comprising the encrypted message, the cryptographic public key, at least the first set of instructions, and a second set of instructions to the members of the congress to cooperate to: in response to reaching a consensus on the event occurring and contingent upon the digital signature being authentic, deploy a ghost chain to perform the first set of instructions, wherein performing the first set of instructions includes at least deriving the decryption key from the cryptographic key and a plurality of private key shares that satisfies the threshold, the decryption key being sufficient cryptographic material to obtain the plaintext message from the encrypted message.