SECURE MULTIPARTY LOSS RESISTANT STORAGE AND TRANSFER OF CRYPTOGRAPHIC KEYS FOR BLOCKCHAIN BASED SYSTEMS IN CONJUNCTION WITH A WALLET MANAGEMENT SYSTEM

摘要

The invention provides a computer- implemented solution for controlling access to a computer-related resource such as, for example, a digital wallet. In one or more embodiments, the wallet may be implemented using a blockchain such as the Bitcoin blockchain but the invention is not limited in this regard. Use of the invention during the initial set-up of the wallet can enable subsequent operations such as wallet transactions to be handled in a secure manner over an insecure channel such as the internet. A method according to an embodiment of the invention can comprise the steps of splitting a verification element (such as a private key in an asymmetric cryptography pair) into a plurality of shares; determining a common secret at two or more nodes in a network; and using the common secret to transmit at least one share of the verification element between the two or more nodes. The shares can be split such that no share on its own is sufficient to arrive at the verification element. This means that no one party stores the entire private key, providing for enhanced security of the key. Two or more shares are required to restore the key. The shares are stored at separate locations one of which is an independent back-up or safe-storage location. If one of the other shares becomes unavailable, the share can be retrieved from back up to ensure that the key (and thus the controlled resource) is still accessible. To ensure safe transmission of the share(s), the common secret is generated at two different nodes independently of each other and then used to generate an encryption key. The encryption key can be used to encrypt at least one share of the verification element, or a message comprising it, to ensure that the share(s) are transmitted securely.