Patent ID: 11943350
Assignee: COINBASE, INC.
Field: Digital communication (Electrical engineering)
Classification: CPC H | IPC H

Claim 14:
15. A non-transitory computer-readable media of storing instructions that, when executed by one or more processors, cause operations comprising:
obtaining, from a removable computer-readable storage medium, via a computer system operating within an offline computing environment, signing key shards corresponding to a signing private key and a blockchain transaction to be signed, wherein the signing key shards satisfy a key shard threshold that is (i) a number of key shards required for reconstructing the signing private key and (ii) less than a number of key shards derived from the signing private key using a ceremony key, wherein the blockchain transaction was received by an online computer system;
forming, via the computer system operating within the offline computing environment, a ciphertext of the signing private key using the signing key shards that satisfy the key shard threshold;
reconstructing, via the computer system operating within the offline computing environment, the signing private key by obtaining the ceremony key from a hardware security module (HSM) and decrypting the ciphertext, derived from the signing key shards that satisfy the key shard threshold, using the ceremony key, wherein the ceremony key is a same symmetric private key previously used to encrypt the signing private key to generate a prior ciphertext from which the signing key shards were derived; and
signing, via the computer system operating within the offline computing environment, the blockchain transaction using the signing private key.