Methods and systems for secure storage and retrieval of information, such as private keys, useable to control access to a blockchain, include: receiving, in a cryptoasset custodial system, a request to authorize a staking operation associated with a blockchain, wherein the staking operation is associated with a private key of an asymmetric cryptographic key pair, the private key is usable to control ownership of a cryptoasset recorded in the blockchain, and the private key is securely held in the custodial system; performing, in response to the request, a portion of the proof-of-stake protocol in a hardware security module using logic designed for the protocol, wherein the logic in the hardware security module is configured to authorize the staking operation by digitally signing an associated staking transaction; and sending the digitally signed staking transaction to another computer to effect the staking operation on behalf of the user.