Methods, and systems for secure storage and retrieval of information, such as private keys, useable to control access to a blockchain, include: receiving a request to take an action with respect to a vault of multiple different vaults in a cryptoasset custodial system, and each of the multiple different vaults has an associated policy map that defines vault control rules; authenticating, by a hardware security module, a policy map for the vault on which the action is requested based on a cryptographic key controlled by the hardware security module; checking the action against the policy map for the vault when the policy map for the vault is authenticated based on the cryptographic key controlled by the hardware security module; and effecting the action when the action is confirmed to be in accordance with the policy map for the vault.