Risk mitigation for a cryptoasset custodial system using a hardware security key

An approval request is transmitted for a cryptoasset transaction in accordance with a policy stored in a hardware security module ("HSM"). The policy specifies at least one specific approver required for approval of the cryptoasset transaction. The approval request is transmitted to a computer device associated with the specific approver and is configured to cause the computer device to prompt the specific approver to approve the cryptoasset transaction. A security key is received from a hardware security token associated with the specific approver. The security key indicates an approval of the cryptoasset transaction. A risk analysis module authenticates an identity of the specific approver based on the security key. Responsive to the authenticating of the identity of the specific approver, the HSM signs the cryptoasset transaction using a cryptographic key stored in the HSM.