Stored authorization status for cryptographic operations

Abstract

A hardware authentication device is disclosed that uses a cryptographic signature verification operation to authorize a subsequent cryptographic operation to be performed using the same or different keys and stores that authorization status in protected memory. The cryptographic algorithm may be an ECDSA signature, SHA-based Message Authentication Code (MAC) or any other cryptographic algorithm. The authorization status may be stored for a number of uses for a period of time or until a certain event occurs. In some implementations, the authorization status and the key that was authorized are stored in the same protected location in memory to preserve their relation to each other and prevent modification of either of them. Depending on system policy, the authorization mechanism might be a static stored external token that authorizes key use or an authorization process that is regenerated using a random (e.g., unique) number.