Smart Card Key Management via Remote Encrypted Storage

The patent extracts the storage burden of keys from the smart card by storing encrypted key versions remotely while maintaining only decryption capabilities locally. This allows the smart card to access keys without storing them permanently, resolving the contradiction between security and storage space.

The patent introduces an intermediary encrypted version of the key stored remotely, which serves as a mediator between the need for key accessibility and the constraint of limited local storage. The local decryption key acts as another intermediary that enables secure access without permanent key storage.

The patent creates encrypted copies of keys stored remotely while maintaining the ability to decrypt and use them locally. This allows the system to manage multiple keys without proportionally increasing local storage requirements, as each key exists as an encrypted copy in remote storage.

The patent moves key storage from the single dimension of local smart card storage to a two-dimensional architecture involving both local decryption capabilities and remote encrypted storage. This dimensional change enables unlimited key management capability while constraining local storage space usage.

The patent incorporates expiration timestamps into encrypted key versions during their creation, performing the key invalidation action in advance of actual compromise. This preliminary action ensures that even if keys are accessed or copied, they become unusable after their designated lifetime, reducing long-term compromise risk while maintaining operational flexibility during the valid period.

The patent implements an automatic key discarding mechanism where expired keys are rendered unusable through decryption failure, while valid keys can be recovered and used. This cycle of discarding expired keys and recovering valid ones balances operational flexibility with reduced compromise risk.