US Patent 8429420 Time-based key management for encrypted information

A method and apparatus are utilized to manage keys associated with encrypted stored information. Sensitive information is stored in an encrypted form, and by creating and deleting the keys needed to decrypt information according to a time-based policy, the convenient expiration of stored data can be realized. By periodically erasing old keys and creating new keys, information that has not been written recently becomes virtually deleted. A refresh policy can be utilized to cause information that is read to be re-encrypted using a newer key, thereby extending the time before it will become inaccessible.