System for automatic decryption of file data on a per-use basis and automatic re-encryption within context of multi-threaded operating system under which applications run in real-time

摘要

A machine system for automatic decryption of confidential file data on a per-use basis and automatic later elimination of the decrypted data by scorching and/or re-encrypting is disclosed. The system can operate within a multi-threaded environment. The following features are provided for secure and automatic recryption: (1) use of file-exclusion lists; (2) use of application-program exclusion lists; (3) decrypting as needed in response to intercepted file-OPEN requests; (4) encrypting as needed in response to intercepted file-CLOSE requests; (5) delaying post-CLOSE encryption in special cases; (6) delaying retry of failed encryption; (7) keeping track of the number of application programs that are using each piece of decrypted plaintext; (8) identifying non-confidential files according to the directories they are contained within; (9) including encryption and decryption rules within directories that contain confidential files; and (10) avoiding unnecessary encryption of non-modified plaintext.