US Patent 7231050 Protection against unintentional file changing

An encrypted file system that uses the encryption of files in a computer to restrict access to the files. Encrypted files are associated with a user. A decryption key is required in order to allow changes to be made to any of those files. Other files, such as those files which are less sensitive, may be unencrypted, and may be accessed even when the user is unavailable. These files may be read only files. A duplicate decryption technique may be allowed to allow access to the files, if the decryption key becomes unavailable. Certificates can verify access to the different files.