Execution protection for floppy disks

• US 5,027,396 A
• Filed: 05/07/1990
• Issued: 06/25/1991
• Est. Priority Date: 05/07/1990
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Platteter, Dale T., Westfall, Robert S., Carter, Jeff C.
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): CAIN, DAVID C
• Application Number:
  US07/520,332
• Time in Patent Office: 414 Days
• Field of Search: 380/3, 380/4, 360/60
• US Class Current: 713/185
• CPC Class Codes: G06F 2211/007 Encryption, En-/decode, En-/decipher, En-/decypher, Scramble, (De-)compress
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/00152 involving a password
• CPC Class Codes: G11B 20/00615 said format change concerning the logical format of the recording medium, e.g. the structure of sectors, blocks, or frames
• CPC Class Codes: G11B 23/283 Security features, e.g. digital codes

Abstract

The method of permitting the execution of a disk loaded into the disk drive, the disk having a plurality of tracks, comprising the steps of writing data in non-standard format and length to a normally unaccessible track of the disk, the data including an encrypted password, the password being located at an arbitary location within the data, reading the data resulting in an error signal, locating an indexing position and applying an offset to identify the password, and unencrypting and authenticating the password in order to execute the disk.

Claims

1. In a control system for an image processing apparatus including a main memory and a floppy disk drive, the method of inhibiting the execution of a floppy disk loaded into the floppy disk drive, the floppy disk having a predetermined key track, the key track including random data unrecognizable to the control but including an arbitrarily positioned index pattern and a password related to the index pattern, comprising the steps of:

transferring the contents of the key track from the floppy disk to the main memory,

recognizing an error signal manifesting the unrecognizable random data,

ignoring the error signal and scanning the random data to find the arbitrarily positioned index pattern,

locating the password related to the index pattern among the random data, and

comparing the password to a second password stored in the main memory to be able to execute the instructions stored on the floppy disk.

2. The method of claim 1 wherein the control includes a user interface and the second password is loaded into the control via the user interface.

3. The method of claim 1 wherein the the key track is the innermost track of the disk.

4. The method of claim 1 wherein the step of comparing the password to a second password stored in the main memory to be able to execute the instructions stored on the floppy disk includes the step of deencrypting the password.

5. The method of claim 1 wherein the step of locating the password related to the index pattern among the random data includes the step of reading the key track on both sides of the floppy disk.

6. In a control system for an image processing apparatus including a main memory and a disk drive, the method of permitting the execution of a disk loaded into the disk drive, the disk having a plurality of tracks, comprising the steps of:

placing a data file including arbitrary data and a password on a normally unaccessible track of the disk,

reading the data file from the normally unaccessible track of the disk and storing in main memory,

decoding the password and comparing the password to a default password, and

upon a permissible comparison of the password with the default password, permitting execution of the disk.

7. The method of claim 6 wherein the default password is located on said disk.

8. The method of claim 6 wherein the control system includes a user interface and the default password is manually entered via the user interface.

9. The method of claim 6 wherein the step of decoding the password includes the step of de-encrypting the password.

10. The method of claim 6 including the step of using a plurality of passwords.

11. The method of claim 6 including the step of using a plurality of default passwords.

12. In a control system for an image processing apparatus including a main memory and a disk drive, the method of permitting the execution of a disk loaded into the disk drive, the disk having a plurality of tracks, comprising the steps of:

writing data in non-standard format and length to a normally unaccessible track of the disk, the data including an encrypted password, the password being located at an arbitrary location within the data,

reading the data resulting in an error signal,

locating a starting position and applying an offset to identify the password, and

unencrypting and authenticating the password in order to execute the disk.

13. The method of claim 12 including the step of reading unaccessible tracks on both sides of the disk.

14. The method of claim 12 including the step of ignoring the error signal and scanning the track for said starting position.