Selectively disabled output

1. A method of preventing a reading of data on an integrated circuit capable of outputting the data, the method comprising:

determining whether to allow a reading of the data based on a setting of a disabling element, wherein once the disabling element is set to not allow the reading of the data, the disabling element cannot be changed to allow the reading of the data;

encrypting the data, independently of the setting of the disabling element, if the reading of the data is not allowed; and

subsequent to the encrypting, outputting the encrypted data, wherein the encrypted data is adapted to be decrypted using a key.

2. The method of claim 1 , wherein the data is configuration data for configuring a functionality of the integrated circuit.

3. The method of claim 1 , wherein the data is read from a plurality of storage circuits.

4. The method of claim 3 , wherein the plurality of storage circuits comprise one or more circuits selected from a group consisting of RAM and registers.

5. The method of claim 1 , wherein the disabling element comprises a fuse.

6. The method of claim 1 , wherein the disabling element comprises an anti-fuse.

7. The method of claim 1 further comprising outputting a plurality bits other than the data when the reading of the data is not allowed.

8. The method of claim 1 , wherein a value stored in the disabling element is used to encrypt the data.

9. An integrated circuit comprising:

a disabling element, wherein once the disabling element is set to not allow the reading of data, the disabling element cannot be changed to allow the reading of the data; and

circuitry operative to:

determine whether to allow a reading of the data based on a setting of a disabling element;

encrypt the data, independently of the setting of the disabling element, if the reading of the data is not allowed; and

output the encrypted data, wherein the encrypted data is adapted to be decrypted using a key.

10. The integrated circuit of claim 9 , wherein the data is configuration data for configuring a functionality of the integrated circuit.

11. The integrated circuit of claim 9 , wherein the data is read from a plurality of storage circuits.

12. The integrated circuit of claim 11 , wherein the plurality of storage circuits comprise one or more circuits selected from a group consisting of RAM and registers.

13. The integrated circuit of claim 9 , wherein the disabling element comprises a fuse.

14. The integrated circuit of claim 9 , wherein the disabling element comprises an anti-fuse.

15. The integrated circuit of claim 9 , wherein the circuitry is further operative to output a plurality bits other than the data when the reading of the data is not allowed.

16. The integrated circuit of claim 9 , wherein a value stored in the disabling element is used to encrypt the data.

17. A method of preventing a reading of data on an integrated circuit capable of outputting the data, the method comprising:

determining a state of a disabling element, wherein the state of the disabling element cannot be changed to allow the reading of the data once the disabling element is set to not allow the reading of the data;

encrypting the data, independently of the state of the disabling element, if the reading of the data is not allowed; and

outputting the encrypted data.

18. The method of claim 17 , wherein the data is configuration data for configuring a functionality of the integrated circuit.

19. The method of claim 17 further comprising outputting a plurality bits other than the data when the reading of the data is not allowed.

20. The method of claim 17 , wherein a value stored in the disabling element is used to encrypt the data.