Method and apparatus for securing a programmable device using a kill switch
View Patent ↗A kill switch is provided that, when triggered, may cause the programmable logic device (PLD) to become at least partially reset, disabled, or both. The kill switch may be implemented as a fuse or a volatile battery-backed memory bit. When, for example, a security threat is detected, the switch may be blown, and a reconfiguration of the device initiated in order to zero or clear some or all of the memory and programmable logic of the PLD.
1. A programmable logic device, comprising:
a core configuration fabric configured to implement a security module;
a control block coupled to the core configuration fabric; and
a kill switch coupled to the control block, wherein the control block and the core configuration fabric are configured to blow the kill switch in response to an occurrence of a predefined event, wherein blowing the kill switch causes data stored within at least a portion of the programmable logic device to be changed.
2. The programmable logic device of claim 1 , wherein the kill switch comprises a fuse.
3. The programmable logic device of claim 1 , wherein at least a portion of the programmable logic device is disabled in response to the kill switch being blown.
4. The programmable logic device of claim 1 , further comprising I/O circuitry, wherein the I/O circuitry is disabled in response to the kill switch being blown.
5. The programmable logic device of claim 1 , further comprising decryption circuitry, wherein the decryption circuitry is disabled in response to the kill switch being blown.
6. The programmable logic device of claim 1 , further comprising:
a battery; and
volatile memory coupled to the battery for storing a decryption key, wherein data stored within the volatile memory is changed in response to the kill switch being blown.
7. The programmable logic device of claim 1 , further comprising key fuses for storing fuse bits representing a decryption key, wherein at least one of the key fuses is blown in response to the kill fuse being blown.
8. The programmable logic device of claim 1 , wherein the core configuration fabric comprises configuration memory.
9. The programmable logic device of claim 1 , wherein the core configuration fabric comprises logic array blocks.
10. A method for disabling a programmable logic device in response to an event, the method comprising:
detecting the event;
blowing a kill switch responsive to detection of the event; and
disabling at least a portion of the programmable logic device in response to the kill switch being blown, wherein disabling the at least a portion of the programmable logic device comprises removing configuration data stored in the programmable logic device.
11. The method of claim 10 , wherein detecting the event comprises using sticky bits stored in the programmable logic device to detect the event.
12. The method of claim 11 , wherein detecting the event comprises comparing a pattern of security bits in a programming object file (POF) bit-stream to at least some of the sticky bits.
13. The method of claim 11 , wherein detecting the event comprises detecting that at least one of the sticky bits has been unintentionally modified.
14. The method of claim 10 , wherein disabling the at least a portion of the programmable logic device comprises zeroing volatile memory that stores a key.
15. The method of claim 10 , wherein disabling the at least a portion of the programmable logic device comprises blowing at least one fuse associated with a key.
16. The method of claim 10 , wherein disabling the at least a portion of the programmable logic device comprises disabling I/O circuitry.
17. The method of claim 10 , wherein disabling the at least a portion of the programmable logic device comprises disabling decryption circuitry.
18. The method of claim 10 , wherein disabling the at least a portion of the programmable logic device comprises initiating a reconfiguration of the programmable logic device.
19. The method of claim 10 , further comprising resetting at least a portion of the programmable logic device in response to the kill switch being blown.
20. A method for disabling a programmable logic device in response to an event, the method comprising:
detecting the event, wherein detecting the event comprises using sticky bits stored in the programmable logic device to detect the event;
blowing a kill switch responsive to detection of the event; and
disabling at least a portion of the programmable logic device in response to the kill switch being blown.
21. The method of claim 20 , wherein detecting the event comprises comparing a pattern of security bits in a programming object file (POF) bit-stream to at least some of the sticky bits.
22. The method of claim 20 , wherein detecting the event comprises detecting that at least one of the sticky bits has been unintentionally modified.
23. The method of claim 20 , wherein disabling the at least a portion of the programmable logic device comprises automatically causing data stored within the at least a portion of the programmable logic device to be changed.
24. The method of claim 20 , wherein disabling the at least a portion of the programmable logic device comprises blowing at least one fuse associated with a key.