Techniques for protecting security features of integrated circuits

An integrated circuit comprising:

• a control circuit;
• a one-time programmable circuit;
• and
• programmable logic circuits, wherein the integrated circuit is a programmable logic integrated circuit, wherein the programmable logic circuits are configured with a configuration bitstream during a configuration mode to implement a user design for the programmable logic integrated circuit,
• wherein the control circuit prevents the integrated circuit from entering the configuration mode to configure the programmable logic circuits until the control circuit determines that the one-time programmable circuit has been programmed, wherein the control circuit causes the one-time programmable circuit to be programmed before the integrated circuit enters the configuration mode,
• and wherein the control circuit generates a signal to indicate to a user of the integrated circuit that the programmable logic circuits have been previously configured if the control circuit determines after the integrated circuit is powered up that the one-time programmable circuit has been programmed.

A method comprising:

• determining if a one-time programmable enable circuit is programmed using a control circuit in response to a request by a user of an integrated circuit to access a security feature, wherein the integrated circuit comprises the control circuit, the one-time programmable enable circuit, a one-time programmable disable circuit, and the security feature;
• generating a signal to indicate to the user of the integrated circuit that the security feature has been accessed by another user if the control circuit determines that the one-time programmable enable circuit has been programmed to indicate a previous access to the security feature;
• causing the one-time programmable enable circuit to be programmed in response to the request if the control circuit determines that the one-time programmable enable circuit has not been programmed;
• and
• preventing a user of the integrated circuit from accessing the security feature using the control circuit if the control circuit determines that the one-time programmable disable circuit has been programmed.