Security-adaptive voltage conversion as a lightweight counter measure against LPA attacks
Methods and systems are provided for a security adaptive (SA) voltage converter that receives input power from a power source and provides power to a cryptographic system. The SA voltage converter triggers countermeasures against leakage power analysis (LPA) attacks that slow down an operating frequency of the cryptographic circuit. When an LPA attack is detected, a discharging resistor sinks redundant current to alter the signature of load power dissipation of at the input to the SA voltage converter system. The SA voltage converter includes a converter reshuffling converter. The power dissipation induced by the discharging resistor, as measured at the input received from the power source, is scrambled by the SA voltage converter to increase noise inserted into the input power and to alter the power profile that is measured for the cryptographic circuit.
1. A system for security adaptive voltage conversion, the system comprising:
a voltage converter, the voltage converter having an input that is coupled to a power source and an output that is coupled to a cryptographic circuit, wherein the voltage converter receives input power from the power source via the input and supplies power to the cryptographic circuit via the output;
a redundant discharge load that is connectable to the output of the voltage converter by a switch that is operable to connect or disconnect the redundant discharge load to the output of the voltage converter; and
a clock frequency sensor coupled to the cryptographic circuit, wherein the clock frequency sensor detects a clock frequency of the cryptographic circuit and controls the connection or the disconnection of the redundant discharge load to the output of the voltage converter in response the detected clock frequency of the cryptographic circuit.
2. The system of claim 1 , wherein the redundant discharge load sinks current from the voltage converter in addition to current sunk by the cryptographic circuit and increases the input power received from the power source.
3. The system of claim 1 , wherein the voltage converter is a converter reshuffling voltage converter that alters the signature of the input power received from the power source.
4. The system of claim 1 , wherein the voltage converter is a converter reshuffling voltage converter that scrambles power dissipation induced by the redundant discharge load.
5. The system of claim 1 , wherein the redundant discharge load is connected to the output of the voltage converter when the clock frequency sensor detects that the clock frequency of the cryptographic circuit is within a specified range of frequencies.
6. The system of claim 1 , wherein the redundant discharge load is connected to the output of the voltage converter when the clock frequency sensor detects that the clock frequency of the cryptographic circuit is within a specified range of frequencies.
7. The system of claim 1 , wherein the redundant discharge load is disconnected from the voltage converter when the cryptographic circuit is in an idle mode.
8. The system of claim 1 , wherein the redundant discharge load is disconnected from the voltage converter when the clock frequency sensor detects an appropriate operational frequency of the cryptographic circuit.
9. The system of claim 1 , wherein the voltage converter functions as a converter reshuffling voltage converter when the redundant discharge load is disconnected from the voltage converter.
10. The system of claim 1 , wherein the switch comprises one or more transistors.
11. A method for security adaptive voltage conversion, the method comprising:
receiving input power from a power source via an input of a voltage converter and supplying power to a cryptographic circuit via an output of the voltage converter;
detecting, by a clock frequency sensor coupled to the cryptographic circuit, a clock frequency of the cryptographic circuit and controlling a connection or a disconnection of a redundant discharge load to the output of the voltage converter in response the detected clock frequency of the cryptographic circuit, wherein
the redundant discharge load is connectable to the output of the voltage converter by a switch that is operable to connect or disconnect the redundant discharge load to the output of the voltage converter.
12. The method of claim 11 , wherein the redundant discharge load sinks current from the voltage converter in addition to current sunk by the cryptographic circuit and increases the input power received from the power source.
13. The method of claim 11 , wherein the voltage converter is a converter reshuffling voltage converter that alters the signature of the input power received from the power source.
14. The method of claim 11 , wherein the voltage converter is a converter reshuffling voltage converter that scrambles power dissipation induced by the redundant discharge load.
15. The method of claim 11 , wherein the redundant discharge load is connected to the output of the voltage converter when the clock frequency sensor detects that the clock frequency of the cryptographic circuit is within a specified range of frequencies.
16. The method of claim 11 , wherein the redundant discharge load is connected to the output of the voltage converter when the clock frequency sensor detects that the clock frequency of the cryptographic circuit is within a specified range of frequencies.
17. The method of claim 11 , wherein the redundant discharge load is disconnected from the voltage converter when the cryptographic circuit is in an idle mode.
18. The method of claim 11 , wherein the redundant discharge load is disconnected from the voltage converter when the clock frequency sensor detects an appropriate operational frequency of the cryptographic circuit.
19. The method of claim 11 , wherein the voltage converter functions as a converter reshuffling voltage converter when the redundant discharge load is disconnected from the voltage converter.
20. The method of claim 11 , wherein the switch comprises one or more transistors.