Dear Friends,
We have implmented a crypto system in a 8051 micro controller.Now we are going to carry out ,what are known as power attacks on the cryptosystem.ie whenever a bit in the KEY string is '1' then certain operations will be performed by the microcontroller otherwise those operations will be skipped.We expect a small surge in current when the KEY bit is '1'.We would like to measure this current and hence determine the KEY.The processor runs at 12 MHz and each instruction cycle requirs 4 clock cycles.We put a toroidal wound inductor around the power cable of the microcontroller and couldn't measure any significant current changes.Also there is a large noise pickup.
What could be ideal core and coil material ,dia for this measurement.Can we make use of a differential amplifier?
Kindly help.
We have implmented a crypto system in a 8051 micro controller.Now we are going to carry out ,what are known as power attacks on the cryptosystem.ie whenever a bit in the KEY string is '1' then certain operations will be performed by the microcontroller otherwise those operations will be skipped.We expect a small surge in current when the KEY bit is '1'.We would like to measure this current and hence determine the KEY.The processor runs at 12 MHz and each instruction cycle requirs 4 clock cycles.We put a toroidal wound inductor around the power cable of the microcontroller and couldn't measure any significant current changes.Also there is a large noise pickup.
What could be ideal core and coil material ,dia for this measurement.Can we make use of a differential amplifier?
Kindly help.