Extract MCU need to go through a series of processes and power analysis has been proved as the one of the most effective methods for MCU extract.
Power analysis technology has mainly two ways: simple power consumption analysis and differential power analysis. simple power consumption analysis is through monitoring the power consumption when enter the password or other security related operation of extract MCU, and can collect the information when device operation such as secret key data. If the MCU extracter knows the algorithm of code, it can find some bits information effortless through monitoring the MCU processor instruction sequence especially the migration term. If the result of algorithm or logic calculation can be viewed easily, such as bit forward status, zero or minus mark, it can obtain more information. differential power analysis is a more effective technology of MCU extract. Since the extracter doesn’t need to know the operation method of code algorithm. It can use the static analysis and tremendous power consumption trace of known code algorithm from MCU extract to obtain the hidden information. Use the statistic method to identify the minor difference of power consumption to recover the single bit information from secret code.
Power Consumption features surely include the noise part, extra noise can be decreased through the careful operation of measure device and short the length of microprobe for signals when extract MCU. There is some advantage when detect the power consumption on the resistor attached on the grounding line. First of all, it help to decrease the noise electrical level for MCU extract. Secondly, it can use the probe of oscillograph to detect the signals directly, since most of the probes has common grounding line connect with external power grounding. In order to increase the signal to noise, the quantity of average sampling can be increased when extract MCU.
Active probe can decrease the input capacitance, and increase the band width of input signals. One of ways is constructing a relative simple probes through high speed low noise operation of MCU extract. Another way is using very short coxial cable to connect directly to input terminal of oscillograph under which the input capacitance value of probe will decrease significantly.
