It is difficult to probe but not at all impossible. However, you can sometimes extract keys by monitoring the chip power supply current over a large number of

It is difficult to probe but not at all impossible. However, you can sometimes extract keys by monitoring the chip power supply current over a large number of crypto operations. Much easier than probing the chip internals. https://scholar.google.com/scholar?as_q=%22Differential+Power+Analysis%2C%22&as_occt=title&hl=en&as_sdt=0%2C31 https://scholar.google.com/scholar?as_q=%22Differential+Powe...