You need both constant power hardware and software to be immune (and to related timing attacks). The libsecp256k1 library for example is designed to be timing attack resistant, but I&#x27;m still working on verifying how power sidechannel resistant it is.<p>Using an internal power source, like a primary lithium cell, is one way to circumvent the power sidechannel. But power sidechannels can also easily become RF sidechannels, so it&#x27;s still good to minimize them.