What Side-Channel Attacks Involve
As a chip performs cryptographic operations, its power consumption and the exact timing of its operations can subtly vary depending on the secret key data being processed – variations that are invisible to normal functional testing but can be captured and statistically analyzed by an attacker with physical access to the device. Given enough measurements, these techniques can sometimes extract secret keys entirely, without ever 'breaking' the underlying cryptographic algorithm itself.
Why It Matters
Side-channel attacks bypass the mathematical strength of cryptography entirely, targeting the physical implementation instead. Any chip handling sensitive keys – payment systems, secure identity, DRM – needs hardware specifically designed to resist these attacks, not just a mathematically sound cryptographic algorithm.