side-channel attack
Beginner
Stealing a secret by watching how a chip behaves, like how much power it uses, instead of cracking the code.
Novice
An attack that learns a secret by measuring a physical effect of the computation, such as how much power it draws, how long it takes or the radio noise it gives off, instead of breaking the encryption itself.
Expert
Includes simple and differential power analysis (SPA, DPA), electromagnetic analysis and timing attacks. Countermeasures include masking (randomizing intermediate values), hiding (constant-power logic, added noise) and protocol-level key updates, and they are validated by measurement on silicon.
Explained in Personal and edge devices (Industries).