sidechannelattacker

A side-channel attacker exploits information leaked from the physical implementation of a cryptosystem rather than theoretical weaknesses in the algorithm itself. This leaked information can include timing, power consumption, electromagnetic radiation, or sound. By measuring and analyzing these physical emanations during the cryptographic operation, an attacker can infer secret keys or other sensitive data.

For example, a timing attack might observe that certain operations take longer to complete depending on the value of a secret bit. A power analysis attack monitors the power drawn by a device, which can vary with the operations being performed and the data being processed. Electromagnetic analysis involves capturing radio waves emitted by the device. These side channels provide a way to "listen in" on the computation.

The effectiveness of side-channel attacks depends on the attacker's ability to precisely measure the physical emanations and the sensitivity of the cryptographic implementation to these physical effects. Countermeasures exist to mitigate these attacks, such as constant-time execution (ensuring operations take the same amount of time regardless of input), blinding (randomizing intermediate values), and adding noise to mask the leakage. Side-channel attacks are a significant concern in the security of embedded systems, smart cards, and other hardware implementations of cryptography.