sivukanavahyökkäysmenetelmä

Sivukanavahyökkäys, also known as a side-channel attack, is a type of cryptanalysis that exploits information leaked from the physical implementation of a cryptosystem, rather than theoretical weaknesses in the algorithm itself. This leaked information can include timing variations, power consumption, electromagnetic radiation, or even sound produced by the device. Attackers analyze these physical characteristics to deduce sensitive data, such as secret keys.

These attacks are particularly effective against hardware implementations of cryptographic algorithms. For instance, a simple power analysis (SPA) might involve observing the power drawn by a processor while it performs cryptographic operations. Different operations, or operations on different data, can result in subtle variations in power consumption that an attacker can measure and analyze. Similarly, timing attacks observe the time it takes for a system to perform cryptographic computations, looking for patterns that reveal information about the secret key.

To defend against sivukanavahyökkäykset, countermeasures are employed. These can include constant-time programming, where operations take a consistent amount of time regardless of the data being processed, or adding noise to the physical signals to mask the exploitable information. Hardware-level defenses, such as power supply filtering or shielding against electromagnetic emissions, are also used. The effectiveness of sivukanavahyökkäykset highlights the importance of considering the physical security of cryptographic systems, not just their theoretical security.