Final answer:
Side-channel attacks are security exploits that use physical information leakages from a system, rather than algorithmic weaknesses, to extract sensitive data. Cache memory-based attacks are popular because they exploit universally present cache mechanisms, which are typically not covered by cryptographic protections, to deduce valuable information like cryptographic keys.
Step-by-step explanation:
Side-channel attacks are a type of security exploit that involves gathering information from the physical implementation of a computer system rather than weaknesses in the implemented algorithm itself. These attacks exploit the dependency of execution time, power consumption, electromagnetic leaks, or even sounds on the processed data. Monitoring these can provide clues about the data and the computing process.
One of the most popular forms of side-channel attacks is based on cache memory. Cache memory is used to speed up the processing by holding frequently accessed data and instructions close to the CPU. However, the way that the cache operates can leak information about what the system is processing. Attackers can monitor cache hits and misses to deduce valuable information like cryptographic keys, hence executing a cache-based side-channel attack.
These attacks are popular because modern computers universally rely on caches; hence virtually all devices are potential targets. Moreover, cache-based attacks are often not mitigated by common cryptographic algorithm protections, making them an attractive vector for gaining unauthorized access to sensitive data.