Komplementtihyökkäysten

Komplementtihyökkäys, known in English as the complement attack, is a type of side-channel attack that targets cryptographic implementations. It exploits vulnerabilities in the way hardware or software handles operations, specifically focusing on timing variations or power consumption patterns. The core idea is to infer secret information, such as cryptographic keys, by observing how the system responds to different inputs over time.

This attack is not limited to a specific cryptographic algorithm but can be applied to various systems, including encryption devices and secure hardware modules. The effectiveness of a complement attack depends on the attacker's ability to precisely measure subtle differences in system behavior. These measurements can reveal information about the internal state of the system during cryptographic operations.

The term "complement" in this context refers to the fact that the attack often involves observing the system's response to inputs that are in some way complementary or related to each other. By comparing the system's behavior for these related inputs, an attacker can isolate the parts of the computation that depend on the secret key.

Mitigation strategies for complement attacks typically involve designing cryptographic implementations that exhibit constant-time behavior, meaning that operations take the same amount of time regardless of the input data or secret keys. Masking techniques, where secret values are split into multiple shares, are also employed to obscure the direct relationship between input and secret information. Another approach is to introduce random delays or noise into the system to make precise timing measurements more difficult.