Chosen / Timing / Time-based Attacks (Side-channels)

Attacker measures how long cryptographic operations take and infers secret data from timing variations.

(Timing Attack) – “Watch the clock.” If differing execution times leak key bits, mitigate with constant-time ops and blinding.

Some systems seed keys or OTPs from system time; changing or resetting the clock can let an attacker reproduce keys.

(Time-Resetting Attack) – “Turn back the clock.” If time is used for key/seed generation, ensure clock integrity and use stronger entropy sources.

Attacker supplies ciphertexts and obtains decryptions (oracle) to exploit padding or protocol behavior (a subtype of CCA).

(Padding Oracle Attack) – “Server reaction reveals padding validity.” If server errors differ by padding correctness, this is likely.

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