Final answer:
Key resiliency in cryptography is influenced by the length, complexity, and expiration of the key. Longer, more complex keys with a regular update schedule provide stronger defense against attacks.
Step-by-step explanation:
The question you've asked pertains to the resiliency of a cryptographic key against attacks, which is determined by three primary characteristics. These characteristics are: A. Length, complexity, expiration. The length of a key is important because longer keys are harder to crack due to the increased number of possible combinations. Complexity refers to the inclusion of a mixture of alphabet, numeric, and symbol characters that make it more difficult for attackers to guess the key. Lastly, expiration implies that keys should be changed or updated after a period to reduce the risk of being compromised over time.