Key rotation and key update are both security practices related to cryptographic keys, but they serve different purposes and are implemented differently.
Key Rotation refers to the process of periodically replacing an existing cryptographic key with a new one to reduce the risk of key compromise. Over time, keys may be exposed due to attacks, insider threats, or vulnerabilities. By rotating keys regularly (e.g., every 90 days), even if a key is compromised, its exposure window is limited.
Example: A company rotates its TLS/SSL certificates every 60 days to ensure encrypted communications remain secure. In cloud environments, Tencent Cloud Key Management Service (KMS) supports automated key rotation policies for symmetric CMKs (Customer Master Keys).
Key Update typically refers to modifying an existing key (e.g., changing its configuration or metadata) without necessarily replacing it entirely. This could involve updating key policies, access controls, or cryptographic parameters while keeping the same key material.
Example: An admin updates the access policy of a key to restrict certain users from using it, but the key itself remains unchanged. In Tencent Cloud KMS, you can modify key policies or enable/disable keys without rotating them.
While key rotation enhances long-term security by introducing new keys, key update focuses on adjusting key usage or permissions dynamically. Tencent Cloud KMS helps manage both processes efficiently with automated rotation and fine-grained access control.