看到 AWS KMS 的公告：「AWS KMS announces more flexible automatic key rotation」。
第一個是增加了 rotation 的彈性，可以設定日期，不過 7 years (2560 days) 是怎麼算出來的？(某種風險公式？)：
You can now customize the frequency of rotation period between 90 days to 7 years (2560 days) as well as invoke key rotation on demand for customer managed KMS keys.
另外一個是降價，看起來是 rotate 第三次以後就不收費？對於有在 rotation 的單位來說是個降價... (如果沒在 rotate 的就 XDDD)
We’re also introducing new pricing for KMS automatic key rotation. Previously, each rotation of a KMS key added $1/month per rotation to a KMS customer managed key. Now, for KMS keys that you rotate automatically or on demand, the first and second rotation of the key adds $1/month (prorated hourly) in cost, but this price increase is capped at the second rotation, and all rotations after your second rotation are not billed. For customers that have keys with 3 or more rotations, all of these keys will see a price reduction to $3/month (prorated) starting the first week of May 2024.
這也算是鼓勵拉高 rotation 的次數吧？