In the last blog post of this series, we discussed in detail how Master Key encryption works. In this post, based on what we already know about Master Key encryption, we look into how Master Key rotation works.
The idea behind Master Key rotation is that we want to generate a new Master Key and use this new Master Key to re-encrypt the tablespace key (stored in tablespace’s header).
Let’s remind ourselves what a Master Key encryption header looks like (it is located in tablespace’s header):
From the previous blog post, we know that when a server starts it goes through all encrypted tablespaces’ encryption headers. During that, it remembers the highest KEY ID it read from all the encrypted tablespaces. For instance, if we have three tables with KEY_ID = 3 and one table with KEY ID = 4, it means that …
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