NSA: If Your Data Is Encrypted, You Might Be Evil, So We'll Keep It Until We're Sure

The minimization procedures say that the NSA has to destroy the communication it receives once it's determined as domestic unless they can demonstrate a few facts about it.

In other words, if your messages are encrypted, the NSA is keeping them until they can decrypt them. And, furthermore, as we noted earlier, the basic default is that if the NSA isn't sure about anything, it can keep your data. And, if it discovers anything at all remotely potentially criminal about your data, it can keep it, even if it didn't collect it for that purpose.