[smudgymcscmudge]

Did you notice the article doesn't say anything about decrypting the messages? It just says they have to turn over encrypted messages.

[squarefoot]

The question should be why on Earth would they ask access to encrypted messages if they couldn't already decrypt them, or be able to do that soon.

[aianus]

You can infer a lot of information from the metadata, like the volume and timing of messages.

[IshKebab]

They're after the metadata. Who contacted who, and how often.