The NSA also focused on meta-data because it was more likely to survive a legal challenge. A law enforcement observer can make note of you entering and leaving a building at certain times. Your entrance and exit is public. What they can&#x27;t do, without warrants (legally, not speaking to technical ability), is observe what happens inside a private place or within (what&#x27;s intended to be) private communications.<p>Meta-data also bypasses codes, as you point out, by revealing the network of communication (who-with-who, when, and how often). So whether the communication&#x2F;interaction is recorded and understandable or not becomes less important. In the case that it is recorded and understandable, excellent, even more intel. If it&#x27;s not, they still have some material to work with.