Why security is hard

It's done by people:

In documents published earlier today, hundreds of pages of previously sealed material related to the Feds' battle with Lavabit were made available. It was immediately noticeable that there were huge swathes of redactions, most of them covering the email address and details of the individual the agents were specifically looking for and why.

It has long been rumored or assumed, though never officially confirmed, that it was Snowden's account that was under scrutiny, particularly given the timing of the case: the documents were filed against Lavabit soon after Snowden said he was the source of the NSA PRISM leaks.

But no one has ever been willing to confirm it, and the huge redactions in the documents made it clear that the FBI was determined to keep up the pretense.

Except...

They missed a single reference. One of the first things we did on downloading the 560‑pages [PDF] was run a search on the word "Snowden" and lo and behold – on page 79, while noting that the entire record was under seal, up pops the email address "Ed_Snowden@lavabit.com."

I'm actually not laughing at the screw up, and you shouldn't, either.  This shows how security goes wrong for people who know better.  Consider:

The FBI is strongly motivated to keep as much of their investigation under wraps.  They're out to get Snowden, one way or another.

They have the expertise to do the job.  Hundreds of references were properly redacted.

Their reputation has been damaged by this - many people's first (and likely last) impression of them will be "screwups".  This is yet another motivation to spend the time to do it right.

And they didn't.  Even with all this motivation and capability, they didn't.  And quite frankly, this sort of thing is inevitable, which is why secrets leak even in wartime.  OPSEC is hard because it has to be 100%, and perfection is only to be found in the next world, not this one.

And so I find myself somewhat sympathetic to the hapless G-Man who did this.  I'm not sympathetic to this, though:

In the case, federal investigators insisted on being given the private keys and source code to the Lavabit encryption engine so that they could access and read all emails without the individuals in question being aware of their actions.

Lavabit founder Ladar Levison fought and lost the order, was found in contempt, and told to pay a fine of $5,000 per day until he handed over the private keys. Two days later he did so and then promptly and publicly shut the entire service down.

Levison later claimed that the Feds changed tactic after that and ordered other email providers to both hand over their keys and keep services running so they were able to snoop on people's communications.

It was a good run for the Republic, but the Praetorians will brook no defiance.