Rebuilding trust
Their only route to credibility is to have someone on the outside vouch for the detailed public postmortem. The FBI agreeing that this was a state actor helps. The lack of a commitment to producing a postmortem certainly does not.
To those who say that this looks like they have a prepared response for this (unavoidable) eventuality, I say this, "Yes, it looks like they had their press releases prepared." What I want is the postmortem.
Biting the hand that feeds IT
