NSA's alleged leaker got tripped up by a secret printer feature
Found on CNet News on Tuesday, 06 June 2017
On Monday, the National Security Agency contractor was charged in a Georgia court with releasing classified material to a news outlet.
The pages from the NSA's printers came with invisible tracking dots. This is a common feature in modern printers for forensics investigations, according to the Electronic Frontier Foundation.
That was pretty much it for The Intercept. No whistleblower will risk it ever again to contact them with important information after that. The tracking feature is no secret, and everybody involved into this should have known.