When Bryan Pagliano, the manager of Clinton’s private server while she Clinton’s is secretary of state, will be interviewed by the FBI in December 2015, he will recall a conversation that takes place around the beginning of Clinton’s tenure. This person, whose name is later redacted, recommends that email transiting from a state.gov account to Clinton’s private server should be sent through a Transport Layer Security (TLS) “tunnel.” Most of Clinton’s email traffic is with State Department officials using state.gov accounts.
A September 2016 FBI report will explain: “TLS is a protocol that ensures privacy between communicating applications, such as web browsing, email, and instant messaging, with their users on the Internet. TLS ensures that no third-party eavesdrops on the two-way communication. TLS is the successor to SSL and is considered more secure.”
Pagliano is the main person to manage problems with the server, but he will tell the FBI that the transition to TLS never occurred. It is not clear why. The FBI will be unable to forensically determine if TLS was ever implemented on the server.
The same unnamed person who gives Pagliano this advice also tells him at the same time that he would not be surprised if classified information was being transmitted to Clinton’s personal server. (Federal Bureau of Investigation, 9/2/2016)