Threats of state-sponsored cyber spying from China are nothing new. In 1999, Congress released a report alleging China was responsible for years of espionage and stealing U.S. nuclear secrets. As Haynes Johnson explained on Washington Week, the threat didn't come from traditional spies, but was a threat "in cyberspace." "It's about computers," he said.

Since the San Bernardino attack, the FBI has been trying to read the contents of a cell phone used by attacker Syed Farook, made impossible by encryption. Now Apple CEO Tim Cook is rejecting a federal court order to create software to unlock the device. Gwen Ifill talks to Stewart Baker, former assistant secretary of Homeland Security, and Nate Cardozo of the Electronic Frontier Foundation.

We’re aware of the risk of hacks that result in theft and espionage, but what about a devastating cyberattack on the power grid? In his new book, “Lights Out,” Ted Koppel argues that not only is this a distinct possibility, but that America is totally unprepared. The author joins Gwen Ifill to discuss the frightening potential fallout.

More than 21 million Americans had personal data stolen from files held by the Office of Personnel Management. Anyone who went through background checks to apply for a government position since 2000 has been affected, according to the OPM. That makes the data breach six times larger than was originally disclosed. Gwen Ifill learns more from Josh Lederman of the Associated Press.

The U.S. government wants to be able to read certain data that's inaccessible to intelligence agencies due to encryption. At a Senate hearing, FBI director James Comey said the privacy technology can be a double-edged sword, detrimental to public safety. Gwen Ifill speaks to former Homeland Security Department official Stewart Baker and Susan Landau of the Worcester Polytechnic Institute.

Congress passed the USA Freedom Act which overhauls the way U.S. intelligence agencies can monitor phone records. Meanwhile, nearly 4 million federal government had personal information stolen in a widespread attack U.S. officials are blaming on China. On the 2016 campaign trail, four new candidates threw their hats in the ring this week.

On the Webcast Extra, Doyle McManus of the Los Angeles Times details the coup in Yemen and the struggle the US government may have trying to work with the Houthi rebel group that is now in power.

In 2014, ISIS, Boko Haram and Crimea became household names and Ebola re-entered the scene as a medical crisis. Gwen Ifill speaks with Indira Lakshmanan of Bloomberg News, David Ignatius of the Washington Post and David Miliband of the International Rescue Committee about this past year’s biggest global challenges, and what conflicts to expect in the coming year.

Some cyber security experts are skeptical of assertions that North Korea is responsible for a massive hack on Sony. To examine the debate, Gwen Ifill gets assessment from Dmitri Alperovitch of CrowdStrike and Marc Rogers of CloudFlare.

After a costly cyber attack on Sony Pictures, a look at how the U.S. plans to confront North Korea and the rise of cyber terrorism; how Obama was able to normalize U.S. relations with Cuba and what it will mean for both countries; and will the 2016 presidential election feature, Jeb Bush and Hillary Clinton of America's political dynasties?