The use of deepfakes to impersonate high-level officials in the U.S. presents a growing security challenge. Deepfakes also disrupt corporate boardrooms and family living rooms. Advances in artificial intelligence mean it's easier and cheaper than ever before to create lifelike audio and video. These deepfakes can be used for gaining access to sensitive systems, for committing corporate espionage and for stealing national security secrets. But the size and scope of the problem are also prompting research into the best ways to counter it. Tech companies say new programs will help governments, businesses and everyday people detect deepfakes and ensure the people they see on the screen are who they say they are.

Sesame Workshop is working to regain control of Elmo's X account after a hacker posted racist and antisemitic messages. A spokesperson confirmed Monday that the account was compromised over the weekend. Instead of its usual uplifting posts, the account shared offensive content, including a reference to the Jeffrey Epstein investigation. The posts were quickly deleted. Elmo's account, with 650,000 followers, has been a platform for mental health awareness. Last year, it gained attention when Elmo asked followers how they were doing, prompting responses from figures like then-President Joe Biden and Chance the Rapper.

The headline-grabbing tale of an Italian man who said he was kidnapped and tortured for weeks inside an upscale Manhattan townhouse by captors seeking his bitcoin highlights a dark corner of the cryptocurrency world: the threat of violence by thieves seeking digital assets. The alleged attempted robbery is known as a "wrench attack." It's a name popularized by an online comic that mocked how easily high-tech security can be undone by hitting someone with a wrench until they give up passwords. Wrench attacks are on the rise thanks in part to cryptocurrency's move into mainstream finance, experts say.

Criminals are exploiting the holiday season to perpetrate scams against shoppers and donors, the Federal Bureau of Investigation San Francisco…