A high-ranking cybersecurity official who has just left the Obama administration says the battle between the government and the tech sector over encryption is already over, and the tech sector won.

Ari Schwartz was the Obama White House's senior director for cybersecurity until the end of September, and he is starting a new job with the law firm Venable as managing director of cybersecurity services on Monday.

In an interview with CNBC, he shared his thoughts on the debate over a U.S. tech sector that, largely in response to the Edward Snowden revelations, has begun selling nearly unbreakable encryption to its customers. American law enforcement and intelligence officials, led by FBI Director James Comey, have argued that such encryption means many valuable leads will "go dark" for investigators trying to solve crimes and prevent terrorism.

But Schwartz said law enforcement can't win the debate.

"Stronger encryption is inevitable," he said. "Law enforcement is going to have to learn to work in that environment."