President Barack Obama is making his position on encryption known: he is a supporter and "believer in strong encryption" but also "sympathetic" to law enforcement's needs to prevent terror attacks.

"I think the only concern is... our law enforcement is expected to stop every plot. Every attack. Any bomb on a plane. The first time that attack takes place, where it turns out we had a lead and couldn't follow up on it, the public's going to demand answers. This is a public conversation that we should be having," Obama said in a Friday interview with Re/Code. "I lean probably further in the direction of strong encryption than some do inside law enforcement. But I am sympathetic to law enforcement, because I know the kind of pressure they're under to keep us safe. And it's not as black and white as it's sometimes portrayed. Now, in fairness, I think those in favor of air tight encryption also want to be protected from terrorists."

Further Reading US top cop decries encryption, demands backdoors

Encryption became a hot-button topic in the wake of the summer 2013 leaks by National Security Agency whistleblower Edward Snowden. His documents, including some seemingly showing that Skype has a backdoor, highlighted a broad online global surveillance society and set off a cottage industry of encryption companies.

Both the FBI and the Justice Department are demanding that companies—like Apple and Google that are beginning to outfit mobile phone devices with encryption by default—should build backdoors to allow law enforcement access. Without a backdoor, the encryption likely prevents authorities from physically accessing contents directly from the phones' hardware, even with a warrant.

The chief executive isn't faulting companies for building encrypted tools. "I think they are properly responding to a market demand." But the president, his second remarks on the topic in a month, said "we can't pretend" that there's not a tradeoff between civil liberties and safety.

One of the interesting things about being in this job, is that it does give you a bird's-eye view. You are smack dab in the middle of these tensions that exist. But, there are times where folks who see this through a civil liberties or privacy lens reject that there's any tradeoffs involved. And, in fact, there are. And you've got to own the fact that it may be that we want to value privacy and civil liberties far more than we do the safety issues. But we can't pretend that there are no tradeoffs whatsoever.

US-based companies are not required to provide the government with backdoors into their wares. The law surrounding this issue is the Communications Assistance for Law Enforcement Act of 1994, commonly referred to as CALEA. It requires that telcos make their phone networks amenable to wiretaps, but it doesn’t apply to phone hardware or most other communication services.

With British Prime Minister David Cameron at his side, the president last month said:

“If we find evidence of a terrorist plot… and despite having a phone number, despite having a social media address or e-mail address, we can’t penetrate that, that’s a problem,” Obama said.

Silicon Valley companies, he said, will help solve the problem because "they’re patriots."