On a recent Saturday morning in an otherwise deserted office building in Roseville, two dozen software developers gathered for a crash course on roaming the Internet incognito.
The class in encrypted communication was courtesy of CryptoParty Minnesota, a branch of a global movement that aims to keep people safe from spying by governments, corporations, stalkers or anyone else who wants to read your e-mails or see where you're browsing.
No one should trust conventional Web browsers and text messaging to protect them, the class was told.
"If you're not encrypting your communications, there's a potential for several entities to have it forever," Christopher Burg, one of CryptoParty's members, told attendees at the Roseville event. "It could come back and bite you."
For the CryptoParty advocates, private communications allow freedom of expression and democracy to flourish around the world. Yet in the aftermath of the attacks in Paris, politicians and intelligence officials in Washington say the government should have a way to sneak around encrypted communications, so that terrorists cannot plan their evil deeds without detection.
Speaking to an intelligence conference in Washington, D.C., last month, CIA Director John Brennan complained about the "technological capabilities that are available right now that make it exceptionally difficult, both technically as well as legally, for intelligence and security services to have the insight they need to uncover" terrorist plots.
Politicians from both parties have called for legislation that provides a back door for intelligence agencies into encrypted communications.
Those calls have come in the face of little or no evidence tying the Paris attacks to terrorists' use of encryption apps. Major technology companies have risen in defense of encryption.