NSA whistleblower Edward Snowden's privacy driven email service, Lavabit, has decided to shut down rather than cooperate with a court order that demanded it work with the US government.
It is the first such company known to have closed rather than comply with government surveillance.
Founder Ladar Levison wrote on the company's blog that he had a choice. He could have been forced to become complicit in crimes against the American people or walk away from nearly ten years of hard work by shutting down Lavabit.
Levison said government-imposed restrictions prevented him from explaining what exactly led to his company's crisis point.
While he would have liked to explain his decision under the First Amendment, he said, Congress has passed laws that say otherwise.
"As things currently stand, I cannot share my experiences over the last six weeks, even though I have twice made the appropriate requests," Levison wrote.
Kurt Opsahl, a lawyer with the Electronic Frontier Foundation, told the Guardian that it was the first time a service provider chose to shut down rather than comply with a court order they felt violated the Constitution.
There are signs that others are following. Silent Circle, another provider of secure online services, is killing off its own encrypted email offering, Silent Mail.
The company said that although it had not received any government orders to hand over information, "the writing is on the wall".
Snowden was a Lavabit customer. A Lavabit email address believed to come from Snowden invited reporters to a press conference at Moscow's Sheremetyevo Airport in mid-July.
Levinson said he intended to mount a legal challenge and a favourable decision would allow him to resurrect Lavabit as an American company.
He warned that he would strongly recommend against anyone trusting their private data to any company with physical ties to the United States.