A fully encrypted smartphone that aims to foil snooping governments and hackers is due to go on the market next month.
The Blackphone has been produced by the secure communications firm Silent Circle and the small Spanish-based manufacturer Geeksphone.
It comes as concern about revelations of vast US surveillance of telephone data has reached fever pitch. But Silent Circle chief executive Mike Janke said his company was working on the handset even before Edward Snowden's leaks about the US National Security Agency's programmes last year.
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"We did this because there was a problem that was not being solved - secure communications," Janke said,
Silent Circle was formed in 2011 and last year launched apps and services that let smartphone and PC users send encrypted messages and videos.
The Blackphone is an extension of that effort, said Janke, a former US Navy SEAL who co-founded the firm with other ex-SEALs and Silicon Valley cryptography experts.
"We offer completely encrypted, peer-to-peer communications. We have encrypted video, encrypted text and secure VoIP (Voice-over-Internet-Protocol) calls," Janke said.
Silent Circle customers include major global corporations, human rights activists and even the Tibetan government in exile.
Because of its work, he said, "almost all of the major smartphone manufacturers came to us" to collaborate on a more secure smartphone.
Janke said Silent Circle chose to form a joint venture for Blackphone with the small Spanish company which recently began making smartphones using the Firefox operating system.
The larger firms, said Janke, "want to own your soul. These companies are in the business of monetising data."
Silent Circle developed a modified or "forked" version of Android called PrivatOS for the phone, which is set to be unveiled at the Mobile World Congress in Barcelona on February 24.
The company declined to release detailed specifications or pricing ahead of the unveiling.
Janke said it would be sold around the world at prices lower than the iPhone 5S or Samsung Galaxy S4.
But he also maintained that it would be comparable in terms of performance to those flagship devices.
It is designed as a user-friendly phone that could be carried by executives, government officials, activists or ordinary people. "It's sexy, it's thin, it's sleek, but it also solves a problem," Janke said.
"You can still go to Google and browse the web, but Google doesn't know who you are. It's a high-end smartphone.
"The user doesn't have to know how to use or how to spell encryption."
As an added assurance to customers, the Blackphone venture is incorporated in Switzerland with a Swiss data centre and has "minimal data retention".
"All we have is the user name you give us and a 10-digit phone number," he said.
Even if the company faced a court order in Switzerland, it could hand over only the user name. Authorities seeking more information would need to subpoena a separate payment processing firm "and try to match that to our users", Janke said.
Janke said there is interest in the device worldwide, and that Blackphone has "verbal preorders" from four international telecom carriers and 30 enterprise customers.
Interest in Blackphone, Janke said, suggests "several million" would be sold within a year and about 10 million over the next four years.
He did not disclose where the Blackphone would be made, but said there would be "neutral" partners making components and a tightly controlled assembly process to ensure no "back doors" are inserted.
Janke said Silent Circle had turned down a purchase request from the US State Department.