Silent Circle, a mobile telephone service provider focused on privacy and encrypted communications, announced Thursday that it would begin offering international calling plans without global roaming charges. The new service will allow employees traveling overseas to use their iOS or Android mobile phones without incurring exorbitant roaming fees.

The company has been providing smartphone apps that allow customers to make encrypted calls and text. Until now, however, the service required that both parties have the app installed on their phone.

Muscling in on the Competition

The move puts Silent Circle in direct competition with Skype and Google Voice, both of which also allow customers to use their phone while traveling abroad. It also represents an attack on traditional carriers that can charge sky-high rates to clients who use their phones while traveling abroad.

"Silent Circle is directly challenging the legacy model of mobile carriers by offering an alternative to costly mobile roaming fees. This is an especially important issue for our enterprise and government customers around the world," said Vic Hyder, Silent Circle's chief of revenue. "International fees and roaming charges account for a significant portion of European and Latin American business overhead. Our encrypted international calling service completely eliminates roaming charges while protecting members' privacy."

The Switzerland-based company said in a statement Thursday that the expansion of its encrypted VoIP service represents "a major disruption to wireless carriers' traditional mobile calling models." Silent Circle claimed its geographic coverage area is now "four to five times more than its closest non-secure competitors like Skype and Viber."

According to Silent Circle's Web site, calling plans for individuals begin at $12.95 a month for 100 minutes of calls to landlines in 79 countries and cell phones in 41, including North America, most European countries, Russia and China. Plans go up to $39.95 a month for 1,000 minutes. The company does not list prices for its enterprise plans. Calls and texts to other Silent Circle members remain free of charge.

Security for Business Customers

The service may prove particularly appealing for corporate and enterprise clients who need to maintain privacy while discussing sensitive or confidential information. The technology is based on a secure voice-over-IP client, similar to services such as Microsoft's Skype. Unlike Skype, which reportedly has given the U.S. National Security Agency unfettered access to its data, Silent Circle explicitly markets itself as the most secure mobile communication possible, while also supporting encrypted file transfers, conferences calls and video chat.

But whether corporations adopt the platform will depend on how easy it is to manage, and how well it fits with their existing communications infrastructure, said Bill Menezes, principal research analyst at Gartner.

"Cell phone carriers haven't done a lot" to keep down international roaming rates, Menezes told us. "Increasingly, enterprises are looking for an over-the-top solution, whether that's a Skype or a Vibe or a Silent Circle." Companies may be reluctant to take on management of a new application, or, if they already have a unified communication deployment in place, they may choose something else that works with their existing technology, he said.

Silent Circle made news earlier this year when it announced it was developing a "Blackphone" in a joint venture with Geeksphone following revelations by former NSA contract employee Edward Snowden of a massive government surveillance program. The company claims the smartphone, which runs an Android-based operating system it calls PrivatOS, is protected against the type of surveillance tactics practiced by agencies such as the NSA.

However, the technology is unlikely to be foolproof against law enforcement or espionage agencies determined to surveil a target.

"Any drug dealer, terrorist or pimp who thinks this sort of service will insulate them would have to be naive," Ben Wood, a senior analyst with mobile research firm CCS Insight, told Reuters. "Nothing is bulletproof in that regard."