Canadian phone maker RIM said after France's national defense agency banned many government officials from using the devices for sensitive government purposes that the communications are protected by sophisticated encryption codes that would take "billions of years" to crack, The Times of London reported Wednesday.

French security officials had expressed concern that communications sent via BlackBerry could be intercepted by the U.S. National Security Agency or other foreign agencies, as the phones use mail servers located in the United States, Cnet News.com reported.

"The risks of interception are real," Alain Juillet, a senior official in charge of economic intelligence for the French government, told the country's Le Monde newspaper.

However, security officials have yet to find an alternative device to replace the smartphones, the newspaper said, and one member of the prime minister's Cabinet claimed that some officials are continuing to use the BlackBerrys "in secret," Cnet said.