Because it uses VoIP, Cellcrypt Mobile works on any 3G network including the EV-DO (Evolution-Data Optimized) data networks used by U.S. CDMA (Code Division Multiple Access) operators such as Verizon Wireless and Sprint Nextel. The company is also seeking certification under the U.S. National Institute of Standards and Technology's FIPS (Federal Information Processing Standards) 140-2 regulation, which would qualify it for contracts with U.S. government agencies.

Although mobile operators have a sometimes- with VoIP, they don't fear Cellcrypt because it is aimed at a limited market and not designed to help users avoid paying for voice minutes, according to Meakin. The software doesn't come cheap: A license for one user costs about £2,500 (US$3,732) per year, though the price varies based on volume and other factors, Meakin said.