The innovative ZRTP Voice-over-IP encryption scheme invented by privacy guru Phil Zimmermann is to be used exclusively in the gateway products of only one company, UM Labs, the latter has announced.

UM Labs, founded by ex-Borderware man Peter Cox, who is also a long-time associate of Zimmermann, has been using ZRTP inside its SIP controller gateways since last November, but the new agreement makes the protocol a unique feature of UM's products. UM Labs has been using Zimmermann's client, Zfone, for three years.

The exact terms of the deal have not been made public, but it is understood that ZRTP will now feature as an option on its RC-2100, EC-4200 and SC-6600 family if SIP controllers for an indefinite period. The agreement does not affect ZRTP's use in non-gateway products, such as VoIP clients.

"By providing ZRTP across our entire product range, we are able to ensure that all remote VoIP connections are protected with high grade security. ZRTP means that we can provide encrypted VoIP connections to devices on mobile networks, as well to those on fixed line networks and on Wi-Fi connections," said UM Lab's Cox.

According to Cox, the current market for voice encryption is in integrating vulnerable mobile phones into secured enterprise voice systems, to provide end-to-end encryption of voice calls. The problem with mobiles is that the native encryption only meets the most basic level of security and only relates to the radio part of a call. More businesses and government institutions now see this as a security vulnerability.

Making matters worse, even end-to-end encryption is theoretically vulnerable because the network handles the key distribution. UM Labs gateways are designed to secure that last chink in the security armour.

"The partnership with UM Labs extends the reach of ZRTP and enables ZRTP users to communicate securely with users linked to any commercial VoIP system. This effectively brings the major PBX vendors, including Avaya, Cisco, Nortel and many others into the ZRTP community," commented Zimmermann himself.

The news will offer Phil Zimmermann some certainty after a development cycle that has seen him paying out of his own pocket for a team of East European developers to b ring his idea to fruition. The product is gaining traction only slowly in terms of being integrated with VoIP clients, a reflection of the slow uptake of voice encryption generally.

Longer-term, the key to ZRTP's long-term success will depend on its adoption on the handset software which sits at the client end of any encrypted call, and not only on its success at finding its way on to the network-level gateways, something that Cox accepts. However, UM's gateways are really about using ZRTP to gain that small but increasingly important layer of key security which he claims rival system don't offer.