KoolSpan says it can provide end-to-end encryption for cell phone calls made over public wireless networks using a microSD card it is expected to ship early next year.

As long as the phones at both ends of the connection are equipped with TrustChips and the accompanying TrustChip Voice software, any call on a GSM network can be secured without help from the carrier, the company says.

While this is the first commercial application of TrustChip, these cards could also be used by utilities for monitoring their networks securely, by banks to secure ATM transactions and to secure communications to robots on factory floors, says Tony Fascenda, KoolSpan’s CEO. The company is expected to announce a third-party developers’ program for the chips in the first quarter of next year.

KoolSpan already makes USB tokens for computers that set up computer-to-computer VPNs, and is expanding to microSD cards as a way to exploit other applications, he says.

TrustChip devices are managed in groups via TrustCener management software that stores groups, group policies and billing interfaces. But the cards authenticate directly to each other without the involvement of a central server, the company says.

People making the secure phone calls punch in the phone number as they normally would. After the connection is made, the receiving phone with a chip chirps a series of dual-tone, multi-frequency (DTMF) tones to signal that it has a TrustChip and to send the phone number for reaching the phone’s data channel.

The phones automatically disconnect and the calling phone calls back on the data channel to set up the secure call. It takes a few seconds for the chips on either end to negotiate session keys used to encrypt the calls.

Each chip contains codecs used by Windows Mobile and Symbian wireless operating systems

The first time two phones establish a secure connection, TrustChip Voice software installed in the phones alter the entries in each phone’s address book. So subsequent calls between the phones will automatically use the data channel - not the voice channel - and set up encrypted sessions, KoolSpan says.

The company plans to sell the chips to customers interested in deploying secure networks of devices and created TrustChip Voice to prove the concept.