Ten corporate customers of Siemens' communications group will take part in a beta of Voltage's identity-based encryption, or IBE, toolkit, set to be unveiled Monday. The technology takes identity information--such as an e-mail address, phone number or IP address--and uses that for the public key for a cryptographic system, said Matt Pauker, company co-founder.

Siemens has integrated the IBE Toolkit into smart phones running Microsoft Windows Mobile operating system, Voltage said.

"Siemens wanted to ensure that content for its e-mails was encrypted," said Wasim Ahmad, Voltage's vice president of marketing.

The interest in cell phone encryption comes as viruses increasingly find their way onto cell phones. A report from IBM last week highlighted mobile devices as the next major target of malicious coders.

Voltage said its SecureMail technology lets users send protected messages from cell phones without the need for security certificates.

"Most public encryption keys require too many security credentials and make it complicated for the end user," Ahmad said.

The company is also expected to announce that Fujitsu, e-mail security company CipherTrust, and instant messaging company IMLogic have also licensed its IBE Toolkit.