Sun, Lucent and Echoworx are banding together to provide an encryption service that can save businesses from having to build their own infrastructure to secure e-mail.

Called Sun Secure Mail, the service will be sold to ISPs and other carriers that can sell it to customers, be it businesses or consumers. While ISPs would set the retail price, Sun says it thinks that could be between $5 and $10 per user per month based on what it will charge the ISPs for the wholesale service.

Sun hasn’t named any service providers that are going to buy it, but it says a U.S. phone carrier/ISP is to announce on Nov. 28 a service based on Sun Secure Mail.

USA.net, an ISP for midsize businesses, says it is evaluating the service and plans to offer an encrypted e-mail service next year. Sun Secure Mail could let USA.net secure customer e-mail without having to invest in its own hardware and software, says David Ramon, president of USA.net.

The company three years ago ran an encrypted e-mail service based on hardware and software it bought, but it posed so many problems that he discontinued the service. Now, with heightened concerns about security, customers are again seeking such a service, he says.

An encrypted e-mail service might be attractive to businesses that want e-mail encryption but lack the resources to set up their own, says Anne MacFarland, director of infrastructure architecture and solutions for Clipper Group. Setting up public-key infrastructure for encryption is complex and costly, and outsourcing it can at least keep the annual costs predictable for budget purposes. “Doing encryption yourself is something that could suddenly create a lot of workload if something goes wrong, and you don’t know when it will,” MacFarland says.

Hardware for the service will be based in a Lucent Worldwide Services network operations center in Broomfield, Colo., and Lucent will take care of provisioning the services. Echoworx technology authenticates users and encrypts the e-mails, and Sun is coordinating the effort and providing the servers needed to support the service.

Customers that have signed up for a retail subscription to Sun Secure Mail can go to the carrier’s provisioning site and download a software plug-in for Microsoft’s Outlook, Outlook Express or BlackBerry e-mail. The plug-in creates a “secure” button next to the “send” button in the e-mail application. Clicking it encrypts the e-mail.