Organizations need an effective certificate infrastructure because certificates are essential to security. The article Windows Phone 7 and certificates discusses several ways of installing certificates on Windows Phone 7, and provides additional relevant certificate information.
Windows Phone 7 trusts most major commercial certification authorities (CAs). All of these CAs and their root certificates that are pre-installed on Windows Phone 7 phones are identified in the article Windows Phone 7 root certificates. Root certificates are included in web browser applications such as Windows® Internet Explorer® and Internet Explorer Mobile because they play a significant role in Secure Sockets Layer (SSL) communications (which are used extensively in online commerce transactions on the World Wide Web).
Certificates for authentication and Microsoft Exchange ActiveSync®
In addition to using certificates for secure communications, organizations use them for authentication purposes—to verify the identity of users, as well as devices.
An increasingly common authentication use works in conjunction with the Microsoft Exchange ActiveSync (EAS) protocol, which provides mobile users with message and calendar synchronization services. With EAS, users can connect directly to Exchange servers without using any middleware. And the ability of Windows Phone 7 to handle multiple Exchange accounts is a real plus!
How Windows Phone 7 uses certificates to help protect against malware
Certificates play an important role in the installation and licensing of Windows Phone 7 applications, which are only available through the Marketplace Hub. All applications are validated, certified, and uniquely signed with a certificate before they are uploaded, which significantly reduces the threat of malware.
Because Microsoft is the only signing authority, malicious software developers cannot self-sign malware code, and application certificates can be revoked if malware is detected after publication. This approach enhances the integrity of the phone, increases consumer confidence, and provides benefits to developers and consumers alike.
Have a look at the articles on the Windows Phone 7 guides for IT pros download center for more details.