Bitfrost: OLPC Security Platform
Bitfrost is the OLPC security platform. The Bitfrost approach is unique in the way that it adheres to four basic principles: Open Design, No Lockdown, No Required Reading and Unobstrucive Security. These principles are aimed towards five main goals: No User Passwords, No Unencrypted Authentication, Out-of-the-box Security, Limited Institutional PKI and No Permanent Data Loss.
Check out the Bitfrost OLPC Wiki for details on how OLPC employs the security platform.