Lockdown provides the user with a red/green system: an isolated and constrained environment for performing online transactions, as well as a high-performance, general-purpose environment for all other (non-security-sensitive) applications. An external device verifies which environment is active and allows the user to securely learn which environment is active and to switch between them.
The original design and implementation of Lockdown is described in:
Lockdown: Towards a Safe and Practical Architecture for Security Applications on Commodity Platforms. Amit Vasudevan and Bryan Parno and Ning Qu and Virgil D. Gligor and Adrian Perrig. Proceedings of the 5th International Conference on Trust and Trustworthy Computing (TRUST), June 2012. http://hypcode.org/paper-lockdown-TRUST-2012.pdf
Lockdown: A Safe and Practical Environment for Security Applications (CMU-CyLab-09-011) Amit Vasudevan and Bryan Parno and Ning Qu and Virgil D. Gligor and Adrian Perrig. Technical Report CMU-CyLab-09-011, June 2009. http://www.cylab.cmu.edu/files/pdfs/tech_reports/CMUCyLab09011.pdf
The implementation of Lockdown contained herein can be via the core build process (see Building uberXMHF (pc-legacy-x86_32)). Note that the implementation is a research prototype and does not yet fully provide the security properties of the design.