This is a good article. Also good, along similar lines, is the W7 paper: "A Security Kernel Based on the Lambda-Calculus", Jonathan A. Rees, MIT AI memo 1564,

This is a good article. Also good, along similar lines, is the W7 paper: "A Security Kernel Based on the Lambda-Calculus", Jonathan A. Rees, MIT AI memo 1564, 1996. Available as PDF at its official home at https://dspace.mit.edu/handle/1721.1/5944 https://dspace.mit.edu/handle/1721.1/5944 and as readable HTML at jar's homepage at http://mumble.net/~jar/pubs/secureos/secureos.html http://mumble.net/~jar/pubs/secureos/secureos.html.