In March 1972, the U.S. Air Force started a review of a Honeywell Multics system to understand whether it could be used in secure environments. The report was issued in mid-1974 and concluded that Multics, while not secure, was better than its peers and might be a reasonable starting point for a secure system.24 The report raised the potential of adding a back door (it was called a “trap door”) to an innocent system call. When passed a specific, very unlikely input, the system call allowe...
