Paul Karger
American computer security researcher who described in 1974 the compiler backdoor Ken Thompson later made famous.
With Roger Schell, Karger ran a penetration test of Multics for the US Air Force in 1974. The system had been designed with security as a goal, and they got in anyway. Among other things, their report suggested an attacker could plant a trapdoor in the compiler so it survived even a review of the source code. Ken Thompson cited it in his 1984 Turing lecture, Reflections on Trusting Trust.
In the 1980s Karger led work on DEC's VAX security kernel, a virtual machine monitor aimed at the highest Orange Book rating. It was cancelled in 1990, partly because few customers wanted to pay for it. He later did research at IBM. In 2002 he and Schell wrote Thirty Years Later, noting that the lessons of Multics still hadn't been absorbed. Karger died in 2010.