Tolkien's Code Breaker

In the run up to the Second World War, Tolkien was emarked as a code breaker. He took an instructional course at the London HQ of the government code and cipher school. A record of his training was found which included the notation keen next to his name,. Although Tolkien's scholar Anders Stenstrom suggested that in all likelihood, that is not a record of Tolkien's interest, but a note about how to pronounce his name.