Cracking the Code

In “Cuba Confidential,” it is implied that during World War II a machine was custom-built to solve messages sent from Berlin to Tokyo using a “onetime pad.” A one-time pad (random key) produces an absolutely undecipherable message if used properly. The key, which is the length of the message, is used only once. In contrast, the Japanese ambassador to Germany, Hiroshi Oshima, sent encrypted messages from Berlin to Tokyo using the Japanese diplomatic code. This was known as “Purple” to U.S. cryptanalysts and it used a Type B cipher machine. It did not create a random key stream and thus was not a one-time pad generator. The U.S. did build a replica machine and that is presumably the machine the article was referring to.

— Iver Cooper | Arlington, Virginia

Thank you for revealing the significant work of Juanita Moody, the woman whose contributions to the security of our country have finally been brought to light.

— Grace Hershman | Philadelphia