Because of the reasons Shiro said, the OTP wasn´t used very often in practice. The military used and invented new encryption methods, which could decide about the wars´endings. For example the Germans used the "Enigma" (it´s a mechanical encryption-machine) to encrypt the messages to the submarines. But the English from "Bletchley-Park" (it was the secret service´s headquater, I think) could break these messages with the first computer. It was a machine called "bomb" to crack the Germans´secret messages and no real computer with transistors; it was a mechanical one.
This was the main reason that the Germans lost the war on the sea.
klausi
