Not quite everything ! The "one time pad" is still uncrackable as a cypher. It can only be compromised by physical capture of the pad, but it's not a practical encryption technique for parties who cannot physically meet.
Ideal though for an agent sent into the field, who is given the one of the unique pair of pads for communication with the holder of the other.
I read David Kahn's "The Codebreakers" (all 2000+ pages) years ago, and recently found James Rusbridger's "Betrayal at Pearl Harbour", which contradicts some of Kahn's book with later info, and claims (with a lot of documented evidence) that UK knew of Japanese intentions, but that Churchill kept it quiet from the US because he wanted them in the war. He also claims that the US had all the same info and capability, but failed to put it together because, unlike the highly integrated British system, they were split by army/navy and inter-agency rivalry and hostility; and that evidence of their culpability has been systematically expunged from the records (but not successfully enough).
Cryptanalysis, because of its strong ties with world politics and history, makes fascinating reading.
Any of you with an interest might like to know that Kahn also contains the full uncracked cypher for a legendary unfound hoard of treasure somewhere near Roanoak Virginia. Do you want to be seriously rich ?
The problem in the Roanoak case is finding the key. It's a bit like the one-time pad, in that the document is half decrypted, using a particular book as the encryption key, but the same book doesn't work for the second half of the message.
What people have been trying to do for centuries, is find what book or document was used as the key for the second half. (Of course, it could always be that the writer was perpetrating a joke on future generations of treasure hunters, and the second half is just jibberish. "the location of the fabulous hoard of gold and jewels, we hid near Roanoak in the state of Virginia, buried under a bush which you can find by nkauh ln flk lalkl. kauyuyrel., jf;; hjsgujkfkjy kfhperty.zgi jlkkd kk ckka kljk j" or then again - It might just be there !)