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Sounds like that poor Luftwaffe general/concerned father "doomed" the Bismarck more directly than someone who happened to transcribe a broken code. I wonder wha

Sounds like that poor Luftwaffe general/concerned father "doomed" the Bismarck more directly than someone who happened to transcribe a broken code. I wonder what his obituary was like.

Arnt 10y ago
Nah, he just made a mistake. People make the occasional mistake. Crypto has to cover that, because it happens. Another general during WW2 made the mistake of always including the same stock paragraph in every transmission. That's bad. That's an O(n) mistake, not an O(1) mistake. And I suppose someone made an O(n) mistake if the British knew the names of a significant number of Bismarck crew.
- greenyoda 10y ago
  Another mistake, which had serious consequences to the Germans, was that a German weather ship in the North Atlantic accidentally transmitted their weather report using the Enigma key reserved for naval operations rather than the key used for routine information, noticed the mistake, and then immediately retransmitted the identical message using the routine key. Since weather forecasts have predictable content and format (and are thus easier to decrypt), this error allowed the Bletchley Park people to crack the operations key much more quickly than they otherwise could have. This episode is described in the book Alan Turing: The Enigma[1], which was the basis for "The Imitation Game" film. I highly recommend this book if you're interested in Turing, cryptography, or the early days of computing. While Turing is best known today for his work on the theoretical underpinnings of computer science (due to the Turing Machine that bears his name), he also worked on the design of one of the early general purpose computers (the ACE[2]) after the war, on voice encryption hardware, and other interesting stuff. [1] http://www.amazon.com/Alan-Turing-Enigma-Inspired-Imitation/dp/069116472X http://www.amazon.com/Alan-Turing-Enigma-Inspired-Imitation/... [2] https://en.wikipedia.org/wiki/Automatic_Computing_Engine https://en.wikipedia.org/wiki/Automatic_Computing_Engine
  - michaelcampbell 10y ago
    > Since weather forecasts have predictable content and format (and are thus easier to decrypt), You can't tell the format from the encrypted data though, right? Would you not have to know apriori what this message was in order to make use of this particular weakness?
    - Arnt 10y ago
      Metadata. In this case, the broadcaster's general location and the timing and (I suppose) size of the messages. And perhaps known/guessed plaintext attacks: if you too have a weather ship in the same area you can guess at the content.
johngossman 10y ago
At least its an interesting lesson in InfoSec: even secure replicas reduce the security of the total system. As well as all the social vulnerabilities implicit.

Sounds like that poor Luftwaffe general/concerned father "doomed" the Bismarck more directly than someone who happened to transcribe a broken code. I wonder what his obituary was like.

Arnt 10y ago

Nah, he just made a mistake. People make the occasional mistake. Crypto has to cover that, because it happens. Another general during WW2 made the mistake of always including the same stock paragraph in every transmission. That's bad. That's an O(n) mistake, not an O(1) mistake. And I suppose someone made an O(n) mistake if the British knew the names of a significant number of Bismarck crew.

greenyoda 10y ago
Another mistake, which had serious consequences to the Germans, was that a German weather ship in the North Atlantic accidentally transmitted their weather report using the Enigma key reserved for naval operations rather than the key used for routine information, noticed the mistake, and then immediately retransmitted the identical message using the routine key. Since weather forecasts have predictable content and format (and are thus easier to decrypt), this error allowed the Bletchley Park people to crack the operations key much more quickly than they otherwise could have. This episode is described in the book Alan Turing: The Enigma[1], which was the basis for "The Imitation Game" film. I highly recommend this book if you're interested in Turing, cryptography, or the early days of computing. While Turing is best known today for his work on the theoretical underpinnings of computer science (due to the Turing Machine that bears his name), he also worked on the design of one of the early general purpose computers (the ACE[2]) after the war, on voice encryption hardware, and other interesting stuff. [1] http://www.amazon.com/Alan-Turing-Enigma-Inspired-Imitation/dp/069116472X http://www.amazon.com/Alan-Turing-Enigma-Inspired-Imitation/... [2] https://en.wikipedia.org/wiki/Automatic_Computing_Engine https://en.wikipedia.org/wiki/Automatic_Computing_Engine
- michaelcampbell 10y ago
  > Since weather forecasts have predictable content and format (and are thus easier to decrypt), You can't tell the format from the encrypted data though, right? Would you not have to know apriori what this message was in order to make use of this particular weakness?
  - Arnt 10y ago
    Metadata. In this case, the broadcaster's general location and the timing and (I suppose) size of the messages. And perhaps known/guessed plaintext attacks: if you too have a weather ship in the same area you can guess at the content.

johngossman 10y ago

At least its an interesting lesson in InfoSec: even secure replicas reduce the security of the total system. As well as all the social vulnerabilities implicit.