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The first comment fills in a key missing piece: > The Russians had two intelligence organisations ... the KGB and the GRU. Both organisations knew that they sh

The first comment fills in a key missing piece: > The Russians had two intelligence organisations ... the KGB and the GRU. Both organisations knew that they should not reuse one-time pads. > [Against clear orders] The printers decided to print four copies of each pad then send two each to the KGB and GRU. Neither the KGB nor the GRU reused the pads they received, except perhaps because of occasional operator error. > ... Subtracting one message from the other cancelled out the unknown key to produce a synthetic message that was the difference between the two original messages. These could then be picked apart using a combination of statistics and predictable words. > - Mark Lomas

gruez 8y ago
> [Against clear orders] The printers decided to print four copies of each pad then send two each to the KGB and GRU. Neither the KGB nor the GRU reused the pads they received, except perhaps because of occasional operator error. why? how much more expensive could it be to generate new random numbers? do they not have cheap/fast RNGs?
- ballenf 8y ago
  He doesn't answer the 'why' but there's an implication that the printing shop had orders to produce X number of one time pads and it was half the work to setup the apparatus this way. Basically it was a shortcut that presumably felt entirely reasonable to folks running the printing press. And maybe even technically compliant with their instructions depending on the wording thereof.
- qop 8y ago
  Lazy press operators. Maybe they thought they were doing someone a favor by shortcutting. Just a guess, obv I wasn't there.
- pdpi 8y ago
  In the 40s? Probably not, no. This was a relevant and useful book when it was published — https://en.m.wikipedia.org/wiki/A_Million_Random_Digits_with_100,000_Normal_Deviates https://en.m.wikipedia.org/wiki/A_Million_Random_Digits_with... Generating randomness is hard, and a recent concern.
  - kragen 8y ago
    One of the useful things about that book was that using it provided evidence that you didn't choose your "random" numbers through some tricky process designed to produce a certain nonrandom result.
- crumpington 8y ago
  why? The answer is really, really, really simple. Have you ever gotten locked out of your house? Might you not keep one more key in a secret place, just in case? Have you ever forgotten a password, and needed to reset it? Have you ever trashed a file allocation table, or lost access to an encrypted disk? Didn't you wish there was a back up for destroyed data? Have you ever left for work without an umbrella, but luckily keep one at your desk (or wish you had), because it suddenly rains unexpectedly? Don't car dealerships provide two copies of keys with each new car by default? Now, here you are, the guy who finds out something incredible and needs to send a message fast. But you left your wallet in your other pants and it went through the wash. Luckily, you stashed your extra pad in a convenient place, and you can still send the message. No one dies, and you don't get fired or thrown in jail for being a negligent drunk! Thank god the printers knew your plight! This was probably a baker's dozen favor, that the printers did with a wink and a nod, because they had been caught in sticky situations, where they had to work with that one guy who couldn't get it together. Instictively, nerd indignance says incompetent idiots deserve to get locked out and thus weeded out by their own bumbling errors, because costing the lives of those weak links is better than risking the lives of everyone. Sure sounds great, but it doesn't always work that way in practice. The truth is that power vests itself where it can, and each officer getting a spare back-up probably noticibly saved face for higher ups, and saved enough people's actual bacon, without ever revealing the hellish risk being taken in any obvious way, that it became the norm to flout the geek's recommended rules for best practice.
georgecmu 8y ago
This comment doesn't make much sense. This one/two-time pad system was in use for all diplomatic traffic; not just by the intelligence agencies. See pages 47-49 here: https://nsarchive2.gwu.edu/NSAEBB/NSAEBB278/01.PDF https://nsarchive2.gwu.edu/NSAEBB/NSAEBB278/01.PDF

gruez 8y ago

> [Against clear orders] The printers decided to print four copies of each pad then send two each to the KGB and GRU. Neither the KGB nor the GRU reused the pads they received, except perhaps because of occasional operator error. why? how much more expensive could it be to generate new random numbers? do they not have cheap/fast RNGs?

ballenf 8y ago
He doesn't answer the 'why' but there's an implication that the printing shop had orders to produce X number of one time pads and it was half the work to setup the apparatus this way. Basically it was a shortcut that presumably felt entirely reasonable to folks running the printing press. And maybe even technically compliant with their instructions depending on the wording thereof.
qop 8y ago
Lazy press operators. Maybe they thought they were doing someone a favor by shortcutting. Just a guess, obv I wasn't there.
pdpi 8y ago
In the 40s? Probably not, no. This was a relevant and useful book when it was published — https://en.m.wikipedia.org/wiki/A_Million_Random_Digits_with_100,000_Normal_Deviates https://en.m.wikipedia.org/wiki/A_Million_Random_Digits_with... Generating randomness is hard, and a recent concern.
- kragen 8y ago
  One of the useful things about that book was that using it provided evidence that you didn't choose your "random" numbers through some tricky process designed to produce a certain nonrandom result.
crumpington 8y ago
why? The answer is really, really, really simple. Have you ever gotten locked out of your house? Might you not keep one more key in a secret place, just in case? Have you ever forgotten a password, and needed to reset it? Have you ever trashed a file allocation table, or lost access to an encrypted disk? Didn't you wish there was a back up for destroyed data? Have you ever left for work without an umbrella, but luckily keep one at your desk (or wish you had), because it suddenly rains unexpectedly? Don't car dealerships provide two copies of keys with each new car by default? Now, here you are, the guy who finds out something incredible and needs to send a message fast. But you left your wallet in your other pants and it went through the wash. Luckily, you stashed your extra pad in a convenient place, and you can still send the message. No one dies, and you don't get fired or thrown in jail for being a negligent drunk! Thank god the printers knew your plight! This was probably a baker's dozen favor, that the printers did with a wink and a nod, because they had been caught in sticky situations, where they had to work with that one guy who couldn't get it together. Instictively, nerd indignance says incompetent idiots deserve to get locked out and thus weeded out by their own bumbling errors, because costing the lives of those weak links is better than risking the lives of everyone. Sure sounds great, but it doesn't always work that way in practice. The truth is that power vests itself where it can, and each officer getting a spare back-up probably noticibly saved face for higher ups, and saved enough people's actual bacon, without ever revealing the hellish risk being taken in any obvious way, that it became the norm to flout the geek's recommended rules for best practice.

georgecmu 8y ago

This comment doesn't make much sense. This one/two-time pad system was in use for all diplomatic traffic; not just by the intelligence agencies. See pages 47-49 here: https://nsarchive2.gwu.edu/NSAEBB/NSAEBB278/01.PDF https://nsarchive2.gwu.edu/NSAEBB/NSAEBB278/01.PDF