8 ms·

Any more details on how the encoding worked? Was this just a substitution cypher with some gibberish sprinkled in?

LeoPanthera 8y ago
Since the article mentions finding duplicate symbols which corresponded to duplicate letters in words, it's probably a simple substitution cipher. Such codes can usually be broken with a combination of frequency analysis, and guesswork. This one was apparently made more difficult by the fact that every other symbol was random. (And apparently using some symbols that did not otherwise appear in the code.)
- rocqua 8y ago
  It feels like they could've figured that out by simply looking at the distribution of triangles on the inside as compared to the outside.
  - gmueckl 8y ago
    For that you simply need to have the sudden inspiration of how the scheme works. Snark aside, I don't think that discarding half of the source material as random junk is such an obvious thing to do.
    - rocqua 8y ago
      You could easily think, 'hey perhaps the outside triangles are different from the inside ones, lets make a histogram of the symbols in both.' From there, you'd certainly notice if one side had a lot more symbols than the other side. Trying to analyze both separately is a decent next step, and we are well along to solving this.
      - unparagoned 8y ago
        That's not something a normal human would easily think. I doubt an experienced God breaker would have, easily thought your suggestion. But don't worry, go on telling yourself it's something you would have easily thought.
brad0 8y ago
Is gibberish called nulls or nonces? I forget.
- lainga 8y ago
  Those are nulls. Nonces are random numbers for one-time-only use
  - kosievdmerwe 8y ago
    Nonce contains "once", which makes it easier to remember.
- cortesoft 8y ago
  Nonce is short for "number used only once"
  - herodotus 8y ago
    A "nonce word" is a word that is created to be used once. For example, if we were surfing off the coast near the Kruger National Park, we might send this tweet: "We are on Surfari!" The wikipedia entry for Cryptographic nonce says: "It is similar in spirit to a nonce word, hence the name."
    - cortesoft 8y ago
      Yeah, I should have said "this is the mnemonic I use to remember what it is"
    - lisper 8y ago
      Also known as a hapax legomenon.
      - TeMPOraL 8y ago
        I... don't understand how it works. Isn't the Wikipedia page listing these words essentially invalidate their "hapax legomenon" status? Also, GP's "Surfari" doesn't sound like a word meant to be used once, but as a word meant to be funny and with high probability of becoming a piece of jargon between a band of friends. My wife & I invent words like these all the time (half of them being born from misspelling or moments of confusions). Are they "nonces" too, even though we keep using them?
Zenst 8y ago
Certainly seems that way. How I read "Noticing some repeated pairs of symbols - which represented letters - the first word cracked by GCHQ boffins was Sidebottom's favourite word, "bobbins"." Though two triangles are used per letter - you can check that with one of the examples which has a message "Why does my nose hurt after concerts?" - 37 characters in total (including spaces), then count the triangles - 74. Hence two inside triangles are used per character. But certainly highlights how adding noise to any encryption has it's upsides.
- otwo3 8y ago
  > Adding noise to any encryption has it's upsides That's assuming that the secret is the encryption algorithm itself rather than the key. Modern symmetric encryption does not work that way - the algorithm is public and well known while the key is the actual secret required for encryption/decryption. I don't see how adding noise in modern encryption can help other than increase the size of the output. Some modes of operation make use of random noise (IV in CBC, nonce in CTR, etc) because it's a convenient way to get a unique number but it's not for obscurity, it's because it's needed to prevent attacks on these modes.
  - moomin 8y ago
    Look up “confounders”, random noise can be extremely useful if you encrypt it as well. This significantly increases the work required to decrypt (since you’ve got to decrypt random noise as well as signal), makes it much harder to tell if you’ve actually decrypted something successfully (depending on how well you can test the plaintext, obviously) and frustrate correlation attacks because every message has a different payload even if the logical payload was the same.

Since the article mentions finding duplicate symbols which corresponded to duplicate letters in words, it's probably a simple substitution cipher. Such codes can usually be broken with a combination of frequency analysis, and guesswork. This one was apparently made more difficult by the fact that every other symbol was random. (And apparently using some symbols that did not otherwise appear in the code.)

rocqua 8y ago
It feels like they could've figured that out by simply looking at the distribution of triangles on the inside as compared to the outside.
- gmueckl 8y ago
  For that you simply need to have the sudden inspiration of how the scheme works. Snark aside, I don't think that discarding half of the source material as random junk is such an obvious thing to do.
  - rocqua 8y ago
    You could easily think, 'hey perhaps the outside triangles are different from the inside ones, lets make a histogram of the symbols in both.' From there, you'd certainly notice if one side had a lot more symbols than the other side. Trying to analyze both separately is a decent next step, and we are well along to solving this.
    - unparagoned 8y ago
      That's not something a normal human would easily think. I doubt an experienced God breaker would have, easily thought your suggestion. But don't worry, go on telling yourself it's something you would have easily thought.

brad0 8y ago

Is gibberish called nulls or nonces? I forget.

lainga 8y ago
Those are nulls. Nonces are random numbers for one-time-only use
- kosievdmerwe 8y ago
  Nonce contains "once", which makes it easier to remember.
cortesoft 8y ago
Nonce is short for "number used only once"
- herodotus 8y ago
  A "nonce word" is a word that is created to be used once. For example, if we were surfing off the coast near the Kruger National Park, we might send this tweet: "We are on Surfari!" The wikipedia entry for Cryptographic nonce says: "It is similar in spirit to a nonce word, hence the name."
  - cortesoft 8y ago
    Yeah, I should have said "this is the mnemonic I use to remember what it is"
  - lisper 8y ago
    Also known as a hapax legomenon.
    - TeMPOraL 8y ago
      I... don't understand how it works. Isn't the Wikipedia page listing these words essentially invalidate their "hapax legomenon" status? Also, GP's "Surfari" doesn't sound like a word meant to be used once, but as a word meant to be funny and with high probability of becoming a piece of jargon between a band of friends. My wife & I invent words like these all the time (half of them being born from misspelling or moments of confusions). Are they "nonces" too, even though we keep using them?

Zenst 8y ago

Certainly seems that way. How I read "Noticing some repeated pairs of symbols - which represented letters - the first word cracked by GCHQ boffins was Sidebottom's favourite word, "bobbins"." Though two triangles are used per letter - you can check that with one of the examples which has a message "Why does my nose hurt after concerts?" - 37 characters in total (including spaces), then count the triangles - 74. Hence two inside triangles are used per character. But certainly highlights how adding noise to any encryption has it's upsides.

otwo3 8y ago
> Adding noise to any encryption has it's upsides That's assuming that the secret is the encryption algorithm itself rather than the key. Modern symmetric encryption does not work that way - the algorithm is public and well known while the key is the actual secret required for encryption/decryption. I don't see how adding noise in modern encryption can help other than increase the size of the output. Some modes of operation make use of random noise (IV in CBC, nonce in CTR, etc) because it's a convenient way to get a unique number but it's not for obscurity, it's because it's needed to prevent attacks on these modes.
- moomin 8y ago
  Look up “confounders”, random noise can be extremely useful if you encrypt it as well. This significantly increases the work required to decrypt (since you’ve got to decrypt random noise as well as signal), makes it much harder to tell if you’ve actually decrypted something successfully (depending on how well you can test the plaintext, obviously) and frustrate correlation attacks because every message has a different payload even if the logical payload was the same.