3 ms·

Can anyone familiar with the matter say how secure is the 4-emoji verification code?

doubleplusgood 10y ago
Based on their tech docs[1], it seems pretty good. 1: https://core.telegram.org/api/end-to-end/voice-calls#key-verification https://core.telegram.org/api/end-to-end/voice-calls#key-ver...
konart 10y ago
Emojis in this case are just sort of visual representation of the keys two users exchange before communication. In theory this makes MitM attack impractical. https://core.telegram.org/techfaq#q-how-are-voice-calls-authenticated https://core.telegram.org/techfaq#q-how-are-voice-calls-auth... https://core.telegram.org/api/end-to-end/voice-calls#key-verification https://core.telegram.org/api/end-to-end/voice-calls#key-ver...
joelthelion 10y ago
I wonder about the possibility to use "collisions" between similar-looking emojis in order to fake a match more easily.
ramshorns 10y ago
I think a while ago someone on HN suggested emoji as a joke as a more information-dense and internationalized alternative to numeric or alphanumeric verification codes. I don't know about security, but if this uses all 1,088 emoji from Unicode 9.0, then four emoji have about 40 bits of information.
- cflee 10y ago
  They say they are using 333 emoji to represent ~34 bits.
  - lucb1e 10y ago
    33.52 bits to be precise, which is where the many-nines claim comes from: 1-(1/(333^4)) = ~0.999999999918
    - deleted 10y ago
      [deleted]
mtgx 10y ago
> Thanks to this modification, it becomes possible to prevent eavesdropping (MitM attacks on DH) with a probability of more than 0.9999999999 by using just over 33 bits of entropy in the visualization. These bits are presented to the users in the form of four emoticons. We have selected a pool of 333 emoji that all look quite different from one another and can be easily described in simple words in any language. 33 bits of entropy seems quite low to me. https://core.telegram.org/techfaq#q-how-are-voice-calls-authenticated https://core.telegram.org/techfaq#q-how-are-voice-calls-auth...
- jessaustin 10y ago
  That would be low if we were considering a long-term key. It seems fine for a one-shot authentication token? Eve is going to have to MitM a lot of calls before she guesses this token correctly.

Based on their tech docs[1], it seems pretty good. 1: https://core.telegram.org/api/end-to-end/voice-calls#key-verification https://core.telegram.org/api/end-to-end/voice-calls#key-ver...

konart 10y ago

Emojis in this case are just sort of visual representation of the keys two users exchange before communication. In theory this makes MitM attack impractical. https://core.telegram.org/techfaq#q-how-are-voice-calls-authenticated https://core.telegram.org/techfaq#q-how-are-voice-calls-auth... https://core.telegram.org/api/end-to-end/voice-calls#key-verification https://core.telegram.org/api/end-to-end/voice-calls#key-ver...

joelthelion 10y ago

I wonder about the possibility to use "collisions" between similar-looking emojis in order to fake a match more easily.

ramshorns 10y ago

I think a while ago someone on HN suggested emoji as a joke as a more information-dense and internationalized alternative to numeric or alphanumeric verification codes. I don't know about security, but if this uses all 1,088 emoji from Unicode 9.0, then four emoji have about 40 bits of information.

cflee 10y ago
They say they are using 333 emoji to represent ~34 bits.
- lucb1e 10y ago
  33.52 bits to be precise, which is where the many-nines claim comes from: 1-(1/(333^4)) = ~0.999999999918
  - deleted 10y ago
    [deleted]

mtgx 10y ago

> Thanks to this modification, it becomes possible to prevent eavesdropping (MitM attacks on DH) with a probability of more than 0.9999999999 by using just over 33 bits of entropy in the visualization. These bits are presented to the users in the form of four emoticons. We have selected a pool of 333 emoji that all look quite different from one another and can be easily described in simple words in any language. 33 bits of entropy seems quite low to me. https://core.telegram.org/techfaq#q-how-are-voice-calls-authenticated https://core.telegram.org/techfaq#q-how-are-voice-calls-auth...

jessaustin 10y ago
That would be low if we were considering a long-term key. It seems fine for a one-shot authentication token? Eve is going to have to MitM a lot of calls before she guesses this token correctly.