Visualizing hex bytes with Unicode emoji • Hacker News Board

Re: Visualizing hex bytes with Unicode emoji

#21

Post by neftaly » Thu, Oct 30, 2014, 8:24 PM UTC

acqq wrote: post #3

The mapping of only one byte to one symbol results in too many symbols in one fingerprint. Using more than 8 bits per symbol would result in something much easier to recognize. The goal should be "staple battery horse" and not "p k b t v r m n z x t c." Was my key "p k t b t v r m n z x t c" or was it "p t k b t v r n m z x t c," who can see the difference? However another danger is all the emoji that look too simila…

I have been experimenting with a dictionary-based encoding system for this kind of data - https://neftaly.github.io/radixWord/

To prevent a similar-looking-fingerprint attack, you could just re-hash the fingerprint with a secret salt before displaying. I wonder if XOR'ing the fingerprint against a plain hash of itself could also be difficult enough?

Re: Visualizing hex bytes with Unicode emoji

#22

Post by acqq » Fri, Oct 31, 2014, 7:39 AM UTC

neftaly wrote: post #21

acqq wrote: post #3

The mapping of only one byte to one symbol results in too many symbols in one fingerprint. Using more than 8 bits per symbol would result in something much easier to recognize. The goal should be "staple battery horse" and not "p k b t v r m n z x t c." Was my key "p k t b t v r m n z x t c" or was it "p t k b t v r n m z x t c," who can see the difference? However another danger is all the emoji that look too simila…

I have been experimenting with a dictionary-based encoding system for this kind of data - https://neftaly.github.io/radixWord/ To prevent a similar-looking-fingerprint attack, you could just re-hash the fingerprint with a secret salt before displaying. I wonder if XOR'ing the fingerprint against a plain hash of itself could also be difficult enough?

It seems you use too small set of words? I can't see the source on this device, but it looks so.

Secret salt would have to be the same everywhere. So it has no sense to think about it. Just a good hash is needed, hard enough not to be brute forced, like scrypt.

Re: Visualizing hex bytes with Unicode emoji

#23

Post by acqq » Fri, Oct 31, 2014, 7:42 AM UTC

userbinator wrote: post #16

windytan wrote: post #11

Earlier quoted context omitted.

It's meant as a shorthand for "hex-encoded bytes".

You're really just interpreting bytes as characters in a different character set. "Visualizing hex bytes" suggests something slightly different, like using an emoji for each of the digits 0-9 and A-F (not much unlike the other proposals for writing hex digits, e.g. http://en.wikipedia.org/wiki/File:Bruce_Martin_hexadecimal_n... .)

What you believe "hex bytes" suggest to you (but falsely) are actually "nibbles"

http://en.m.wikipedia.org/wiki/Nibble

Re: Visualizing hex bytes with Unicode emoji

#24

Post by neftaly » Tue, Nov 04, 2014, 9:34 PM UTC

acqq wrote: post #22

neftaly wrote: post #21

Earlier quoted context omitted.

I have been experimenting with a dictionary-based encoding system for this kind of data - https://neftaly.github.io/radixWord/ To prevent a similar-looking-fingerprint attack, you could just re-hash the fingerprint with a secret salt before displaying. I wonder if XOR'ing the fingerprint against a plain hash of itself could also be difficult enough?

It seems you use too small set of words? I can't see the source on this device, but it looks so. Secret salt would have to be the same everywhere. So it has no sense to think about it. Just a good hash is needed, hard enough not to be brute forced, like scrypt.

You only need ~4k words for 2 bytes-per-word alphanumeric encoding (keyspaceLength^bytesPerWord). There is a "special" dictionary identifier prefix and a padding indicator postfix, however (mostly for dev purposes).

Scrypt would probably be fine, though the addition of a secret salt (wouldn't need entropy, just secrecy) would be much better. On reflection, XOR would be stupid bad :B