Improved fingerprint representation

Neal H. Walfield neal at
Thu Apr 9 10:58:34 CEST 2015

At Thu, 09 Apr 2015 10:14:28 +0200,
Werner Koch wrote:
> On Thu,  9 Apr 2015 00:18, rjh at said:
> > I think you've reinvented the PGP Biometric Word List.  I'd much rather
> > see GnuPG use the BWL than this, if for no other reason than
> This discussion pops up every few years.  We recently had it again at
> cryptography: 

Thanks for the pointer.

> the usual outcome of these discussions is that the word lists are fine
> for English speaking people but problematic for the rest of the world.
> This problem is very old and the reason why more than 50 years ago the
> ICAO came up with a spelling alphabet to be used on noisy channels and
> between people of different mother tongue.
>   $ gpg --fingerprint --with-icao-spelling wheatstone
>   pub   ed25519/E3FDFF218E45B72B 2015-02-18 [expires: 2025-02-15]
>         Key fingerprint = C1D3 4B69 219E 4AEE C0BA  1C21 E3FD FF21 8E45 B72B
>                           "Charlie One Delta Three  Four Bravo Six Niner
>                            Two One Niner Echo  Four Alfa Echo Echo
>                            Charlie Zero Bravo Alfa  One Charlie Two One
>                            Echo Three Foxtrot Delta  Foxtrot Foxtrot Two One
>                            Eight Echo Four Five  Bravo Seven Two Bravo"
>   uid               [ultimate] Werner Koch (wheatstone commit signing)
> agreed, that is longer than a word list but easier to pronounce and
> understand by most people.  And the alphabet is easy to learn so that
> the new gpg option is not always needed.

The encodings clearly have different trade offs.  ICAO is easier for
more people.  But, it is also grounded in English and only really
generalizes to Western European languages.  Thus, it also excludes a
huge (but slightly smaller) portion of the world's population.

Further, using ICAO encoding of a fingerprint requires about 2.5 times
as much space.  And, due to the limited vocabulary, it includes more
repetition, which is a cause of errors both in transmission (e.g., via
phone) and for quick visual comparisons (e.g., comparing

Since gpg already has a --with-icao-spelling option, how about also
supporting a --with-word-spelling or --with-bwl-spelling?


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