[tor-dev] Mnemonic 80-bit phrases (proposal)

Brandon Wiley brandon at blanu.net
Wed Feb 29 01:04:26 UTC 2012

Hi Sai,

It looks like you've put a lot of thought into what would make a good
hash-to-word system. However, you have a false assumption, that dictionary
systems can simultaneously have all three properties of Zooko's Triangle.
This is a popular idea, but unfortunately untrue.

Hashes are effectively random and so have maximum information density.
Words do not have maximum information density, they have redundancy, which
is why they are easier to remember and tell apart from each other than
random strings. However, this comes at the cost of making the words longer.
The more redundant information that you add in terms of constraints such as
part of speech, the longer you will need to make the words (on average) so
that they can contain this additional information. If you look at the 4
little words post you will notice that the phrases are about 5 characters
longer than the IPv4 addresses. Of course you could make the claim that
sometimes longer strings are easier to remember than shorter ones. There is
an intuitive appeal to the idea that words are more memorable than
hexadecimal strings (or base64 or whatever). That might be true sometimes
for special cases, but there is no evidence that it is true generally or in
this particular case.

On Tue, Feb 28, 2012 at 3:27 PM, Sai <tor at saizai.com> wrote:

> Hello all.
> We've written up our proposal for mnemonic .onion URLs.
> See
> https://docs.google.com/document/d/sT5CulCVl0X5JeOv4W_wC_A/edit?disco=AAAAAERhFsE
> for details; please read the full intro for explanations and caveats,
> as some are important.
> tl;dr: It's a system that would have all three properties of being
> secure, distributed, and human-meaningful… but would *not* also have
> choice of name (though it has the required *canonicality* of names),
> and has a somewhat absurdist definition of 'meaningful'. :-P
> Please feel free to put comments there or on list.
> Right now we're at the stage just before implementation; namely, we
> haven't yet collated the necessary dictionaries, but we have a
> reasonably good idea of how the system would work, including needed
> constraints on the dictionaries. If you have suggestions or comments,
> now is a good time to talk about them, so that if any of it affects
> the dictionary collation step we don't waste work.
> Thanks,
> Sai
> _______________________________________________
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> tor-dev at lists.torproject.org
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