please prefer base 64 over base 32 (was: Re: [p2p-hackers] Bitzi (was Various identifier choices))

Zooko zooko at zooko.com
Wed Sep 19 07:24:01 UTC 2001


Having URLs which are short enough to cut and paste is important.  Encoding six
bits per character (base 64) is that much better than encoding five bits per
character.

A mojoid in base-32 would look like this:

http://localhost:4004/id/1b17864eeb6c68294c9b2db0324a2b773401f0da0537d82626c24a7850e15ef2d6c4265dcd5e85f1

The same mojoid in base-64 would look like this:

http://localhost:4004/id/GxeGTutsaClMmy2wMkordzQB8NoFN9gmJsJKeFDhXvLWxCZdzV6F8Q

That can make a significant difference in terms of usability, due to
line-wrapping in SMTP gateways and in GUIs, the awkwardness of layout when
representing this mojoid e.g. in HTML, and the general user experience.  The
bigger and uglier the URL, the less a user likes to deal with it.

By the way, we might try to squeeze mojoids.  I think we can get down to 30
bytes from 40 (by convincing ourselves that an 80-bit symmetric key has the
same attack work factor as a 160-bit hash id), so then it would look like:

http://localhost:4004/id/1b17864eeb6c68294c9b2db0324a2b773401f0da0537d82626c24a7850e1

or

http://localhost:4004/id/GxeGTutsaClMmy2wMkordzQB8NoFN9gmJsJKeFDh

We might also have an unencrypted mojoid, which would be 20 bytes, like this:

http://localhost:4004/id/1b17864eeb6c68294c9b2db0324a2b773401f0da

or

http://localhost:4004/id/GxeGTutsaClMmy2wMkordzQB8No

Regards,

Zooko




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