The automated search converged to an optimized solution in about 40 hours on a DEC Alpha, a particularly fast machine in that era.
The Zimmermann–Juola list was originally designed to be used in PGPfone, a secure VoIP application, to allow the two parties to verbally compare a short authentication string to detect a man-in-the-middle attack (MiTM).
When it was applied to PGP, the list of words was further refined, with contributions by Jon Callas.
For example, the leftmost (i.e. byte 0) is considered "even" and is encoded using the PGP Even Word table.
There are several other word lists for conveying data in a clear unambiguous way via a voice channel: