title: Human readable alternative for UUIDs
body: <p>I am working on a system that makes heavy use of pseudonyms to make privacy-critical data available to researchers. These pseudonyms should have the following properties:</p>
  <ol>
  <li>They should not contain any information (e.g. time of creation, relation to other pseudonyms, encoded data, …).</li>
  <li>It should be easy to create unique pseudonyms.</li>
  <li>They should be human readable. That means they should be easy for humans to compare, copy, and understand when read out aloud.</li>
  </ol>
  <p>My first idea was to use <a href="https://www.rfc-editor.org/rfc/rfc4122" rel="noreferrer">UUID4</a>. They are quite good on (1) and (2), but not so much on (3).</p>
  <p>An variant is to encode UUIDs with a wider alphabet, resulting in shorter strings (see for example <a href="https://github.com/skorokithakis/shortuuid" rel="noreferrer">shortuuid</a>). But I am not sure whether this actually improves readability.</p>
  <p>Another approach I am currently looking into is a paper from 2005 titled <a href="https://www.sciencedirect.com/science/article/pii/S0169260705000672" rel="noreferrer">&quot;An optimal code for patient identifiers&quot;</a> which aims to tackle exactly my problem. The algorithm described there creates 8-character pseudonyms with 30 bits of entropy. I would prefer to use a more widely reviewed standard though.</p>
  <p>Then there is also the git approach: only display the first few characters of the actual pseudonym. But this would mean that a pseudonym could lose its uniqueness after some time.</p>
  <p>So my question is: Is there any widely-used standard for human-readable unique ids?</p>