Identifiers and Locators

We had a need for identifiers that could be used by humans. The requirement to be able to say these over the phone complicated matters.

Most people approach this problem by using a phonetic alphabet. The trouble comes when you hear people saying stuff like "A as in ... uh, Apple?" (should be Alpha, of course) and "U as in ... um, what's a word that starts with U?" It gets worse. Ever been to a GPG keysigning? Listen to people attempt to read out the digits of their key fingerprints. "...C 3 E D 0 0 0 0 0 0 0 2 B D B D..." "Did you say C or D?" and "how many zeros was that?" Brutal.

So what we need is a symbol set where each digit is unambiguous and doesn't collide with the phonetics of another symbol. This package provides English16, a set of 16 letters and numbers that, when spoken aloud in English, have unique pronunciations.

Ironically, however, when used in written applications the English16 set is a bit restrictive. If the application is transcription or identification then the criteria is shapes that are visually distinct, rather than their sound being so. For these uses we thus provide Latin25, a set of 25 symbols useful for identifiers in automated systems that nevertheless have to be operated or debugged by humans.

Also included is code to work in base 62, which is simply ['0'-'9', 'A'-'Z', and 'a'-'z']. These are frequently used to express short codes in URL redirectors; you may find them a more useful encoding for expressing numbers than base 16 hexadecimal.