It appears that Phillip Hallam-Baker <phill@xxxxxxxxxxxxxxx> said: >> The collision risk itself depends on the population size. If call signs >> are used as "pet names", they are only expected to be unique in the small >> scope of "pets". But if thy are expected to be unique worldwide and >> forever, then they have pretty much the same design constraints as IPv6 >> addresses. They can probably be a little shorter because there is no >> expectation of routability, but I would be surprised if this required fewer >> than 80 bits -- I would probably go for 96 bits ... >A registry allows for human readable identifiers. Human readable is quite different from human memorable. This problem sounds a lot like the one of picking a Gmail username, where you tell it the name you want, and it offers one with a bunch of digits added to make it unique. Anyone who joined gmail long enough ago that we got the name without digits can tell you that people remember the name they asked for, but not the extra part. I get an endless stream of mail intended for people with names similar to mine who imagine that my address is their address. I don't see why the situation here would be any different. Venmo has the same problem, which they have tried to fix by letting people upload a picture, and use the last four digits of the recipient's phone number as a check code the first time you send someone money. But those are hacks and are unlikely to scale to billions of names. R's, John
