3 ms·
32-bit hashes are not useful for content addressing pretty much at all. If you look at the table here: https://en.wikipedia.org/wiki/Birthday_problem#Probabilit
by btrask 11y ago
32-bit hashes are not useful for content addressing pretty much at all. If you look at the table here: https://en.wikipedia.org/wiki/Birthday_problem#Probability_table https://en.wikipedia.org/wiki/Birthday_problem#Probability_t... (50% chance of collision with only 77,000 resources)
See also: https://lkml.org/lkml/2010/10/28/287 https://lkml.org/lkml/2010/10/28/287 where Linus Torvalds says 12 hex digits (96 bits) is pretty much the minimum short-hash for the Linux kernel commit history.
Extremely short hashes can be useful briefly for manually transcribing between devices, as long as you immediately "resolve" them back into a longer form, before new collisions can happen. But this is more on par with clicking "I'm feeling lucky" than creating a link. :)
- batbomb 11y agoI came here to talk about this. I deal with data management for a bunch of physics and astronomy experiments it's quite typical to have many millions of files for any given experiment (say, 1PB of storage for a medium size experiment, 10 million 100MB files). CERN's experiments would easily have billions of files, so I was thinking 64 bits would be a minimal truncation, but 96 is probably more reasonable.