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The probability of a hash collision (2022)

(kevingal.com)
140 points subset | 1 comments | 22 Jun 25 03:34 UTC | HN request time: 0.241s | source
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rienbdj ◴[25 Jun 25 06:09 UTC] No.44374088[source]▶
How many values can a UUID v4 take?

How many do you have to generate before a collision becomes a remote possibility?

replies(5): >>44374322 #>>44374323 #>>44375553 #>>44379431 #>>44380082 #
1. toast0 ◴[25 Jun 25 10:15 UTC] No.44375553[source]▶
The question becomes, how bad is your random.

If your random is not uniformly distributed, you might get duplication from bias.

If your random is setup wrong and you get the same seeding multiple times, you might get duplication from that.

If your random is good, the birthday math should hold.