Rare Git Hashes

Last week this happened:

Finding and securing the rare hashes

For those curious, the methodology is detailed further in this post. The short procedure:

1. Define rare: English words, repeated characters, repeated sequences of characters, palindromes, and ascending and descending sequences.
2. Pattern match: combine possible paths to the pattern(s), divide over 16⁷ possible hashes. That yields our drop rate, assignable to a tier.
3. Seek fortune.

How it works

Below you'll find a detailed (and configurable!) breakdown of how the scorer matches patterns. I can't vouch for every permutation of the configuration, but I can vouch for the one I like!

Everything below is computed in the browser:

• Scoring a hash: each run of 3 to 7 characters is checked against every pattern, and patterns that don't overlap stack. The probability is the rarest stack's matching hashes ÷ 16⁷.
• Saving new rules: a Web Worker recounts all 16⁷ hashes, marking each stack's matches in a 2²⁸-bit table. That gives the tier sizes and the map's data.
• Moving a tier threshold: no recount; the counted stacks are regrouped into the new tiers.
• The map: saved rules also compile to a GLSL shader, which calculates the scores of the hashes in view on the GPU.

Forging rare hashes