# spawnmason/randar-explanation

"Randar" is an exploit for Minecraft which uses LLL lattice reduction to crack the internal state of an incorrectly reused java.util.Random in the Minecraft server, then works backwards from that to locate other players currently loaded into the world.

Repository: https://github.com/spawnmason/randar-explanation
Canonical: https://ross.abutalabs.com/products/randar-explanation
Language: Shell
License Family: other
Topics: 2b2t, exploit, exploitation, minecraft, papermc, radar, random, rng, randar, spawnmason, spawnmasons, munmap, lattice, lattice-reduction, lll
Last push: 2026-08-11T05:10:32+00:00

## Health v2 (maintenance only)
Score: 72/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 97, release rhythm 35, longevity 83
- inputs: {"age_days": 1162, "days_push": 22, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1020, forks 29 (observed 2026-08-28T04:03:15.498628+00:00)

## What it is
An explanation and writeup of 'Randar', a Minecraft exploit that uses LLL lattice reduction to crack the internal state of a reused java.util.Random in Minecraft servers and derive other players' coordinates. It documents the vulnerability affecting Minecraft Beta 1.8 through 1.12.2, notably used on the 2b2t anarchy server.

## Use cases
- find other players' coordinates on a minecraft server
- crack java.util.Random seed from dropped item positions
- learn how LLL lattice reduction breaks weak RNG
- understand the randar exploit on 2b2t
- study minecraft server RNG vulnerabilities
- locate players on an anarchy server without a radar

## When to choose
- You want to understand or reproduce the Randar coordinate exploit on Minecraft Beta 1.8-1.12.2 servers
- You're researching RNG reuse vulnerabilities or lattice-based seed recovery
- You play on or study anarchy servers like 2b2t

## When to avoid
- You run a modern (1.13+) Minecraft server - the vulnerable code was fixed
- You need a ready-to-use production tool rather than an explanation/writeup
- You want a legitimate radar or minimap mod

## Facets
- artifact type: learning-resource
- maturity: active
- function: cryptography, security, reverse-engineering
- domain: gaming-tools, security
- platform: cli
- tags: minecraft-exploit, rng-cracking, lattice-reduction, lll, 2b2t, coord-exploit, writeup, algorithms, minecraft

## Member repositories
- spawnmason/randar-explanation (main) score 72

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:15.498628+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T07:09:19.598344+00:00, confidence not recorded.
  - readme: https://github.com/spawnmason/randar-explanation (fetched 2026-08-28T04:03:15.498628+00:00, sha 653ee7e46a9d)
- Data as of 2026-08-30T08:39:29.467469+00:00.