# ryancdotorg/brainflayer

A proof-of-concept cracker for cryptocurrency brainwallets and other low entropy key algorithms.

Repository: https://github.com/ryancdotorg/brainflayer
Canonical: https://ross.abutalabs.com/products/brainflayer
Homepage: https://rya.nc/brainflayer
Language: C
License Family: other
Topics: brainwallet, bitcoin, password-cracker, cryptography, ethereum, secp256k1
Last push: 2024-05-16T20:31:23+00:00

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 4094, "days_push": 839, "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 1010, forks 487 (observed 2026-08-28T04:03:13.090381+00:00)

## What it is
Brainflayer is a proof-of-concept command-line cracker for cryptocurrency brainwallets and other low-entropy key derivation schemes, using libsecp256k1 for fast public key generation. It checks candidate passphrases against bloom-filtered sets of target addresses for Bitcoin and Ethereum.

## Use cases
- crack a bitcoin brainwallet passphrase
- test weak brainwallet keys for security research
- audit low entropy cryptocurrency key generation
- check if a passphrase maps to a known ethereum address
- demonstrate brainwallet insecurity in a talk or paper

## When to choose
- you need fast, large-scale brainwallet passphrase testing against a precomputed bloom filter
- you are doing security research on low-entropy key derivation in Bitcoin or Ethereum
- you want a Unix-philosophy tool that fits into a passphrase-generation pipeline

## When to avoid
- you need a maintained tool with support - the author explicitly no longer maintains it
- you want to crack strong, high-entropy private keys - this only works on weak brainwallet-style keys
- you need a supported Windows or GUI tool - it is a Linux-oriented C command-line program
- you are looking for a general-purpose password cracker like hashcat

## Facets
- artifact type: cli-tool
- maturity: maintenance
- function: cryptography, security, cli
- domain: security, blockchain
- platform: cli, cpp
- tags: brainwallet, bitcoin, ethereum, secp256k1, password-cracking, security-research, proof-of-concept, cryptocurrency, linux

## Member repositories
- ryancdotorg/brainflayer (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:13.090381+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 2026-08-30T07:11:58.169823+00:00, confidence not recorded.
  - readme: https://github.com/ryancdotorg/brainflayer (fetched 2026-08-28T04:03:13.090381+00:00, sha a42fecf8c254)
  - homepage: https://rya.nc/brainflayer (fetched 2026-08-29T13:11:48.389960+00:00, sha 1eeb1522b807)
- Data as of 2026-08-30T08:39:29.467469+00:00.