# iagox86/hash_extender

Repository: https://github.com/iagox86/hash_extender
Canonical: https://ross.abutalabs.com/products/hash_extender
Language: C
License: BSD-3-Clause
License Family: permissive
Last push: 2025-01-27T18:44:38+00:00

## Health v2 (maintenance only)
Score: 34/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 3, release rhythm 35, longevity 100
- inputs: {"age_days": 5121, "days_push": 583, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1211, forks 194 (observed 2026-08-28T04:04:00.131022+00:00)

## What it is
A C command-line tool that automates hash length extension attacks against algorithms like MD4, MD5, SHA-1, SHA-256, SHA-512, RIPEMD-160, and WHIRLPOOL. It lets an attacker forge valid hashes for data appended to a string whose hash uses an unknown secret prefix.

## Use cases
- perform a hash length extension attack
- forge a signature when a secret is prepended to hashed data
- test whether an application is vulnerable to length extension attacks
- solve CTF challenges involving hash extension
- generate valid hashes for appended data without knowing the secret key
- demonstrate weaknesses in MD5/SHA1-based MAC schemes

## When to choose
- you need a ready-made, multi-algorithm tool for length extension attacks
- you're doing security research, penetration testing, or CTF challenges
- you want a small, dependency-free C tool

## When to avoid
- you need to hash data normally rather than forge extension hashes
- the target uses HMAC or length-extension-resistant algorithms like SHA-224/384 or SHA-3
- you need a library API rather than a command-line tool

## Facets
- artifact type: cli-tool
- maturity: maintenance
- function: security, cryptography, cli, developer-tools
- domain: security, penetration-testing
- platform: windows, cli, cpp
- tags: hash-length-extension-attack, md5, sha1, sha256, sha512, ctf, offensive-security, c, cryptography, linux, macos

## Member repositories
- iagox86/hash_extender (main) score 34

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:04:00.131022+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 2026-08-30T06:18:03.874692+00:00, confidence not recorded.
  - readme: https://github.com/iagox86/hash_extender (fetched 2026-08-28T04:04:00.131022+00:00, sha 05dd1c250997)
- Data as of 2026-08-30T08:39:29.467469+00:00.