macOS
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brew install sha1dclocal Homebrew formula metadata
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Install sha1dc with Homebrew
Tool to detect SHA-1 collisions in files, including SHAttered. Version 1.0.3 via Homebrew; verified 2026-09-14.
install
Additional install commands
overview
Package summary
Tool to detect SHA-1 collisions in files, including SHAttered
Project links
Commands and aliases
- sha1dcsum
- sha1dcsum_partialcoll
history
Project history and usage
SHA-1 Collision Detection is an MIT-licensed C library and command-line tool by Marc Stevens and Dan Shumow. It computes SHA-1 digests while detecting files produced with known cryptanalytic SHA-1 collision techniques.
Project history
Marc Stevens and Dan Shumow published the implementation in 2017 in the context of practical SHA-1 collision attacks. Its detection method builds on Stevens's counter-cryptanalysis research and explicitly recognizes files produced by attacks such as SHAttered; later support also references SHA-mbles.
Adoption history
The project was designed as a near drop-in replacement for common SHA-1 implementations and sha1sum, lowering the cost of adding collision detection to existing software. The input confirms packaging as the Homebrew formula sha1dc.
How it is used
sha1dcsum hashes files and warns when a full SHA-1 collision attack is detected; sha1dcsum_partialcoll also checks reduced-round collision examples. Developers can integrate the library through its SHA1DC API and use safe-hash mode so colliding inputs receive different defensive hashes.
Why package nerds care
sha1dc lets package and release engineers continue verifying legacy SHA-1 material while detecting known cryptanalytic collision constructions. It is particularly relevant to archives and software-distribution systems that cannot immediately remove every SHA-1 dependency.
Timeline
- 2013: Marc Stevens published the counter-cryptanalysis research cited by the project.
- 2017: Project copyright begins and the SHAttered collision became a principal real-world test case.
- Later: The official documentation added reference to detection of attacks derived from SHA-mbles.
Related projects
- The official README relates the tool to ordinary SHA-1 libraries and sha1sum, the SHAttered collision demonstration, SHA-mbles, and Marc Stevens's counter-cryptanalysis research.
Sources
- Official library header: https://github.com/cr-marcstevens/sha1collisiondetection/blob/master/lib/sha1.h
- Official repository and README: https://github.com/cr-marcstevens/sha1collisiondetection
- input.source_facts.package-manager
security posture
Risk level: green
narrow executable package without higher-risk signals.
Risk classifier
green risk · low confidence · appliance
Why
- narrow executable package without higher-risk signals
Signals
- metadata:no-higher-risk-signals
Install behavior
- No Homebrew post-install hook is recorded in formula metadata.
- Homebrew bottle metadata is available for 12 platform targets.
- Build metadata lists 2 build dependencies.
Recommended review
Before unattended agent use, check whether the tool reads plaintext credentials, writes remote state, publishes artifacts, or shells out to plugins.
executables
Installed executables
| Command | Kind | Exposure | Note |
|---|---|---|---|
sha1dcsum | cli | global executable | |
sha1dcsum_partialcoll | cli | global executable |
freshness
Version and freshness
These signals separate page generation age, package-manager activity, and upstream release comparison. Version lag is warned only when an evidence URL and comparable versions are present.
page generated2026-09-19
manager version1.0.3
manager updated2026-09-14
local dataok
upstreamnot checked
latest detectednot detected
https://github.com/cr-marcstevens/sha1collisiondetection
- infoNo cached GitHub release or tag data was available.https://github.com/cr-marcstevens/sha1collisiondetectionnone confidence
install metadata
Package metadata
| Package key | brew:sha1dc |
|---|---|
| Version | 1.0.3 |
| Package manager | Homebrew |
| Package manager page | https://formulae.brew.sh/formula/sha1dc |
| Homepage | https://github.com/cr-marcstevens/sha1collisiondetection |
| Repository | https://github.com/cr-marcstevens/sha1collisiondetection |
| License | MIT |
| Source archive | https://github.com/cr-marcstevens/sha1collisiondetection/archive/refs/tags/stable-v1.0.3.tar.gz |
| Last updated | 2026-09-14T12:20:13+02:00 |
| Pulse | updated |
| Build dependencies | coreutils, libtool |
| Bottle | available (on arm64_big_sur, arm64_linux, arm64_monterey, arm64_sequoia, arm64_sonoma, arm64_tahoe, arm64_ventura, big_sur, monterey, sonoma, ventura, x86_64_linux) |
| Homebrew post-install | not defined |
| Service | none declared |
registry facts
Source database details
| Source Database | Homebrew formula API |
|---|---|
| Tap | homebrew/core |
| Full Name | sha1dc |
| Version Scheme | 0 |
| Revision | 0 |
| Head Version | HEAD |
| Bottle Stable Root URL | https://ghcr.io/v2/homebrew/core |
| Deprecated | no |
| Disabled | no |
| Keg Only | no |
| URL Keys |
|
source trail
Generated from repository data
This page is generated by av-web from the private package SQLite artifact built by scripts/generate-pkg-sqlite.py.
Combined YAML source
View the package source record on GitHub.
Used sources
- Geiger risk classifier
- cross-ecosystem install command graph
- curated package history
- package relationship graph
- package version freshness
- package-page enrichment
- pkg.so package database
- pkgdb category and tag curation