install

Additional install commands

macOS

Homebrewverified · 100%

brew install bkcrack

local Homebrew formula metadata

Linux

Nixverified · 92%

nix profile install nixpkgs#bkcrack

nixpkgs package indexes · pkgs/by-name/bk/bkcrack/package.nix · source: api.github.com

openSUSE zypperverified · 92%

sudo zypper install bkcrack

openSUSE Tumbleweed package metadata · bkcrack · source: download.opensuse.org

overview

Package summary

Crack legacy zip encryption with Biham and Kocher's known plaintext attack

Project links

Commands and aliases

bkcrack

history

Project history and usage

bkcrack is a command-line cryptanalysis tool for legacy ZIP encryption, specifically the traditional PKWARE/ZipCrypto scheme. Its package-manager identity is narrow and practical: a small utility installed when a user needs a known-plaintext attack workflow against old encrypted ZIP archives.

Project history

The project was published on GitHub in 2016 and describes itself as an implementation of Eli Biham and Paul C. Kocher's known-plaintext attack on the PKZIP stream cipher. Its documentation explains the ZipCrypto keystream model and frames bkcrack as a way to recover internal keys, remove or change archive passwords, and attempt password recovery.

Adoption history

bkcrack grew from a specialist security tool into a packaged CLI available through Homebrew, Nix, openSUSE/zypper, and upstream GitHub release artifacts for Ubuntu, macOS, and Windows. That distribution pattern reflects a tool useful enough for repeatable incident-response and recovery workflows but still niche compared with general password crackers.

How it is used

Typical use starts with a ciphertext entry and 12 or more bytes of known plaintext, often supplied from another ZIP entry or file. Users run bkcrack to recover the ZipCrypto internal state, then decrypt data, create an unencrypted copy of the archive, change the password, or search for the original password from recovered keys.

Why package nerds care

Package nerds care about bkcrack because it packages a classic academic break of legacy ZIP encryption into a reproducible CLI with cross-platform binaries. It is a reminder that 'ZIP password support' in archive tools historically meant weak ZipCrypto unless AES or another modern scheme was explicitly used.

Timeline

1994: Biham and Kocher publish the known-plaintext attack on the PKZIP stream cipher.
2016: bkcrack repository is created on GitHub.
2020: v1.0.0 appears as the first GitHub release in the current release history.
2020s: bkcrack becomes available through Homebrew and other Unix package sets.

Related projects

Related tools include zip password recovery and auditing utilities, but bkcrack is specifically centered on ZipCrypto known-plaintext recovery rather than generic brute-force cracking.
The underlying cryptanalytic reference is Biham and Kocher's PKZIP stream-cipher paper, which bkcrack cites directly from its README.

Sources

https://doi.org/10.1007/3-540-60590-8_12
https://github.com/kimci86/bkcrack#readme
https://github.com/kimci86/bkcrack/releases
source_facts.package-manager

security posture

Risk level: blue

broad file, network, media, or database tool signal.

Risk classifier

blue risk · medium confidence · tool

Why

broad file, network, media, or database tool signal

Signals

text:encrypt

Install behavior

No Homebrew post-install hook is recorded in formula metadata.
Homebrew bottle metadata is available for 6 platform targets.
Build metadata lists 1 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
`bkcrack`	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 generated2026-08-04

manager version1.8.1

manager updated

local dataok

upstreamcurrent

latest detectedv1.8.1

https://github.com/kimci86/bkcrack

infoNo package-manager update timestamp was available.low confidence

install metadata

Package metadata

Package key	brew:bkcrack
Version	1.8.1
Package manager	Homebrew
Package manager page	https://formulae.brew.sh/formula/bkcrack
Homepage	https://github.com/kimci86/bkcrack
Repository	https://github.com/kimci86/bkcrack
License	Zlib
Source archive	https://github.com/kimci86/bkcrack/archive/refs/tags/v1.8.1.tar.gz
Build dependencies	cmake
Bottle	available (on arm64_linux, arm64_sequoia, arm64_sonoma, arm64_tahoe, sonoma, 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	bkcrack
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	head stable

source database matches

Other package-manager records

Matches are pulled from external package-manager indexes and kept separate from local Automic Vault package links.

Nix95%

bkcrack

nix profile install nixpkgs#bkcrack

normalized package name match
Matched by: Bkcrack

nixpkgs package indexes · api.github.com · nixpkgs package indexes: pkgs/by-name/bk/bkcrack/package.nix from https://api.github.com/repos/NixOS/nixpkgs/git/trees/master?recursive=1

zypper95%

bkcrack 1.8.1-1.5

Crack legacy zip encryption with Biham and Kocher's known plaintext attack

https://github.com/kimci86/bkcrack/

sudo zypper install bkcrack

License: Zlib
Category: Unspecified
Architecture: x86_64
Source Package: bkcrack
3 dependencies
1 provides
normalized package name match
Matched by: Bkcrack

openSUSE Tumbleweed package metadata · download.opensuse.org · openSUSE Tumbleweed package metadata: bkcrack from https://download.opensuse.org/tumbleweed/repo/oss/repodata/50b07339cb64c8ed4091bdbabddadc1ff5737b090e478818a195b40d8a3292861a879139b4a3987c31109699fde9fbf4a716367ddf4eef77da75f96e3193d6ed-primary.xml.zst

package graph

Links come from deterministic package relationships, av.db category and tag curation, ecosystem matches, and package hub membership.

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.

combined/bkcrack.yml

Used sources

Geiger risk classifier
cross-ecosystem install command graph
curated package history
external package-manager database matches
package relationship graph
package version freshness
package-page enrichment
pkg.so package database
pkgdb category and tag curation

Install bkcrack with Homebrew, Nix, zypper