crcmod
CRC Generator
Decision gist · record as of 2026-08-14
Yes, but with caution. The package is stable and widely used (8.2M monthly downloads), carries no known vulnerabilities, and is MIT-licensed. However, it is abandoned (last release 2010-06-27) with no documented support beyond Python 3.1. Install only if you need CRC computation and can verify compatibility with your Python version; for modern projects, consider whether a maintained alternative exists or whether you can vendor the pure Python fallback.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- C compiler required to build the optional extension module for performance; pure Python fallback available but significantly slower.
- Package tested only on Python 2.4–2.7 and 3.1; compatibility with modern Python versions is unverified.
- High install friction: the package is abandoned (last release 2010-06-27) and relies on optional C extension compilation.
License · maintenance · safety
MIT (permissive) — MIT license (permissive) imposes no restrictions on use, modification, or distribution in proprietary or open-source projects.
last release 2010-06-27 (5892 days)
0 known vulnerabilities (OSV.dev, 2026-08-14) · 8,213,276 downloads/mo, #1,649 on PyPI
Alternatives
Verify before relying
import crcmod
# Create a CRC function for a standard polynomial
pred_crc32 = crcmod.predefined.mkCrcFun('crc-32')
checksum = pred_crc32(b'data')
print(checksum)- Whether the package works on Python versions beyond 3.1 (last tested version documented)
- Current compatibility with modern C compilers and build toolchains
- Whether the pure Python fallback remains functional on current Python releases
What it is and what it does
crcmod is a Python module for generating CRC computation objects. It supports any 8, 16, 24, 32, or 64-bit CRC polynomial and can produce either a standalone Python function or a Crc class instance with an interface matching the standard library's md5 and sha modules. The package includes a predefined module with standard polynomials, eliminating the need to research and specify your own in common cases.
The module can also generate C/C++ source code for CRC computation in other applications. Installation attempts to build a C extension for performance; if compilation fails, a pure Python implementation is used instead, though it runs significantly slower. The package is abandoned and has not been updated since 2010, with no documented support for Python versions beyond 3.1.
Use it for
- Verify data integrity in network protocols or file transfers by computing and comparing CRC checksums
- Generate CRC functions for embedded systems or legacy protocols that specify particular polynomials
- Export C/C++ code for CRC computation to be compiled and used in non-Python applications
- Validate messages in communication systems that use standard CRC polynomials like CRC-32
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, but with caution.
The package is stable and widely used (8.2M monthly downloads), carries no known vulnerabilities, and is MIT-licensed. However, it is abandoned (last release 2010-06-27) with no documented support beyond Python 3.1. Install only if you need CRC computation and can verify compatibility with your Python version; for modern projects, consider whether a maintained alternative exists or whether you can vendor the pure Python fallback.
Install
crcmod on PyPI
Before you install
High install friction: the package is abandoned (last release 2010-06-27) and relies on optional C extension compilation. Friction evidence shows only legacy Windows installers and source distributions; no wheels or modern packaging. Installation falls back to pure Python if compilation fails, but the C extension is significantly faster.
C compiler required to build the optional extension module for performance; pure Python fallback available but significantly slower. Package tested only on Python 2.4–2.7 and 3.1; compatibility with modern Python versions is unverified.
License in practice
MIT license (permissive) imposes no restrictions on use, modification, or distribution in proprietary or open-source projects.
Quickstart
import crcmod
# Create a CRC function for a standard polynomial
pred_crc32 = crcmod.predefined.mkCrcFun('crc-32')
checksum = pred_crc32(b'data')
print(checksum)Verify before relying
- Whether the package works on Python versions beyond 3.1 (last tested version documented)
- Current compatibility with modern C compilers and build toolchains
- Whether the pure Python fallback remains functional on current Python releases
Package facts
| License | MIT permissive |
| Python support | Not specified |
| Install friction | High. Source build required |
| Runtime dependencies | None |
| Maintenance | Abandoned 5,892 days since the last release |
| First released | |
| Downloads | 8,213,276 / month, #1,649 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 5 - Production/StableIntended Audience :: DevelopersIntended Audience :: EducationIntended Audience :: End Users/DesktopIntended Audience :: Information TechnologyIntended Audience :: Science/ResearchLicense :: OSI Approved :: MIT LicenseOperating System :: OS IndependentProgramming Language :: CProgramming Language :: C++Programming Language :: PythonProgramming Language :: Python :: 2Programming Language :: Python :: 2.4Programming Language :: Python :: 2.5Programming Language :: Python :: 2.6Programming Language :: Python :: 2.7Programming Language :: Python :: 3Programming Language :: Python :: 3.1Topic :: CommunicationsTopic :: Scientific/Engineering :: Interface Engine/Protocol TranslatorTopic :: Scientific/Engineering :: MathematicsTopic :: Utilities |
Evidence: crcmod-1.7.tar.gz; crcmod-1.7.win32-py2.6.msi; crcmod-1.7.win32-py2.7.msi; crcmod-1.7.win32-py3.1.msi
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See also fastcrc · crc · anycrc · crcengine · crccheck · libscrc · filehash · red-black-tree-mod · checksumdir · crc32c