Fast CRC Checksum Library

0.3.5 · active · verified Mon Apr 13

fastcrc is a hyper-fast Python module for computing CRC (Cyclic Redundancy Check) checksums across 8, 16, 32, and 64-bit standards. It leverages highly optimized Rust code for performance. The current version is 0.3.5, and it maintains an active release cadence with several updates per year, focusing on performance, platform support, and new CRC algorithms.

Warnings

breaking Support for Python 3.6 was dropped in version 0.3.0. Users on Python 3.6 must use an older version of fastcrc.
Fix: Upgrade to Python 3.7 or newer, or pin fastcrc to <0.3.0.
deprecated The functions `fastcrc.crc16.ibm_refin` and `fastcrc.crc32.reversed_reciprocal_refin` were introduced as experimental in v0.2.1 and may be removed in future releases without further notice.
Fix: Avoid using these experimental functions for production code, or be prepared for potential removal or API changes.
gotcha All CRC functions in `fastcrc` expect bytes-like objects as input data. Passing other types (e.g., string) will result in a TypeError.
Fix: Ensure data is encoded to bytes (e.g., `my_string.encode('utf-8')`) before passing it to CRC functions.
gotcha Version 0.2.0 introduced an `initial` optional parameter to all CRC functions, allowing for chained CRC calculations. If migrating from older versions, ensure you are aware of this parameter for multi-part data processing.
Fix: Consult the documentation for proper usage of the `initial` parameter when performing incremental CRC calculations across multiple data chunks.

Install

pip install fastcrc Install stable version

Imports

crc8
```
from fastcrc import crc8
```
Imports specific CRC bit-width modules to access various algorithms.
crc16
```
from fastcrc import crc16
```
Imports specific CRC bit-width modules to access various algorithms.
crc32
```
from fastcrc import crc32
```
Imports specific CRC bit-width modules to access various algorithms.
crc64
```
from fastcrc import crc64
```
Imports specific CRC bit-width modules to access various algorithms.

Quickstart

This quickstart demonstrates how to import and use the fastcrc library to compute checksums for various CRC standards (8, 16, 32, 64-bit) using different algorithms. It also shows an example of chained CRC calculation using the optional 'initial' parameter.

from fastcrc import crc8, crc16, crc32, crc64

data = b"123456789"

# Compute CRC-8 using the cdma2000 algorithm
print(f"crc8 checksum with cdma2000 algorithm: {crc8.cdma2000(data)}")

# Compute CRC-16 using the xmodem algorithm
print(f"crc16 checksum with xmodem algorithm: {crc16.xmodem(data)}")

# Compute CRC-32 using the aixm algorithm
print(f"crc32 checksum with aixm algorithm: {crc32.aixm(data)}")

# Compute CRC-64 using the ecma_182 algorithm
print(f"crc64 checksum with ecma_182 algorithm: {crc64.ecma_182(data)}")

# Chained CRC calculation with initial data
initial_crc = crc16.xmodem(b'1234')
final_crc = crc16.xmodem(b'56789', initial_crc)
print(f"crc16 checksum with xmodem algorithm (chained): {final_crc}")

view raw JSON →