crccheck library

1.3.1 · active · verified Sat Apr 11

crccheck is a Python library (currently v1.3.1) for calculating various Cyclic Redundancy Checks (CRCs) and checksums from binary data. It includes over 170 CRC algorithms and simple additive/XOR checksums. The library maintains an active, though somewhat irregular, release schedule, with recent updates adding new CRC algorithms.

Warnings

breaking Older versions (prior to v0.3) had a different package name (not specified but taken on PyPI) and used `bigendian=True/False` arguments. These were changed to `crccheck` and `byteorder='big'/'little'` respectively.
Fix: Ensure your code uses `crccheck` for imports and `byteorder='big'` or `byteorder='little'` for endianness specification.
gotcha Input data for CRC and checksum calculations must be binary (bytes or bytearray) in Python 3. Passing a regular string will result in a TypeError or incorrect results, as the library operates on byte sequences.
Fix: Convert string data to bytes using `your_string.encode('utf-8')` or `bytearray.fromhex('...')` before passing it to `crccheck` functions.
gotcha The `calc()` class method is suitable for quick calculations on a single complete data block. For calculations involving multiple sequential data blocks, you must instantiate the CRC/checksum class, feed data using `process()`, and retrieve the final result with `final()`.
Fix: For fragmented or streaming data, use an instance: `crc_inst = Crc32(); crc_inst.process(block1); crc_inst.process(block2); final_crc = crc_inst.final()`.

Install

pip install crccheck Install latest version

Imports

Crc32
```
from crccheck.crc import Crc32
```
Checksum8
```
from crccheck.checksum import Checksum8
```
Crc
```
from crccheck.crc import Crc
```
Use the general Crc class for custom CRC parameters not pre-implemented.

Quickstart

Demonstrates how to perform a quick CRC calculation on a single data block and how to process multiple data blocks sequentially. Input data should be in bytes or bytearray format.

from crccheck.crc import Crc32

data_bytes = bytearray.fromhex("DEADBEEF01020304")

# Quick calculation for a single data block
calculated_crc = Crc32.calc(data_bytes)
print(f"CRC-32 for {data_bytes.hex()}: {calculated_crc:08X}")

# Calculation over multiple data blocks
multi_block_data1 = b"Hello"
multi_block_data2 = b"World"

crc_instance = Crc32()
crc_instance.process(multi_block_data1)
crc_instance.process(multi_block_data2)
final_crc = crc_instance.final()
print(f"CRC-32 for multiple blocks: {final_crc:08X}")

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