crc 1.2.0

Library and CLI to calculate and verify all kinds of CRC checksums

Overview

Library and CLI tool for calculating and verifying CRC checksums.

Provided Default Configuration(s) of CRC Algorithms:

CRC8	CRC16	CRC32	CRC64
CCITT	CCITT	CRC32	CRC64
AUTOSAR	GSM	AUTOSAR
SAJ1850	PROFIBUS	BZIP2
BLUETOOTH		POSIX
MAXIM-DOW

Requirements

• Python 3.7 and newer

Examples

Calculate crc using the CrcCalculator

from crc import CrcCalculator, Crc8
data = bytes([0, 1, 2, 3, 4, 5 ])
expected_checksum = 0xBC
crc_calculator = CrcCalculator(Crc8.CCITT)

checksum = crc_calculator.calculate_checksum(data)

assert checksum == expected_checksum
assert crc_calculator.verify_checksum(data, expected_checksum)

Speed up the calculation by using a table based CrcCalculator

from crc import CrcCalculator, Crc8

data = bytes([0, 1, 2, 3, 4, 5 ])
expected_checksum = 0xBC
use_table = True
crc_calculator = CrcCalculator(Crc8.CCITT, use_table)

checksum = crc_calculator.calculate_checksum(data)

assert checksum == expected_checksum
assert crc_calculator.verify_checksum(data, expected_checksum)

Create a custom crc configuration for the crc calculation

from crc import CrcCalculator, Configuration

data = bytes([0, 1, 2, 3, 4, 5 ])
expected_checksum = 0xBC

width = 8
poly=0x07
init_value=0x00
final_xor_value=0x00
reverse_input=False
reverse_output=False

configuration = Configuration(width, poly, init_value, final_xor_value, reverse_input, reverse_output)

use_table = True
crc_calculator = CrcCalculator(configuration, use_table)

checksum = crc_calculator.calculate_checksum(data)
assert checksum == expected_checksum
assert crc_calculator.verify_checksum(data, expected_checksum)

Use bare bones crc registers

from crc import Crc8, TableBasedCrcRegister, CrcRegister

data = bytes([0, 1, 2, 3, 4, 5 ])
expected_checksum = 0xBC

reg = CrcRegister(Crc8.CCITT)
table_reg = TableBasedCrcRegister(Crc8.CCITT)

reg.init()
reg.update(data)
assert expected_checksum == reg.digest()

table_reg.init()
table_reg.update(data)
assert expected_checksum == table_reg.digest()

Command line tool

See crc --help

subcommand(s)

table

Subcommand to pre-compute crc lookup tables. See also crc table --help.

checksum

Subcommand to calculate crc checksums of input file(s). See also crc checksum --help.

References & Resources

• A Painless guide to crc error detection algorithms
• Project on Github
• CRC-Catalogue