crc — CRC Computation

The crc module computes CRC16 and CRC32 checksums over byte-like buffers. Each function may be called with only data to start a new CRC, or with a previous value to continue an existing CRC across multiple buffers.

Example:

import crc

c = crc.crc32(b"hello ")
c = crc.crc32(b"world", value=c)
print(hex(c))

Functions

crc.crc16(data: bytes, *, value: int = None) → int

Computes a CRC16 checksum over data, which must be a buffer-like object (e.g. bytes, bytearray, or memoryview).

If value is not provided, a new CRC16 is started over data and returned. If value is provided, it is used as the previous CRC16 state and updated with data before being returned, allowing CRC16 computation across multiple buffers. Only the lower 16 bits of value are used.

Returns the resulting CRC16 as an int.

crc.crc32(data: bytes, *, value: int = None) → int

Computes a CRC32 checksum over data, which must be a buffer-like object (e.g. bytes, bytearray, or memoryview).

If value is not provided, a new CRC32 is started over data and returned. If value is provided, it is used as the previous CRC32 state and updated with data before being returned, allowing CRC32 computation across multiple buffers.

Returns the resulting CRC32 as an int.