CRC-32 Checksum (crc32)

CRC-32 cyclic redundancy check, using the CRC-32 (ISO 3309) algorithm standard. Chainable by feeding the previous CRC output as the initial value.

Algorithm Parameters

Parameter	Value
Name	CRC-32 (ISO 3309 / ITU-T V.42)
Polynomial	0x04C11DB7
Init	0xFFFFFFFF
RefIn	True
RefOut	True
XorOut	0xFFFFFFFF
Check	"123456789" → 0xCBF43926

API

uint32_t crc32_sum(uint32_t crc, const uint8_t * buf, int len);

• crc — Initial value (typically 0 for the first call)
• buf — Data buffer
• len — Data length

Returns the CRC-32 checksum.

Example

Single Checksum

uint8_t msg[] = { 'x', 'b', 'o', 'o', 't' };
uint32_t checksum = crc32_sum(0, msg, sizeof(msg));
/* checksum = 0x68292dcb */

Chained Calls

uint8_t part1[] = { 0x01, 0x02 };
uint8_t part2[] = { 0x03, 0x04 };
uint32_t crc = crc32_sum(0, part1, sizeof(part1));
crc = crc32_sum(crc, part2, sizeof(part2));