Standard test vector
CRC implementations are commonly verified with the ASCII input 123456789.
- Input format
- ASCII
- Input
- 123456789
- Expected CRC
- 0xA1
- Residue
- 0xAC
CRC-8 / I-432-1
Width8-bitRefInNoRefOutNoInput data9 bytesUTF-8 bytesText is converted to UTF-8 bytes.
Standard test string
Result
Similar CRC Algorithms
5 modelsBrowse all algorithms
Result is calculated from the current input. Check is the published verification value for the standard input 123456789. Click another algorithm to view its detail page.
CRC-8 / DVB-S2
8-bitPoly 0xD5In No Out No
Result
0xBC
Check
0xBC
CRC-8 / GSM-A
8-bitPoly 0x1DIn No Out No
Result
0x37
Check
0x37
CRC-8 / I-432-1 Current
8-bitPoly 0x07In No Out No
Result
0xA1
Check
0xA1
CRC-8 / ROHC
8-bitPoly 0x07In Yes Out Yes
Result
0xD0
Check
0xD0
CRC-8 / SMBUS
8-bitPoly 0x07In No Out No
Result
0xF4
Check
0xF4
CRC Lookup Table
CRC-8 / I-432-1 · Poly 0x07 · Init 0x00 · XorOut 0x55 · 256 entries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 Source Code
CRC-8 / I-432-1 · Poly 0x07 · Init 0x00 · XorOut 0x55 · C · 56 lines
/*
* Model: CRC-8 / I-432-1 (8-bit)
* Poly: 0x07, Init: 0x00, XorOut: 0x55
* CRC Table C Source Code & Lookup Table Generator
*/
#include <stdint.h>
#include <stddef.h>
const uint8_t crc_table[256] = {
0x00, 0x07, 0x0E, 0x09, 0x1C, 0x1B, 0x12, 0x15,
0x38, 0x3F, 0x36, 0x31, 0x24, 0x23, 0x2A, 0x2D,
0x70, 0x77, 0x7E, 0x79, 0x6C, 0x6B, 0x62, 0x65,
0x48, 0x4F, 0x46, 0x41, 0x54, 0x53, 0x5A, 0x5D,
0xE0, 0xE7, 0xEE, 0xE9, 0xFC, 0xFB, 0xF2, 0xF5,
0xD8, 0xDF, 0xD6, 0xD1, 0xC4, 0xC3, 0xCA, 0xCD,
0x90, 0x97, 0x9E, 0x99, 0x8C, 0x8B, 0x82, 0x85,
0xA8, 0xAF, 0xA6, 0xA1, 0xB4, 0xB3, 0xBA, 0xBD,
0xC7, 0xC0, 0xC9, 0xCE, 0xDB, 0xDC, 0xD5, 0xD2,
0xFF, 0xF8, 0xF1, 0xF6, 0xE3, 0xE4, 0xED, 0xEA,
0xB7, 0xB0, 0xB9, 0xBE, 0xAB, 0xAC, 0xA5, 0xA2,
0x8F, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9D, 0x9A,
0x27, 0x20, 0x29, 0x2E, 0x3B, 0x3C, 0x35, 0x32,
0x1F, 0x18, 0x11, 0x16, 0x03, 0x04, 0x0D, 0x0A,
0x57, 0x50, 0x59, 0x5E, 0x4B, 0x4C, 0x45, 0x42,
0x6F, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7D, 0x7A,
0x89, 0x8E, 0x87, 0x80, 0x95, 0x92, 0x9B, 0x9C,
0xB1, 0xB6, 0xBF, 0xB8, 0xAD, 0xAA, 0xA3, 0xA4,
0xF9, 0xFE, 0xF7, 0xF0, 0xE5, 0xE2, 0xEB, 0xEC,
0xC1, 0xC6, 0xCF, 0xC8, 0xDD, 0xDA, 0xD3, 0xD4,
0x69, 0x6E, 0x67, 0x60, 0x75, 0x72, 0x7B, 0x7C,
0x51, 0x56, 0x5F, 0x58, 0x4D, 0x4A, 0x43, 0x44,
0x19, 0x1E, 0x17, 0x10, 0x05, 0x02, 0x0B, 0x0C,
0x21, 0x26, 0x2F, 0x28, 0x3D, 0x3A, 0x33, 0x34,
0x4E, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5C, 0x5B,
0x76, 0x71, 0x78, 0x7F, 0x6A, 0x6D, 0x64, 0x63,
0x3E, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2C, 0x2B,
0x06, 0x01, 0x08, 0x0F, 0x1A, 0x1D, 0x14, 0x13,
0xAE, 0xA9, 0xA0, 0xA7, 0xB2, 0xB5, 0xBC, 0xBB,
0x96, 0x91, 0x98, 0x9F, 0x8A, 0x8D, 0x84, 0x83,
0xDE, 0xD9, 0xD0, 0xD7, 0xC2, 0xC5, 0xCC, 0xCB,
0xE6, 0xE1, 0xE8, 0xEF, 0xFA, 0xFD, 0xF4, 0xF3
};
uint8_t calculate_crc(const uint8_t *data, size_t length) {
uint8_t crc = 0x00;
for (size_t i = 0; i < length; i++) {
#if 0
uint8_t idx = (uint8_t)(crc ^ data[i]);
crc = (crc >> 8) ^ crc_table[idx];
#else
uint8_t idx = (uint8_t)((crc >> 0) ^ data[i]);
crc = (crc << 8) ^ crc_table[idx];
#endif
}
return crc ^ 0x55;
}About CRC-8/I-432-1
CRC-8/I-432-1 is historically known as CRC-8/ITU and is associated with ATM header error control.
CRC-8/I-432-1 is a 8-bit CRC model defined by polynomial 0x07, an initial register value of 0x00, and final XOR 0x55. It uses normal, non-reflected input and output processing.
Documented application context for this model includes ATM, Telecommunications, Header error control. The calculator above applies this exact parameter set to the current input; the published Check value below is instead the fixed verification result for ASCII 123456789.
Model characteristics
A model is identified by its complete parameter set, not its polynomial alone.
- Bit order
- Normal
- Register start
- 0x00
- Final XOR
- 0x55
- Published check
- 0xA1
Implementation checks for CRC-8/I-432-1
- Use a 8-bit register and polynomial 0x07.
- Initialize the register to 0x00 and use XorOut 0x55 exactly as listed; changing either value defines a different model.
- Verify the implementation with ASCII “123456789”; the expected result is 0xA1.
Continue with the main calculator, browse the algorithm catalog, compare models in the Algorithm Reference section, or generate a lookup table.
Complete CRC-8/I-432-1 parameters
| Parameter | Value | Meaning | Reference |
|---|---|---|---|
| Width | 8 bits | CRC register and result width | Read guide |
| Poly | 0x07 | Generator polynomial without the leading term | Read guide |
| Init | 0x00 | Initial CRC register value | Read guide |
| RefIn | No | Reflect each input byte before processing | Read guide |
| RefOut | No | Reflect the register before XOR Out | Read guide |
| XorOut | 0x55 | Final value XORed with the CRC register | Read guide |
| Check | 0xA1 | CRC of ASCII “123456789” | Read guide |
| Residue | 0xAC | Expected residue after appending a valid CRC | Read guide |
AliasesCRC-8/ITUATM HEC
Where CRC-8/I-432-1 is used
- 01ATM
- 02Telecommunications
- 03Header error control
CRC-8/I-432-1 FAQ
What is the check value for CRC-8/I-432-1?
For the standard ASCII test input 123456789, the check value of CRC-8/I-432-1 is 0xA1.
What polynomial does CRC-8/I-432-1 use?
CRC-8/I-432-1 uses the 8-bit polynomial 0x07.
Does CRC-8/I-432-1 use reflected input and output?
For CRC-8/I-432-1, RefIn is No and RefOut is No.
What is CRC-8/I-432-1 commonly confused with?
CRC-8/SMBUS uses the same polynomial (0x07), which is the usual source of mix-ups — matching the polynomial alone does not reproduce CRC-8/I-432-1. The two models differ in final XOR value, so a port from one to the other needs those fields checked explicitly, not just the poly.