1. Introduction

Data can get corrupted during transmission due to noise. **CRC** is a robust error-detection technique using polynomial division. It is widely used in Ethernet, Wi-Fi, and ATM.

2. Working Principle

1. Both sender and receiver agree on a **Generator Polynomial** (Divisor).
2. Sender appends 0s to the Data unit (equal to degree of generator).
3. Sender divides the augmented data by the generator (Binary Division).
4. The **Remainder** (CRC) is appended to the original data and sent.
5. Receiver divides the received data by the same generator.
6. If Remainder is **0**, data is correct. If non-zero, error detected.

3. Example