Error correction codes (ECC) are techniques used to detect and correct errors in data transmission or storage. They add extra bits to the original data, allowing the system to identify and fix mistakes that may occur due to noise, interference, or hardware malfunctions. These codes work by using algorithms that can recognize patterns in the data. When the data is received or retrieved, the ECC checks for discrepancies and can often restore the original information. This is crucial in applications like computer memory, data storage, and communication systems, where accuracy is essential.