Cyclic Redundancy Check

Definition of Cyclic Redundancy Check

A Cyclic Redundancy Check (CRC) is an error-detecting technique used in digital data storage and communication to ensure data integrity. It works by running a mathematical algorithm on the data being transmitted or stored, generating a short, fixed-size check value, known as a checksum. When the data is retrieved or received, the same algorithm is run again to generate a new checksum, which is then compared to the original to detect if any errors or corruption occurred during transmission or storage.


The phonetic representation of the keyword “Cyclic Redundancy Check” in the International Phonetic Alphabet (IPA) would be:/ˈsaɪklɪk rɪˈdʌndənsi tʃɛk/

Key Takeaways

  1. Cyclic Redundancy Check (CRC) is an error-detecting technology commonly used in digital networks and storage devices to detect accidental alterations of raw data.
  2. CRC uses a mathematical algorithm based on polynomial division to generate a fixed-size hash, called a checksum, which is appended to the transmitted data to check its integrity upon receipt.
  3. While CRC is highly effective in detecting common errors, such as noise and data corruption, it is not foolproof and may fail to identify more complex errors, like those caused by malicious activities.

Importance of Cyclic Redundancy Check

The Cyclic Redundancy Check (CRC) is an essential technology term because it plays a crucial role in ensuring data integrity during communication and storage processes.

As a widely-used error-detection technique, CRC finds accidental alterations in raw data by utilizing mathematical algorithms to generate a unique code, or checksum, for each data block.

When the data is transmitted or retrieved, the CRC code is recalculated and compared with the original code.

Any discrepancy between the two codes indicates potential data corruption, enabling prompt detection and correction of errors before further processing.

Consequently, CRC contributes significantly to maintaining the quality and accuracy of stored or transmitted data, making it indispensable in a variety of applications, including digital networks, storage devices, and file systems.


Cyclic Redundancy Check (CRC) is an error-detection technique widely used in digital networks and storage devices to ensure data integrity. The primary purpose of CRC is to identify any alterations or corruption in the data being transmitted or stored, enabling early detection of potential problems.

As a result, this increases the reliability and efficiency of communication systems, including data transfers and other storage solutions, by ensuring that the original, error-free data is maintained. In practice, CRC involves appending a specific set of check bits to the original data, derived from polynomial division.

These check bits are generated using pre-defined algorithms and are based on the actual bits of the data being transmitted or stored. When the data is retrieved or received, the check bits are recalculated, and a comparison is made against the original check bits attached to the data.

If a discrepancy is detected, this indicates that there has been data corruption or an alteration during transmission, necessitating further actions such as retransmission or correction. By providing a proactive method for identifying data errors, CRC helps to maintain overall system performance and integrity, significantly reducing the likelihood of critical systems failures and data loss.

Examples of Cyclic Redundancy Check

Cyclic Redundancy Check (CRC) is a widely used error detection technique in various technological systems to ensure the integrity of data during transmission or storage. Here are three real-world examples where CRC plays a crucial role:

Data Storage Devices: CRC is implemented in hard drives, solid-state drives (SSDs), and external storage devices, such as USB drives and memory cards. It ensures that the written data is free from errors by checking its integrity before confirming a read or write operation. When a file is accessed or saved, the CRC value is calculated and compared with the value stored alongside the data to confirm whether the data is intact or corrupt.

Networking and Communication Protocols: CRC is employed in numerous communication protocols, including Ethernet, Wi-Fi, Bluetooth, and cellular networks. It acts as a vital element in data packet transmission, where an error may occur due to signal interference, noise, or hardware failures. A CRC code is embedded within each transmitted packet, and at the receiving end, the same CRC calculation is performed to detect any discrepancies indicating data corruption.

Embedded Systems and Microcontroller Applications: CRC is widely used in embedded systems and microcontrollers for tasks such as firmware updates, sensor data transmission, or validating data received from other devices. For instance, many automotive systems use Controller Area Network (CAN) or Serial Peripheral Interface (SPI) protocols, which incorporate CRC to ensure error-free communication between electronic control units while monitoring various components like engine, transmission, and safety systems.

FAQs about Cyclic Redundancy Check

What is a Cyclic Redundancy Check?

A Cyclic Redundancy Check (CRC) is an error-detection technique used in digital networks and storage devices to detect accidental changes to raw data. It’s implemented as a function that takes a data stream as input and produces a fixed-size output, called checksum. If a single bit gets altered, the resulting checksum will be different, enabling the detection of errors.

How does Cyclic Redundancy Check work?

CRC works by treating the data as a binary number and dividing it by a pre-defined generator polynomial. The remainder from this division acts as the checksum and is attached to the original data. When the receiver gets the data, it performs the same division. If the receiver’s remainder matches the transmitted remainder, it assumes that no error has occurred.

Why is Cyclic Redundancy Check important?

CRC is crucial for maintaining data integrity during transmission and storage. It ensures accurate and error-free communication between systems, reducing the possibility of corrupted or lost data. It’s widely used in various applications such as network protocols, file formats, and storage systems to ensure data reliability.

What types of errors can Cyclic Redundancy Check detect?

CRC can detect errors such as single or multiple bit changes, burst errors, and random error patterns. It’s particularly efficient in identifying common errors caused by noise in communication channels. However, CRC can’t fix these errors – its primary role is to detect errors, enabling further corrective measures to be taken.

Are there any limitations to Cyclic Redundancy Check?

While CRC is effective in detecting common error patterns, it’s not foolproof. It might not catch certain error patterns that result in the same remainder as the correct data. Moreover, CRC cannot detect errors that occur simultaneously in both data and checksum. Lastly, it’s unable to correct the detected errors, requiring additional mechanisms for error correction.

Related Technology Terms

  • Error detection
  • Data transmission
  • Checksum
  • Polynomial division
  • Parity bit

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