Cipher Block Chaining (CBC) is a mode of operation for block ciphers that enhances data encryption security. In CBC, each block of plaintext is combined with the previous ciphertext block before encryption. This process ensures that identical plaintext blocks yield different ciphertext outputs, making patterns harder to identify.The operation begins with an initial vector (IV) that is randomly generated for each encryption session. The first plaintext block is XORed with this IV, and the result is then encrypted. The subsequent plaintext blocks follow the same process, where each block is XORed with the previous ciphertext. This chaining effect means that an error in one block will affect all subsequent blocks, adding a layer of robustness.CBC is commonly used for encrypting messages in various applications, providing confidentiality and integrity. However, it does require careful management of the IV and has vulnerabilities to specific attack methods if not implemented correctly. Overall, CBC is an important building block in ensuring secure data communication.