Cipher Block Chaining (CBC)
Definition - What does Cipher Block Chaining (CBC) mean?
In a cipher block chaining process, data is encrypted in specific blocks, and each block is dependent on the blocks before it for decryption. The process uses something called an initialization vector to help tie these blocks of encrypted data together.
Techopedia explains Cipher Block Chaining (CBC)
Invented in 1976, cipher block chaining provides a consistent way to encrypt and decrypt large amounts of data. In a block cipher process, text blocks are treated as isolated units to be encrypted and decrypted sequentially. An alternative is a stream cipher method, where each bit gets acted on independently.
In cipher block chaining, each cipher text block is decrypted in a process that requires observing the blocks that have already been processed. The cipher block chaining process uses a logical gate called XOR to administer this process of observation.
Cipher block chaining is often suggested as a stronger method of decryption, ensuring quality. However, some experts warn against certain vulnerabilities of cipher block chaining, including the use of predictable initialization vectors.