CFB

A block cipher mode that turns a block cipher into a self-synchronizing stream cipher.

CFB is a block cipher mode that feeds prior ciphertext back into the cipher to generate a keystream, effectively turning a block cipher into a self synchronizing stream cipher able to process data in smaller units. Like CBC it needs an initialization vector and chains blocks, so encryption is sequential. Self synchronization lets decryption recover after limited transmission errors. It is less common today than authenticated modes such as GCM, which add integrity protection that CFB alone does not provide.