Cryptography Questions Medium
Cipher Feedback (CFB) mode is a mode of operation used in cryptography to encrypt and decrypt data. It is a block cipher mode that allows encryption of individual bits or bytes, rather than fixed-size blocks.
In CFB mode, the previous ciphertext block is used as the input to the encryption algorithm, and the resulting output is then XORed with the plaintext to produce the ciphertext. This process is repeated for each bit or byte of the plaintext, creating a stream of ciphertext.
One of the key advantages of CFB mode is its ability to support encryption and decryption of data in a streaming fashion, where the data can be processed in real-time as it is received. This makes it suitable for applications such as secure communication protocols or disk encryption.
CFB mode also provides a level of error propagation, meaning that if an error occurs in the transmission of the ciphertext, it will only affect the corresponding block of plaintext and not the entire message. This can be useful in scenarios where data integrity is important.
However, it is worth noting that CFB mode is vulnerable to certain attacks, such as bit-flipping attacks, where an attacker can modify the ciphertext to manipulate the corresponding plaintext. Therefore, it is important to use proper integrity checks, such as message authentication codes (MACs), in conjunction with CFB mode to ensure data integrity and security.