Cryptography Questions Medium
Propagating Cipher Block Chaining (PCBC) mode is a symmetric encryption mode that operates on blocks of data. It is a modification of the Cipher Block Chaining (CBC) mode, where the previous ciphertext block is XORed with the current plaintext block before encryption.
In PCBC mode, the XOR operation is extended to include the previous plaintext block as well. This means that the current plaintext block is XORed with both the previous ciphertext block and the previous plaintext block before encryption. The resulting ciphertext block is then used as the input for the next block.
The main advantage of PCBC mode is that it provides error propagation. If a single bit error occurs in the ciphertext, it will affect the decryption of the current block and all subsequent blocks. This makes it easier to detect and correct errors in the encrypted data.
However, PCBC mode has some limitations. It requires the encryption and decryption processes to be performed sequentially, which can limit parallel processing capabilities. Additionally, if an error occurs in the transmission of the ciphertext, it can cause the decryption process to become out of sync, resulting in the corruption of subsequent blocks.
Overall, PCBC mode offers enhanced error detection and correction capabilities compared to CBC mode, but it also introduces some limitations that need to be considered when choosing an encryption mode for a specific application.