About Lesson
Modes of Operation for Block Ciphers
Block ciphers require specific modes of operation to encrypt data larger than a single block. These modes also enhance security by adding randomness to the encryption process.
Electronic Codebook (ECB):
- Encrypts each block independently.
- Vulnerable to pattern attacks since identical plaintext blocks produce identical ciphertext blocks.
- Rarely used in modern applications.
Cipher Block Chaining (CBC):
- Adds randomness by XORing each plaintext block with the ciphertext of the previous block.
- Requires an Initialization Vector (IV) for the first block.
Counter (CTR):
- Converts a block cipher into a stream cipher by combining plaintext with a counter value.
- Enables parallel encryption and decryption, improving efficiency.
Galois/Counter Mode (GCM):
- Provides both encryption and message authentication, ensuring data integrity.
- Widely used in secure communications, such as TLS.