Modes of Operation Flashcards
1
Q
Describe Electronic Codebook mode (ECB).
A
Each block is encoded independently using the same key. ECB is used for short messages (e.g. key transmission) and is also a vulnerable mode of operation if used for long messages (e.g. repeated blocks in plaintext will produce repeated blocks in ciphertext).
2
Q
Describe Counter Mode (CTR).
A
CTR mode combines the ideas of a block cipher and a stream cipher. A keystream is produced and then XORed with the plaintext stream to produce the cipherstream.
