CBC
Cipher block chaining
A block cipher mode in which each plaintext block is XORed with the previous ciphertext block before encryption, starting from an unpredictable IV. It provides no integrity, so it needs a MAC over the IV and ciphertext checked before decryption, or padding oracles follow; prefer an AEAD.
Covered in
Reference
Padding oracle attacks
Use a byte-level CBC example to see how a tiny validity signal becomes plaintext information, then design verification that checks more than the error message.
Case study
Lucky Thirteen and POODLE: two different oracles
Compare two CBC oracles by their signal, protocol rules, and attacker prerequisites instead of treating them as interchangeable padding bugs.