Ciphertext Integrity (CI)
Ciphertext integrity is a notion which closely resembles message authentication codes (MACs) and is the cipher analogue of CMA-security for them.
The adversary Eve is given oracle access and can query it with messages in order to obtain their ciphertexts . Her goal is to produce a new valid ciphertext , i.e. a ciphertext such that .
A cipher provides ciphertext integrity (CI), if for all keys , the probability that Mallory achieves her goal is negligible, i.e.