IND-CCA(Chosen cipher text attack)

• let the adversary choose cipher texts and have them decrypted (attackers can make decryption queries)
• Conditions:
  • No Cheating B can refuse to decrypt the challenge cipher text. A can generate new ciphertexts based on the challenge cipher text... i.e. the challenge cipher text concatenated with '0'
  • Only Valid Cipher Texts Allowed some strings don't have associated plain texts, so B can only decrypt those that do.

IND-CCA1 (Non-Adaptive Chosen Ciphertext Attack)

Lunchtime attack Adversary makes queries til challenge cipher text is issued. B decrypts any valid ciphertexts.

IND-CCA2 (Adaptive Chosen Ciphertext Attack)

best protects against range of real world attacks decryption queries can continue after the challenge B decrypts any ciphertexts but not the challenge itself