Chosen-ciphertext attack

A chosen-ciphertext attack (CCA) is a type of cryptographic attack where an attacker is able to choose a ciphertext and obtain its corresponding decrypted plaintext. This capability allows the attacker to gather information about the decryption process and potentially exploit vulnerabilities in the encryption scheme. In a CCA, the attacker has access to a decryption oracle, which is a mechanism that can decrypt arbitrary ciphertexts.