Attack Types
Let's talk about Attack Types in the security field today.
Attack types specify how much information which a crypto analyst has access to when cracking an encrypted message. We can sum up the common attach models as the following:
1) Ciphertext-only attack: The attacker is assumed to have access only to a set of ciphertexts; e.g. In any case where a stream cipher like RC4 is used twice with the same key it is open to ciphertext-only attack.; Brute force attack can succeed if a cipher's key space is too small;
2) Known-plain attack: The attacker has samples of both the plaintext and its ciphertext. Then the attacker makes use of them to reveal further secret information, typically secret key;
3) Chosen-plaintext attack: The attacker has the capability to choose arbitrary plaintexts to be encrypted and obtain the corresponding ciphertexts. The goal of the attack is to gain some further information which reduces the security of the encryption scheme. In the worst case, a chosen-plaintext attack could reveal the scheme's secret key;
4) Chosen-ciphertext attack: The attacker gathers information, at least in part, by choosing a ciphertext and obtaining its decryption under an unknown key.
