Attack models or attack types specify how much information a cryptanalyst has access to when breaking or cracking an encrypted message, commonly known as codebreaking or cracking the code. Some common attack models are:
- Ciphertext-only attack
- Known-plaintext attack
- Chosen-plaintext attack
- Chosen-ciphertext attack
The ciphertext-only attack model is the weakest because it implies that the cryptanalyst has just the encoded message.
Different attack models are used for other cryptographic systems, or more generally for all kind of security systems. Examples for such attack models are: