Attack models Ciphertext-only: the cryptanalyst has access only to a collection of ciphertexts or code texts. This is the weakest attack model because the cryptanalyst has limited information. Modern ciphers rarely fail under this attack. Known-plaintext: the attacker has a set of ciphertexts to which they know the corresponding plaintext Chosen-plaintext attack: the attacker can obtain the ciphertexts corresponding to an arbitrary set of plaintexts of their own choosing Batch chosen-plaintext attack: where the cryptanalyst chooses all plaintexts before any of them are encrypted. This is often the meaning of an unqualified use of "chosen-plaintext attack". Adaptive chosen-plaintext attack: where the cryptanalyst makes a series of interactive queries, choosing subsequent plaintexts based on the information from the previous encryptions. Chosen-ciphertext attack: the attacker can obtain the plaintexts corresponding to an arbitrary set of ciphertexts of their own choosing Adaptive chosen-ciphertext attack Indifferent chosen-ciphertext attack Related-key attack: similar to a chosen-plaintext attack, except the attacker can obtain ciphertexts encrypted under two different keys. The keys are unknown, but the relationship between them is known (e.g., two keys that differ in the one bit).
Attack models Ciphertext-only the cryptanalyst has access only to a collection of ciphertexts or code texts This is the weakest attack model because the cryptanalyst has limited information Modern ciphers rarely fail under this attack Known-plaintext the attacker has a set of ciphertexts to which they know the corresponding plaintext Chosen-plaintext attack the attacker can obtain the ciphertexts corresponding to an arbitrary set of plaintexts of their own choosing Batch chosen-plaintext attack where the cryptanalyst chooses all plaintexts before any of them are encrypted This is often the meaning of an unqualified use of "chosen-plaintext attack" Adaptive chosen-plaintext attack where the cryptanalyst makes a series of interactive queries choosing subsequent plaintexts based on the information from the previous encryptions Chosen-ciphertext attack the attacker can obtain the plaintexts corresponding to an arbitrary set of ciphertexts of their own choosing Adaptive chosen-ciphertext attack Indifferent chosen-ciphertext attack Related-key attack similar to a chosen-plaintext attack except the attacker can obtain ciphertexts encrypted under two different keys The keys are unknown but the relationship between them is known (eg two keys that differ in the one bit)