A chosen plaintext attack is an attack on a cryptosystem in which the cryptanalyst chooses plaintext to be encrypted as a way further the attack. The name is somewhat misleading as few cryptanalysts are in a position to request their victims to do such things. More commonly information is leaked which is expected to be encrypted and transmitted over an eavesdroppable channel (this is called a known plaintext attack). There are two kinds:
- batch chosen-plaintext attack, where the cryptanalyst chooses all plaintexts before any of them is encrypted, and
- adaptive chosen-plaintext attack, where the cryptanalyst sees the ciphertext of a chosen plaintext before choosing another plaintext.
But note that the RSA asymmetric key algorithm is inherently susceptible to a chosen ciphertext attack.
See also:
- chosen ciphertext attack
- chosen key attack.