Explanation/Reference:
Explanation:
A chosen-ciphertext attack is one in which a cryptanalyst may choose a piece of ciphertext and attempt to obtain the corresponding decrypted plaintext. This type of attack is generally most applicable to public-key cryptosystems.
Incorrect Answers:
B: A Ciphertext-Only attack is one which the cryptanalyst obtains a sample of ciphertext without the plaintext associated with it. This data is relatively easy to obtain in many scenarios, but a successful ciphertext-only attack is generally difficult and requires a very large ciphertext sample. This attack is not generally most applicable to public-key cryptosystems.
C: Plaintext Only Attack it not a defined attack type.
D: An Adaptive-Chosen-Plaintext attack is a special case of chosen-plaintext attack in which the cryptanalyst is able to choose plaintext samples dynamically and alter his or her choices based on the results of previous encryptions. This attack is not generally most applicable to public-key cryptosystems.