What type of encryption is proven to be unbreakable?

A.
AES

B.
ECC

C.
One-time pad

D.
RSA

Explanation:
Answer C is correct; a one-time pad is unbreakable if the pad is truly random, the confidentiality of the pad is maintained, and the pad is not reused.

Incorrect Answers and Explanations: A, B, and D: Answers A, B, and D are incorrect. AES, ECC, and RSA can all be broken via brute-force attacks. It may take a long time (perhaps thousands of years or more using current technology), but it is possible.