Public-key cryptography (a form of asymmetric cryptography) is an encryption method that's widely used because: 1) it is computationally infeasible to computer the private key based on the public key, 2) it's easier to share one public key than billions of private keys, 3) it's much tough to crack asymmetric encryption than symmetric, 4) it's more secure because the private keys do not even need to be transmitted or revealed to anyone. A. 1 only
B. 2 only
C. 3 and 4 only
D. All 1-4 are correct