Longer key lengths, often measures in the thousands of bits, are common for public keys/asymmetric algorithm of modern cryptographic algorithms.
Option: A
Explanation:
Asymmetric Encryption Algorithms is an algorithm which is considered secure when the key size is large enough. DSA was originally proposed with a 512 bit key size but later on revised to support key sizes up to 1024 bits. AEA isn't an actual encryption algorithm. Its a key agreement protocol that enables users to exchange encryption keys of an insecure medium.
One time pad play fair algorithms is a type of encryption when it applied practically it works securely but theoretically it can't compromise. Algorithm is based on the prime numbers obtained from public and private keys.
