Which cryptographic method relies on the use of a public and private key?

The answer is D, Asymmetric Encryption, which is the correct choice because this method specifically employs a pair of keys: one public and one private. The public key can be shared with anyone and is used for encryption or verifying digital signatures, while the private key is kept secret and is used for decryption or creating digital signatures.

This dual key approach allows for secure communication and ensures that only the intended recipient, who possesses the private key, can access the information encrypted with the corresponding public key. It also enables features such as non-repudiation and authentication in digital signatures, establishing trust in electronic communications.

In contrast, methods like symmetric encryption use a single key for both encryption and decryption, hashing does not involve keys and is a one-way function used to ensure data integrity, and digital signatures utilize asymmetric cryptography but do not inherently define the use of a public and private key pair in the context of encryption. Therefore, asymmetric encryption is uniquely defined by its reliance on both a public and a private key for its security functions.