Which encryption method uses the same key for both the encryption and decryption processes?

The correct answer is symmetric key encryption because this method relies on a single shared key to perform both the encryption and decryption processes. In symmetric key encryption, both the sender and the receiver must have access to the same key and keep it secret from unauthorized users. This approach is efficient in terms of speed and performance, making it suitable for encrypting large amounts of data.

In contrast, public key encryption uses a pair of keys—a public key for encryption and a private key for decryption. This allows secure communications without needing to share a secret key in advance. Asymmetric key encryption refers to this type of encryption method, characterized by separate keys for encryption and decryption.

Multi-factor encryption is not a standard type of encryption on its own; rather, it usually refers to the use of multiple authentication factors to enhance security. Thus, symmetric key encryption distinctly utilizes the same key throughout both stages of the process, distinguishing it clearly from the other methods mentioned.