Microsoft Azure Architect Technologies (AZ-300) Practice Exam

Which type of encryption uses the same key for both encryption and decryption?

1. Symmetric encryption

2. Asymmetric encryption

3. Hashing

4. Hybrid encryption

The correct answer is: Symmetric encryption

Symmetric encryption is the correct choice because it employs the same key for both the processes of encryption and decryption. This means that the key used to convert plaintext into ciphertext is identical to the key used to revert ciphertext back into plaintext. This method is efficient for handling large volumes of data due to its speed and lower computational overhead compared to other types of encryption. In contrast, asymmetric encryption utilizes a pair of keys: a public key for encryption and a private key for decryption. This mechanism enhances security, especially for key exchange, but generally involves more complex calculations and is slower than symmetric encryption. Hashing is another distinct process that transforms data into a fixed-length string of characters through a one-way function. It is primarily used for data integrity verification and not for encryption, as it cannot be reversed to retrieve the original data. Hybrid encryption combines symmetric and asymmetric encryption techniques to leverage the benefits of both. Typically, it uses asymmetric encryption to securely exchange symmetric keys, and then symmetric encryption is employed to encrypt the actual data, maintaining efficiency while enhancing security during the key exchange. Thus, symmetric encryption stands out as the method that requires just one key for both phases, simplifying the encryption and decryption process.