Information Technology Specialist (ITS) Cybersecurity Practice Exam

Which type of encryption algorithm uses a pre-shared key to encrypt and decrypt data?

1. Asymmetric

2. Hashing

3. Symmetric

4. Non-reversible

The correct answer is: Symmetric

Symmetric encryption algorithms utilize a pre-shared key for both the encryption and decryption of data. In symmetric encryption, the same key is used to lock (encrypt) the data and unlock (decrypt) it, meaning that both the sender and the receiver must possess the same key for successful communication. This approach allows for fast processing speeds and efficient operation when encrypting large amounts of data. The key characteristic of symmetric encryption is its reliance on this shared secret, which requires secure key exchange methods to ensure that unauthorized parties do not gain access to the key. This is critical in maintaining the confidentiality and integrity of the encrypted data. In contrast, asymmetric encryption employs a pair of keys—one public and one private—where the public key encrypts data, and only the corresponding private key can decrypt it, eliminating the need for a shared key beforehand. Hashing algorithms, on the other hand, are designed to produce a unique fixed-length output from data, but they do not involve encryption or decryption processes since they are non-reversible by design. Non-reversible methods also relate to hashing, as they do not allow for the original data to be retrieved from the hash, reinforcing the idea that symmetric encryption relies specifically on the shared key mechanism.