Information Technology Specialist (ITS) Cybersecurity Practice Exam

Which type of encryption uses a single key for both encryption and decryption?

1. Asymmetric encryption

2. Hashing

3. Symmetric encryption

4. Tokenization

The correct answer is: Symmetric encryption

The correct response is based on the fundamental characteristics of symmetric encryption. This type of encryption uses the same key for both the encryption of plaintext and the decryption of the resulting ciphertext. This means that both the sender and the receiver must have access to the same key and keep it secret to maintain confidentiality. In symmetric encryption, the speed of encryption and decryption tends to be faster than asymmetric methods, making it suitable for processing large volumes of data. Because of the shared key requirement, symmetric encryption also raises challenges regarding key distribution and management, which are crucial factors to address in a secure communications system. In contrast, asymmetric encryption utilizes a pair of keys—one public and one private—for the encryption and decryption processes, allowing secure key exchange without sharing the keys directly. Hashing, on the other hand, is a one-way function that converts data into a fixed-length string, primarily used for data integrity verification rather than encryption. Tokenization involves the substitution of sensitive data elements with non-sensitive equivalents, but it does not involve traditional encryption techniques. Thus, the key characteristic that defines symmetric encryption is the use of a single key for both encrypting and decrypting data, making it the correct choice in this context.