(ISC)2 Certified in Cybersecurity Practice Exam

Keys used for which type of encryption and decryption must be from the same pair?

1. Symmetric

2. Asymmetric

3. Hashing

4. Salting

The correct answer is: Symmetric

The correct answer is based on the principle of symmetric encryption, where the same key is used for both encrypting and decrypting the data. This means that the sender and the receiver must both possess the identical secret key to successfully communicate securely. In symmetric encryption, if the key used to encrypt the message is different from the key used to decrypt it, the decryption process will not yield the original data, making it essential for both parties to have the same key. This method is often faster and more efficient for encrypting large amounts of data compared to asymmetric encryption, which uses a pair of keys (a public key for encryption and a private key for decryption). The other options represent different concepts. Asymmetric encryption utilizes a key pair (public and private), meaning that the keys are distinct and serve different purposes. Hashing is a one-way function designed to convert data into a fixed-size string of characters, which cannot be decrypted back to the original data. Salting involves adding random data to the input of a hash function to ensure that hash outputs are unique, even for identical inputs, which also does not involve encryption and decryption operations in the same way that symmetric encryption does.