(ISC)2 Certified in Cybersecurity Practice Exam

How does symmetric encryption differ from asymmetric encryption?

1. Symmetric uses the same key for both encryption and decryption

2. Symmetric relies solely on public keys

3. Symmetric offers faster decryption than asymmetric

4. Symmetric is used exclusively in hardware security

The correct answer is: Symmetric uses the same key for both encryption and decryption

Symmetric encryption is characterized by the use of a single key for both the encryption and decryption processes. This means that the same secret key is shared among the parties involved in the communication, allowing them to encrypt a message and later decrypt it using that same key. This method is efficient for encrypting large amounts of data due to its speed and lower computational overhead compared to asymmetric encryption. In many scenarios, symmetric encryption is preferred for its speed and efficiency, especially when dealing with bulk data encryption. However, it does require that both parties securely share the key beforehand, which can pose challenges in terms of key distribution and management. Options that mention public keys or specify that symmetric encryption relies solely on them would be referring to asymmetric encryption, which uses a pair of keys (a public key for encryption and a private key for decryption). Additionally, the claim that symmetric encryption is exclusively used in hardware security is not accurately reflective of its broad application across various sectors, including software solutions. Overall, the defining characteristic of symmetric encryption is indeed the use of the same key for both processes, which succinctly differentiates it from asymmetric encryption techniques.