Which of the following is characteristic of symmetric encryption?

In symmetric encryption, the defining characteristic is that it utilizes the same key for both the encryption and decryption processes. This means that the sender and the receiver must possess the same secret key to communicate securely. The efficiency of using one key facilitates faster processing as compared to asymmetric encryption, where two distinct keys are used—a public key for encryption and a private key for decryption. The reliance on a single shared key simplifies the encryption process but also presents challenges in key distribution and management, as both parties must keep the key confidential and be able to transmit it securely.

The other choices reflect concepts related to encryption but do not accurately describe symmetric encryption. For example, the notion of using a pair of keys pertains to asymmetric encryption, while the comparison in terms of speed does not take into account various implementations or circumstances that can affect performance in both encryption types. Web security often employs both symmetric and asymmetric methods, but symmetric encryption is particularly favored for encrypting data in bulk due to its speed and efficiency.