Which of the following is characteristic of symmetric encryption?

In symmetric encryption, the defining characteristic is that it uses a single key for both the encryption and decryption processes. This means that the same secret key is shared between the sender and the receiver, which allows for both parties to securely encode and decode the information without needing to exchange multiple keys. This method is efficient for encrypting large amounts of data quickly, as the operations performed during encryption and decryption can be done rapidly with the same key.

Using one key simplifies the encryption mechanism and reduces the overhead associated with key management, making symmetric encryption suitable for numerous applications, such as encrypting files or securing communications in scenarios where the key can be securely exchanged in advance. This contrasts with asymmetric encryption, where a pair of keys (public and private) is utilized, leading to a more complex system that is typically slower. Symmetric encryption is commonly implemented in scenarios where speed is crucial, and it is not directly used for digital signatures, which rely on asymmetric algorithms for verification purposes.