What is the primary difference between asymmetric and symmetric encryption?

The primary difference between asymmetric and symmetric encryption lies in the number of keys used in the encryption and decryption processes. Asymmetric encryption employs a pair of keys: a public key and a private key. The public key is used to encrypt data, while the corresponding private key is required for decryption. This dual-key system enhances security since the private key remains confidential and only the public key is shared.

In contrast, symmetric encryption relies on a single shared key for both encryption and decryption. Both the sender and the recipient must possess and maintain this secret key to communicate securely. If the key is exposed, the security of the encrypted data can be compromised.

The other options address different aspects of encryption but do not highlight the foundational distinction inherent to their mechanisms. Asymmetric encryption is generally slower and requires more processing power compared to symmetric encryption due to the complexity of its algorithms, but this is secondary to the critical difference in key usage. Therefore, the emphasis on the number of keys used is fundamental to understanding the operational differences between asymmetric and symmetric encryption.