Symmetric encryption is a method of encrypting data where the same key is used for both encryption and decryption. This means that both the sender and the receiver must have access to the same secret key to securely communicate. Because of its simplicity and speed, symmetric encryption is often used for encrypting large amounts of data. However, the main challenge with symmetric encryption is key management. If the key is intercepted or shared with unauthorized users, the security of the encrypted data is compromised. Therefore, it is crucial to keep the key secure and to use secure methods for key exchange.