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 possess the same secret key to access the original information. It is efficient and fast, making it suitable for encrypting large amounts of data. However, the main challenge with symmetric encryption is key management. If the key is intercepted or shared improperly, unauthorized users can easily decrypt the data. Therefore, secure key distribution and storage are crucial to maintaining the confidentiality of the encrypted information.