What are the primary differences between symmetric and asymmetric encryption, and provide a practical use case for each?

Symmetric and asymmetric encryption are two fundamentally different approaches to encrypting data. The primary difference is the key usage. Symmetric encryption uses the same secret key for both encryption and decryption. This means that the sender and receiver must both possess the same key. Examples of symmetric encryption algorithms include AES (Advanced Encryption Standard) and DES (Data Encryption Standard). Symmetric encryption is generally faster and more efficient than asymmetric encryption, making it suitable for encrypting large amounts of data. A practical use case for symmetric encryption is encrypting data at rest, such as files on a hard drive or data in a database. AES is commonly used for this purpose because it provides strong encryption with relatively low overhead. Asymmetric encryption, also known as public-key cryptography, uses a pair of keys: a public key and a private key. The public key can be freely distributed, while the private key must be kept secret. Data encrypted with the public key can only be decrypted with the corresponding private key, and vice versa. Examples of asymmetric encryption algorithms include RSA (Rivest-Shamir-Adleman) and ECC (Elliptic Curve Cryptography). Asymmetric encryption is slower than symmetric encryption, but it provides a more secure way to exchange keys and authenticate communications. A practical use case for asymmetric encryption is securing communication over the internet using SSL/TLS. When you connect to a website using HTTPS, the web server uses its private key to encrypt a session key, and your browser uses the server's public key to verify the server's identity. The session key is then used for symmetric encryption of the data exchanged between your browser and the server. This combination of asymmetric and symmetric encryption provides both security and performance.