Encryption works to protect online communications by converting data into a ciphertext format that cannot be easily understood without a decryption key. This process involves algorithms that encode the original data, ensuring that only authorized users with the correct keys can access it. Two common types of encryption are symmetrical, where the same key is used for both encryption and decryption, and asymmetrical, which uses a pair of keys (public and private). Proper implementation helps safeguard sensitive information during transmission, making it difficult for unauthorized parties to intercept or manipulate it.