Encryption and decryption work together to secure communication by transforming readable data (plaintext) into an unreadable format (ciphertext) through encryption. This process uses algorithms and keys to obscure the original message, ensuring that only authorized parties have access to it. Decryption reverses this process, converting the ciphertext back into plaintext for authorized recipients using a decryption key. Together, these processes protect sensitive information transmitted over networks, making data interception or unauthorized access significantly more difficult while preserving confidentiality and integrity.