What is the main purpose of encryption in data transmission?

Encryption plays a crucial role in data transmission primarily by preventing unauthorized access to the data as it travels from one point to another. The main purpose of encryption is to transform the original data into a format that is unreadable for anyone who does not have the appropriate decryption key or credentials. This security measure is vital for protecting sensitive information, such as personal details, financial transactions, or confidential communications, from being intercepted and accessed by malicious actors during transmission.

While other aspects such as data integrity and compression are important in data handling, they do not primarily relate to the fundamental purpose of encryption. Data integrity focuses on ensuring that the content remains unchanged during transmission, which might involve different techniques like checksums or hashing rather than encryption itself. Similarly, data compression aims to reduce the size of data to enhance efficiency in storage or transmission speed but does not provide security against unauthorized access. Enhanced transmission speed is not a direct result of encryption; in fact, encryption often requires additional processing that could slightly slow down data transfer. Therefore, the main emphasis of encryption in the context of data transmission is ensuring that only authorized parties can access the information, which is why preventing unauthorized access is identified as the correct answer.