What role does cryptography primarily serve in data transmission?

Cryptography primarily serves the role of providing security during data transmission. This involves the use of algorithms and protocols to encrypt data, ensuring that only authorized parties can access and interpret the information being transmitted. By encrypting data, cryptography protects it from unauthorized access and interception, which is crucial in maintaining confidentiality and integrity.

When data is transmitted over networks, it is particularly vulnerable to various threats such as eavesdropping, tampering, and impersonation. Cryptography addresses these threats by encoding the data in a way that makes it unreadable without the proper decryption key. This secure communication is vital for sensitive information, including personal data, financial transactions, and confidential communications.

The other options highlight aspects that are not the primary focus of cryptography in the context of data transmission. While speed may be affected by encryption processes, it is not a primary goal of cryptography. Similarly, capacity refers to the volume of data that can be transmitted and is not directly related to security measures. Facilitating access may relate to providing authorized users with the means to access data, but cryptography emphasizes protection and confidentiality over mere access.