Content Security and Message Authentication Techniques

C.

The correct answer is C. Cryptography.

Cryptography is a technique used for securing information by transforming it into an unreadable format using encryption algorithms. It is used to provide information and cybersecurity and reduce the risk of hacking attacks during communication and message passing over the internet.

When data is transmitted over a network, it is susceptible to being intercepted and read by unauthorized parties. Cryptography can protect this data by encoding it into an unreadable format, which can only be decoded by someone who has the key to unlock it. This key is only available to authorized parties, ensuring that the data is kept secure and confidential.

There are two main types of cryptography: symmetric and asymmetric. Symmetric cryptography involves the use of a single key that is used to encrypt and decrypt data. Asymmetric cryptography, on the other hand, involves the use of a public key to encrypt data and a private key to decrypt it.

Cryptography is used in many areas of information security, including secure communications, data encryption, digital signatures, and authentication. It is an essential component of modern information systems security architecture.

In contrast, risk analysis is a process used to identify and assess potential risks to an organization's information assets. The OODA loop is a decision-making framework used to guide actions in high-stress situations. Firewall security is a network security measure used to protect against unauthorized access to a computer network. While all of these techniques are important in information security, none of them are specifically used for modifying messages or reducing the risk of hacking attacks during communication and message passing over the internet.