What mechanism is used to authenticate information transmitted between two parties sharing a secret key?

What mechanism is used to authenticate information transmitted between two parties sharing a secret key?

• A. Digital Certificates
• B. Message Authentication Codes
• C. Pre-Master Secret
• D. Elliptical Curve Token

Answer: (B)

The mechanism used to authenticate information transmitted between two parties sharing a secret key is known as Message Authentication Codes (MACs). A MAC is a short piece of information used to confirm the authenticity and integrity of a message, ensuring that it was generated by someone who knows the secret key and that the message has not been altered during transmission. In a typical scenario involving two parties that share a secret key, each message can have a MAC appended to it. When one party sends a message, the MAC is generated based on both the message content and the shared secret key. The receiving party can then compute the MAC using the same secret key and compare it to the MAC attached to the received message. If they match, it confirms that the message is from the legitimate sender and has not been tampered with. Understanding the role of MACs is crucial in securing communications, particularly in various protocols used over the internet, where maintaining both integrity and authenticity is paramount for secure data exchange. The other mechanisms listed, such as digital certificates, pre-master secrets, and elliptical curve tokens, serve different purposes in security and cryptographic protocols, but they do not specifically focus on authenticating data in the way that MACs do.

The mechanism used to authenticate information transmitted between two parties sharing a secret key is known as Message Authentication Codes (MACs). A MAC is a short piece of information used to confirm the authenticity and integrity of a message, ensuring that it was generated by someone who knows the secret key and that the message has not been altered during transmission.

In a typical scenario involving two parties that share a secret key, each message can have a MAC appended to it. When one party sends a message, the MAC is generated based on both the message content and the shared secret key. The receiving party can then compute the MAC using the same secret key and compare it to the MAC attached to the received message. If they match, it confirms that the message is from the legitimate sender and has not been tampered with.

Understanding the role of MACs is crucial in securing communications, particularly in various protocols used over the internet, where maintaining both integrity and authenticity is paramount for secure data exchange. The other mechanisms listed, such as digital certificates, pre-master secrets, and elliptical curve tokens, serve different purposes in security and cryptographic protocols, but they do not specifically focus on authenticating data in the way that MACs do.