Why do we authenticate?

• A. To distinguish genuine and fraudulent transmissions
• B. To speed up transmissions
• C. To reduce power
• D. To simplify crypto

Answer: (A)

Authentication focuses on verifying who sent a message and that its content hasn’t been altered. In radio communications, this is crucial so you can trust that you’re receiving a legitimate transmission and not a forged or tampered one. That’s why the purpose is to distinguish genuine transmissions from fraudulent ones, preventing impersonation or spoofing.

The other options don’t fit because authentication isn’t about speeding up transmissions, reducing transmit power, or simply making cryptography easier. It adds a trust layer that protects origin and integrity, often using techniques like MACs or digital signatures to prove the sender and ensure the message hasn’t changed.