Secure Channel

Starting Point, we have a Man-in-the-middle situation:

How can we achieve a secure channel? Meaning:

• Confidential: Adversary cannot eavesdrop, i.e., does not learn the message.
• Authenticity: Adversary cannot tamper with Alice’s message.
• Correctness: With no interference, Bob will receive Alice’s message

One way is to make the Assumption that Alice and Bob have a shared secret key (through a Key Exchange), then we can use Secure Channel using Symmetric Key Cryptography.

Or if you want one-step construction from an Insecure to a Secure Channel: Authenticated Encryption

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Relevant Note(s): Cryptography