We’ve been using codes and ciphers for thousands of years to protect secrets. A clay tablet from Mesopotamia (dated 1500 BC), for example, encrypted a craftsman’s recipe for pottery glaze. We can assume this was commercially valuable to him, and so perhaps only his trusty apprentice knew how to translate the code.
However, it’s all very well encrypting information so that it can’t be understood if it’s intercepted, but what if the sender and receiver can’t verify each other’s identity? How do you know that you’re really talking to your banks, and how does your bank know that it’s you that they’re dealing with? This is the challenge that typical man-in-the-middle attacks exploit – the hacker can impersonate the sender or receiver to intercept or alter the information being sent.
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