From the course: Symmetric Cryptography Essential Training

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Diffie–Hellman key exchange

Diffie–Hellman key exchange

From the course: Symmetric Cryptography Essential Training

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Diffie–Hellman key exchange

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- [Instructor] Now that we know that calculating the discrete logarithm is difficult, let's take a look at a method for exchanging keys whose strength relies on this difficulty. It's called the Diffie-Hellman, or DH, Key Exchange. It was published in 1976 by its inventors, Whitfield Diffie and Martin Hellman. It's one of the first instances of asymmetric or public key cryptography and represents a significantly different approach to cryptography than what I've described previously in this course. This remains a very common method for keys to be exchanged on the internet today. And if it's not exactly Diffie-Hellman, your browser is doing something that looks quite similar to this. Let's get into it. Suppose Alice and Bob are friends, but live in different cities and have some messages that they want to securely send to one another. With this message, they can agree on a shared secret that we'll call S. First, they have to agree on two values which are shared publicly, a modulus m and…

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