A cryptographic key exchange method developed by Whitfield Diffie and Martin Hellman in 1976. Also known as the "Diffie-Hellman-Merkle" method and "exponential key agreement." Diffie-Hellman enables parties at both ends to derive a shared, secret key from a common starting point without the key ever being transmitted from one side to the other.

Although Diffie-Hellman is an asymmetric algorithm, it does not use public and private keys like the popular RSA method. Its logarithms and modular arithmetic are complicated mathematics; however, the example below is simplified to explain the concept. The numbers used are minuscule by comparison to those used in a real exchange. See elliptic curve cryptography, RSA and key management.

**Very Clever Math**

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