Diffie-Hellman Key Exchange

What Does Diffie-Hellman Key Exchange Mean?

The Diffie-Hellmann key exchange is a secure method for exchanging cryptographic keys.


This method allows two parties which have no prior knowledge of each other to establish a shared, secret key, even over an insecure channel.

The concept uses multiplicative group of integers modulo, which without knowledge of the private keys of any of the parties, would present a mathematically overwhelming task to a code breaker .

Techopedia Explains Diffie-Hellman Key Exchange

The key exchange was invented by Whitfield Diffie and Martin Hellmann in 1976 as the first practical method for establishing a shared secret code over an open communications channel.

The general idea of the Diffie-Hellmann key exchange involves two parties exchanging numbers and doing simple calculations in order to get a common number which serves as the secret key.

Both parties may not know beforehand what the final secret number is, but after some calculations, both are left with a value that only they know about which they can use for various purposes like identification and as a secret key for other cryptographic methods.


Related Terms

Margaret Rouse

Margaret Rouse is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical, business audience. Over the past twenty years her explanations have appeared on TechTarget websites and she's been cited as an authority in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine and Discovery Magazine.Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages. If you have a suggestion for a new definition or how to improve a technical explanation, please email Margaret or contact her…