Key Exchange Algorithms

Visualize Diffie-Hellman and ECDHE key exchange. See how two parties derive a shared secret securely.

Interactive Demo

How two parties agree on a shared secret over a public channel, even when someone is watching.

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Alice

Public Channel

Bob

Eve (Eavesdropper)Intercepting Public Channel

INTERCEPTED DATA:

Public Common:

Yellow

Alice's Mix:

Orange

Bob's Mix:

Green

Final Secret?...

•Eve sees the Common Color and both Mixed Colors.
•To get the Secret Color, she needs either Alice's or Bob's Private Color.
•"Unmixing" colors is impossible. In math, this is the Discrete Logarithm Problem.

This is exactly how DHE (Diffie-Hellman Ephemeral) and ECDHE (Elliptic Curve DHE) work in TLS 1.2 and 1.3.

TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384

The "ECDHE" part creates the shared session key securely. The "AES" part uses that key to encrypt data.

Read our complete guide on Diffie-Hellman key exchange