Active Attack Lab

Diffie-Hellman Man-in-the-Middle Simulator

Unauthenticated Diffie-Hellman is vulnerable to active interception: Eve substitutes both public keys, then relays and decrypts every message while Alice and Bob believe they share a key with each other. Toggle on digital signatures to see the attack fail.

Alice private key a

Bob private key b

Eve private key e

Eve Active InterceptionDigital Signatures (Station-to-Station protection)

Alice

A = g^a = 8

Receives E₂ = 11 (Eve's key)

K_AE = 9

Eve (MitM)

E₁ = g^e₁ = 11

E₂ = g^e₂ = 11

K_EA = 9

K_EB = 10

Bob

B = g^b = 19

Receives E₁ = 11 (Eve's key)

K_BE = 10

Payload Inspection

Alice's message

Eve's altered message

Step-by-Step Trace

Run the key exchange to see the trace.

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