Diffie-Hellman (EN)

Diffie-Hellman Key Exchange

sequenceDiagram     participant Alice als A     participant Bob als B     A->>B: p (public modulus), g (public generator)     B->>A: p, g     A->>A: a (private key), A = g^a mod p (public value)     B->>B: b (private key), B = g^b mod p (public value)     A->>B: A (public value)     B->>A: B (public value)     A->>A: s = B^a mod p (shared secret key)     B->>B: s = A^b mod p (shared secret key) 

In Context

• Typically used together with RSA or Elliptic Curve Cryptography (ECC)
• Related to: Perfect Forward Secrecity, TLS/SSL, VPN
• Example use: SSH connections, Signal protocol, IPsec