Diffie-Hellman Key Exchange
Diffie-Hellman solves an impossible-sounding problem: two parties who have never met can establish a shared secret over a public channel, even if an attacker is watching every message.
DH Parameters
Public g
-
Public p
-
Alice private a
-
Alice public A
-
Bob private b
-
Bob public B
-
Shared Secret s
-
Party States
Alice
IDLE
Eve
WATCHING
Bob
IDLE
Security Note
Eve sees: g, p, A, B (all public values).
To break DH, Eve must solve: 2^a mod 23 = 18
This is the Discrete Logarithm Problem - no efficient algorithm exists for large primes. Real DH uses 2048-bit primes.
To break DH, Eve must solve: 2^a mod 23 = 18
This is the Discrete Logarithm Problem - no efficient algorithm exists for large primes. Real DH uses 2048-bit primes.
Event Log