I am trying to work out the shared key between Alice and Bob in DHKE equation. The generator is 7 and the Prime P = 71. Bobs private choice of number is 28 and he also receives g ^ A = 70 from Alice. Alice does not seem to have a private choice of number in this equation, all I know is that g ^ A = 70. So how can I calculate the value of the shared key?
I am just having difficulty working it all out. The modulus arithmetic involved is also confusing me. If someone could try to explain it to me.
I know that it must be: A = 7^x (Mod 71) = 70; and: B = 7^28 (Mod 71);
Then Alice Computes: gB ^ A (Mod 71); and Bob Computes: (gA)^28 (Mod 71);