### Alice

##### Parameters known by Alice:

Chooses the secret value:

Computes the public value:

Receives $B$

Computes the shared secret key:

### Step y/x

Before Alice and Bob can compute the shared secret key they need two parameters: a prime number $p$ and a generator $g$ of the group $\mathbb{Z}_{p}^{*}$, which are public and chosen by a trusted third party:

• $p$
• $g$

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Alice and Bob receives the prime number $p$ and the generator $g$ of the group $\mathbb{Z}_{p}^{*}$.

Alice then chooses the secret value $a$ and Bob chooses the secret value $b$ which both are integers between $1$ and $p-1$.

First Alice computes her public value $A$ and sends it to Bob.

Then Bob computes his public value $B$ and sends it to Alice.

With their secret values $a$ and $b$ and their received public values $A$ and $B$ Alice and Bob computes the shared secret key, which is only known by them.

### Bob

##### Parameters known by Bob:

Chooses the secret value:

Receives $A$

Computes the public value:

Computes the shared secret key: