I stumbled upon this question in some textbook.
Propose a variant of ElGamal signature scheme such that there is no need to calculate the inverse $k^{-1}$ as it is usually done using the EEA.
Recalling what ElGamal signature is about: we fix a prime number $p$ and a generator $\alpha$ of $Z_p^*$. User $A$ then chooses a number $a \in \{0, \ldots, p-1\}$ as its private key and sets $ \beta = \alpha^a \pmod{p}$ as its public key. To sign a message $x$, $A$ chooses a random $k \in Z_{p-1}^*$. The signed message is then $(\gamma, \delta)$ where $$\gamma \equiv \alpha^k \pmod{p} \quad{} \hbox{and} \quad{} \delta \equiv (x-a\gamma)k^{-1} \pmod{(p-1)}$$
To verify the validity of the signature, $B$ verifies that $$ \beta^\gamma \gamma^\delta \equiv \alpha^x \pmod{p}$$
I have no idea how to solve this problem without breaking the security of the system. Browsing the internet, I've found some papers related to this problem, but the proposed solutions seemed too complicated for a question posed at the undergrad level. Does anyone know a clever solution?