In my question here Zero knowledge set membership protocol
The suggested solution allows a prover to choose a commitment $C$. Then, A trusted third party ($T$) can validate if $C$ is valid or not. The $C$ is in form of $C = rG + [age]H$. How to make a similar protocol with $C = g^{r}h^{[age]}$ as in Pedersen commitment scheme where $g,h$ are elements in a group $G$ of prime order $q$
Here is the answer form the previous question: Notation: $P$ is the prover, $T$ is the trusted party, $V$ is the verifier, $a$ is the information to convince $T$ of $P$'s age, $A \rightarrow B: x$ means that party $A$ send information $x$ to party $B$.
- $P$ chooses a random $r$ and calculates the commit $C = rG + [age]H$.
- $P$ signs $a$ with $r$ as private key
- $P \leftarrow T: C,a, signature_a$
- $T$ looks up $P$'s age, calculates $R=C-[age]H$, verifies $signature_a$ against $R$ and sign's $C$ using $T$'s private key.
- $T \rightarrow P: signature_c$
- $P \rightarrow V: C, signature_c, proof$