From e6cf4bf14e14329cb1f79fff0a7b3b3c9f00eaae Mon Sep 17 00:00:00 2001
From: Han <tinghan0110@gmail.com>
Date: Mon, 4 Sep 2023 16:56:29 +0800
Subject: [PATCH] feat: expose `transcript_repr` of `VerifyingKey` and reduce
 the trait constraint (#200)

---
 halo2_proofs/src/plonk.rs | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/halo2_proofs/src/plonk.rs b/halo2_proofs/src/plonk.rs
index 5b22acfc74..2a3e11caf2 100644
--- a/halo2_proofs/src/plonk.rs
+++ b/halo2_proofs/src/plonk.rs
@@ -167,10 +167,7 @@ where
     }
 }
 
-impl<C: CurveAffine> VerifyingKey<C>
-where
-    C::ScalarExt: FromUniformBytes<64>,
-{
+impl<C: CurveAffine> VerifyingKey<C> {
     fn bytes_length(&self) -> usize {
         8 + (self.fixed_commitments.len() * C::default().to_bytes().as_ref().len())
             + self.permutation.bytes_length()
@@ -188,7 +185,10 @@ where
         permutation: permutation::VerifyingKey<C>,
         cs: ConstraintSystem<C::Scalar>,
         selectors: Vec<Vec<bool>>,
-    ) -> Self {
+    ) -> Self
+    where
+        C::ScalarExt: FromUniformBytes<64>,
+    {
         // Compute cached values.
         let cs_degree = cs.degree();
 
@@ -256,6 +256,11 @@ where
     pub fn cs(&self) -> &ConstraintSystem<C::Scalar> {
         &self.cs
     }
+
+    /// Returns representative of this `VerifyingKey` in transcripts
+    pub fn transcript_repr(&self) -> C::Scalar {
+        self.transcript_repr
+    }
 }
 
 /// Minimal representation of a verification key that can be used to identify