From d3161e5a7a36facca04ada325134ee7a802a78c9 Mon Sep 17 00:00:00 2001
From: Daniel Sanchez Quiros <sanchez.quiros.daniel@gmail.com>
Date: Mon, 15 Apr 2024 15:06:55 +0200
Subject: [PATCH] Fix lib and types exposures

---
 nomos-da/kzgrs-backend/Cargo.toml    |  2 ++
 nomos-da/kzgrs-backend/src/common.rs | 25 +++++++++++++++++++++++++
 nomos-da/kzgrs/src/common.rs         |  1 +
 nomos-da/kzgrs/src/kzg.rs            |  2 +-
 nomos-da/kzgrs/src/lib.rs            |  2 +-
 5 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/nomos-da/kzgrs-backend/Cargo.toml b/nomos-da/kzgrs-backend/Cargo.toml
index 82dffc88..67b59815 100644
--- a/nomos-da/kzgrs-backend/Cargo.toml
+++ b/nomos-da/kzgrs-backend/Cargo.toml
@@ -6,6 +6,8 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+blake2 = "0.10"
+ark-serialize = "0.4.2"
 ark-poly = "0.4.2"
 kzgrs = { path = "../kzgrs" }
 rand = "0.8.5"
diff --git a/nomos-da/kzgrs-backend/src/common.rs b/nomos-da/kzgrs-backend/src/common.rs
index 5732ea04..422c2ab2 100644
--- a/nomos-da/kzgrs-backend/src/common.rs
+++ b/nomos-da/kzgrs-backend/src/common.rs
@@ -1,3 +1,8 @@
+use ark_serialize::CanonicalSerialize;
+use blake2::digest::{Update, VariableOutput};
+use kzgrs::Commitment;
+use std::io::Cursor;
+
 #[derive(Clone)]
 pub struct Chunk(Vec<u8>);
 pub struct Row(Vec<Chunk>);
@@ -68,3 +73,23 @@ impl FromIterator<Row> for ChunksMatrix {
         Self(iter.into_iter().collect())
     }
 }
+
+pub fn hash_column_and_commitment<const HASH_SIZE: usize>(
+    column: &Column,
+    commitment: &Commitment,
+) -> [u8; HASH_SIZE] {
+    use ark_serialize::CanonicalSerialize;
+    let mut hasher = blake2::Blake2bVar::new(HASH_SIZE)
+        .unwrap_or_else(|e| panic!("Blake2b should work for size {HASH_SIZE}, {e}"));
+    hasher.update(column.as_bytes().as_ref());
+    let mut buff = Cursor::new(vec![]);
+    commitment
+        .serialize_uncompressed(&mut buff)
+        .expect("Serialization of commitment should work");
+    hasher.update(buff.into_inner().as_ref());
+    hasher
+        .finalize_boxed()
+        .to_vec()
+        .try_into()
+        .unwrap_or_else(|_| panic!("Size is guaranteed by constant {HASH_SIZE:?}"))
+}
diff --git a/nomos-da/kzgrs/src/common.rs b/nomos-da/kzgrs/src/common.rs
index 9f6636d9..1dcb968b 100644
--- a/nomos-da/kzgrs/src/common.rs
+++ b/nomos-da/kzgrs/src/common.rs
@@ -1,5 +1,6 @@
 // std
 // crates
+use crate::Commitment;
 use ark_bls12_381::fr::Fr;
 use ark_ff::{BigInteger256, PrimeField, Zero};
 use ark_poly::domain::general::GeneralEvaluationDomain;
diff --git a/nomos-da/kzgrs/src/kzg.rs b/nomos-da/kzgrs/src/kzg.rs
index d64ddfdc..6c94b29d 100644
--- a/nomos-da/kzgrs/src/kzg.rs
+++ b/nomos-da/kzgrs/src/kzg.rs
@@ -28,7 +28,7 @@ pub fn generate_element_proof(
     element_index: usize,
     polynomial: &DensePolynomial<Fr>,
     global_parameters: &UniversalParams<Bls12_381>,
-    domain: &GeneralEvaluationDomain<Fr>,
+    domain: GeneralEvaluationDomain<Fr>,
 ) -> Result<Proof<Bls12_381>, KzgRsError> {
     let u = domain.element(element_index);
     let v = polynomial.evaluate(&u);
diff --git a/nomos-da/kzgrs/src/lib.rs b/nomos-da/kzgrs/src/lib.rs
index 03e4c224..188bee30 100644
--- a/nomos-da/kzgrs/src/lib.rs
+++ b/nomos-da/kzgrs/src/lib.rs
@@ -1,5 +1,5 @@
 pub mod common;
-mod global_parameters;
+pub mod global_parameters;
 pub mod kzg;
 pub mod rs;