From 5f2b441ae7e352f4ef2485b74649b735b5ccac56 Mon Sep 17 00:00:00 2001
From: Daniel Sanchez Quiros <sanchez.quiros.daniel@gmail.com>
Date: Tue, 16 Apr 2024 18:37:58 +0200
Subject: [PATCH] Implemented dablob

---
 nomos-da/kzgrs-backend/Cargo.toml      |  2 +-
 nomos-da/kzgrs-backend/src/common.rs   | 40 ++++++++++++++++++++------
 nomos-da/kzgrs-backend/src/lib.rs      |  1 +
 nomos-da/kzgrs-backend/src/verifier.rs | 24 ++++++++++++++++
 4 files changed, 58 insertions(+), 9 deletions(-)
 create mode 100644 nomos-da/kzgrs-backend/src/verifier.rs

diff --git a/nomos-da/kzgrs-backend/Cargo.toml b/nomos-da/kzgrs-backend/Cargo.toml
index 22f7efa7..d5cb4281 100644
--- a/nomos-da/kzgrs-backend/Cargo.toml
+++ b/nomos-da/kzgrs-backend/Cargo.toml
@@ -12,9 +12,9 @@ ark-poly = "0.4.2"
 kzgrs = { path = "../kzgrs" }
 rand = "0.8.5"
 once_cell = "1.19"
+sha3 = "0.10"
 
 [dev-dependencies]
 rand = "0.8"
 itertools = "0.12"
 ark-ff = "0.4"
-num-bigint = "0.4.4"
\ No newline at end of file
diff --git a/nomos-da/kzgrs-backend/src/common.rs b/nomos-da/kzgrs-backend/src/common.rs
index 6d348a47..3d9d9ecc 100644
--- a/nomos-da/kzgrs-backend/src/common.rs
+++ b/nomos-da/kzgrs-backend/src/common.rs
@@ -1,6 +1,11 @@
-use blake2::digest::{Update, VariableOutput};
-use kzgrs::Commitment;
+// std
+use ark_serialize::CanonicalSerialize;
 use std::io::Cursor;
+// crates
+use blake2::digest::{Update, VariableOutput};
+use sha3::{Digest, Sha3_256};
+// internal
+use kzgrs::Commitment;
 
 #[derive(Clone, Eq, PartialEq, Debug)]
 pub struct Chunk(pub Vec<u8>);
@@ -101,18 +106,37 @@ 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.update(commitment_to_bytes(commitment).as_ref());
     hasher
         .finalize_boxed()
         .to_vec()
         .try_into()
         .unwrap_or_else(|_| panic!("Size is guaranteed by constant {HASH_SIZE:?}"))
 }
+
+pub fn build_attestation_message(
+    aggregated_column_commitment: &Commitment,
+    rows_commitments: &[Commitment],
+) -> Vec<u8> {
+    let mut hasher = Sha3_256::new();
+    Digest::update(
+        &mut hasher,
+        commitment_to_bytes(aggregated_column_commitment),
+    );
+    for c in rows_commitments {
+        Digest::update(&mut hasher, commitment_to_bytes(c));
+    }
+    hasher.finalize().to_vec()
+}
+
+pub fn commitment_to_bytes(commitment: &Commitment) -> Vec<u8> {
+    use ark_serialize::CanonicalSerialize;
+    let mut buff = Cursor::new(vec![]);
+    commitment
+        .serialize_uncompressed(&mut buff)
+        .expect("Serialization of commitment should work");
+    buff.into_inner()
+}
diff --git a/nomos-da/kzgrs-backend/src/lib.rs b/nomos-da/kzgrs-backend/src/lib.rs
index ac01ae55..3916547d 100644
--- a/nomos-da/kzgrs-backend/src/lib.rs
+++ b/nomos-da/kzgrs-backend/src/lib.rs
@@ -1,3 +1,4 @@
 mod common;
 mod encoder;
 mod global;
+mod verifier;
diff --git a/nomos-da/kzgrs-backend/src/verifier.rs b/nomos-da/kzgrs-backend/src/verifier.rs
new file mode 100644
index 00000000..821bfd76
--- /dev/null
+++ b/nomos-da/kzgrs-backend/src/verifier.rs
@@ -0,0 +1,24 @@
+use crate::common::{build_attestation_message, Column};
+use kzgrs::{Commitment, Proof};
+use sha3::{Digest, Sha3_256};
+
+pub struct DaBlob {
+    column: Column,
+    column_commitment: Commitment,
+    aggregated_column_commitment: Commitment,
+    aggregated_column_proof: Proof,
+    rows_commitments: Vec<Commitment>,
+    rows_proofs: Vec<Proof>,
+}
+
+impl DaBlob {
+    pub fn id(&self) -> Vec<u8> {
+        build_attestation_message(&self.aggregated_column_commitment, &self.rows_commitments)
+    }
+
+    pub fn column_id(&self) -> Vec<u8> {
+        let mut hasher = Sha3_256::new();
+        hasher.update(self.column.as_bytes());
+        hasher.finalize().as_slice().to_vec()
+    }
+}