From 2f99d7375809616345f44832c0006b737f23f519 Mon Sep 17 00:00:00 2001
From: Rostyslav Tyshko <tyshko.rostyslav@gmail.com>
Date: Mon, 2 Dec 2024 01:14:31 +0100
Subject: [PATCH] add generate_commitments and generate_nullifiers to de module

---
 node_core/src/executions/de.rs | 67 ++++++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100644 node_core/src/executions/de.rs

diff --git a/node_core/src/executions/de.rs b/node_core/src/executions/de.rs
new file mode 100644
index 0000000..268f0fa
--- /dev/null
+++ b/node_core/src/executions/de.rs
@@ -0,0 +1,67 @@
+use k256::Scalar;
+use secp256k1_zkp::{compute_adaptive_blinding_factor, verify_commitments_sum_to_equal, CommitmentSecrets, Generator, PedersenCommitment, Tag, Tweak, SECP256K1};
+use rand::thread_rng;
+use sha2::{Digest, Sha256};
+use serde::{Serialize, Deserialize};
+use storage::{commitment::Commitment, commitments_sparse_merkle_tree::CommitmentsSparseMerkleTree, nullifier::UTXONullifier, nullifier_sparse_merkle_tree::NullifierSparseMerkleTree};
+use utxo::{
+    utxo_core::{UTXOPayload, UTXO},
+    utxo_tree::UTXOSparseMerkleTree,
+};
+use monotree::hasher::Blake3;
+use monotree::{Hasher, Monotree, Proof};
+use bincode;
+
+fn commitment_secrets_random(value: u64) -> CommitmentSecrets {
+    CommitmentSecrets {
+        value,
+        value_blinding_factor: Tweak::new(&mut thread_rng()),
+        generator_blinding_factor: Tweak::new(&mut thread_rng()),
+    }
+}
+
+pub fn tag_random() -> Tag {
+    use rand::thread_rng;
+    use rand::RngCore;
+
+    let mut bytes = [0u8; 32];
+    thread_rng().fill_bytes(&mut bytes);
+
+    Tag::from(bytes)
+}
+
+pub fn commit(comm: &CommitmentSecrets, tag: Tag) -> PedersenCommitment {
+    let generator = Generator::new_blinded(SECP256K1, tag, comm.generator_blinding_factor);
+
+    PedersenCommitment::new(SECP256K1, comm.value, comm.value_blinding_factor, generator)
+}
+
+// Hash function placeholder (replace with your cryptographic library's hash).
+fn hash(input: &[u8]) -> Vec<u8> {
+    Sha256::digest(input).to_vec()
+}
+
+// Generate nullifiers
+
+// takes the input_utxo and nsk 
+// returns the nullifiers[i], where the nullifier[i] = hash(in_commitments[i] || nsk) where the hash function
+pub fn generate_nullifiers(input_utxo: &UTXO, nsk: &[u8]) -> Vec<u8> {
+    let mut input = bincode::serialize(input_utxo).unwrap().to_vec();
+    input.extend_from_slice(nsk);
+    hash(&input)
+}
+
+// Generate commitments for output UTXOs
+
+//  uses the list of input_utxos[] 
+//  returns in_commitments[] where each in_commitments[i] = Commitment(in_utxos[i]) where the commitment 
+pub fn generate_commitments(input_utxos: &[UTXO]) -> Vec<Vec<u8>> {
+    input_utxos
+        .iter()
+        .map(|utxo| {
+            let serialized = bincode::serialize(utxo).unwrap(); // Serialize UTXO.
+            hash(&serialized)
+        })
+        .collect()
+}
+