refactor: update semaphore artifacts

.gitignore

@@ -1,3 +1,7 @@
 /target
 /zkey
 .DS_Store
+
+# witness graph
+semaphore/
+circom-witnesscalc/

README.md

@@ -96,3 +96,9 @@ cargo clippy
 ```bash
 cargo test
 ```
+
+### Update `witness_graph` with [`circom-witnesscalc`](https://github.com/iden3/circom-witnesscalc)
+
+```bash
+./script build_witness_graph.sh
+```

script/build_witness_graph.sh

@@ -0,0 +1,40 @@
+#! /bin/bash
+
+CIRCOM_WITNESSCALC_DIR="circom-witnesscalc"
+SEMAPHORE_DIR="semaphore"
+WITNESS_GRAPH_DIR="witness_graph"
+CURRENT_DIR=$(pwd)
+
+# download the circom-witnesscalc repository
+if [ ! -d "$CIRCOM_WITNESSCALC_DIR" ]; then
+    git clone https://github.com/iden3/circom-witnesscalc.git
+fi
+# download the semaphore circuit repository
+if [ ! -d "$SEMAPHORE_DIR" ]; then
+    git clone https://github.com/semaphore-protocol/semaphore.git
+fi
+# Function to generate Circom circuit code for a given depth
+create_circuit_code() {
+    local depth=$1
+    cat <<EOF
+pragma circom 2.1.5;
+
+include "semaphore.circom";
+
+component main {public [message, scope]} = Semaphore(${depth});
+EOF
+}
+
+# install the dependencies
+cd $CURRENT_DIR/$SEMAPHORE_DIR
+yarn install
+# build all semaphore circuits
+for depth in {1..32}; do
+    create_circuit_code $depth > $CURRENT_DIR/$SEMAPHORE_DIR/semaphore-${depth}.circom
+done
+# build the witness graph
+cd $CURRENT_DIR/$CIRCOM_WITNESSCALC_DIR
+for depth in {1..32}; do
+    cargo run --package build-circuit --bin build-circuit --release $CURRENT_DIR/$SEMAPHORE_DIR/semaphore-${depth}.circom $CURRENT_DIR/$WITNESS_GRAPH_DIR/semaphore-${depth}.bin -l $CURRENT_DIR/$SEMAPHORE_DIR/node_modules/@zk-kit/binary-merkle-root.circom/src -l $CURRENT_DIR/$SEMAPHORE_DIR/node_modules/circomlib/circuits -l $CURRENT_DIR/$SEMAPHORE_DIR/packages/circuits/src
+done
+# save the witness graph to the witness_graph directory

src/proof.rs

@@ -124,13 +124,8 @@ impl Proof {
         let merkle_proof = group.merkle_proof(&to_element(*identity.commitment()));
         let merkle_proof_length = merkle_proof.siblings.len();
 
-        // The index must be converted to a list of indices, 1 for each tree level.
-        // The missing siblings can be set to 0, as they won"t be used in the circuit.
-        let mut merkle_proof_indices = Vec::new();
         let mut merkle_proof_siblings = Vec::<Element>::new();
         for i in 0..merkle_tree_depth {
-            merkle_proof_indices.push((merkle_proof.index >> i) & 1);
-
             if let Some(sibling) = merkle_proof.siblings.get(i as usize) {
                 merkle_proof_siblings.push(*sibling);
             } else {
@@ -150,8 +145,8 @@ impl Proof {
                 vec![merkle_proof_length.to_string()],
             ),
             (
-                "merkleProofIndices".to_string(),
-                merkle_proof_indices.iter().map(|i| i.to_string()).collect(),
+                "merkleProofIndex".to_string(),
+                vec![merkle_proof.index.to_string()],
             ),
             (
                 "merkleProofSiblings".to_string(),
@@ -516,14 +511,14 @@ mod tests {
         fn test_semaphore_js_proof() {
             let points = [
                 // Proof generated from `Semaphore-js`
-                "12803714274658725282520630356048215594611199462892068647123162130999777821470",
-                "14790427909013880978103423555540996578520237818660256715698081866578524307407",
-                "3103638479093034897036418556462341694689838452017242207620861422678426008987",
-                "13727581952519649861097277152692845564872363841132502933894854130976607522628",
-                "9411534790044921634269896122419705846815252106674427620586249081562203834159",
-                "10009619289272081097084761045154085973406496068797344071367935854823051916935",
-                "19672409605818107675150930119466509196235828486217699330399295338263828234556",
-                "15472461797587690185190826432462453505284546376663377924961837387512711582919",
+                "2448901300518098096993075752654536134313649038239216706400667219963346227679",
+                "11383357624181217239434984412545229801919536849542936327488167664579097021171",
+                "4740704242184999702574958393302343834384154042177684026319208048433986938524",
+                "2103898499672759617084297744151588687300569178309824227315704845907524437637",
+                "18126651739688030584140960766793516019865850111238360168731489534891060767936",
+                "13293264290162772264887787723520088518667325866686508255341288441681546077334",
+                "13860303418198054644271827809984867757526756615344099647083475463061491185143",
+                "7750331146056656453454308267328134694500438800080743301030181391570997944788",
             ]
             .iter()
             .map(|&p| BigUint::from_str(p).unwrap())

src/utils.rs

@@ -40,7 +40,7 @@ pub fn to_element(value: Fq) -> Element {
 
 /// Download zkey from artifacts: https://snark-artifacts.pse.dev/
 pub fn download_zkey(depth: u16) -> Result<String, Box<dyn Error>> {
-    let version = "4.0.0";
+    let version = "4.13.0";
     let base_url = format!("https://snark-artifacts.pse.dev/semaphore/{version}/");
     let filename = format!("semaphore-{depth}.zkey");
     let dest_filename = format!("semaphore-{version}-{depth}.zkey");