diff --git a/.cargo/mutants.toml b/.cargo/mutants.toml
new file mode 100644
index 00000000..e81728fc
--- /dev/null
+++ b/.cargo/mutants.toml
@@ -0,0 +1 @@
+examine_globs = ["src/zk_range_proof.rs", "src/verkle.rs"]
diff --git a/.github/workflows/mutation.yml b/.github/workflows/mutation.yml
new file mode 100644
index 00000000..db2239cb
--- /dev/null
+++ b/.github/workflows/mutation.yml
@@ -0,0 +1,57 @@
+name: Mutation Testing
+
+on:
+  schedule:
+    # Nightly at 03:00 UTC — mutation testing is slow so not run per-PR
+    - cron: '0 3 * * *'
+  workflow_dispatch:
+    # Allow manual trigger from the Actions tab
+    inputs:
+      filter:
+        description: 'Test name filter (optional)'
+        required: false
+        default: ''
+        type: string
+
+env:
+  CARGO_TERM_COLOR: always
+  RUSTFLAGS: -D warnings
+
+jobs:
+  mutants:
+    name: cargo-mutants (zk_range_proof.rs, verkle.rs)
+    runs-on: ubuntu-latest
+    timeout-minutes: 120
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Rust toolchain
+        uses: dtolnay/rust-toolchain@stable
+
+      - name: Install cargo-mutants
+        run: cargo install cargo-mutants --locked
+
+      - name: Run mutation tests
+        run: |
+          FILTER="${{ inputs.filter }}"
+          if [ -n "$FILTER" ]; then
+            cargo mutants \
+              --file src/zk_range_proof.rs \
+              --file src/verkle.rs \
+              --timeout 300 \
+              -- -- "$FILTER"
+          else
+            cargo mutants \
+              --file src/zk_range_proof.rs \
+              --file src/verkle.rs \
+              --timeout 300
+          fi
+        working-directory: contracts/ledgerlens-score
+
+      - name: Upload mutation report
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: mutation-report
+          path: contracts/ledgerlens-score/mutants.out
+          retention-days: 30
diff --git a/contracts/ledgerlens-score/src/test_verkle.rs b/contracts/ledgerlens-score/src/test_verkle.rs
index 91e90c95..878237b8 100644
--- a/contracts/ledgerlens-score/src/test_verkle.rs
+++ b/contracts/ledgerlens-score/src/test_verkle.rs
@@ -15,6 +15,11 @@ use soroban_sdk::{
 };
 
 use crate::{
+    verkle::{
+        self, xor32, derive_evaluation_point, derive_value_element, hash_leaf,
+        encode_proof, decode_proof, commitment_to_bytes48, bytes48_to_commitment,
+        verify_proof,
+    },
     LedgerLensScoreContract, LedgerLensScoreContractClient, ScoreSubmission,
 };
 
@@ -777,3 +782,168 @@ fn range_proof_all_scores_below_80() {
 
     assert!(all_below_80, "range claim 'all < 80' must hold");
 }
+
+// ── Pure verkle primitive tests (catch mutants in verkle.rs) ───────────────
+
+#[test]
+fn test_xor32_commutative() {
+    let a = [1u8; 32];
+    let b = [2u8; 32];
+    let ab = xor32(&a, &b);
+    let ba = xor32(&b, &a);
+    assert_eq!(ab, ba, "xor32 must be commutative");
+}
+
+#[test]
+fn test_xor32_identity() {
+    let a = [0xABu8; 32];
+    let zero = [0u8; 32];
+    assert_eq!(xor32(&a, &zero), a, "a XOR 0 == a");
+}
+
+#[test]
+fn test_xor32_self_inverse() {
+    let a = [0xABu8; 32];
+    let zero = [0u8; 32];
+    assert_eq!(xor32(&a, &a), zero, "a XOR a == 0");
+}
+
+#[test]
+fn test_derive_evaluation_point_deterministic() {
+    let env = Env::default();
+    let wallet_bytes = [3u8; 56];
+    let pair_bytes = [4u8; 9];
+    let z1 = derive_evaluation_point(&env, &wallet_bytes, &pair_bytes);
+    let z2 = derive_evaluation_point(&env, &wallet_bytes, &pair_bytes);
+    assert_eq!(z1, z2, "derive_evaluation_point must be deterministic");
+}
+
+#[test]
+fn test_derive_evaluation_point_differs_for_diff_inputs() {
+    let env = Env::default();
+    let wallet_a = [1u8; 56];
+    let wallet_b = [2u8; 56];
+    let pair = [3u8; 9];
+    let za = derive_evaluation_point(&env, &wallet_a, &pair);
+    let zb = derive_evaluation_point(&env, &wallet_b, &pair);
+    assert_ne!(za, zb, "different wallets must produce different z");
+}
+
+#[test]
+fn test_derive_value_element_deterministic() {
+    let env = Env::default();
+    let z = [5u8; 32];
+    let v1 = derive_value_element(&env, 42, 1000, &z);
+    let v2 = derive_value_element(&env, 42, 1000, &z);
+    assert_eq!(v1, v2, "derive_value_element must be deterministic");
+}
+
+#[test]
+fn test_derive_value_element_differs_for_diff_scores() {
+    let env = Env::default();
+    let z = [5u8; 32];
+    let v1 = derive_value_element(&env, 42, 1000, &z);
+    let v2 = derive_value_element(&env, 99, 1000, &z);
+    assert_ne!(v1, v2, "different scores must produce different v");
+}
+
+#[test]
+fn test_hash_leaf_deterministic() {
+    let env = Env::default();
+    let z = [6u8; 32];
+    let v = [7u8; 32];
+    let h1 = hash_leaf(&env, &z, &v);
+    let h2 = hash_leaf(&env, &z, &v);
+    assert_eq!(h1, h2, "hash_leaf must be deterministic");
+}
+
+#[test]
+fn test_encode_decode_roundtrip_member() {
+    let env = Env::default();
+    let z = [8u8; 32];
+    let v = [9u8; 32];
+    let witness = [10u8; 32];
+    let encoded = encode_proof(&env, true, &z, &v, &witness);
+    let decoded = decode_proof(&encoded);
+    assert!(decoded.is_some(), "decode must succeed for valid proof");
+    let (is_member, dz, dv, dw) = decoded.unwrap();
+    assert!(is_member, "round-tripped is_member must be true");
+    assert_eq!(dz, z, "round-tripped z must match");
+    assert_eq!(dv, v, "round-tripped v must match");
+    assert_eq!(dw, witness, "round-tripped witness must match");
+}
+
+#[test]
+fn test_encode_decode_roundtrip_nonmember() {
+    let env = Env::default();
+    let z = [11u8; 32];
+    let v = [0u8; 32];
+    let witness = [12u8; 32];
+    let encoded = encode_proof(&env, false, &z, &v, &witness);
+    let decoded = decode_proof(&encoded);
+    assert!(decoded.is_some(), "decode must succeed for non-member proof");
+    let (is_member, _dz, _dv, _dw) = decoded.unwrap();
+    assert!(!is_member, "round-tripped is_member must be false");
+}
+
+#[test]
+fn test_decode_fails_for_short_input() {
+    let env = Env::default();
+    let short = Bytes::from_array(&env, &[1u8, 2u8]);
+    assert!(decode_proof(&short).is_none(), "decode must fail for too-short input");
+}
+
+#[test]
+fn test_commitment_bytes48_roundtrip() {
+    let env = Env::default();
+    let commit = [13u8; 32];
+    let b48 = commitment_to_bytes48(&env, &commit);
+    let decoded = bytes48_to_commitment(&b48);
+    assert!(decoded.is_some(), "bytes48_to_commitment must succeed for valid prefix");
+    assert_eq!(decoded.unwrap(), commit, "round-tripped commitment must match");
+}
+
+#[test]
+fn test_commitment_bytes48_prefix_check() {
+    let env = Env::default();
+    // A 48-byte array without the correct prefix should be rejected.
+    let bad = BytesN::<48>::from_array(&env, &[0xFFu8; 48]);
+    assert!(bytes48_to_commitment(&bad).is_none(), "must reject missing prefix");
+}
+
+#[test]
+fn test_verify_proof_with_bogus_witness() {
+    let env = Env::default();
+    let commitment = [0u8; 32];
+    let z = [14u8; 32];
+    let v = [15u8; 32];
+    let bogus_witness = [16u8; 32];
+    // A random witness should not verify against empty commitment.
+    assert!(
+        !verify_proof(&env, &commitment, &z, &v, &bogus_witness),
+        "bogus witness must not verify"
+    );
+}
+
+#[test]
+fn test_update_commitment_is_deterministic() {
+    let env = Env::default();
+    let prev = [17u8; 32];
+    let z = [18u8; 32];
+    let v = [19u8; 32];
+    let c1 = verkle::update_commitment(&env, &prev, &z, &v);
+    let c2 = verkle::update_commitment(&env, &prev, &z, &v);
+    assert_eq!(c1, c2, "update_commitment must be deterministic");
+}
+
+#[test]
+fn test_update_commitment_different_z_different_result() {
+    let env = Env::default();
+    let prev = [20u8; 32];
+    let v = [22u8; 32];
+    let z1 = [21u8; 32];
+    let z2 = [23u8; 32];
+    let c1 = verkle::update_commitment(&env, &prev, &z1, &v);
+    let c2 = verkle::update_commitment(&env, &prev, &z2, &v);
+    assert_ne!(c1, c2, "different z must produce different commitments");
+}
diff --git a/contracts/ledgerlens-score/src/test_zk_range_proof.rs b/contracts/ledgerlens-score/src/test_zk_range_proof.rs
index 54817607..ed55a3a9 100644
--- a/contracts/ledgerlens-score/src/test_zk_range_proof.rs
+++ b/contracts/ledgerlens-score/src/test_zk_range_proof.rs
@@ -1,7 +1,7 @@
 extern crate std;
 
 use crate::{
-    zk_range_proof::{Sc, SeededPrng, get_generators, compress_pt, prove_range_proof},
+    zk_range_proof::{Fe, Pt, Sc, SeededPrng, Bulletproof, get_generators, compress_pt, decompress_pt_32, is_on_curve, prove_range_proof},
     LedgerLensScoreContract, LedgerLensScoreContractClient,
 };
 use soroban_sdk::{testutils::Address as _, Address, Bytes, BytesN, Env, Symbol, Vec};
@@ -257,3 +257,137 @@ fn test_verify_score_range_proof_tampered_proof() {
     );
     assert!(!result);
 }
+
+// ── Pure arithmetic tests (catch mutants in Fe/Sc operations) ──────────────
+
+#[test]
+fn test_fe_arithmetic_add_identity() {
+    let a = Fe::from_u64(42);
+    let zero = Fe::zero();
+    assert_eq!(a.add(zero).to_bytes(), a.to_bytes(), "a + 0 == a");
+}
+
+#[test]
+fn test_fe_arithmetic_mul_identity() {
+    let a = Fe::from_u64(7);
+    let one = Fe::one();
+    let r = a.mul(one);
+    assert_eq!(r.to_bytes(), a.to_bytes(), "a * 1 == a");
+}
+
+#[test]
+fn test_fe_arithmetic_mul_zero() {
+    let a = Fe::from_u64(99);
+    let zero = Fe::zero();
+    let r = a.mul(zero);
+    assert!(r.is_zero(), "a * 0 == 0");
+}
+
+#[test]
+fn test_fe_arithmetic_neg_add() {
+    let a = Fe::from_u64(123);
+    let neg = a.neg();
+    let r = a.add(neg);
+    assert!(r.is_zero(), "a + (-a) == 0");
+}
+
+#[test]
+fn test_fe_arithmetic_mul_invert() {
+    let env = Env::default();
+    let a = Fe::from_u64(5);
+    let inv = a.invert();
+    let r = a.mul(inv);
+    let one = Fe::one();
+    assert_eq!(r.to_bytes(), one.to_bytes(), "a * a^(-1) == 1");
+}
+
+#[test]
+fn test_fe_arithmetic_sub_self() {
+    let a = Fe::from_u64(77);
+    let r = a.sub(a);
+    assert!(r.is_zero(), "a - a == 0");
+}
+
+#[test]
+fn test_sc_arithmetic_mul_identity() {
+    let a = Sc::from_u64(42);
+    let one = Sc::one();
+    let r = a.mul(one);
+    assert_eq!(r.to_bytes(), a.to_bytes(), "a * 1 == a");
+}
+
+#[test]
+fn test_sc_arithmetic_mul_zero() {
+    let a = Sc::from_u64(99);
+    let zero = Sc::zero();
+    let r = a.mul(zero);
+    assert!(r.is_zero(), "a * 0 == 0");
+}
+
+#[test]
+fn test_sc_arithmetic_add_neg() {
+    let a = Sc::from_u64(7);
+    let r = a.add(a.neg());
+    assert!(r.is_zero(), "a + (-a) == 0");
+}
+
+// ── Curve point tests ──────────────────────────────────────────────────────
+
+#[test]
+fn test_is_on_curve_valid_points() {
+    let (g_pt, h_pt, d) = get_generators();
+    assert!(is_on_curve(g_pt.x, g_pt.y, d), "generator G is on curve");
+    assert!(is_on_curve(h_pt.x, h_pt.y, d), "generator H is on curve");
+}
+
+#[test]
+fn test_point_add_identity() {
+    let (g_pt, _h_pt, d) = get_generators();
+    let id = Pt::identity();
+    let r = g_pt.add(id, d);
+    assert_eq!(r.x.to_bytes(), g_pt.x.to_bytes(), "G + identity == G (x)");
+    assert_eq!(r.y.to_bytes(), g_pt.y.to_bytes(), "G + identity == G (y)");
+}
+
+#[test]
+fn test_point_mul_scalar_zero() {
+    let (g_pt, _h_pt, d) = get_generators();
+    let zero = Sc::zero();
+    let r = g_pt.mul(zero, d);
+    assert!(r.is_identity(), "G * 0 == identity");
+}
+
+#[test]
+fn test_point_mul_scalar_one() {
+    let (g_pt, _h_pt, d) = get_generators();
+    let one = Sc::one();
+    let r = g_pt.mul(one, d);
+    assert_eq!(r.x.to_bytes(), g_pt.x.to_bytes(), "G * 1 == G (x)");
+    assert_eq!(r.y.to_bytes(), g_pt.y.to_bytes(), "G * 1 == G (y)");
+}
+
+// ── Serialisation round-trip tests ─────────────────────────────────────────
+
+#[test]
+fn test_compress_decompress_roundtrip() {
+    let env = Env::default();
+    let (g_pt, _h_pt, _d) = get_generators();
+    let compressed = compress_pt(&env, &g_pt);
+    let decompressed = decompress_pt_32(&env, &compressed);
+    assert!(decompressed.is_some(), "decompress must succeed");
+    let pt = decompressed.unwrap();
+    assert_eq!(pt.x.to_bytes(), g_pt.x.to_bytes(), "x must match after round-trip");
+    assert_eq!(pt.y.to_bytes(), g_pt.y.to_bytes(), "y must match after round-trip");
+}
+
+#[test]
+fn test_bulletproof_roundtrip() {
+    let env = Env::default();
+    let v = 9u32;
+    let r = Sc::from_u64(123456789);
+    let prng = SeededPrng::new([2u8; 32]);
+    let proof = prove_range_proof(&env, v, r, prng);
+    let bytes = proof.to_bytes(&env);
+    let decoded = Bulletproof::from_bytes(&bytes);
+    assert!(decoded.is_some(), "deserialize must succeed");
+}
diff --git a/scripts/mutation-test.sh b/scripts/mutation-test.sh
new file mode 100755
index 00000000..45bb2701
--- /dev/null
+++ b/scripts/mutation-test.sh
@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+# ──────────────────────────────────────────────────────────────────────────────
+#   mutation-test.sh — Run cargo-mutants scoped to zk_range_proof & verkle
+#
+#   Usage:
+#     ./scripts/mutation-test.sh               # run all tests (slow)
+#     ./scripts/mutation-test.sh -- test_verkle # filter to verkle only
+#     ./scripts/mutation-test.sh -- test_zk     # filter to range proof only
+#
+#   Requires: cargo-mutants >= 27
+#   Install:  cargo install cargo-mutants --locked
+# ──────────────────────────────────────────────────────────────────────────────
+set -euo pipefail
+
+CRATE_DIR="$(dirname "$0")/../contracts/ledgerlens-score"
+FILTER_ARGS=("$@")
+
+echo "==> cargo-mutants: zk_range_proof.rs + verkle.rs"
+echo "    Filter args: ${FILTER_ARGS[*]:-(none)}"
+echo ""
+
+exec cargo mutants \
+    --manifest-path "$CRATE_DIR/Cargo.toml" \
+    --file src/zk_range_proof.rs \
+    --file src/verkle.rs \
+    --timeout 300 \
+    "${FILTER_ARGS[@]}"