diff --git a/Cargo.toml b/Cargo.toml
index b9a21e461..7c6b2b17e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -2,9 +2,7 @@
 resolver = "2"
 members = [
     "constantine-rust/constantine-sys",
-    "constantine-rust/constantine-curves",
     "constantine-rust/constantine-zal-halo2kzg",
-    "constantine-rust/constantine-proto-ethereum-bls-signatures",
 ]
 
 # The Nim static library is compiled with ThinLTO, always enable it
diff --git a/bindings/c_curve_decls_parallel.nim b/bindings/c_curve_decls_parallel.nim
index f81bc6b68..f9c5fcb2a 100644
--- a/bindings/c_curve_decls_parallel.nim
+++ b/bindings/c_curve_decls_parallel.nim
@@ -28,8 +28,8 @@ template genParallelBindings_EC_ShortW_NonAffine*(ECP, ECP_Aff: untyped) =
   # --------------------------------------------------------------------------------------
   proc `ctt _ ECP _ multi_scalar_mul_vartime_parallel`(
           tp: Threadpool,
-          r: ptr ECP,
+          r: var ECP,
           coefs: ptr UncheckedArray[BigInt[ECP.F.C.getCurveOrderBitwidth()]],
           points: ptr UncheckedArray[ECP_Aff],
           len: csize_t) {.libExport.} =
-    tp.multiScalarMul_vartime_parallel(r, coefs, points, cast[int](len))
+    tp.multiScalarMul_vartime_parallel(r.addr, coefs, points, cast[int](len))
diff --git a/constantine-rust/constantine-curves/Cargo.toml b/constantine-rust/constantine-curves/Cargo.toml
deleted file mode 100644
index 65dc12de5..000000000
--- a/constantine-rust/constantine-curves/Cargo.toml
+++ /dev/null
@@ -1,9 +0,0 @@
-[package]
-name = "constantine-curves"
-version = "0.1.0"
-edition = "2021"
-
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
-[dependencies]
-constantine-sys = { path = "../constantine-sys" }
\ No newline at end of file
diff --git a/constantine-rust/constantine-curves/src/lib.rs b/constantine-rust/constantine-curves/src/lib.rs
deleted file mode 100644
index f4f216dc1..000000000
--- a/constantine-rust/constantine-curves/src/lib.rs
+++ /dev/null
@@ -1,40 +0,0 @@
-//! Constantine
-//! Copyright (c) 2018-2019    Status Research & Development GmbH
-//! Copyright (c) 2020-Present Mamy André-Ratsimbazafy
-//! Licensed and distributed under either of
-//!   * MIT license (license terms in the root directory or at http://opensource.org/licenses/MIT).
-//!   * Apache v2 license (license terms in the root directory or at http://www.apache.org/licenses/LICENSE-2.0).
-//! at your option. This file may not be copied, modified, or distributed except according to those terms.
-
-use constantine_sys::*;
-
-pub struct CttThreadpool {
-    ctx: *mut ctt_threadpool,
-}
-
-impl CttThreadpool {
-    #[inline(always)]
-    pub fn new(num_threads: usize) -> CttThreadpool {
-        let ctx = unsafe{ ctt_threadpool_new(num_threads) };
-        CttThreadpool{ctx}
-    }
-}
-
-impl Drop for CttThreadpool {
-    fn drop(&mut self) {
-        unsafe { ctt_threadpool_shutdown(self.ctx) }
-    }
-}
-
-
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn t_threadpool() {
-        let tp = CttThreadpool::new(4);
-        drop(tp);
-    }
-}
diff --git a/constantine-rust/constantine-proto-ethereum-bls-signatures/Cargo.toml b/constantine-rust/constantine-proto-ethereum-bls-signatures/Cargo.toml
deleted file mode 100644
index 15ec5f3ad..000000000
--- a/constantine-rust/constantine-proto-ethereum-bls-signatures/Cargo.toml
+++ /dev/null
@@ -1,9 +0,0 @@
-[package]
-name = "constantine-proto-ethereum-bls-signatures"
-version = "0.1.0"
-edition = "2021"
-
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
-[dependencies]
-constantine-sys = { path = "../constantine-sys" }
\ No newline at end of file
diff --git a/constantine-rust/constantine-proto-ethereum-bls-signatures/src/lib.rs b/constantine-rust/constantine-proto-ethereum-bls-signatures/src/lib.rs
deleted file mode 100644
index 7d12d9af8..000000000
--- a/constantine-rust/constantine-proto-ethereum-bls-signatures/src/lib.rs
+++ /dev/null
@@ -1,14 +0,0 @@
-pub fn add(left: usize, right: usize) -> usize {
-    left + right
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn it_works() {
-        let result = add(2, 2);
-        assert_eq!(result, 4);
-    }
-}
diff --git a/constantine-rust/constantine-sys/src/bindings.rs b/constantine-rust/constantine-sys/src/bindings.rs
index 34161a8a2..da448b64c 100644
--- a/constantine-rust/constantine-sys/src/bindings.rs
+++ b/constantine-rust/constantine-sys/src/bindings.rs
@@ -3536,7 +3536,7 @@ fn bindgen_test_layout_big254() {
 extern "C" {
     pub fn ctt_bls12_381_g1_jac_multi_scalar_mul_vartime_parallel(
         tp: *const ctt_threadpool,
-        r: *const bls12_381_g1_jac,
+        r: *mut bls12_381_g1_jac,
         coefs: *const big255,
         points: *const bls12_381_g1_aff,
         len: usize,
@@ -3545,7 +3545,7 @@ extern "C" {
 extern "C" {
     pub fn ctt_bls12_381_g1_prj_multi_scalar_mul_vartime_parallel(
         tp: *const ctt_threadpool,
-        r: *const bls12_381_g1_prj,
+        r: *mut bls12_381_g1_prj,
         coefs: *const big255,
         points: *const bls12_381_g1_aff,
         len: usize,
@@ -3554,7 +3554,7 @@ extern "C" {
 extern "C" {
     pub fn ctt_bn254_snarks_g1_jac_multi_scalar_mul_vartime_parallel(
         tp: *const ctt_threadpool,
-        r: *const bn254_snarks_g1_jac,
+        r: *mut bn254_snarks_g1_jac,
         coefs: *const big254,
         points: *const bn254_snarks_g1_aff,
         len: usize,
@@ -3563,7 +3563,7 @@ extern "C" {
 extern "C" {
     pub fn ctt_bn254_snarks_g1_prj_multi_scalar_mul_vartime_parallel(
         tp: *const ctt_threadpool,
-        r: *const bn254_snarks_g1_prj,
+        r: *mut bn254_snarks_g1_prj,
         coefs: *const big254,
         points: *const bn254_snarks_g1_aff,
         len: usize,
@@ -3572,7 +3572,7 @@ extern "C" {
 extern "C" {
     pub fn ctt_pallas_ec_jac_multi_scalar_mul_vartime_parallel(
         tp: *const ctt_threadpool,
-        r: *const pallas_ec_jac,
+        r: *mut pallas_ec_jac,
         coefs: *const big255,
         points: *const pallas_ec_aff,
         len: usize,
@@ -3581,7 +3581,7 @@ extern "C" {
 extern "C" {
     pub fn ctt_pallas_ec_prj_multi_scalar_mul_vartime_parallel(
         tp: *const ctt_threadpool,
-        r: *const pallas_ec_prj,
+        r: *mut pallas_ec_prj,
         coefs: *const big255,
         points: *const pallas_ec_aff,
         len: usize,
@@ -3590,7 +3590,7 @@ extern "C" {
 extern "C" {
     pub fn ctt_vesta_ec_jac_multi_scalar_mul_vartime_parallel(
         tp: *const ctt_threadpool,
-        r: *const vesta_ec_jac,
+        r: *mut vesta_ec_jac,
         coefs: *const big255,
         points: *const vesta_ec_aff,
         len: usize,
@@ -3599,7 +3599,7 @@ extern "C" {
 extern "C" {
     pub fn ctt_vesta_ec_prj_multi_scalar_mul_vartime_parallel(
         tp: *const ctt_threadpool,
-        r: *const vesta_ec_prj,
+        r: *mut vesta_ec_prj,
         coefs: *const big255,
         points: *const vesta_ec_aff,
         len: usize,
diff --git a/constantine-rust/constantine-zal-halo2kzg/Cargo.toml b/constantine-rust/constantine-zal-halo2kzg/Cargo.toml
index 9ab2f4310..dafb05313 100644
--- a/constantine-rust/constantine-zal-halo2kzg/Cargo.toml
+++ b/constantine-rust/constantine-zal-halo2kzg/Cargo.toml
@@ -6,4 +6,10 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-constantine-curves = { path = "../constantine-curves" }
\ No newline at end of file
+constantine-sys = { path = "../constantine-sys" }
+halo2curves = { git = 'https://github.com/taikoxyz/halo2curves', branch = "pr-pse-exec-engine" }
+
+[dev-dependencies]
+ark-std = "0.3"
+rand_core = { version = "0.6", default-features = false }
+num_cpus = "1.16.0"
\ No newline at end of file
diff --git a/constantine-rust/constantine-zal-halo2kzg/src/lib.rs b/constantine-rust/constantine-zal-halo2kzg/src/lib.rs
index 7d12d9af8..9c746183c 100644
--- a/constantine-rust/constantine-zal-halo2kzg/src/lib.rs
+++ b/constantine-rust/constantine-zal-halo2kzg/src/lib.rs
@@ -1,14 +1,109 @@
-pub fn add(left: usize, right: usize) -> usize {
-    left + right
+//! Constantine
+//! Copyright (c) 2018-2019    Status Research & Development GmbH
+//! Copyright (c) 2020-Present Mamy André-Ratsimbazafy
+//! Licensed and distributed under either of
+//!   * MIT license (license terms in the root directory or at http://opensource.org/licenses/MIT).
+//!   * Apache v2 license (license terms in the root directory or at http://www.apache.org/licenses/LICENSE-2.0).
+//! at your option. This file may not be copied, modified, or distributed except according to those terms.
+
+//! See https://github.com/privacy-scaling-explorations/halo2/issues/216
+
+use std::mem;
+use ::core::mem::MaybeUninit;
+use constantine_sys::*;
+use halo2curves::bn256;
+use halo2curves::zal::{ZalEngine, MsmAccel};
+
+pub struct CttEngine {
+    ctx: *mut ctt_threadpool,
+}
+
+impl CttEngine {
+    #[inline(always)]
+    pub fn new(num_threads: usize) -> CttEngine {
+        let ctx = unsafe{ ctt_threadpool_new(num_threads) };
+        CttEngine{ctx}
+    }
+}
+
+impl Drop for CttEngine {
+    fn drop(&mut self) {
+        unsafe { ctt_threadpool_shutdown(self.ctx) }
+    }
+}
+
+impl ZalEngine for CttEngine{}
+
+impl MsmAccel<bn256::G1Affine> for CttEngine {
+    fn msm(&self, coeffs: &[bn256::Fr], bases: &[bn256::G1Affine]) -> bn256::G1 {
+
+        assert_eq!(coeffs.len(), bases.len());
+        let mut result: MaybeUninit<bn254_snarks_g1_prj> = MaybeUninit::uninit();
+        unsafe {
+            ctt_bn254_snarks_g1_prj_multi_scalar_mul_vartime_parallel(
+               self.ctx,
+               result.as_mut_ptr(),
+               coeffs.as_ptr() as *const big254,
+               bases.as_ptr() as *const bn254_snarks_g1_aff,
+               bases.len()
+            );
+            mem::transmute::<MaybeUninit<bn254_snarks_g1_prj>, bn256::G1>(result)
+        }
+    }
 }
 
 #[cfg(test)]
 mod tests {
     use super::*;
 
+    use ark_std::{end_timer, start_timer};
+    use rand_core::OsRng;
+
+    use halo2curves::bn256;
+    use halo2curves::ff::Field;
+    use halo2curves::group::{Curve, Group};
+    use halo2curves::group::prime::PrimeCurveAffine;
+    use halo2curves::zal::MsmAccel;
+    use halo2curves::msm::best_multiexp;
+
     #[test]
-    fn it_works() {
-        let result = add(2, 2);
-        assert_eq!(result, 4);
+    fn t_threadpool() {
+        let tp = CttEngine::new(4);
+        drop(tp);
     }
+
+    fn run_msm_zal(min_k: usize, max_k: usize) {
+        let points = (0..1 << max_k)
+            .map(|_| bn256::G1::random(OsRng))
+            .collect::<Vec<_>>();
+        let mut affine_points = vec![bn256::G1Affine::identity(); 1 << max_k];
+        bn256::G1::batch_normalize(&points[..], &mut affine_points[..]);
+        let points = affine_points;
+
+        let scalars = (0..1 << max_k)
+            .map(|_| bn256::Fr::random(OsRng))
+            .collect::<Vec<_>>();
+
+        for k in min_k..=max_k {
+            let points = &points[..1 << k];
+            let scalars = &scalars[..1 << k];
+
+            let t0 = start_timer!(|| format!("freestanding msm k={}", k));
+            let e0 = best_multiexp(scalars, points);
+            end_timer!(t0);
+
+            let engine = CttEngine::new(num_cpus::get());
+            let t1 = start_timer!(|| format!("CttEngine msm k={}", k));
+            let e1 = engine.msm(scalars, points);
+            end_timer!(t1);
+
+            assert_eq!(e0, e1);
+        }
+    }
+
+    #[test]
+    fn t_msm_zal() {
+        run_msm_zal(3, 14);
+    }
+
 }
diff --git a/include/constantine/curves/bls12_381_parallel.h b/include/constantine/curves/bls12_381_parallel.h
index eadbfcdfe..9a9a0a94b 100644
--- a/include/constantine/curves/bls12_381_parallel.h
+++ b/include/constantine/curves/bls12_381_parallel.h
@@ -18,8 +18,8 @@
 extern "C" {
 #endif
 
-void        ctt_bls12_381_g1_jac_multi_scalar_mul_vartime_parallel(const ctt_threadpool* tp, const bls12_381_g1_jac* r, const big255 coefs[], const bls12_381_g1_aff points[], size_t len);
-void        ctt_bls12_381_g1_prj_multi_scalar_mul_vartime_parallel(const ctt_threadpool* tp, const bls12_381_g1_prj* r, const big255 coefs[], const bls12_381_g1_aff points[], size_t len);
+void        ctt_bls12_381_g1_jac_multi_scalar_mul_vartime_parallel(const ctt_threadpool* tp, bls12_381_g1_jac* r, const big255 coefs[], const bls12_381_g1_aff points[], size_t len);
+void        ctt_bls12_381_g1_prj_multi_scalar_mul_vartime_parallel(const ctt_threadpool* tp, bls12_381_g1_prj* r, const big255 coefs[], const bls12_381_g1_aff points[], size_t len);
 
 #ifdef __cplusplus
 }
diff --git a/include/constantine/curves/bn254_snarks_parallel.h b/include/constantine/curves/bn254_snarks_parallel.h
index 8a9a59547..565aaf71a 100644
--- a/include/constantine/curves/bn254_snarks_parallel.h
+++ b/include/constantine/curves/bn254_snarks_parallel.h
@@ -18,8 +18,8 @@
 extern "C" {
 #endif
 
-void        ctt_bn254_snarks_g1_jac_multi_scalar_mul_vartime_parallel(const ctt_threadpool* tp, const bn254_snarks_g1_jac* r, const big254 coefs[], const bn254_snarks_g1_aff points[], size_t len);
-void        ctt_bn254_snarks_g1_prj_multi_scalar_mul_vartime_parallel(const ctt_threadpool* tp, const bn254_snarks_g1_prj* r, const big254 coefs[], const bn254_snarks_g1_aff points[], size_t len);
+void        ctt_bn254_snarks_g1_jac_multi_scalar_mul_vartime_parallel(const ctt_threadpool* tp, bn254_snarks_g1_jac* r, const big254 coefs[], const bn254_snarks_g1_aff points[], size_t len);
+void        ctt_bn254_snarks_g1_prj_multi_scalar_mul_vartime_parallel(const ctt_threadpool* tp, bn254_snarks_g1_prj* r, const big254 coefs[], const bn254_snarks_g1_aff points[], size_t len);
 
 #ifdef __cplusplus
 }
diff --git a/include/constantine/curves/pallas_parallel.h b/include/constantine/curves/pallas_parallel.h
index c07bbe434..d4a29e444 100644
--- a/include/constantine/curves/pallas_parallel.h
+++ b/include/constantine/curves/pallas_parallel.h
@@ -18,8 +18,8 @@
 extern "C" {
 #endif
 
-void        ctt_pallas_ec_jac_multi_scalar_mul_vartime_parallel(const ctt_threadpool* tp, const pallas_ec_jac* r, const big255 coefs[], const pallas_ec_aff points[], size_t len);
-void        ctt_pallas_ec_prj_multi_scalar_mul_vartime_parallel(const ctt_threadpool* tp, const pallas_ec_prj* r, const big255 coefs[], const pallas_ec_aff points[], size_t len);
+void        ctt_pallas_ec_jac_multi_scalar_mul_vartime_parallel(const ctt_threadpool* tp, pallas_ec_jac* r, const big255 coefs[], const pallas_ec_aff points[], size_t len);
+void        ctt_pallas_ec_prj_multi_scalar_mul_vartime_parallel(const ctt_threadpool* tp, pallas_ec_prj* r, const big255 coefs[], const pallas_ec_aff points[], size_t len);
 
 #ifdef __cplusplus
 }
diff --git a/include/constantine/curves/vesta_parallel.h b/include/constantine/curves/vesta_parallel.h
index fbc08884a..e52002d94 100644
--- a/include/constantine/curves/vesta_parallel.h
+++ b/include/constantine/curves/vesta_parallel.h
@@ -18,8 +18,8 @@
 extern "C" {
 #endif
 
-void        ctt_vesta_ec_jac_multi_scalar_mul_vartime_parallel(const ctt_threadpool* tp, const vesta_ec_jac* r, const big255 coefs[], const vesta_ec_aff points[], size_t len);
-void        ctt_vesta_ec_prj_multi_scalar_mul_vartime_parallel(const ctt_threadpool* tp, const vesta_ec_prj* r, const big255 coefs[], const vesta_ec_aff points[], size_t len);
+void        ctt_vesta_ec_jac_multi_scalar_mul_vartime_parallel(const ctt_threadpool* tp, vesta_ec_jac* r, const big255 coefs[], const vesta_ec_aff points[], size_t len);
+void        ctt_vesta_ec_prj_multi_scalar_mul_vartime_parallel(const ctt_threadpool* tp, vesta_ec_prj* r, const big255 coefs[], const vesta_ec_aff points[], size_t len);
 
 #ifdef __cplusplus
 }