diff --git a/tinysnark/src/lib.rs b/tinysnark/src/lib.rs
index a8c6bbc..39d9fb9 100644
--- a/tinysnark/src/lib.rs
+++ b/tinysnark/src/lib.rs
@@ -50,8 +50,8 @@ mod tests {
             assert!(!cs.test(&[10.into()], &[6.into(), 2.into()]));
 
             let kp = Keypair::new(&cs);
-            let proof = Proof::new(&kp, &cs, &[10.into()], &[5.into(), 2.into()]);
-            assert!(proof.verify(&kp, &cs, &[10.into()]));
+            let proof = Proof::new(&kp, &[10.into()], &[5.into(), 2.into()]);
+            assert!(proof.verify(&kp, &[10.into()]));
         }
         {
             let mut cs = ConstraintSystem::new(0, 1);
@@ -66,8 +66,8 @@ mod tests {
             assert!(!cs.test(&[], &[2.into()]));
 
             let kp = Keypair::new(&cs);
-            let proof = Proof::new(&kp, &cs, &[], &[1.into()]);
-            assert!(proof.verify(&kp, &cs, &[]));
+            let proof = Proof::new(&kp, &[], &[1.into()]);
+            assert!(proof.verify(&kp, &[]));
         }
     }
 
diff --git a/tinysnark/src/r1cs.rs b/tinysnark/src/r1cs.rs
index e589924..f7db5b4 100644
--- a/tinysnark/src/r1cs.rs
+++ b/tinysnark/src/r1cs.rs
@@ -75,13 +75,17 @@ impl ConstraintSystem {
 struct R1CSKeypair;
 
 pub struct Keypair {
-    kp: *mut R1CSKeypair
+    kp: *mut R1CSKeypair,
+    primary_size: usize,
+    aux_size: usize
 }
 
 impl Keypair {
     pub fn new(constraint_system: &ConstraintSystem) -> Keypair {
         Keypair {
-            kp: unsafe { tinysnark_gen_keypair(constraint_system.cs) }
+            kp: unsafe { tinysnark_gen_keypair(constraint_system.cs) },
+            primary_size: constraint_system.primary_size,
+            aux_size: constraint_system.aux_size
         }
     }
 }
@@ -105,22 +109,24 @@ pub struct Proof {
 }
 
 impl Proof {
-    pub fn new(keypair: &Keypair, constraint_system: &ConstraintSystem, primary: &[FieldT], aux: &[FieldT])
+    pub fn new(keypair: &Keypair, primary: &[FieldT], aux: &[FieldT])
         -> Proof
     {
-        assert_eq!(primary.len(), constraint_system.primary_size);
-        assert_eq!(aux.len(), constraint_system.aux_size);
+        assert_eq!(primary.len(), keypair.primary_size);
+        assert_eq!(aux.len(), keypair.aux_size);
 
         unsafe {
             Proof {
-                proof: tinysnark_gen_proof(keypair.kp, constraint_system.cs, primary.get_unchecked(0), aux.get_unchecked(0))
+                proof: tinysnark_gen_proof(keypair.kp, primary.get_unchecked(0), aux.get_unchecked(0))
             }
         }
     }
 
-    pub fn verify(&self, keypair: &Keypair, constraint_system: &ConstraintSystem, primary: &[FieldT]) -> bool {
+    pub fn verify(&self, keypair: &Keypair, primary: &[FieldT]) -> bool {
+        assert_eq!(primary.len(), keypair.primary_size);
+
         unsafe {
-            tinysnark_verify_proof(self.proof, keypair.kp, constraint_system.cs, primary.get_unchecked(0))
+            tinysnark_verify_proof(self.proof, keypair.kp, primary.get_unchecked(0))
         }
     }
 }
@@ -133,12 +139,10 @@ impl Drop for Proof {
 
 extern "C" {
     fn tinysnark_gen_proof(keypair: *mut R1CSKeypair,
-                           cs: *mut R1ConstraintSystem,
                            primary: *const FieldT,
                            aux: *const FieldT) -> *mut R1CSProof;
     fn tinysnark_verify_proof(proof: *mut R1CSProof,
                               keypair: *mut R1CSKeypair,
-                              cs: *mut R1ConstraintSystem,
                               primary: *const FieldT) -> bool;
     fn tinysnark_drop_proof(proof: *mut R1CSProof);
 }
\ No newline at end of file
diff --git a/tinysnark/tinysnark.cpp b/tinysnark/tinysnark.cpp
index a25ba52..1313c68 100644
--- a/tinysnark/tinysnark.cpp
+++ b/tinysnark/tinysnark.cpp
@@ -18,12 +18,11 @@ struct tinysnark_linear_term {
     size_t index;
 };
 
-extern "C" void * tinysnark_gen_proof(void * kp, void * ics, FieldT* primary, FieldT* aux) {
-    r1cs_constraint_system<FieldT>* cs = static_cast<r1cs_constraint_system<FieldT>*>(ics);
+extern "C" void * tinysnark_gen_proof(void * kp, FieldT* primary, FieldT* aux) {
     r1cs_ppzksnark_keypair<default_r1cs_ppzksnark_pp>* keypair = static_cast<r1cs_ppzksnark_keypair<default_r1cs_ppzksnark_pp>*>(kp);
 
-    r1cs_primary_input<FieldT> primary_input(primary, primary+(cs->primary_input_size));
-    r1cs_auxiliary_input<FieldT> aux_input(aux, aux+(cs->auxiliary_input_size));
+    r1cs_primary_input<FieldT> primary_input(primary, primary+(keypair->pk.constraint_system.primary_input_size));
+    r1cs_auxiliary_input<FieldT> aux_input(aux, aux+(keypair->pk.constraint_system.auxiliary_input_size));
 
     auto proof = new r1cs_ppzksnark_proof<default_r1cs_ppzksnark_pp>(
         r1cs_ppzksnark_prover<default_r1cs_ppzksnark_pp>(keypair->pk, primary_input, aux_input)
@@ -32,12 +31,11 @@ extern "C" void * tinysnark_gen_proof(void * kp, void * ics, FieldT* primary, Fi
     return static_cast<void*>(std::move(proof));
 }
 
-extern "C" bool tinysnark_verify_proof(void * iproof, void * kp, void * ics, FieldT* primary) {
+extern "C" bool tinysnark_verify_proof(void * iproof, void * kp, FieldT* primary) {
     r1cs_ppzksnark_proof<default_r1cs_ppzksnark_pp>* proof = static_cast<r1cs_ppzksnark_proof<default_r1cs_ppzksnark_pp>*>(iproof);
-    r1cs_constraint_system<FieldT>* cs = static_cast<r1cs_constraint_system<FieldT>*>(ics);
     r1cs_ppzksnark_keypair<default_r1cs_ppzksnark_pp>* keypair = static_cast<r1cs_ppzksnark_keypair<default_r1cs_ppzksnark_pp>*>(kp);
 
-    r1cs_primary_input<FieldT> primary_input(primary, primary+(cs->primary_input_size));
+    r1cs_primary_input<FieldT> primary_input(primary, primary+(keypair->pk.constraint_system.primary_input_size));
 
     return r1cs_ppzksnark_verifier_strong_IC<default_r1cs_ppzksnark_pp>(keypair->vk, primary_input, *proof);
 }