diff --git a/halo2_debug/src/check_witness.rs b/halo2_debug/src/check_witness.rs
new file mode 100644
index 000000000..e4299e6bf
--- /dev/null
+++ b/halo2_debug/src/check_witness.rs
@@ -0,0 +1,178 @@
+use crate::display::FDisp;
+use halo2_middleware::circuit::{Any, CompiledCircuit, ExpressionMid, VarMid};
+use halo2_middleware::ff::PrimeField;
+use rand_chacha::ChaCha20Rng;
+use rand_core::SeedableRng;
+use std::collections::HashSet;
+
+fn rotate(n: usize, offset: usize, rotation: i32) -> usize {
+    let offset = offset as i32 + rotation;
+    if offset < 0 {
+        (offset + n as i32) as usize
+    } else if offset >= n as i32 {
+        (offset - n as i32) as usize
+    } else {
+        offset as usize
+    }
+}
+
+struct Assignments<'a, F: PrimeField> {
+    public: &'a [Vec<F>],
+    witness: &'a [Vec<F>],
+    fixed: &'a [Vec<F>],
+    blinders: &'a [Vec<F>],
+    blinded: &'a [bool],
+    usable_rows: usize,
+    n: usize,
+}
+
+impl<'a, F: PrimeField> Assignments<'a, F> {
+    // Query a particular Column at an offset
+    fn query(&self, column_type: Any, column_index: usize, offset: usize) -> F {
+        match column_type {
+            Any::Instance => self.public[column_index][offset],
+            Any::Advice => {
+                if offset >= self.usable_rows && self.blinded[column_index] {
+                    self.blinders[column_index][offset - self.usable_rows]
+                } else {
+                    self.witness[column_index][offset]
+                }
+            }
+            Any::Fixed => self.fixed[column_index][offset],
+        }
+    }
+
+    // Evaluate an expression using the assingment data
+    fn eval(&self, expr: &ExpressionMid<F>, offset: usize) -> F {
+        expr.evaluate(
+            &|s| s,
+            &|v| match v {
+                VarMid::Query(q) => {
+                    let offset = rotate(self.n, offset, q.rotation.0);
+                    self.query(q.column_type, q.column_index, offset)
+                }
+                VarMid::Challenge(_c) => unimplemented!(),
+            },
+            &|ne| -ne,
+            &|a, b| a + b,
+            &|a, b| a * b,
+        )
+    }
+
+    // Evaluate multiple expressions and return the result as concatenated bytes from the field
+    // element representation.
+    fn eval_to_buf(&self, f_len: usize, exprs: &[ExpressionMid<F>], offset: usize) -> Vec<u8> {
+        let mut eval_buf = Vec::with_capacity(exprs.len() * f_len);
+        for eval in exprs.iter().map(|e| self.eval(e, offset)) {
+            eval_buf.extend_from_slice(eval.to_repr().as_ref())
+        }
+        eval_buf
+    }
+}
+
+/// Check that the wintess passes all the constraints defined by the circuit.  Panics if any
+/// constraint is not satisfied.
+pub fn check_witness<F: PrimeField>(
+    circuit: &CompiledCircuit<F>,
+    k: u32,
+    blinding_rows: usize,
+    witness: &[Vec<F>],
+    public: &[Vec<F>],
+) {
+    let n = 2usize.pow(k);
+    let usable_rows = n - blinding_rows;
+    let cs = &circuit.cs;
+
+    // Calculate blinding values
+    let mut rng = ChaCha20Rng::seed_from_u64(0xdeadbeef);
+    let mut blinders = vec![vec![F::ZERO; blinding_rows]; cs.num_advice_columns];
+    for column_blinders in blinders.iter_mut() {
+        for v in column_blinders.iter_mut() {
+            *v = F::random(&mut rng);
+        }
+    }
+
+    let mut blinded = vec![true; cs.num_advice_columns];
+    for advice_column_index in &cs.unblinded_advice_columns {
+        blinded[*advice_column_index] = false;
+    }
+
+    let assignments = Assignments {
+        public,
+        witness,
+        fixed: &circuit.preprocessing.fixed,
+        blinders: &blinders,
+        blinded: &blinded,
+        usable_rows,
+        n,
+    };
+
+    // Verify all gates
+    for (i, gate) in cs.gates.iter().enumerate() {
+        for offset in 0..n {
+            let res = assignments.eval(&gate.poly, offset);
+            if !res.is_zero_vartime() {
+                panic!(
+                    "Unsatisfied gate {} \"{}\" at offset {}",
+                    i, gate.name, offset
+                );
+            }
+        }
+    }
+
+    // Verify all copy constraints
+    for (lhs, rhs) in &circuit.preprocessing.permutation.copies {
+        let value_lhs = assignments.query(lhs.column.column_type, lhs.column.index, lhs.row);
+        let value_rhs = assignments.query(rhs.column.column_type, rhs.column.index, rhs.row);
+        if value_lhs != value_rhs {
+            panic!(
+                "Unsatisfied copy constraint ({:?},{:?}): {} != {}",
+                lhs,
+                rhs,
+                FDisp(&value_lhs),
+                FDisp(&value_rhs)
+            )
+        }
+    }
+
+    // Verify all lookups
+    let f_len = F::Repr::default().as_ref().len();
+    for (i, lookup) in cs.lookups.iter().enumerate() {
+        let mut virtual_table = HashSet::new();
+        for offset in 0..usable_rows {
+            let table_eval_buf = assignments.eval_to_buf(f_len, &lookup.table_expressions, offset);
+            virtual_table.insert(table_eval_buf);
+        }
+        for offset in 0..usable_rows {
+            let input_eval_buf = assignments.eval_to_buf(f_len, &lookup.input_expressions, offset);
+            if !virtual_table.contains(&input_eval_buf) {
+                panic!(
+                    "Unsatisfied lookup {} \"{}\" at offset {}",
+                    i, lookup.name, offset
+                );
+            }
+        }
+    }
+
+    // Verify all shuffles
+    for (i, shuffle) in cs.shuffles.iter().enumerate() {
+        let mut virtual_shuffle = Vec::with_capacity(usable_rows);
+        for offset in 0..usable_rows {
+            let shuffle_eval_buf =
+                assignments.eval_to_buf(f_len, &shuffle.shuffle_expressions, offset);
+            virtual_shuffle.push(shuffle_eval_buf);
+        }
+        let mut virtual_input = Vec::with_capacity(usable_rows);
+        for offset in 0..usable_rows {
+            let input_eval_buf = assignments.eval_to_buf(f_len, &shuffle.input_expressions, offset);
+            virtual_input.push(input_eval_buf);
+        }
+
+        virtual_shuffle.sort_unstable();
+        virtual_input.sort_unstable();
+
+        if virtual_input != virtual_shuffle {
+            panic!("Unsatisfied shuffle {} \"{}\"", i, shuffle.name);
+        }
+    }
+}
diff --git a/halo2_debug/src/lib.rs b/halo2_debug/src/lib.rs
index 911e90e6d..d9343e50d 100644
--- a/halo2_debug/src/lib.rs
+++ b/halo2_debug/src/lib.rs
@@ -1,3 +1,8 @@
+mod check_witness;
+pub mod display;
+
+pub use check_witness::check_witness;
+
 use rand_chacha::ChaCha20Rng;
 use rand_core::SeedableRng;
 use tiny_keccak::Hasher;
@@ -34,5 +39,3 @@ pub fn test_result<F: FnOnce() -> Vec<u8> + Send>(test: F, _expected: &str) -> V
 
     result
 }
-
-pub mod display;
diff --git a/p3_frontend/Cargo.toml b/p3_frontend/Cargo.toml
index 34dceddde..bc91918ae 100644
--- a/p3_frontend/Cargo.toml
+++ b/p3_frontend/Cargo.toml
@@ -36,3 +36,4 @@ p3-keccak-air = { git = "https://github.com/Plonky3/Plonky3", rev = "7b5b8a6" }
 p3-keccak = { git = "https://github.com/Plonky3/Plonky3", rev = "7b5b8a6" }
 p3-util = { git = "https://github.com/Plonky3/Plonky3", rev = "7b5b8a6" }
 rand = "0.8.5"
+halo2_debug = { path = "../halo2_debug" }
diff --git a/p3_frontend/src/lib.rs b/p3_frontend/src/lib.rs
index 5ba49e25c..947b9bb83 100644
--- a/p3_frontend/src/lib.rs
+++ b/p3_frontend/src/lib.rs
@@ -5,8 +5,8 @@
 extern crate alloc;
 
 use halo2_middleware::circuit::{
-    Any, Cell, ColumnMid, CompiledCircuit, ConstraintSystemMid, ExpressionMid, GateMid,
-    Preprocessing, QueryMid, VarMid,
+    Any, Cell, ColumnMid, ConstraintSystemMid, ExpressionMid, GateMid, Preprocessing, QueryMid,
+    VarMid,
 };
 use halo2_middleware::ff::{Field, PrimeField};
 use halo2_middleware::permutation;
@@ -184,7 +184,7 @@ fn extract_copy_public<F: PrimeField + Hash>(
 pub fn get_public_inputs<F: Field>(
     preprocessing_info: &PreprocessingInfo,
     size: usize,
-    witness: &[Option<Vec<F>>],
+    witness: &[Vec<F>],
 ) -> Vec<Vec<F>> {
     if preprocessing_info.num_public_values == 0 {
         return Vec::new();
@@ -196,7 +196,7 @@ pub fn get_public_inputs<F: Field>(
             Location::LastRow => size - 1,
             Location::Transition => unreachable!(),
         };
-        public_inputs[*public_index] = witness[cell.0].as_ref().unwrap()[offset]
+        public_inputs[*public_index] = witness[cell.0][offset]
     }
     vec![public_inputs]
 }
@@ -293,7 +293,7 @@ where
     (cs, preprocessing_info)
 }
 
-pub fn trace_to_wit<F: Field>(k: u32, trace: RowMajorMatrix<FWrap<F>>) -> Vec<Option<Vec<F>>> {
+pub fn trace_to_wit<F: Field>(k: u32, trace: RowMajorMatrix<FWrap<F>>) -> Vec<Vec<F>> {
     let n = 2usize.pow(k);
     let num_columns = trace.width;
     let mut witness = vec![vec![F::ZERO; n]; num_columns];
@@ -302,56 +302,5 @@ pub fn trace_to_wit<F: Field>(k: u32, trace: RowMajorMatrix<FWrap<F>>) -> Vec<Op
             witness[column_index][row_offset] = row[column_index].0;
         }
     }
-    witness.into_iter().map(Some).collect()
-}
-
-// TODO: Move to middleware
-pub fn check_witness<F: Field>(
-    circuit: &CompiledCircuit<F>,
-    k: u32,
-    witness: &[Option<Vec<F>>],
-    public: &[Vec<F>],
-) {
-    let n = 2usize.pow(k);
-    let cs = &circuit.cs;
-    let preprocessing = &circuit.preprocessing;
-    // TODO: Simulate blinding rows
-    // Verify all gates
-    for (i, gate) in cs.gates.iter().enumerate() {
-        for offset in 0..n {
-            let res = gate.poly.evaluate(
-                &|s| s,
-                &|v| match v {
-                    VarMid::Query(q) => {
-                        let offset = offset as i32 + q.rotation.0;
-                        // TODO: Try to do mod n with a rust function
-                        let offset = if offset < 0 {
-                            (offset + n as i32) as usize
-                        } else if offset >= n as i32 {
-                            (offset - n as i32) as usize
-                        } else {
-                            offset as usize
-                        };
-                        match q.column_type {
-                            Any::Instance => public[q.column_index][offset],
-                            Any::Advice => witness[q.column_index].as_ref().unwrap()[offset],
-                            Any::Fixed => preprocessing.fixed[q.column_index][offset],
-                        }
-                    }
-                    VarMid::Challenge(_c) => unimplemented!(),
-                },
-                &|ne| -ne,
-                &|a, b| a + b,
-                &|a, b| a * b,
-            );
-            if !res.is_zero_vartime() {
-                println!(
-                    "Unsatisfied gate {} \"{}\" at offset {}",
-                    i, gate.name, offset
-                );
-                panic!("KO");
-            }
-        }
-    }
-    println!("Check witness: OK");
+    witness
 }
diff --git a/p3_frontend/tests/common/mod.rs b/p3_frontend/tests/common/mod.rs
index d762b5f2d..5ea7e8682 100644
--- a/p3_frontend/tests/common/mod.rs
+++ b/p3_frontend/tests/common/mod.rs
@@ -11,14 +11,15 @@ use halo2_backend::{
         Blake2bRead, Blake2bWrite, Challenge255, TranscriptReadBuffer, TranscriptWriterBuffer,
     },
 };
+use halo2_debug::check_witness;
 use halo2_debug::test_rng;
 use halo2_middleware::circuit::CompiledCircuit;
 use halo2_middleware::zal::impls::H2cEngine;
 use halo2curves::bn256::{Bn256, Fr, G1Affine};
 use p3_air::Air;
 use p3_frontend::{
-    check_witness, compile_circuit_cs, compile_preprocessing, get_public_inputs, trace_to_wit,
-    CompileParams, FWrap, SymbolicAirBuilder,
+    compile_circuit_cs, compile_preprocessing, get_public_inputs, trace_to_wit, CompileParams,
+    FWrap, SymbolicAirBuilder,
 };
 use p3_matrix::dense::RowMajorMatrix;
 use std::time::Instant;
@@ -50,8 +51,12 @@ where
     let witness = trace_to_wit(k, trace);
     let pis = get_public_inputs(&preprocessing_info, size, &witness);
 
-    check_witness(&compiled_circuit, k, &witness, &pis);
-    (compiled_circuit, witness, pis)
+    check_witness(&compiled_circuit, k, 5, &witness, &pis);
+    (
+        compiled_circuit,
+        witness.into_iter().map(Some).collect(),
+        pis,
+    )
 }
 
 pub(crate) fn setup_prove_verify(