moving from eval to coeff based on discussion

arbitrator/prover/src/kzgbn254.rs

@@ -41,12 +41,11 @@ pub fn prove_kzg_preimage_bn254(
     // expand roots of unity
     kzg.calculate_roots_of_unity(preimage.len() as u64)?;
 
-    // preimage is already padded, unpadding and repadding already padded data can destroy context post IFFT
-    // as some elements in the bn254 field are represented by 32 bytes, we know that the preimage is padded
-    // to 32 bytes per DA spec as the preimage is retrieved from DA, so we can use this unchecked function
+    // preimage is already padded and is expected to be in data domain i.e, this is the actual data but padded
+    // to power of 2
     let blob = Blob::from_padded_bytes_unchecked(preimage);
 
-    let blob_polynomial_evaluation_form = blob.to_polynomial(PolynomialFormat::InEvaluationForm)?;
+    let blob_polynomial_evaluation_form = blob.to_polynomial(PolynomialFormat::InCoefficientForm)?;
     let blob_commitment = kzg.commit(&blob_polynomial_evaluation_form)?;
 
     let mut commitment_bytes = Vec::new();