diff --git a/src/main.rs b/src/main.rs
index fb63d5e..16b0eec 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -6,7 +6,9 @@ use aes::{
     cipher::{BlockEncrypt, KeyInit, generic_array::GenericArray},
 };
 use clap::Parser;
-use rayon::iter::{IntoParallelIterator, ParallelIterator};
+use rayon::iter::{
+    IndexedParallelIterator, IntoParallelIterator, IntoParallelRefMutIterator, ParallelIterator,
+};
 use std::{
     io::{BufRead, Read},
     path::{Path, PathBuf},
@@ -75,14 +77,13 @@ fn calculate_models(ciphertexts: &[[u8; 16]]) -> Vec<[Vec<u8>; 16]> {
         })
         .collect();
 
-    for k in 0..16 {
-        for j in 0..256 {
+    r.par_iter_mut().enumerate().for_each(|(j, r)| {
+        for k in 0..16 {
             for (i, c) in ciphertexts.iter().enumerate() {
-                r[j][k][i] = RSBOX[(c[k] ^ (j as u8)) as usize];
+                r[k][i] = RSBOX[(c[k] ^ (j as u8)) as usize];
             }
         }
-    }
-
+    });
     r
 }