perfomance improvements

src/main.rs

@@ -30,21 +30,21 @@ static RSBOX: [u8; 256] = [
     0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d,
 ];
 
-fn calculate_models(ciphertexts: &[[u8; 16]]) -> Vec<[[u8; 16]; 256]> {
+fn calculate_models(ciphertexts: &[[u8; 16]]) -> Vec<Vec<[u8; 16]>> {
-    ciphertexts
+    let mut r = vec![Vec::with_capacity(ciphertexts.len()); 256];
-        .iter()
-        .map(|c| {
-            let mut row = [[0; 16]; 256];
 
-            for i in 0..256 {
+    for (i, c) in ciphertexts.iter().enumerate() {
-                for j in 0..16 {
+        for j in 0..256 {
-                    row[i][j] = RSBOX[(c[j] ^ (i as u8)) as usize];
+            let mut row = [0; 16];
-                }
+
+            for k in 0..16 {
+                row[k] = RSBOX[(c[k] ^ (j as u8)) as usize];
             }
+            r[j].push(row);
+        }
+    }
 
-            row
+    r
-        })
-        .collect()
 }
 
 fn read_msgs(path: impl AsRef<Path>) -> Vec<[u8; 16]> {
@@ -108,7 +108,7 @@ fn correlation(
     bit: usize,
     key_hypothesis: usize,
     trace_index: usize,
-    cyphtertext: &[[[u8; 16]; 256]],
+    cyphtertext: &[Vec<[u8; 16]>],
     traces: &[[u8; TRACES]],
 ) -> f64 {
     let mut x = 0i64;
@@ -118,7 +118,7 @@ fn correlation(
     let mut ysqr = 0i64;
 
     for i in 0..traces.len() {
-        let xi = (cyphtertext[i][key_hypothesis][bit / 8] & (1 << (bit % 8))) as i64;
+        let xi = (cyphtertext[key_hypothesis][i][bit / 8] & (1 << (bit % 8))) as i64;
         let yi = traces[i][trace_index] as i64;
 
         x += xi;