Adaptation du code de α₂

1 files changed, 8 insertions, 5 deletions

diff --git a/src/add_tweakeyunrolled/tweakey.c b/src/add_tweakeyunrolled/tweakey.c
index 348de51..a5b88a8 100644
--- a/src/add_tweakeyunrolled/tweakey.c
+++ b/src/add_tweakeyunrolled/tweakey.c
@@ -96,12 +96,15 @@ static void _multiply_M(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES])
 
 static void _multiply_M2(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES])
 {
+    uint8_t x_M_5 = x[5]<<3 ^ x[4];
+    uint8_t x_M_4 = x[4]>>3 ^ x[3];
+
     y[7] = x[5];
-    y[6] = x[5]<<3 ^ x[4];
-    y[5] = x[5]<<6 ^ _M1(x[4]) ^ x[3];
-    y[4] = x[4]>>6 ^ x[3]>>3   ^ x[2];
-    y[3] = x[6]<<2 ^ x[1];
-    y[2] = x[5]<<2 ^ x[0];
+    y[6] = x_M_5;
+    y[5] = x_M_5<<3 ^ x_M_4;
+    y[4] = x_M_4>>3 ^ x[2];
+    y[3] = x[6]<<2  ^ x[1];
+    y[2] = x[5]<<2  ^ x[0];
     y[1] = x[7];
     y[0] = x[6];
 }