lilliput-ae-reference-implementation

commit 1ea3b9a3fe91c54c9be7dd7014f3af0c861260c3
parent 590637c9e555d6ba6b9b0e8e871d1ed926b49911
Author: Kévin Le Gouguec <kevin.legouguec@airbus.com>
Date:   Wed, 20 Feb 2019 15:37:26 +0100

Adaptation du code de α₆

Diffstat:
M
src/add_tweakeyunrolled/tweakey.c
 | 
26
+++++++-------------------

1 file changed, 7 insertions(+), 19 deletions(-)
diff --git a/src/add_tweakeyunrolled/tweakey.c b/src/add_tweakeyunrolled/tweakey.c
@@ -62,21 +62,6 @@ void tweakey_state_extract(
 }
 
 
-static uint8_t _M1(uint8_t x)
-{
-    return x<<3 ^ x>>3;
-}
-
-static uint8_t _M3(uint8_t x)
-{
-    return (uint8_t)(x<<3) >> 3;
-}
-
-static uint8_t _M4(uint8_t x)
-{
-    return (uint8_t)(x<<2) >> 3;
-}
-
 static void _multiply_M(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES])
 {
     y[7] = x[6];
@@ -149,12 +134,15 @@ static void _multiply_MR2(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES])
 
 static void _multiply_MR3(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES])
 {
+    uint8_t x_MR_4 = x[5]     ^ x[6]<<3;
+    uint8_t x_MR2_4 = x[3]<<2 ^ x[6]    ^ x[7]<<3;
+
     y[0] = x[3]      ^ x[4]>>3;
-    y[1] = x[4]      ^ x[5]>>3 ^ _M3(x[6]);
-    y[2] = _M4(x[3]) ^ x[5]    ^ _M1(x[6]) ^ _M3(x[7]);
-    y[3] = x[3]<<2   ^ x[6]    ^ x[7]<<3;
+    y[1] = x[4]      ^ x_MR_4>>3;
+    y[2] = x_MR_4    ^ x_MR2_4>>3;
+    y[3] = x_MR2_4;
     y[4] = x[0]<<3   ^ x[4]<<2 ^ x[7];
-    y[5] = x[0]      ^ x[5]<<2 ^ x[6]<<5;
+    y[5] = x_MR_4<<2 ^ x[0];
     y[6] = x[1];
     y[7] = x[2];
 }