lilliput-ae-reference-implementation

commit 89d08745d767ef36ac1694ba80403dabdf6ee9cb
parent 6726d240017eb64ea042115005251e457bbb112b
Author: Kévin Le Gouguec <kevin.legouguec@airbus.com>
Date:   Mon,  4 Feb 2019 09:04:26 +0100

Implémentation de M₃

Diffstat:
M
src/add_developedtweakey/tweakey.c
 | 
16
+++++++++++++---

1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/src/add_developedtweakey/tweakey.c b/src/add_developedtweakey/tweakey.c
@@ -53,6 +53,11 @@ static uint8_t _M2(uint8_t x)
     return x<<6 ^ (x & 0xf8) ^ x>>6;
 }
 
+static uint8_t _M3(uint8_t x)
+{
+    return x & 0x1f;
+}
+
 static void _multiply_M(const uint8_t X[LANE_BYTES], uint8_t Y[LANE_BYTES])
 {
     Y[7] = X[6];
@@ -103,9 +108,14 @@ static void _multiply_MR(const uint8_t X[LANE_BYTES], uint8_t Y[LANE_BYTES])
 
 static void _multiply_MR2(const uint8_t X[LANE_BYTES], uint8_t Y[LANE_BYTES])
 {
-    uint8_t MR_X[LANE_BYTES];
-    _multiply_MR(X, MR_X);
-    _multiply_MR(MR_X, Y);
+    Y[0] = X[2];
+    Y[1] = X[3]    ^ X[4]>>3;
+    Y[2] = X[4]    ^ X[5]>>3 ^ _M3(X[6]);
+    Y[3] = X[5]    ^ X[6]<<3;
+    Y[4] = X[3]<<2 ^ X[6]    ^ X[7]<<3;
+    Y[5] = X[4]<<2 ^ X[7];
+    Y[6] = X[0];
+    Y[7] = X[1];
 }
 
 static void _multiply_MR3(const uint8_t X[LANE_BYTES], uint8_t Y[LANE_BYTES])