lilliput-ae-reference-implementation

commit bbc9f0fcb03183c9f8cff2bf8a5c5a34607fa126
parent ae461f64bd249f959411b8b7cf56e549bb2ecb5c
Author: Kévin Le Gouguec <kevin.legouguec@gmail.com>
Date:   Fri,  1 Feb 2019 14:22:00 +0100

Implémentation de M₂

Diffstat:
M
src/add_developedtweakey/tweakey.c
 | 
18
+++++++++++++-----

1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/src/add_developedtweakey/tweakey.c b/src/add_developedtweakey/tweakey.c
@@ -48,6 +48,11 @@ static uint8_t _M1(uint8_t x)
     return x<<3 ^ x>>3;
 }
 
+static uint8_t _M2(uint8_t x)
+{
+    return x<<6 ^ (x & 0xf8) ^ x>>6;
+}
+
 static void _multiply_M(const uint8_t X[LANE_BYTES], uint8_t Y[LANE_BYTES])
 {
     Y[7] = X[6];
@@ -74,11 +79,14 @@ static void _multiply_M2(const uint8_t X[LANE_BYTES], uint8_t Y[LANE_BYTES])
 
 static void _multiply_M3(const uint8_t X[LANE_BYTES], uint8_t Y[LANE_BYTES])
 {
-    uint8_t M_X[LANE_BYTES];
-    uint8_t M2_X[LANE_BYTES];
-    _multiply_M(X, M_X);
-    _multiply_M(M_X, M2_X);
-    _multiply_M(M2_X, Y);
+    Y[7] = X[5]<<3   ^ X[4];
+    Y[6] = X[5]<<6   ^ _M1(X[4]) ^ X[3];
+    Y[5] = _M2(X[4]) ^ _M1(X[3]) ^ X[2];
+    Y[4] = X[6]<<2   ^ X[3]>>6   ^ X[2]>>3 ^ X[1];
+    Y[3] = X[5]<<2   ^ X[0];
+    Y[2] = X[7]      ^ X[5]<<5   ^ X[4]<<2;
+    Y[1] = X[6];
+    Y[0] = X[5];
 }
 
 static void _multiply_MR(const uint8_t X[LANE_BYTES], uint8_t Y[LANE_BYTES])