1 files changed, 11 insertions, 0 deletions
diff --git a/src/add_tweakeyloop/multiplications.h b/src/add_tweakeyloop/multiplications.h
index 45b9eaa..650373b 100644
--- a/src/add_tweakeyloop/multiplications.h
+++ b/src/add_tweakeyloop/multiplications.h
@@ -55,6 +55,17 @@ static void _multiply_M3(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES])
     _multiply_M(M2_x, y);
 }
 
+static void _multiply_M4(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES])
+{
+    uint8_t M_x[LANE_BYTES];
+    uint8_t M2_x[LANE_BYTES];
+    uint8_t M3_x[LANE_BYTES];
+    _multiply_M(x, M_x);
+    _multiply_M(M_x, M2_x);
+    _multiply_M(M2_x, M3_x);
+    _multiply_M(M3_x, y);
+}
+
 static void _multiply_MR(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES])
 {
     y[0] = x[1];