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diff --git a/src/add_tweakeyloop/multiplications.h b/src/add_tweakeyloop/multiplications.h
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+/*
+Implementation of the Lilliput-AE tweakable block cipher.
+
+Authors, hereby denoted as "the implementer":
+    Kévin Le Gouguec,
+    2019.
+
+For more information, feedback or questions, refer to our website:
+https://paclido.fr/lilliput-ae
+
+To the extent possible under law, the implementer has waived all copyright
+and related or neighboring rights to the source code in this file.
+http://creativecommons.org/publicdomain/zero/1.0/
+
+---
+
+This file implements the alpha-multiplications used in Lilliput-TBC's
+tweakey schedule, where matrices M and M_R to the power n>1 are
+implemented by applying functions for M and M_R n times.
+*/
+
+#ifndef MULTIPLICATIONS_H
+#define MULTIPLICATIONS_H
+
+static void _multiply_M(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES])
+{
+    y[7] = x[6];
+    y[6] = x[5];
+    y[5] = x[5]<<3 ^ x[4];
+    y[4] = x[4]>>3 ^ x[3];
+    y[3] = x[2];
+    y[2] = x[6]<<2 ^ x[1];
+    y[1] = x[0];
+    y[0] = x[7];
+}
+
+static void _multiply_M2(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES])
+{
+    uint8_t M_x[LANE_BYTES];
+    _multiply_M(x, M_x);
+    _multiply_M(M_x, y);
+}
+
+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);
+}
+
+static void _multiply_MR(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES])
+{
+    y[0] = x[1];
+    y[1] = x[2];
+    y[2] = x[3]    ^ x[4]>>3;
+    y[3] = x[4];
+    y[4] = x[5]    ^ x[6]<<3;
+    y[5] = x[3]<<2 ^ x[6];
+    y[6] = x[7];
+    y[7] = x[0];
+}
+
+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);
+}
+
+static void _multiply_MR3(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES])
+{
+    uint8_t MR_x[LANE_BYTES];
+    uint8_t MR2_x[LANE_BYTES];
+    _multiply_MR(x, MR_x);
+    _multiply_MR(MR_x, MR2_x);
+    _multiply_MR(MR2_x, y);
+}
+
+#endif /* MULTIPLICATIONS_H */