From 1989002054111cc5301f9aa229957cbd59a9e2f5 Mon Sep 17 00:00:00 2001
From: Kévin Le Gouguec <kevin.legouguec@airbus.com>
Date: Wed, 20 Feb 2019 17:30:10 +0100
Subject: Changement de l'implémentation de référence
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Et suppression de l'implémentation  add_tweakeysequences, qui n'a plus
aucun intérêt (plus lente et plus grosse que les deux autres).
---
 src/add_tweakeyloop/tweakey.c | 146 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 146 insertions(+)
 create mode 100644 src/add_tweakeyloop/tweakey.c

(limited to 'src/add_tweakeyloop/tweakey.c')

diff --git a/src/add_tweakeyloop/tweakey.c b/src/add_tweakeyloop/tweakey.c
new file mode 100644
index 0000000..b1f349e
--- /dev/null
+++ b/src/add_tweakeyloop/tweakey.c
@@ -0,0 +1,146 @@
+/*
+Implementation of the Lilliput-AE tweakable block cipher.
+
+Author: 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 provides an implementation of Lilliput-TBC's tweakey schedule,
+where multiplications by matrices M and M_R to the power n are performed
+by applying functions for M and M_R n times.
+*/
+
+#include <stdint.h>
+#include <string.h>
+
+#include "constants.h"
+#include "tweakey.h"
+
+
+#define LANE_BITS  64
+#define LANE_BYTES (LANE_BITS/8)
+#define LANES_NB   (TWEAKEY_BYTES/LANE_BYTES)
+
+
+void tweakey_state_init(
+    uint8_t TK[TWEAKEY_BYTES],
+    const uint8_t key[KEY_BYTES],
+    const uint8_t tweak[TWEAK_BYTES]
+)
+{
+    memcpy(TK,             tweak, TWEAK_BYTES);
+    memcpy(TK+TWEAK_BYTES, key,   KEY_BYTES);
+}
+
+
+void tweakey_state_extract(
+    const uint8_t TK[TWEAKEY_BYTES],
+    uint8_t round_constant,
+    uint8_t round_tweakey[ROUND_TWEAKEY_BYTES]
+)
+{
+    memset(round_tweakey, 0, ROUND_TWEAKEY_BYTES);
+
+    for (size_t j=0; j<LANES_NB; j++)
+    {
+        const uint8_t *TKj = TK + j*LANE_BYTES;
+
+        for (size_t k=0; k<LANE_BYTES; k++)
+        {
+            round_tweakey[k] ^= TKj[k];
+        }
+    }
+
+    round_tweakey[0] ^= round_constant;
+}
+
+
+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);
+}
+
+typedef void (*matrix_multiplication)(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES]);
+
+static const matrix_multiplication ALPHAS[6] = {
+    _multiply_M,
+    _multiply_M2,
+    _multiply_M3,
+    _multiply_MR,
+    _multiply_MR2,
+    _multiply_MR3
+};
+
+
+void tweakey_state_update(uint8_t TK[TWEAKEY_BYTES])
+{
+    /* Skip lane 0, as it is multiplied by the identity matrix. */
+
+    for (size_t j=1; j<LANES_NB; j++)
+    {
+        uint8_t *TKj = TK + j*LANE_BYTES;
+
+        uint8_t TKj_old[LANE_BYTES];
+        memcpy(TKj_old, TKj, LANE_BYTES);
+
+        ALPHAS[j-1](TKj_old, TKj);
+    }
+}
-- 
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