From 1b70dc0fdb7c445f526a51ced73e531ac31cf438 Mon Sep 17 00:00:00 2001
From: Kévin Le Gouguec <kevin.legouguec@airbus.com>
Date: Wed, 21 Nov 2018 10:29:44 +0100
Subject: Implémentation de la multiplication du tweakey
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---
 crypto_aead/lilliputaei128v1/ref/tweakey.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

(limited to 'crypto_aead/lilliputaei128v1/ref/tweakey.c')

diff --git a/crypto_aead/lilliputaei128v1/ref/tweakey.c b/crypto_aead/lilliputaei128v1/ref/tweakey.c
index d7a5805..71bc030 100644
--- a/crypto_aead/lilliputaei128v1/ref/tweakey.c
+++ b/crypto_aead/lilliputaei128v1/ref/tweakey.c
@@ -8,6 +8,7 @@
 
 #define LANE_BITS  64
 #define LANE_BYTES (LANE_BITS/8)
+#define LANES_NB (TWEAKEY_BYTES/LANE_BYTES)
 
 
 static void _dump_buffer(FILE *output, size_t len, const uint8_t buf[len], int indent)
@@ -90,8 +91,22 @@ static void _permute_state(tweakey_state *TK)
     }
 }
 
-static void _multiply_state(__attribute__((unused)) tweakey_state *TK)
+static void _multiply_state(tweakey_state *TK)
 {
+    /* Lane 0 is multiplied by Id; lane 1 by P_0, lane 2 by P_1... */
+
+    for (size_t lane=1; lane<LANES_NB; lane++)
+    {
+        const uint8_t* P_lane = P[lane-1];
+
+        /* TODO: homogenize indices; here b=byte */
+
+        for (size_t b=0; b<LANE_BYTES; b++)
+        {
+            size_t offset = lane*LANE_BYTES + b;
+            TK->TK[offset] = P_lane[TK->TK[offset]];
+        }
+    }
 }
 
 void tweakey_state_update(tweakey_state *TK)
-- 
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