From fc7f6f86fb89adfb12289e69ed1e57f6bfa7e607 Mon Sep 17 00:00:00 2001
From: Kévin Le Gouguec <kevin.legouguec@airbus.com>
Date: Thu, 22 Nov 2018 17:21:29 +0100
Subject: Implémentation du mode ΘCB3 (suite)
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---
 crypto_aead/lilliputaei128v1/ref/lilliput-ae-i.c | 27 ++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/crypto_aead/lilliputaei128v1/ref/lilliput-ae-i.c b/crypto_aead/lilliputaei128v1/ref/lilliput-ae-i.c
index a52049e..f67be07 100644
--- a/crypto_aead/lilliputaei128v1/ref/lilliput-ae-i.c
+++ b/crypto_aead/lilliputaei128v1/ref/lilliput-ae-i.c
@@ -2,15 +2,42 @@
 #include <stdint.h>
 #include <string.h>
 
+#include "cipher.h"
 #include "lilliput-ae.h"
 
 
+static void _lilliput_tbc(const uint8_t key[KEY_BYTES],
+                          const uint8_t tweak[TWEAK_BYTES],
+                          const uint8_t message[BLOCK_BYTES],
+                          uint8_t ciphertext[BLOCK_BYTES])
+{
+    lilliput_tbc_encrypt(key, tweak, message, ciphertext, NULL);
+}
+
+static void _xor_into(size_t len, uint8_t dest[len], uint8_t src[len])
+{
+    for (size_t i=0; i<len; i++)
+        dest[i] ^= src[i];
+}
+
 static void _process_associated_data(
     const uint8_t key[KEY_BYTES],
     size_t auth_data_len, const uint8_t auth_data[auth_data_len],
     uint8_t auth[BLOCK_BYTES]
 )
 {
+    size_t l_a = auth_data_len / BLOCK_BYTES;
+
+    memset(auth, 0, BLOCK_BYTES);
+
+    for (size_t i=0; i<l_a; i++)
+    {
+        uint8_t tweak[TWEAK_BYTES];
+        /* TODO: generate tweak */
+        uint8_t Ek_Ai[BLOCK_BYTES];
+        _lilliput_tbc(key, tweak, auth_data+i*BLOCK_BYTES, Ek_Ai);
+        _xor_into(BLOCK_BYTES, auth, Ek_Ai);
+    }
 }
 
 static void _encrypt_message(
-- 
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