From 504c32f4bd4d6e90864fec066de950a1b8925709 Mon Sep 17 00:00:00 2001
From: Kévin Le Gouguec <kevin.legouguec@airbus.com>
Date: Thu, 14 Mar 2019 13:06:45 +0100
Subject: [implem-python] Ajout de NONCE_BYTES dans constants.py

---
 python/constants.py     |  1 +
 python/lilliput.py      |  6 ++----
 python/lilliput_ae_1.py | 15 +++++++--------
 python/lilliput_ae_2.py |  2 --
 4 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/python/constants.py b/python/constants.py
index 94a3e0e..02bbc1f 100644
--- a/python/constants.py
+++ b/python/constants.py
@@ -1,4 +1,5 @@
 BLOCK_BYTES = 16
+NONCE_BYTES = 15
 
 
 def rounds(key_bits):
diff --git a/python/lilliput.py b/python/lilliput.py
index f6679a8..e92ed5f 100644
--- a/python/lilliput.py
+++ b/python/lilliput.py
@@ -1,8 +1,6 @@
 import lilliput_ae_1
 import lilliput_ae_2
-
-
-N_BYTES = 15
+from constants import NONCE_BYTES
 
 
 def _checkInputs(key, nonce):
@@ -11,7 +9,7 @@ def _checkInputs(key, nonce):
     if len(key)*8 not in valid_key_lengths:
         raise ValueError('invalid key size: {} not in {}'.format(len(key)*8, valid_key_lengths))
 
-    if len(nonce) != N_BYTES:
+    if len(nonce) != NONCE_BYTES:
         raise ValueError('nonce must be {}-byte long'.format(N_BYTES))
 
 
diff --git a/python/lilliput_ae_1.py b/python/lilliput_ae_1.py
index 688148f..92cfa6e 100644
--- a/python/lilliput_ae_1.py
+++ b/python/lilliput_ae_1.py
@@ -3,7 +3,7 @@
 """
 
 import lilliput_tbc as ltbc
-from constants import rounds
+from constants import NONCE_BYTES, rounds
 from helpers import ArrayToBlockbytesMatrix, BlockbytesMatrixToBytes
 
 
@@ -22,8 +22,7 @@ TWEAKEY_BYTES = int(TWEAKEY_BITS / 8)
 
 A_BITS = BLOCK_BITS
 M_BITS = BLOCK_BITS
-N_BITS = 120
-N_BYTES = int(N_BITS / 8)
+
 
 def InitParameters(key_bits) :
     global KEY_BITS
@@ -131,12 +130,12 @@ def BuildAuth(A, key) :
 
 def TweakMessage(N, j, null = 0, padded = 0, final_padded = 0) :
     tweak = [0 for byte in range(0,  TWEAK_BYTES)]
-    for byte in range(N_BYTES - 1, -1, -1) :
-        tweak[byte + (TWEAK_BYTES - N_BYTES)] |= (N[byte] & 0xf0) >> 4
-        tweak[byte + (TWEAK_BYTES - N_BYTES - 1)] |= (N[byte] & 0x0f) << 4
+    for byte in range(NONCE_BYTES-1, -1, -1) :
+        tweak[byte + (TWEAK_BYTES-NONCE_BYTES)] |= (N[byte] & 0xf0) >> 4
+        tweak[byte + (TWEAK_BYTES-NONCE_BYTES-1)] |= (N[byte] & 0x0f) << 4
 
-    tweak[TWEAK_BYTES - N_BYTES - 1] |= ((j >> 64) & 0xf)
-    for byte in range(TWEAK_BYTES - N_BYTES - 2, -1, -1) :
+    tweak[TWEAK_BYTES-NONCE_BYTES-1] |= ((j >> 64) & 0xf)
+    for byte in range(TWEAK_BYTES-NONCE_BYTES-2, -1, -1) :
         tweak[byte] = (j >> (8 * byte)) & 0xff
 
     if null == 1 :
diff --git a/python/lilliput_ae_2.py b/python/lilliput_ae_2.py
index d333be2..d072935 100644
--- a/python/lilliput_ae_2.py
+++ b/python/lilliput_ae_2.py
@@ -22,8 +22,6 @@ TWEAKEY_BYTES = int(TWEAKEY_BITS / 8)
 
 A_BITS = BLOCK_BITS
 M_BITS = BLOCK_BITS
-N_BITS = 120
-N_BYTES = int(N_BITS / 8)
 
 
 def InitParameters(key_bits) :
-- 
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