[implem-python] Suppression de paramètres redondants

tweak_bits est  constant pour un mode  donné ; rounds se  déduit de la
taille de clé.

4 files changed, 28 insertions, 42 deletions

diff --git a/python/constants.py b/python/constants.py
index acedfa7..94a3e0e 100644
--- a/python/constants.py
+++ b/python/constants.py
@@ -1,6 +1,15 @@
 BLOCK_BYTES = 16
 
 
+def rounds(key_bits):
+    r = {
+        128: 32,
+        192: 36,
+        256: 42
+    }
+    return r[key_bits]
+
+
 Sbox = [32,  0,   178, 133, 59,  53,  166, 164,
     48,  228, 106, 44,  255, 89,  226, 14,
     248, 30,  122, 128, 21,  189, 62,  177,
diff --git a/python/lilliput.py b/python/lilliput.py
index 21feb60..f6679a8 100644
--- a/python/lilliput.py
+++ b/python/lilliput.py
@@ -1,24 +1,9 @@
 import lilliput_ae_1
 import lilliput_ae_2
 
-N_BYTES = 15
-
-def _getParameters(mode=1, key_length=128) :
-    rounds = {
-        128: 32,
-        192: 36,
-        256: 42
-    }
-
-    tweak_lengths = {
-        1: 192,
-        2: 128
-    }
-
-    return tweak_lengths[mode], rounds[key_length]
 
+N_BYTES = 15
 
-############################################
 
 def _checkInputs(key, nonce):
     valid_key_lengths = (128, 192, 256)
@@ -33,29 +18,25 @@ def _checkInputs(key, nonce):
 def mainEnc(plaintext, adata, key, nonce, mode):
     _checkInputs(key, nonce)
 
-    tweak_bits, rounds = _getParameters(mode, len(key)*8)
-
     A = adata
     M = plaintext
     N = nonce
 
     if(mode == 1) :
-        return lilliput_ae_1.OCB3Enc(A, M, N, key, tweak_bits, rounds)
+        return lilliput_ae_1.OCB3Enc(A, M, N, key)
     if(mode == 2) :
-        return lilliput_ae_2.SCT2Enc(A, M, N, key, tweak_bits, rounds)
+        return lilliput_ae_2.SCT2Enc(A, M, N, key)
 
 
 def mainDec(ciphertext, tag, adata, key, nonce, mode):
     _checkInputs(key, nonce)
 
-    tweak_bits, rounds = _getParameters(mode, len(key)*8)
-
     A = adata
     C = ciphertext
     N = nonce
     tag = list(tag)
 
     if(mode == 1) :
-        return lilliput_ae_1.OCB3Dec(A, C, N, tag, key, tweak_bits, rounds)
+        return lilliput_ae_1.OCB3Dec(A, C, N, tag, key)
     if(mode == 2) :
-        return lilliput_ae_2.SCT2Dec(A, C, N, tag, key, tweak_bits, rounds)
+        return lilliput_ae_2.SCT2Dec(A, C, N, tag, key)
diff --git a/python/lilliput_ae_1.py b/python/lilliput_ae_1.py
index 3629fec..688148f 100644
--- a/python/lilliput_ae_1.py
+++ b/python/lilliput_ae_1.py
@@ -3,6 +3,7 @@
 """
 
 import lilliput_tbc as ltbc
+from constants import rounds
 from helpers import ArrayToBlockbytesMatrix, BlockbytesMatrixToBytes
 
 
@@ -24,23 +25,19 @@ M_BITS = BLOCK_BITS
 N_BITS = 120
 N_BYTES = int(N_BITS / 8)
 
-def InitParameters(key_bits = 128, tweak_bits = 192, rounds = 32) :
+def InitParameters(key_bits) :
     global KEY_BITS
     global KEY_BYTES
-    global TWEAK_BITS
-    global TWEAK_BYTES
     global TWEAKEY_BITS
     global TWEAKEY_BYTES
     global LANES
     global ROUNDS
 
     KEY_BITS = key_bits
-    TWEAK_BITS = tweak_bits
     TWEAKEY_BITS = KEY_BITS + TWEAK_BITS
     LANES = int((TWEAKEY_BITS) / LANE_BITS)
-    ROUNDS = rounds
+    ROUNDS = rounds(key_bits)
     KEY_BYTES = int(KEY_BITS / 8)
-    TWEAK_BYTES = int(TWEAK_BITS / 8)
     TWEAKEY_BYTES = int(TWEAKEY_BITS / 8)
 
 
@@ -221,8 +218,8 @@ def TreatMessageDec(C, N, key) :
 
 
 ################################################################################
-def OCB3Enc(A, M, N, key, tweak_bits, rounds) :
-    InitParameters(len(key)*8, tweak_bits, rounds)
+def OCB3Enc(A, M, N, key) :
+    InitParameters(len(key)*8)
 
     global A_BITS
     global M_BITS
@@ -255,8 +252,8 @@ def OCB3Enc(A, M, N, key, tweak_bits, rounds) :
     return BlockbytesMatrixToBytes(C), bytes(tag)
 
 
-def OCB3Dec(A, C, N, tag, key, tweak_bits, rounds) :
-    InitParameters(len(key)*8, tweak_bits, rounds)
+def OCB3Dec(A, C, N, tag, key) :
+    InitParameters(len(key)*8)
 
     global A_BITS
     global M_BITS
diff --git a/python/lilliput_ae_2.py b/python/lilliput_ae_2.py
index 757088d..d333be2 100644
--- a/python/lilliput_ae_2.py
+++ b/python/lilliput_ae_2.py
@@ -3,6 +3,7 @@
 """
 
 import lilliput_tbc as ltbc
+from constants import rounds
 from helpers import ArrayToBlockbytesMatrix, BlockbytesMatrixToBytes
 
 
@@ -25,7 +26,7 @@ N_BITS = 120
 N_BYTES = int(N_BITS / 8)
 
 
-def InitParameters(key_bits = 128, tweak_bits = 128, rounds = 32) :
+def InitParameters(key_bits) :
     global KEY_BITS
     global KEY_BYTES
     global TWEAK_BITS
@@ -36,12 +37,10 @@ def InitParameters(key_bits = 128, tweak_bits = 128, rounds = 32) :
     global ROUNDS
 
     KEY_BITS = key_bits
-    TWEAK_BITS = tweak_bits
     TWEAKEY_BITS = KEY_BITS + TWEAK_BITS
     LANES = int((TWEAKEY_BITS) / LANE_BITS)
-    ROUNDS = rounds
+    ROUNDS = rounds(key_bits)
     KEY_BYTES = int(KEY_BITS / 8)
-    TWEAK_BYTES = int(TWEAK_BITS / 8)
     TWEAKEY_BYTES = int(TWEAKEY_BITS / 8)
 
 
@@ -217,8 +216,8 @@ def MessageEncryption(M, N, tag, key) :
     return C
 
 ################################################################################
-def SCT2Enc(A, M, N, key, tweak_bits, rounds) :
-    InitParameters(len(key)*8, tweak_bits, rounds)
+def SCT2Enc(A, M, N, key) :
+    InitParameters(len(key)*8)
 
     global A_BITS
     global M_BITS
@@ -251,8 +250,8 @@ def SCT2Enc(A, M, N, key, tweak_bits, rounds) :
     return BlockbytesMatrixToBytes(C), bytes(tag)
 
 
-def SCT2Dec(A, C, N, tag, key, tweak_bits, rounds) :
-    InitParameters(len(key)*8, tweak_bits, rounds)
+def SCT2Dec(A, C, N, tag, key) :
+    InitParameters(len(key)*8)
 
     global A_BITS
     global M_BITS