[implem-python] Simplification du contrôle des paramètres

Encore un peu  de duplication sur les longueurs de  clés valides. On y
travaille.

8 files changed, 26 insertions, 69 deletions

diff --git a/python/genkat_aead.py b/python/genkat_aead.py
index 3a69d72..6d7ca51 100755
--- a/python/genkat_aead.py
+++ b/python/genkat_aead.py
@@ -64,11 +64,11 @@ def generate_test_vectors(mode, keylen):
                 print_bstr(output, 'PT', msg)
                 print_bstr(output, 'AD', ad)
 
-                ct, tag = lilliput.mainEnc(msg, ad, key, nonce, mode, keylen)
+                ct, tag = lilliput.mainEnc(msg, ad, key, nonce, mode)
 
                 print_bstr(output, 'CT', ct+tag)
 
-                msg2 = lilliput.mainDec(ct, tag, ad, key, nonce, mode, keylen)
+                msg2 = lilliput.mainDec(ct, tag, ad, key, nonce, mode)
 
                 if msg != msg2:
                     raise DecryptionError(msg, msg2, mode, keylen)
diff --git a/python/lilliput.py b/python/lilliput.py
index 79f14e5..3fe41bf 100644
--- a/python/lilliput.py
+++ b/python/lilliput.py
@@ -1,34 +1,23 @@
 import lilliput_ae_1
 import lilliput_ae_2
 
-import parameters_i_128 as i_128
-import parameters_i_192 as i_192
-import parameters_i_256 as i_256
-import parameters_ii_128 as ii_128
-import parameters_ii_192 as ii_192
-import parameters_ii_256 as ii_256
-
 BLOCK_BYTES = 16
 N_BYTES = 15
 
-def GetParameters(mode = 1, length = 128) :
-    if(mode == 1 and length == 128) :
-        return (i_128.KEY_BITS, i_128.TWEAK_BITS, i_128.ROUNDS)
-
-    if(mode == 1 and length == 192) :
-        return (i_192.KEY_BITS, i_192.TWEAK_BITS, i_192.ROUNDS)
+def _getParameters(mode=1, key_length=128) :
+    rounds = {
+        128: 32,
+        192: 36,
+        256: 42
+    }
 
-    if(mode == 1 and length == 256) :
-        return (i_256.KEY_BITS, i_256.TWEAK_BITS, i_256.ROUNDS)
+    tweak_lengths = {
+        1: 192,
+        2: 128
+    }
 
-    if(mode == 2 and length == 128) :
-        return (ii_128.KEY_BITS, ii_128.TWEAK_BITS, ii_128.ROUNDS)
+    return tweak_lengths[mode], rounds[key_length]
 
-    if(mode == 2 and length == 192) :
-        return (ii_192.KEY_BITS, ii_192.TWEAK_BITS, ii_192.ROUNDS)
-
-    if(mode == 2 and length == 256) :
-        return (ii_256.KEY_BITS, ii_256.TWEAK_BITS, ii_256.ROUNDS)
 
 def ArrayToBlockbytesMatrix(array) :
     length = len(array)
@@ -53,18 +42,21 @@ def BlockbytesMatrixToBytes(matrix):
 
 ############################################
 
-def _checkInputs(key, length, nonce):
-    if len(key) != length//8:
-        raise ValueError('invalid key size: {} != {}'.format(len(key), length//8))
+def _checkInputs(key, nonce):
+    valid_key_lengths = (128, 192, 256)
+
+    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:
         raise ValueError('nonce must be {}-byte long'.format(N_BYTES))
 
 
-def mainEnc(plaintext, adata, key, nonce, mode=1, length=128):
-    _checkInputs(key, length, nonce)
+def mainEnc(plaintext, adata, key, nonce, mode):
+    _checkInputs(key, nonce)
 
-    (key_bits, tweak_bits, rounds) = GetParameters(mode, length)
+    key_bits = len(key)*8
+    tweak_bits, rounds = _getParameters(mode, key_bits)
 
     A = adata
     M = plaintext
@@ -84,10 +76,11 @@ def mainEnc(plaintext, adata, key, nonce, mode=1, length=128):
     return BlockbytesMatrixToBytes(C), bytes(tag)
 
 
-def mainDec(ciphertext, tag, adata, key, nonce, mode=1, length=128):
-    _checkInputs(key, length, nonce)
+def mainDec(ciphertext, tag, adata, key, nonce, mode):
+    _checkInputs(key, nonce)
 
-    (key_bits, tweak_bits, rounds) = GetParameters(mode, length)
+    key_bits = len(key)*8
+    tweak_bits, rounds = _getParameters(mode, key_bits)
 
     A = adata
     C = ciphertext
diff --git a/python/parameters_i_128.py b/python/parameters_i_128.py
deleted file mode 100644
index 7f0675a..0000000
--- a/python/parameters_i_128.py
+++ /dev/null
@@ -1,6 +0,0 @@
-"""
-    Lilliput ae i 128
-"""
-KEY_BITS = 128
-TWEAK_BITS = 192
-ROUNDS = 32
diff --git a/python/parameters_i_192.py b/python/parameters_i_192.py
deleted file mode 100644
index c513331..0000000
--- a/python/parameters_i_192.py
+++ /dev/null
@@ -1,6 +0,0 @@
-"""
-    Lilliput ae i 128
-"""
-KEY_BITS = 192
-TWEAK_BITS = 192
-ROUNDS = 36
diff --git a/python/parameters_i_256.py b/python/parameters_i_256.py
deleted file mode 100644
index ab81130..0000000
--- a/python/parameters_i_256.py
+++ /dev/null
@@ -1,6 +0,0 @@
-"""
-    Lilliput ae i 128
-"""
-KEY_BITS = 256
-TWEAK_BITS = 192
-ROUNDS = 42
diff --git a/python/parameters_ii_128.py b/python/parameters_ii_128.py
deleted file mode 100644
index 8647a66..0000000
--- a/python/parameters_ii_128.py
+++ /dev/null
@@ -1,6 +0,0 @@
-"""
-    Lilliput ae i 128
-"""
-KEY_BITS = 128
-TWEAK_BITS = 128
-ROUNDS = 32
diff --git a/python/parameters_ii_192.py b/python/parameters_ii_192.py
deleted file mode 100644
index d17d6ec..0000000
--- a/python/parameters_ii_192.py
+++ /dev/null
@@ -1,6 +0,0 @@
-"""
-    Lilliput ae i 128
-"""
-KEY_BITS = 192
-TWEAK_BITS = 128
-ROUNDS = 36
diff --git a/python/parameters_ii_256.py b/python/parameters_ii_256.py
deleted file mode 100644
index 159c78f..0000000
--- a/python/parameters_ii_256.py
+++ /dev/null
@@ -1,6 +0,0 @@
-"""
-    Lilliput ae i 128
-"""
-KEY_BITS = 256
-TWEAK_BITS = 128
-ROUNDS = 42