* cosmetic

eax.py

@@ -25,13 +25,13 @@ def ctr(cfg, key, data, nonce):
     enc = cfg.ECB(key)
     out = b''
 
-    nonce_int = int.from_bytes(nonce, byteorder=cfg.ENDIAN, signed=False)
+    nonce_int = int.from_bytes(nonce, cfg.ENDIAN, signed=False)
 
     cnt = 0
     for i in range(0, len(data), cfg.BLOCKSIZE):
         block = data[i:i+cfg.BLOCKSIZE]
         k = (nonce_int + cnt) & cfg.BLOCKSIZE_MASK
-        k = k.to_bytes(cfg.BLOCKSIZE, byteorder=cfg.ENDIAN)
+        k = k.to_bytes(cfg.BLOCKSIZE, cfg.ENDIAN)
         xorbuf = enc.run(k)
         out += xorstrings(block, xorbuf)
         cnt += 1
@@ -41,13 +41,13 @@ def omac(cfg, key, data, k):
     enc = cfg.ECB(key)
 
     L = enc.run(bytes([0] * cfg.BLOCKSIZE))
-    L_int = int.from_bytes(L, byteorder=cfg.ENDIAN, signed=False)
+    L_int = int.from_bytes(L, cfg.ENDIAN, signed=False)
 
     L2_int = gf_double(L_int, cfg.BLOCKSIZE)
     L4_int = gf_double(L2_int, cfg.BLOCKSIZE)
 
-    L2 = L2_int.to_bytes(cfg.BLOCKSIZE, byteorder=cfg.ENDIAN)
-    L4 = L4_int.to_bytes(cfg.BLOCKSIZE, byteorder=cfg.ENDIAN)
+    L2 = L2_int.to_bytes(cfg.BLOCKSIZE, cfg.ENDIAN)
+    L4 = L4_int.to_bytes(cfg.BLOCKSIZE, cfg.ENDIAN)
 
     data = bytes([0] * (cfg.BLOCKSIZE - 1) + [k]) + data
     data = bytearray(data)

eax_stream.py

@@ -5,14 +5,14 @@ class OMAC_stream:
     def __init__(self, cfg, key, k):
         enc = cfg.ECB(key)
         L = enc.run(bytes([0] * cfg.BLOCKSIZE))
-        L_int = int.from_bytes(L, byteorder=cfg.ENDIAN, signed=False)
+        L_int = int.from_bytes(L, cfg.ENDIAN, signed=False)
 
         L2_int = gf_double(L_int, cfg.BLOCKSIZE)
         L4_int = gf_double(L2_int, cfg.BLOCKSIZE)
 
         self.cfg = cfg
-        self.L2 = L2_int.to_bytes(cfg.BLOCKSIZE, byteorder=cfg.ENDIAN)
-        self.L4 = L4_int.to_bytes(cfg.BLOCKSIZE, byteorder=cfg.ENDIAN)
+        self.L2 = L2_int.to_bytes(cfg.BLOCKSIZE, cfg.ENDIAN)
+        self.L4 = L4_int.to_bytes(cfg.BLOCKSIZE, cfg.ENDIAN)
 
         self.enc = enc
         self.readyblock = bytes([0] * (cfg.BLOCKSIZE - 1) + [k])
@@ -52,7 +52,7 @@ def digest(self):
 class CTR_stream:
     def __init__(self, cfg, key, nonce):
         enc = cfg.ECB(key)
-        nonce_int = int.from_bytes(nonce, byteorder=cfg.ENDIAN, signed=False)
+        nonce_int = int.from_bytes(nonce, cfg.ENDIAN, signed=False)
 
         self.cfg = cfg
         self.enc = enc
@@ -64,7 +64,7 @@ def process_byte(self, byte):
         cfg = self.cfg
         if self.pos % cfg.BLOCKSIZE == 0:
             counter = (self.nonce + self.pos // cfg.BLOCKSIZE) & cfg.BLOCKSIZE_MASK
-            counter = counter.to_bytes(cfg.BLOCKSIZE, byteorder=cfg.ENDIAN)
+            counter = counter.to_bytes(cfg.BLOCKSIZE, cfg.ENDIAN)
             self.xorbuf = self.enc.run(counter)
 
         pt = self.xorbuf[self.pos % cfg.BLOCKSIZE] ^ byte

xtea.py

@@ -1,24 +1,29 @@
-import struct
-
 MASK32 = (1 << 32) - 1
 
 class XTEA:
     def __init__(self, key, rounds=32):
-        self.keywords = struct.unpack('<IIII', key)
+        if len(key) != 16:
+            raise Exception('Expecting the 128 bit (16 bytes) key')
+
+        key = int.from_bytes(key, 'little', signed=False)
+        keywords = (key >> 0) & MASK32, (key >> 32) & MASK32, (key >> 64) & MASK32, (key >> 96) & MASK32,
+
         schkey = []
         # schedule the key for 32 rounds to move it out of enc loop
         sum = 0
         delta = 0x9E3779B9
         for round in range(rounds):
-            k0 = (sum + self.keywords[sum & 3]) & MASK32
+            k0 = (sum + keywords[sum & 3]) & MASK32
             sum = (sum + delta) & MASK32
-            k1 = (sum + self.keywords[(sum>>11) & 3]) & MASK32
+            k1 = (sum + keywords[(sum>>11) & 3]) & MASK32
             schkey.append((k0, k1))
         self.schkey = schkey
 
     def encrypt(self, pt):
-        v0, v1 = struct.unpack('<II', pt)
+        pt = int.from_bytes(pt, 'little', signed=False)
+        v0, v1 = (pt >> 0) & MASK32, (pt >> 32) & MASK32
         for schkey in self.schkey:
             v0 = (v0 + ((((v1<<4) ^ (v1>>5)) + v1) ^ schkey[0])) & MASK32
             v1 = (v1 + ((((v0<<4) ^ (v0>>5)) + v0) ^ schkey[1])) & MASK32
-        return struct.pack('<II', v0, v1)
+        ct = (v1 << 32) | v0
+        return ct.to_bytes(8, 'little')