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authorJoachim StroĢˆmbergson <joachim@secworks.se>2018-06-29 09:45:28 +0200
committerJoachim StroĢˆmbergson <joachim@secworks.se>2018-06-29 09:45:28 +0200
commitc74cf5f6120d344da8646814d14766a2a49d3fcd (patch)
tree166df6c672cb93afec00eed6850b7e86ca9aa6c8 /src/model
parentd50f8723dc82f35a92c352a6d7fdb9d76bbad848 (diff)
Starting to add verbose debug print statements to get internal values during processing. This includes breaking up code statements.
Diffstat (limited to 'src/model')
-rwxr-xr-xsrc/model/aes_keywrap.py43
1 files changed, 31 insertions, 12 deletions
diff --git a/src/model/aes_keywrap.py b/src/model/aes_keywrap.py
index 49d02e1..6d99d0c 100755
--- a/src/model/aes_keywrap.py
+++ b/src/model/aes_keywrap.py
@@ -49,21 +49,26 @@
#
#======================================================================
-"""
-Python implementation of RFC 5649 AES Key Wrap With Padding,
-using PyCrypto to supply the AES code.
-"""
+from struct import pack, unpack
+from os import urandom
+from Crypto.Cipher import AES
+import unittest
+
+
+verbose = True
+
class AESKeyWrapWithPadding(object):
"""
Implementation of AES Key Wrap With Padding from RFC 5649.
+ using PyCrypto to supply the AES code.
"""
class UnwrapError(Exception):
"Something went wrong during unwrap."
def __init__(self, key):
- from Crypto.Cipher import AES
+ self.key = key
self.ctx = AES.new(key, AES.MODE_ECB)
def _encrypt(self, b1, b2):
@@ -79,6 +84,9 @@ class AESKeyWrapWithPadding(object):
step = -1 if start > stop else 1
return xrange(start, stop + step, step)
+ @staticmethod
+ def bin2hex(bytes, sep = ":"):
+ return sep.join("{:02x}".format(ord(b)) for b in bytes)
def wrap_key(self, Q):
"""
@@ -89,7 +97,12 @@ class AESKeyWrapWithPadding(object):
Returns C, the wrapped ciphertext.
"""
- from struct import pack, unpack
+ if verbose:
+ print("")
+ print("Performing key wrap.")
+ print("key: %s" % (self.bin2hex(self.key)))
+ print("plaintext: %s" % (self.bin2hex(Q)))
+ print("")
m = len(Q) # Plaintext length
if m % 8 != 0: # Pad Q if needed
@@ -107,9 +120,20 @@ class AESKeyWrapWithPadding(object):
# RFC 3394 section 2.2.1
for j in self._start_stop(0, 5):
for i in self._start_stop(1, n):
+ if verbose:
+ print("Iteration %d, %d" % (j, i))
+
+ if verbose:
+ print("Before encrypt: R[0] = %s R[i] = %s" % (self.bin2hex(R[0]), self.bin2hex(R[i])))
+
R[0], R[i] = self._encrypt(R[0], R[i])
+
+ if verbose:
+ print("After encrypt: R[0] = %s R[i] = %s" % (self.bin2hex(R[0]), self.bin2hex(R[i])))
+
W0, W1 = unpack(">LL", R[0])
- W1 ^= n * j + i
+ xorval = n * j + i
+ W1 ^= xorval
R[0] = pack(">LL", W0, W1)
assert len(R) == (n + 1) and all(len(r) == 8 for r in R)
@@ -125,8 +149,6 @@ class AESKeyWrapWithPadding(object):
Returns Q, the unwrapped plaintext.
"""
- from struct import pack, unpack
-
if len(C) % 8 != 0:
raise self.UnwrapError("Ciphertext length {} is not an integral number of blocks"
.format(len(C)))
@@ -168,8 +190,6 @@ if __name__ == "__main__":
# Test code from here down
- import unittest
-
class TestAESKeyWrapWithPadding(unittest.TestCase):
@staticmethod
@@ -306,7 +326,6 @@ if __name__ == "__main__":
self.loopback_test("Hello! My name is Inigo Montoya. You killed my AES key wrapper. Prepare to die.")
def test_joachim_loopback(self):
- from os import urandom
I = "31:32:33"
K = AESKeyWrapWithPadding(urandom(256/8))
C = K.wrap_key(I)