XOR function differences between Python 3 and Python 2?

Question

Running in IDLE, Python 3.6.5 and Python 2.7.15 I have a strange problem with XOR. I get the correct answer with Python 2.7, and rubbish with Python 3.6. The Python 3.6 and 2.7 are not agreeing on a simple XOR. This is not an IDLE issue, since the behavior is the same in cygwin.

>>> ciphertext

'466d06ece998b7a2fb1d464fed2ced7641ddaa3cc31c9941cf110abbf409ed39598005b3399ccfafb61d0315fca0a314be138a9f32503bedac8067f03adbf3575c3b8edc9ba7f537530541ab0f9f3cd04ff50d66f1d559ba520e89a2cb2a83'

Python 2.7

>>> ciphertext.decode('hex')
'Fm\x06\xec\xe9\x98\xb7\xa2\xfb\x1dFO\xed,\xedvA\xdd\xaa<\xc3\x1c\x99A\xcf\x11\n\xbb\xf4\t\xed9Y\x80\x05\xb39\x9c\xcf\xaf\xb6\x1d\x03\x15\xfc\xa0\xa3\x14\xbe\x13\x8a\x9f2P;\xed\xac\x80g\xf0:\xdb\xf3W\\;\x8e\xdc\x9b\xa7\xf57S\x05A\xab\x0f\x9f<\xd0O\xf5\rf\xf1\xd5Y\xbaR\x0e\x89\xa2\xcb*\x83'
>>> for x, y in zip(ciphertext.decode('hex'), ' '*10):
    print "ord(x): " + chr(ord(x))
    print "ord(y): " + chr(ord(y))
    print(chr(ord(x) ^ ord(y)))


ord(x): F
ord(y):  
f
ord(x): m
ord(y):  
M
ord(x): 
ord(y): 
&
ord(x): ì
ord(y):  
Ì
ord(x): é
ord(y):  
É
ord(x): ˜
ord(y):  
¸
ord(x): ·
ord(y):  
—
ord(x): ¢
ord(y):  
‚
ord(x): û
ord(y):  
Û
ord(x): 
ord(y):  
=

Python 3.6

 >>> bytes.fromhex(ciphertext)

   b'Fm\x06\xec\xe9\x98\xb7\xa2\xfb\x1dFO\xed,\xedvA\xdd\xaa<\xc3\x1c\x99A\xcf\x11\n\xbb\xf4\t\xed9Y\x80\x05\xb39\x9c\xcf\xaf\xb6\x1d\x03\x15\xfc\xa0\xa3\x14\xbe\x13\x8a\x9f2P;\xed\xac\x80g\xf0:\xdb\xf3W\\;\x8e\xdc\x9b\xa7\xf57S\x05A\xab\x0f\x9f<\xd0O\xf5\rf\xf1\xd5Y\xbaR\x0e\x89\xa2\xcb*\x83'
>>> for x, y in zip(bytes.fromhex(ciphertext), ' '*10):
    print("x: ", chr(x))
    print("ord(y): ", chr(ord(y)))
    print(chr(x^ord(y)))


x:  F
ord(y):   
f
x:  m
ord(y):   
M
x:  
ord(y):   
&
x:  ì
ord(y):   
Ì
x:  é
ord(y):   
É
x:  
ord(y):   
¸
x:  ·
ord(y):   
<- different value
x:  ¢
ord(y):   
<- different value
x:  û
ord(y):   
Û
x:  
ord(y):   
=

In a cygwin window I get the following:
$ ./python2_test.py
Fm▒阷▒▒FO▒,▒vAݪ<▒▒A▒
f▒▒Y▒R▒▒▒*▒▒▒9▒ϯ▒▒▒▒▒▒▒2P;▒g▒:▒▒W\;▒ܛ▒▒7SA▒▒<▒O▒
ord(x): F
ord(y):
f
ord(x): m
ord(y):
M
ord(x):
ord(y):
&
ord(x): ▒
ord(y):
▒
ord(x): ▒
ord(y):
▒
ord(x): ▒
ord(y):
▒
ord(x): ▒
ord(y):
▒
ord(x): ▒
ord(y):
▒
ord(x): ▒
ord(y):
▒
ord(x):
ord(y):
=
$ ./python3_test.py
b'Fm\x06\xec\xe9\x98\xb7\xa2\xfb\x1dFO\xed,\xedvA\xdd\xaa<\xc3\x1c\x99A\xcf\x11\n\xbb\xf4\t\xed9Y\x80\x05\xb39\x9c\xcf\xaf\xb6\x1d\x03\x15\xfc\xa0\xa3\x14\xbe\x13\x8a\x9f2P;\xed\xac\x80g\xf0:\xdb\xf3W\\;\x8e\xdc\x9b\xa7\xf57S\x05A\xab\x0f\x9f<\xd0O\xf5\rf\xf1\xd5Y\xbaR\x0e\x89\xa2\xcb*\x83'
x:  F
ord(y):
f
x:  m
ord(y):
M
x:
ord(y):
&
x:  ì
ord(y):
Ì
x:  é
ord(y):
É
x:  
ord(y):
¸
x:  ·
ord(y):
<- missing
x:  ¢
ord(y):
<- missing
x:  û
ord(y):
Û
x:
ord(y):
=

Any help in sorting this out, would be greatly appreciated. Cheers.

Answer 1

I think you're seeing a problem of encoding. If you try to reproduce the steps printing numbers instead of chars, you'll see no difference. These are the scripts:

Python2:

ciphertext = '466d06ece998b7a2fb1d464fed2ced7641ddaa3cc31c9941cf110abbf409ed39598005b3399ccfafb61d0315fca0a314be138a9f32503bedac8067f03adbf3575c3b8edc9ba7f537530541ab0f9f3cd04ff50d66f1d559ba520e89a2cb2a83'

out1 = []
out2 = []
out3 = []
for x, y in zip(ciphertext.decode('hex'), ' '*10):
    out1.append(hex(ord(x)))
    out2.append(hex(ord(y)))
    out3.append(hex(ord(x) ^ ord(y)))
print out1
print out2
print out3

Python 3:

ciphertext = '466d06ece998b7a2fb1d464fed2ced7641ddaa3cc31c9941cf110abbf409ed39598005b3399ccfafb61d0315fca0a314be138a9f32503bedac8067f03adbf3575c3b8edc9ba7f537530541ab0f9f3cd04ff50d66f1d559ba520e89a2cb2a83'
out1 = []
out2 = []
out3 = []
for x, y in zip(bytes.fromhex(ciphertext), ' '*10):
    out1.append(x)
    out2.append(ord(y))
    out3.append(x ^ ord(y))
print(out1)
print(out2)
print(out3)

If you execute them both, you'll see that the output is the same.

You can see it directly on ideone, python2 and python3

EDIT: The execution of the script that I have given, slightly modified to show hex instead of raw numbers, give me as an output:

Python2:

['0x46', '0x6d', '0x6', '0xec', '0xe9', '0x98', '0xb7', '0xa2', '0xfb', '0x1d']
['0x20', '0x20', '0x20', '0x20', '0x20', '0x20', '0x20', '0x20', '0x20', '0x20']
['0x66', '0x4d', '0x26', '0xcc', '0xc9', '0xb8', '0x97', '0x82', '0xdb', '0x3d']

Python3:

['0x46', '0x6d', '0x6', '0xec', '0xe9', '0x98', '0xb7', '0xa2', '0xfb', '0x1d']
['0x20', '0x20', '0x20', '0x20', '0x20', '0x20', '0x20', '0x20', '0x20', '0x20']
['0x66', '0x4d', '0x26', '0xcc', '0xc9', '0xb8', '0x97', '0x82', '0xdb', '0x3d']

With the same input data you gave, I have a different input but my output data are coherent between Python2 and Python3.