XORing long strings opimization?

[Noen]

Peter Otten wrote:
> Noen wrote:
> 
> 
>>Oh, didnt notice that as I wrote it. Thanks...
>>Anyway, this is how it should be.
>>
>>def XOR(s1,s2):
>>     """ XOR string s1 with s2 """
>>     output = ""
>>     # Argument check
>>     if (type(s1) and type(s2)) != type(""):
>>         raise TypeError, "Arguments are not strings"
>>     if len(s1) != len(s2):
>>         raise ValueError, "Size differs in strings"
>>     # Xoring
>>     for i in range(len(s1)):
>>         output += chr(ord(s1[i]) ^ ord(s2[i]))
>>     return output
> 
> 
> Oops, I missed one: 
> 
> 
>>>>xor2.XOR(1, "")
> 
> Traceback (most recent call last):
>   File "<stdin>", line 1, in ?
>   File "xor2.py", line 7, in XOR
>     if len(s1) != len(s2):
> TypeError: len() of unsized object
> 
> Did you expect this?
> 
> Peter
nope, thought the Argument check would do it, but I used and opeartor 
instead of or. Well, here is XOR v.0.3b :P Any comments how to make it 
faster?

def XOR(s1,s2):
     """ XOR string s1 with s2 """
     output = ""
     # Argument check
     if (type(s1) or type(s2)) != type(""):
         raise TypeError, "Arguments are not strings"
     if len(s1) != len(s2):
         raise ValueError, "Size differs in strings"
     # Xoring
     for i in range(len(s1)):
         output += chr(ord(s1[i]) ^ ord(s2[i]))
     return output