Question

ok so my issue is i have the string ‘\222\222\223\225’ which is stored as latin-1 in the db. What I get from django (by printing it) is the following string, ‘âââ⢒ which I assume is the UTF conversion of it. Now I need to pass the string into a function that does this operation:

strdecryptedPassword + chr(ord(c) - 3 - intCounter - 30) 

I get this error:

chr() arg not in range(256)

If I try to encode the string as latin-1 first I get this error:

‘latin-1’ codec can’t encode characters in position 0-3: ordinal not in range(256)

I have read a bunch on how character encoding works, and there is something I am missing because I just don’t get it!

Answer 1

Your first error ‘chr() arg not in range(256)’ probably means you have underflowed the value, because chr cannot take negative numbers. I don’t know what the encryption algorithm is supposed to do when the inputcounter + 33 is more than the actual character representation, you’ll have to check what to do in that case.

About the second error. you must decode() and not encode() a regular string object to get a proper representation of your data. encode() takes a unicode object (those starting with u’) and generates a regular string to be output or written to a file. decode() takes a string object and generate a unicode object with the corresponding code points. This is done with the unicode() call when generated from a string object, you could also call a.decode(‘latin-1’) instead.

>>> a = '\222\222\223\225' >>> u = unicode(a,'latin-1') >>> u u'\x92\x92\x93\x95' >>> print u.encode('utf-8') ÂÂÂÂ >>> print u.encode('utf-16') ÿþ >>> print u.encode('latin-1')  >>> for c in u: ...   print chr(ord(c) - 3 - 0 -30) ... q q r t >>> for c in u: ...   print chr(ord(c) - 3 -200 -30) ... Traceback (most recent call last):   File '<stdin>', line 2, in <module> ValueError: chr() arg not in range(256)