[pycrypto] AES, python 2.7 vs 3

[Dave Pawson]

Thanks Paul. I was going along those lines, but without much understanding?
Is it correct that pycrypto relies on byte strings and *cannot* deal
with Unicode strings?

regards

On 7 February 2014 16:26,  <Paul_Koning at dell.com> wrote:
>
> On Feb 7, 2014, at 1:29 AM, Dave Pawson <dave.pawson at gmail.com> wrote:
>
>> On 6 February 2014 16:49, Dwayne Litzenberger <dlitz at dlitz.net> wrote:
>>> On Mon, Feb 03, 2014 at 03:51:06PM +0100, Mirko Dziadzka wrote:
>>>>
>>>> Hi
>>>>
>>>> Without testing or verifying:
>>>>
>>>> You should probably use bytes in Python 3, not characters.
>>>
>>>
>>> Yeah, this is a known bug.   Under Python 3, PyCrypto should raise a
>>> TypeError in most places where unicode strings are used instead of bytes,
>>> but right now it just does weird things.  Sorry about that.
>>
>>
>> Recently playing about with reading / writing between Linux / Windows,
>> one symptom I came across was that the decrypted string contained b' <string>'
>> is that a part of this bug?
>
> b’something’ is Python 3 syntax for a “bytes” literal.
>
> It’s a good idea to spend some time reading the Python 3 documentation on text vs. bytes — “str” vs. “bytes” type.  They really got this right, and it completely cures the ugly mess you get in Python 2 when dealing with strings vs. their encoding.
>
> But it is new, and it’s different from what was done before — for good reasons.
>
> One short summary is: “str” contains text, it’s abstract, it represents Unicode characters but does not talk about encoding.  “bytes” contains sequences of bytes (octets — 8 bit integers), it’s concrete, it represents encoding of data in the outside world.  You convert “str” to/from “bytes” when doing I/O.  Anytime you are doing operations that need sequences of bytes, the type has to be “bytes”.  Encryption is one such operation.
>
>         paul
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