help tranlating perl expressions

[David Bear]

Fredrik Lundh wrote:

> David Bear wrote:
> 
>  > I am trying to translate some perl code to python and I need some
>  > advice on making fixed sized strings.
> 
> looks like you're reimplementing HMAC; there's no need to do that in
> Python, really, since it's part of the standard library:
> 
>      http://docs.python.org/lib/module-hmac.html
> 
> pass in hashlib.sha1 instead of the default, and you're done.
> 
> if you insist on doing it yourself, read on:
> 
>>  my $ipad = chr(0x36)x$blen;
>>  my $opad = chr(0x5c)x$blen;
>> 
>> I don't know if I ever seen any way in python of created a fixed size
>> string. Can anyone show me how to implement the same statements in
>> python?
> 
> just remove all the junk, and use multiply instead of "x":
> 
>      ipad = chr(0x36) * blen
>      opad = chr(0x5c) * blen
> 
> however, Python strings are not mutable, so to implement the rest of
> that algorithm, you probably want to use a list or array object instead.
>   the md5-example-4.py script on this page shows one way to do that:
> 
>      http://effbot.org/librarybook/md5.htm
> 
> to get a SHA-1 hmac, you have to replace "md5" with "sha".
> 
> </F>

Yes, this is what I am doing. Because I am using code sold to me by a vendor
-- I was worried that they are doing something with it that had some
dependencies on the way perl was making the digest. So I was trying to
better understand the perl by doing it in python.

-- 
David Bear
-- let me buy your intellectual property, I want to own your thoughts --