Question

I’m trying to compute hmac using sha-512.

The Perl code:

use Digest::SHA qw(hmac_sha512_hex);  $key = '\x0b'x20; $data = 'Hi There';  $hash = hmac_sha512_hex($data, $key); print '$hash\n'; 

and gives the correct hash of

87aa7cdea5ef619d4ff0b4241a1d6cb02379f4e2ce4ec2787ad0b30545e17cde   daa833b7d6b8a702038b274eaea3f4e4be9d914eeb61f1702e696c203a126854 

Python version:

import hashlib, hmac  print hmac.new('\x0b'*20, 'Hi There', hashlib.sha512).hexdigest() 

which gives the incorrect hash of

9656975ee5de55e75f2976ecce9a04501060b9dc22a6eda2eaef638966280182 477fe09f080b2bf564649cad42af8607a2bd8d02979df3a980f15e2326a0a22a 

any ideas why the Python version is giving me the wrong hash?

Edit:
version is
Python 2.5.1 (r251:54863, Jan 13 2009, 10:26:13)
[GCC 4.0.1 (Apple Inc. build 5465)] on darwin

Answer 1

yes indeed — it seems the Leopard version of python2.5 is the one that is broken.

below run on a Penryn-based MBP…

$ **uname -a** Darwin lizard-wifi 9.6.0 Darwin Kernel Version 9.6.0: Mon Nov 24 17:37:00 PST 2008; root:xnu-1228.9.59~1/RELEASE_I386 i386 dpc@lizard-wifi:~$ **which python** /usr/bin/python 

Running this version installed in Leopard OS

dpc@lizard-wifi:~$ python Python 2.5.1 (r251:54863, Jan 13 2009, 10:26:13)  [GCC 4.0.1 (Apple Inc. build 5465)] on darwin Type 'help', 'copyright', 'credits' or 'license' for more information. >>> import hashlib, hmac >>> print hmac.new('\x0b'*20, 'Hi There', hashlib.sha512).hexdigest() 9656975ee5de55e75f2976ecce9a04501060b9dc22a6eda2eaef638966280182477fe09f080b2bf564649cad42af8607a2bd8d02979df3a980f15e2326a0a22a >>>  

And then the MacPorts version of python2.5

$ /opt/local/bin/python2.5 Python 2.5.4 (r254:67916, Feb  3 2009, 21:40:31)  [GCC 4.0.1 (Apple Inc. build 5488)] on darwin Type 'help', 'copyright', 'credits' or 'license' for more information. >>> import hashlib, hmac >>> print hmac.new('\x0b'*20, 'Hi There', hashlib.sha512).hexdigest() 87aa7cdea5ef619d4ff0b4241a1d6cb02379f4e2ce4ec2787ad0b30545e17cdedaa833b7d6b8a702038b274eaea3f4e4be9d914eeb61f1702e696c203a126854 >>>