Hi,
I try the exemple :
import jws
header = { 'alg': 'HS256' }
payload = { 'claim': 'JSON is the raddest.', 'iss': 'brianb' }
signature = jws.sign(header, payload, 'secret')
With Python 2.7.9 et 3.4.3, I get 2 signatures different : 9CG_vCmpr-UFKbkTtelFS2o9hJm1groP5vqUUKeV84c (3) and jn0z1avR1-tKtXjuEEVsGeBWHVx5E6YjzHEWmrkAdCY (2).
Python 2 seems to be ok (same as another language).