def MGF1(mgfSeed, maskLen, hash):
 T = b('')
 for counter in xrange(ceil_div(maskLen, hash.digest_size)):
  c = long_to_bytes(counter, 4)
  try:
   T = (T + hash.new((mgfSeed + c)).digest())
  except AttributeError:
   T = (T + Hash_new(hash, (mgfSeed + c)).digest())
 assert (len(T) >= maskLen)
 return T[:maskLen]

def MGF1 ( mgfSeed , maskLen , hash ) : T = b ( '' ) for counter in xrange ( ceil_div ( maskLen , hash . digest_size ) ) : c = long_to_bytes ( counter , 4 ) try : T = ( T + hash . new ( ( mgfSeed + c ) ) . digest ( ) ) except AttributeError : T = ( T + Hash_new ( hash , ( mgfSeed + c ) ) . digest ( ) ) assert ( len ( T ) >= maskLen ) return T [ : maskLen ]
mask generation function .