Authorize.net integration problem

[Lakshman]

I am trying to integrate Authorize.net SIM API into django views.

I am facing a problem in the fingerprint generation. I am repeatedly
getting that the fingerprint generated doesn't match the one the
server generates.

I have generated the md5 hash with the key provided as specified in
the SIM documentation.

Here is the code:

    params = {
        'x_login' : '4ffrBT36La',
        'x_amount' : '100.00',
        'x_show_form' : 'PAYMENT_FORM',
        'x_type' : 'AUTH_CAPTURE',
        'x_method' : 'CC',
        'x_fp_sequence' : '123',
        'x_version' : '3.1',
        'x_relay_response' : 'FALSE',
        }
    params['x_fp_timestamp'] = int(time.time())

    msg = '^'.join([params['x_login'],
           str(params['x_fp_sequence']),
           str(params['x_fp_timestamp']),
           str(params['x_amount'])
           ])+'^'

    fingerprint = hmac.new('9LyEU8t87h9Hj49Y',msg).hexdigest()


I would be glad if some one that has dealt with this earlier, points
out what the glitch is. Thanks in advance.