t.py

import base64
import urllib
import codecs

from Crypto.Cipher import AES
from Crypto.Hash import MD5

temp_token = "value from propay"
temp_token = codecs.encode(temp_token, 'utf-8')
settings = {
    'AuthToken' : temp_token,
    'PayerId' : propay_payer_id,
    'PaymentProcessType' : 'CreditCard',
    'ProcessMethod' : 'None',
    'PaymentMethodStorageOption' : 'Always',
    'ReturnURL' : "http://example_url.com/example"
}
encoded_settings = urllib.urlencode(settings)
encoded_settings = codecs.encode(encoded_settings, 'utf-8')

md = MD5.new()
md.update(temp_token)
key = md.digest()
iv = key

block_size = 16
pad = block_size - (len(encoded_settings) % block_size)
encoded_settings = encoded_settings + pad*chr(pad)

aes = AES.new(key, IV=iv, mode=AES.MODE_CBC)
settings_cipher = base64.b64encode(aes.encrypt(encoded_settings))