MD5 checksum fix for the QuickPay provider in TeaCommerce. See this link for details http://our.umbraco.org/projects/website-utilities/tea-commerce/tea-commerce-support/39333-Quickpay-MD5-checksum-problem

gistfile1.txt

protected string MD5CheckSum(IDictionary<string, string> inputFields, string md5secret)
{
  string[] keys = { "protocol", "msgtype", "merchant", "language", "ordernumber", "amount", "currency", "continueurl", "cancelurl", "callbackurl" };
  string values = "";
  foreach (string key in keys)
    if (inputFields.Any(s => s.Key == key))
      values += inputFields[key];

  return GetMd5Hash(values + md5secret);
}