title: How we generate CheckSum and Open Paytm
body: <p>I want to Use Payment Gateway with Paytm.First I am unable to generate CHECKSUMHASH . Then if I am hardcord. Then it show OOPS page of Paytm.Please Help .Any Help would be appreciated. Thanks in Advance   </p>
  
  <pre><code>PGMerchantConfiguration *mc = [PGMerchantConfiguration defaultConfiguration];
  mc.checksumGenerationURL = @"http://lucky7.co.in/paytm/generateChecksum.php";
  mc.checksumValidationURL = @"http://lucky7.co.in/paytm/verifyChecksum.php";
  
  //Step 2: Create the order with whatever params you want to add. But make sure that you include the merchant mandatory params
  NSMutableDictionary *orderDict = [NSMutableDictionary new];
  
  //Merchant configuration in the order object
  orderDict[@"MID"] = @"SSMENT54168661059890";
  orderDict[@"ORDER_ID"] = @"Order000111008";
  orderDict[@"CUST_ID"] = @"12";
  orderDict[@"INDUSTRY_TYPE_ID"] = @"Retail";
  orderDict[@"CHANNEL_ID"] = @"WAP";
  orderDict[@"TXN_AMOUNT"] = @"1";
  orderDict[@"WEBSITE"] = @"APP_STAGING";
  orderDict[@"CALLBACK_URL"] = @"http://lucky7.co.in/paytm/verifyChecksum.php";
  orderDict[@"EMAIL"] = @"eee@gmail.com";
  orderDict[@"MOBILE_NO"] = @"9996725992";
  orderDict[@"REQUEST_TYPE"] = @"DEFAULT";
  //    orderDict[@"CHECKSUMHASH"] = @"ohpYnZUoSUqFsQ0uUVArWPnlTdLPSZWhinaCWSGKME5HJzAlZephJuaCFxs5tJbSKViPbrlEsJEIEVIcJARFANm4rN1pk7n4193CBs53Zg=";
  
  
  PGOrder *order = [PGOrder orderWithParams:orderDict];
  
  //Step 3: Choose the PG server. In your production build dont call selectServerDialog. Just create a instance of the
  //PGTransactionViewController and set the serverType to eServerTypeProduction
  [PGServerEnvironment selectServerDialog:self.view completionHandler:^(ServerType type)
   {
       PGTransactionViewController *txnController = [[PGTransactionViewController alloc] initTransactionForOrder:order];
  
          //txnController.merchant = [PGMerchantConfiguration defaultConfiguration];
  
       if (type != eServerTypeNone) {
           txnController.serverType = type;
           txnController.merchant = mc;
           txnController.delegate = self;
           [self showController:txnController];
       }
  
  }];
  </code></pre>