#define MY_SHARED_SECRET   @"1234567890abcdef1234567890abcdef"

- (void)paymentQueue:(id)queue updatedTransactions:(NSArray *)transactions
{
    [RRVerificationController sharedInstance].itcContentProviderSharedSecret = MY_SHARED_SECRET;

    for (SKPaymentTransaction *transaction in transactions)
    {
        switch ([transaction transactionState])
        {
            case SKPaymentTransactionStatePurchasing:
                break;
            case SKPaymentTransactionStatePurchased:
                 /* If verification is successful, the delegate's verificationControllerDidVerifyPurchase:isValid: method will be called to take appropriate action and complete the transaction */
                if ([[RRVerificationController sharedInstance] verifyPurchase:transaction
                                                                 withDelegate:self
                                                                        error:NULL] == FALSE) {
                    [self failedTransaction:transaction];
                }
                break;
            case SKPaymentTransactionStateFailed:
                [self failedTransaction:transaction];
                break;
            case SKPaymentTransactionStateRestored:
                /* If verification is successful, the delegate's verificationControllerDidVerifyPurchase:isValid: method will be called to take appropriate action and complete the transaction */
                if ([[RRVerificationController sharedInstance] verifyPurchase:transaction
                                                                 withDelegate:self
                                                                        error:NULL] == FALSE) {
                    [self failedTransaction:transaction];
                }
            default:
                break;
        }
    }
}

- (void)completeTransaction:(SKPaymentTransaction *)transaction 
{
 /* Handled a completed and verified new transcation */
}

- (void)restoreTransaction:(SKPaymentTransaction *)transaction 
{
 /* Handled a completed and verified restored transcation.
  * For many use cases this is simply [self completeTransaction:transaction]
  */
}

/*!
 * @brief Verification with Apple's server completed successfully
 *
 * @param transaction The transaction being verified
 * @param isValid YES if Apple reported the transaction was valid; NO if Apple said it was not valid or if the server's validation reply was inconsistent with validity
 */
 - (void)verificationControllerDidVerifyPurchase:(SKPaymentTransaction *)transaction isValid:(BOOL)isValid
 {
    if (isValid) {
       switch (transaction.transactionState) {
            case SKPaymentTransactionStatePurchased:
                [self completeTransaction:transaction];
                break;
            case SKPaymentTransactionStateRestored:
                [self restoreTransaction:transaction];
            default:
                break;
        }

    } else
        [self displayFailureMessage];

    if (transaction.transactionState != SKPaymentTransactionStatePurchasing)
        [[SKPaymentQueue defaultQueue] finishTransaction:transaction];
 }

 /*!
  * @brief The attempt at verification could not be completed
  *
  * This does not mean that Apple reported the transaction was invalid, but
  * rather indicates a communication failure, a server error, or the like.
  *
  * @param transaction The transaction being verified
  * @param error An NSError describing the error. May be nil if the cause of the error was unknown (or if nobody has written code to report an NSError for that failure...)
  */
 - (void)verificationControllerDidFailToVerifyPurchase:(SKPaymentTransaction *)transaction error:(NSError *)error
 {
    NSString *message = NSLocalizedString(@"Your purchase could not be verified with Apple's servers. Please try again later.", nil);
    if (error) {
        message = [message stringByAppendingString:@"\n\n"];
        message = [message stringByAppendingFormat:NSLocalizedString(@"The error was: %@.", nil), error.localizedDescription];
    }

    [[[UIAlertView alloc] initWithTitle:NSLocalizedString(@"Purchase Verification Failed", nil)
        message:message
        delegate:nil
        cancelButtonTitle:NSLocalizedString(@"Dismiss", nil)
        otherButtonTitles:nil] show];
 }