ios – 应用程序内的应用程序采购收据验证

这是我的代码,

- (void)recordtransaction:(SKPaymenttransaction *)transaction {

    NSData *receiptData = [NSData dataWithData:transaction.transactionReceipt];

    NSString *encodedString = [Base64 encode:receiptData];

     NSURL *url = [NSURL URLWithString:@"https://sandBox.itunes.apple.com/verifyReceipt"];

    ASIFormDatarequest *request = [[ASIFormDatarequest alloc] initWithURL:url];

    [request setPostValue:encodedString forKey:@"receipt-data"];

    [request setrequestMethod:@"POST"];

    [request setDelegate:self];

    [request startAsynchronous];

}

我得到的输出：

有人可以帮我找到正确的收据验证吗？