C# Online Compiler | .NET Fiddle

using System;
using System.Security.Cryptography;
					
public class Program
{
	private const string SALT = "{'$c),VFuXW}j&*U]d/8k^xvZ<M=zzB)s:)}WzesV6%w$Mg;\"7jS9qd5T&4FV=9B";
	private const string CHECKSUM_KEYWORD= "&checksum=";
	
	public static void Main()
	{
		var urlQueryString = "formId=1&productId=1&stepId=1";
		
		var securedUrl = CreateSecureUrl(urlQueryString);
		
		Console.WriteLine("SecuredUrl is: " + securedUrl);
						
		// Not valid Url, not step Id changed
		var validationUrl2 = "formId=1&productId=1&stepId=3&checksum=fea1788b96061394d57ca66b44fb22d40d820481";
		
		ValidateSecureUrl(securedUrl);
		ValidateSecureUrl(validationUrl2);
		
	}
	
	public static string CreateSecureUrl(string url)
	{
		return url + CHECKSUM_KEYWORD + CreateChecksum(url);
	}
	
	public static string CreateChecksum(string input)
	{
		byte[] buffer = System.Text.ASCIIEncoding.ASCII.GetBytes(input);
		using(var cryptoProvider = new SHA1CryptoServiceProvider()) 
		{
			string hash = String.Concat(Array.ConvertAll(cryptoProvider.ComputeHash(buffer), x => x.ToString("x2"))); 
			
			return hash;			
		}			
	}
	
	public static void ValidateSecureUrl(string url)
	{
		var urlWithoutChecksum = url.Substring(0, url.IndexOf(CHECKSUM_KEYWORD));
		
		var checksum = url.Substring(url.IndexOf(CHECKSUM_KEYWORD)+CHECKSUM_KEYWORD.Length);
		
		if(checksum == CreateChecksum(urlWithoutChecksum))
		{
			Console.WriteLine("This url is VALID!: " + url);
		}
		else
		{			
			Console.WriteLine("This url is NOT VALID!: " + url);			
		}

	}
	
}

 
using System;
using System.Security.Cryptography;
                    
public class Program
{
    private const string SALT = "{'$c),VFuXW}j&*U]d/8k^xvZ<M=zzB)s:)}WzesV6%w$Mg;\"7jS9qd5T&4FV=9B";
    private const string CHECKSUM_KEYWORD= "&checksum=";
    
    public static void Main()
    {
        var urlQueryString = "formId=1&productId=1&stepId=1";
        
        var securedUrl = CreateSecureUrl(urlQueryString);
        
        Console.WriteLine("SecuredUrl is: " + securedUrl);
                        
        // Not valid Url, not step Id changed
        var validationUrl2 = "formId=1&productId=1&stepId=3&checksum=fea1788b96061394d57ca66b44fb22d40d820481";
        
        ValidateSecureUrl(securedUrl);
        ValidateSecureUrl(validationUrl2);
        
    }
    

Cached Result

5
1

OrderDetailID	OrderID	ProductID	Quantity
1	10248	11	12
2	10248	42	10
3	10248	72	5
4	10249	14	9
5	10249	51	40

OrderDetailID	OrderID	ProductID	Quantity
1	10248	11	12