DSACryptoServiceProvider.VerifyData Method

using System;
using System.Security.Cryptography;

class DSACSPSample
{
		
	static void Main()
	{
		try
		{
			//Create a new instance of DSACryptoServiceProvider to generate
			//a new key pair.
			DSACryptoServiceProvider DSA = new DSACryptoServiceProvider();

			//The data to sign.
			byte[] Data = {59,4,248,102,77,97,142,201,210,12,224,93,25,41,100,197,213,134,130,135};
				
			//The value to hold the signed value.
			byte[] SignedValue = DSASignData(Data, DSA.ExportParameters(true));

			//Verify the data and display the results.
			if(DSAVerifyData(Data, SignedValue, DSA.ExportParameters(false)))
			{
				Console.WriteLine("The hash value was verified.");
			}
			else
			{
				Console.WriteLine("The hash value was not verified.");
			}


		}
		catch(ArgumentNullException e)
		{
			Console.WriteLine(e.Message);
		}
	}

	public static byte[] DSASignData(byte[] DataToSign, DSAParameters DSAKeyInfo)
	{
		try
		{
			//Create a new instance of DSACryptoServiceProvider.
			DSACryptoServiceProvider DSA = new DSACryptoServiceProvider();

			//Import the key information.   
			DSA.ImportParameters(DSAKeyInfo);

			//Compute hash value, sign the hash, and return the signed hash.
			return DSA.SignData(DataToSign);
		}
		catch(CryptographicException e)
		{
			Console.WriteLine(e.Message);

			return null;
		}

	}

	public static bool DSAVerifyData(byte[] Data, byte[] SignedData, DSAParameters DSAKeyInfo)
	{
		try
		{
			//Create a new instance of DSACryptoServiceProvider.
			DSACryptoServiceProvider DSA = new DSACryptoServiceProvider();

			//Import the key information. 
			DSA.ImportParameters(DSAKeyInfo);

			//Verify the signature and return the result.	
			return DSA.VerifyData(Data, SignedData);

		}
		catch(CryptographicException e)
		{
			Console.WriteLine(e.Message);

			return false;
		}
			
	}

}

using System;
using System.Security.Cryptography;
using System.Text;

class DSACSPSample
{
    static void Main()
    {
        try
        {
            //Create a UnicodeEncoder to convert between byte array and string.
            ASCIIEncoding ByteConverter = new ASCIIEncoding();

            string dataString = "Data to Sign";

            //Create byte arrays to hold original, encrypted, and decrypted data.
            byte[] dataToSign = ByteConverter.GetBytes(dataString);
            byte[] hashedData;
            byte[] signedData;

            // Create a SHA1CryptoServiceProvider object 
            // to hash the data that will be signed.
            SHA1CryptoServiceProvider SHA1alg = new SHA1CryptoServiceProvider();

            // Hash the data to sign.
            hashedData = SHA1alg.ComputeHash(dataToSign);

            //Create a new instance of the DSACryptoServiceProvider class 
            // and automatically create a new key-pair.
            DSACryptoServiceProvider DSAalg = new DSACryptoServiceProvider();

            //Use the MapNameToOID method to get an object identifier  
            //(OID) from the string name of the SHA1 algorithm.
            string OID = CryptoConfig.MapNameToOID("SHA1");

            // Sign the hash and pass the OID.
            signedData = DSAalg.SignHash(hashedData, OID);

            // Verify the signature and display the results to the
            // console.
            if(DSAalg.VerifySignature(hashedData, signedData))
            {
                Console.WriteLine("The data was verified.");
            }
            else
            {
                Console.WriteLine("The data does not match the signature.");
            }

        }
        catch(CryptographicException e)
        {
            //Catch this exception in case the encryption did
            //not succeed.
            Console.WriteLine(e.Message);

        }
    }
}