Cryptography - Digital Signature

using System.Security.Cryptography;

namespace CryptographyInDotNet
{
    public class DigitalSignature
    {
        private RSAParameters _publicKey;
        private RSAParameters _privateKey;

        public void AssignNewKey()
        {
            using (var rsa = new RSACryptoServiceProvider(2048))
            {                
                rsa.PersistKeyInCsp = false;               
                _publicKey = rsa.ExportParameters(false);
                _privateKey = rsa.ExportParameters(true);                
            }
        }

        public byte[] SignData(byte[] hashOfDataToSign)
        {
            using (var rsa = new RSACryptoServiceProvider(2048))
            {
                rsa.PersistKeyInCsp = false;
                rsa.ImportParameters(_privateKey);
                
                var rsaFormatter = new RSAPKCS1SignatureFormatter(rsa);                
                rsaFormatter.SetHashAlgorithm("SHA256");

                return rsaFormatter.CreateSignature(hashOfDataToSign);
            }
        }

        public bool VerifySignature(byte[] hashOfDataToSign, byte[] signature)
        {
            using (var rsa = new RSACryptoServiceProvider(2048))
            {
                rsa.ImportParameters(_publicKey);

                var rsaDeformatter = new RSAPKCS1SignatureDeformatter(rsa);
                rsaDeformatter.SetHashAlgorithm("SHA256");

                return rsaDeformatter.VerifySignature(hashOfDataToSign, signature);
            }
        }   
    }
}

program.cs

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

namespace CryptographyInDotNet
{
    class Program
    {
        static void Main()
        {                                               
            var document = Encoding.UTF8.GetBytes("Document to Sign");
            byte[] hashedDocument;

            using (var sha256 = SHA256.Create())
            {
                hashedDocument = sha256.ComputeHash(document);
            }

            var digitalSignature = new DigitalSignature();
            digitalSignature.AssignNewKey();

            var signature = digitalSignature.SignData(hashedDocument);
            var verified = digitalSignature.VerifySignature(hashedDocument, signature);
            
            Console.WriteLine("Digital Signature Demonstration in .NET");
            Console.WriteLine("---------------------------------------");
            Console.WriteLine();            
            Console.WriteLine();
            Console.WriteLine("   Original Text = " + 
                Encoding.Default.GetString(document));

            Console.WriteLine();
            Console.WriteLine("   Digital Signature = " + 
                Convert.ToBase64String(signature));

            Console.WriteLine();

            Console.WriteLine(verified
                ? "The digital signature has been correctly verified."
                : "The digital signature has NOT been correctly verified.");

            Console.ReadLine();
        }
    }
}