Program problem statement https://corevoila.in/computer-science/cryptography/asymmetric-cryptography-public-key-cryptography-part-i/

AsymmetricRsa.cs

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

namespace AsymmetricCryptography
{
    public class AsymmetricRsa     
    {
        static void Main()
        {
            var rsaCryptoService = new RSACryptoServiceProvider();

            var publicKey = rsaCryptoService.ToXmlString(false); // false to get the public key   
            var privateKey = rsaCryptoService.ToXmlString(true); // true to get the private key   

            Console.WriteLine("Enter message to encrypt");
            var message = Console.ReadLine();

            var encryptedMessage = EncryptMessage(publicKey, message, rsaCryptoService);
            Console.WriteLine(new UnicodeEncoding().GetString(encryptedMessage));

            var decryptData = DecryptData(privateKey,encryptedMessage);
            Console.WriteLine(new UnicodeEncoding().GetString(decryptData));
            Console.ReadLine();
        }

        static byte[] EncryptMessage(string publicKey, string message, RSACryptoServiceProvider rsaCryptoService)
        {
            var dataToEncrypt = new UnicodeEncoding().GetBytes(message);
            rsaCryptoService.FromXmlString(publicKey);//We can even create new instance for RSACryptoServiceProvider
            return rsaCryptoService.Encrypt(dataToEncrypt, false);
        }
 
        static byte[] DecryptData(string privateKey, byte[] dataToDecrypt)
        {
            var rsaCryptoService = new RSACryptoServiceProvider(); //a new instance for receiver;
            rsaCryptoService.FromXmlString(privateKey);
            return rsaCryptoService.Decrypt(dataToDecrypt, false);
        }
    }
}