Is there any way to encrypt a string using private key in RSA algorithm and decrypt the same using public key in C# .NET?

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Is there any way to encrypt a string using private key in RSA algorithm and decrypt the same using public key in C# .NET?

Try using the NuGet package BouncyCastle.NetCore. It is more flexible than the RSACryptoServiceProvider and its associated classes. Here is a NetCore Console example. The size of the message that can be encrypted is limited to the size of the keys.

//Derived from http://www.go4expert.com/articles/bouncy-castle-net-implementationrsa-t24827/
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.Engines;
using Org.BouncyCastle.Crypto.Generators;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Security;
using System;
using System.Text;

namespace EncryptString
{
    class Program
    {
        public static void Main()
        {
            RsaKeyPairGenerator rsaKeyPairGenerator = new RsaKeyPairGenerator();
            int keySize = 2048;//in bits
            rsaKeyPairGenerator.Init(new KeyGenerationParameters(new SecureRandom(), keySize));
            var keyPair = rsaKeyPairGenerator.GenerateKeyPair();
            var publicKey = keyPair.Public;
            var privateKey = keyPair.Private;
            var rsa = new RsaEngine();
            rsa.Init(true, privateKey);//use private key for encryption-not recommended
            string message = "Hello World";
            Console.WriteLine($"Original text: {message}");
            var plainTextBytes = Encoding.UTF8.GetBytes(message);
            byte[] cipherBytes = rsa.ProcessBlock(plainTextBytes, 0, message.Length);
            Console.WriteLine("Encrypted text as a byte array:");
            Console.WriteLine(BitConverter.ToString(cipherBytes));
            rsa.Init(false, publicKey);//use public key for decryption
            byte[] decryptedData = rsa.ProcessBlock(cipherBytes, 0, cipherBytes.Length);
            string decipheredText = Encoding.UTF8.GetString(decryptedData);
            Console.WriteLine($"Decrypted text: {decipheredText}");
            Console.ReadLine();
          
        }
    
    }
}