utilitydelta / dotnet-encryption

Simplifies methods to send encrypted data from one machine to another. Exchange a secret key using asymmetric encryption, then transfer streams of data using symmetric encryption with the shared secret key

dotnet-encryption

Simplifies methods to send encrypted data from one machine to another. Exchange a secret key using asymmetric encryption, then transfer streams of data using symmetric encryption with the shared secret key

Usage

using System;
using System.IO;
using System.Text;
using Newtonsoft.Json;
using UtilityDelta.Encryption;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            //Step 1 - Machine 1 generates public and private keys
            var m1AsymmetricKeys = new PublicPrivateKeyGenerator();

            //Step 2 - Machine 1 sends public key to machine 2
            var m2PublicKey =
                JsonConvert.DeserializeObject<RsaParametersSerializable>(
                    JsonConvert.SerializeObject(m1AsymmetricKeys.PublicKey));

            //Step 3 - Machine 2 decides on a key for symmetric encryption
            const string m2SymmetricKey = "password123";

            //Step 4 - Encrypts it for secure transfer to machine 1 with the public key
            var m1EncryptedKey =
                AsymmetricEncryptionOfSymmetricKey.EncryptKey(m2SymmetricKey, m2PublicKey.GetRsaParameters());

            //Step 5 - Machine 1 decrypts key that machine 2 sent over
            var m1DecryptedKey =
                AsymmetricEncryptionOfSymmetricKey.DecryptKey(m1EncryptedKey,
                    m1AsymmetricKeys.PrivateKey.GetRsaParameters());

            //Step 6 - Now we can encrypt symmetrically using the common key.
            //         We can encrypt large amounts of data using symmetric encryption
            var m1SymmetricEncryption = new SymmetricEncryptionWithKnownKey(m1DecryptedKey);

            //Step 7 - encrypt some important data and send it to machine 2
            var m1UnencryptedTextFileStream = new MemoryStream(Encoding.UTF8.GetBytes("this is a file with text in it"));
            var m2ReceivedEncryptedFile = new MemoryStream();
            m1SymmetricEncryption.Encrypt(m1UnencryptedTextFileStream, m2ReceivedEncryptedFile);
            var m2ReceivedEncryptedFileBytes = m2ReceivedEncryptedFile.ToArray();

            //Step 8 - machine 2 decrypts the file using its password that it chose originally
            var m2SymmetricEncryption = new SymmetricEncryptionWithKnownKey(m2SymmetricKey);
            var m2DecryptedFile = new MemoryStream();
            m2SymmetricEncryption.Decrypt(new MemoryStream(m2ReceivedEncryptedFileBytes), m2DecryptedFile);
            m2DecryptedFile.Position = 0;
            if ("this is a file with text in it" != Encoding.UTF8.GetString(m2DecryptedFile.ToArray()))
            {
                throw new Exception("Not working");
            }
        }
    }
}