C# Encryption and Decryption by Rijndael Method

Another flawlessly written program to up your C# skills! The code is written and tested in Visual Studio 2012. Features of this project are:
  • Encrypt and Decrypt any type of file/s in your computer system.
  • Easy to use interface. Few clicks required only.
  • Choose passkey also known as a password. May consist of letters and numbers[Maximum 8]. 
  • Keep original files intact. You may change code to delete original files but we did not implement this currently. 
  • A class with functions to encrypt and decrypt files is created. This file may be reused.
  • The Rijndael algorithm of Encryption and Decryption is used internally to Cipher & Decipher. 
C# Encryption Decryption
    public partial class MainForm : Form
    {
        public MainForm()
        {
            InitializeComponent();
        }

        string encfileextention;
        bool encflagOpen;
        bool encflagSave;

        ENC_DEC ed = new ENC_DEC();

        string decfileextention;
        bool decflagOpen;
        bool decflagSave;
       
         
        private void rdoEncryption_CheckedChanged(object sender, EventArgs e)
        {
            if (rdoEncryption.Checked == true)
            {
                gbEncryption.Visible = true;
                gbDecryption.Visible = false;
            }
            else
            {
                gbEncryption.Visible = false;
                gbDecryption.Visible = true;
            }
        }

        private void rdoDecryption_CheckedChanged(object sender, EventArgs e)
        {
            //Same as for the above radio button
        }

        private void MainForm_Load(object sender, EventArgs e)
        {
            MessageBox.Show("Welcome!");
        }


        private void btnEncOpen_Click(object sender, EventArgs e)
        {
            OpenFileDialog dlg = new OpenFileDialog();

            dlg.Filter = "All files (*.*)|*.*";

            if (dlg.ShowDialog() == DialogResult.OK)
            {
                String s = dlg.FileName;
                txtEncInput.Text = s;
                FileInfo myfile = new FileInfo(s);

                if ((myfile.Length / 1024000) == 0)
                {
                    lblEncSize.Text = "SIZE : " + Convert.ToString(myfile.Length / 1024) + " Kb";
                }
                else
                {
                    lblEncSize.Text = "SIZE : " + Convert.ToString(myfile.Length / 1024000) + " Mb";
                }

                encfileextention = myfile.Extension;
                encflagOpen = true;
                if ((encflagSave == true) && (encflagOpen == true))
                {
                    btnEncrypt.Enabled = true;
                    encflagOpen = false;
                    encflagSave = false;
                }
            }
        }


        private void btnEncSave_Click(object sender, EventArgs e)
        {
            SaveFileDialog dlg = new SaveFileDialog();

            dlg.Filter = "All files (*.*)|*.*";
            if (dlg.ShowDialog() == DialogResult.OK)
            {
                string s = dlg.FileName;
                txtEncOutput.Text = s;
                String m = dlg.FileName;
                FileInfo myfile = new FileInfo(m);
                if (myfile.Extension == null)
                    txtEncOutput.Text = m;
                else
                    txtEncOutput.Text = m + encfileextention;
                encflagSave = true;
            }

            if ((encflagSave == true) && (encflagOpen == true))
            {
                btnEncrypt.Enabled = true;
                encflagOpen = false;
                encflagSave = false;
            }
        }


        private void btnDecOpen_Click(object sender, EventArgs e)
        {
            OpenFileDialog dlg = new OpenFileDialog();

            dlg.CheckFileExists = true;
            dlg.Filter = "All files (*.*)|*.*";
            if (dlg.ShowDialog() == DialogResult.OK)
            {
                String s = dlg.FileName;
                txtDecInput.Text = s;
                FileInfo myfile = new FileInfo(s);
                if ((myfile.Length / 1024000) == 0)
                {
                    lblDecSize.Text = "SIZE : " + Convert.ToString(myfile.Length / 1024) + " Kb";
                }
                else
                {
                    lblDecSize.Text = "SIZE : " + Convert.ToString(myfile.Length / 1024000) + " Mb";
                }
                decfileextention = myfile.Extension;
                decflagOpen = true;
            }
            else
                MessageBox.Show("You did not select any file");

            if ((decflagSave == true) && (decflagOpen == true))
            {
                btnDecrypt.Enabled = true;
                decflagOpen = false;
                decflagSave = false;
            }
        }


        private void btnDecSave_Click(object sender, EventArgs e)
        {
            SaveFileDialog dlg = new SaveFileDialog();
            dlg.Filter = "All files (*.*)|*.*";
            if (dlg.ShowDialog() == DialogResult.OK)
            {
                string m = dlg.FileName;
                txtDecOutput.Text = m;
                FileInfo myfile = new FileInfo(m);
                if (myfile.Extension == null)
                    txtDecOutput.Text = m;
                else
                    txtDecOutput.Text = m + decfileextention;
            }
            else
                MessageBox.Show("You have not selected any file");
            decflagSave = true;
            if ((decflagSave == true) && (decflagOpen == true))
            {
                btnDecrypt.Enabled = true;
                decflagOpen = false;
                decflagSave = false;
            }
        }


        private void btnEncrypt_Click(object sender, EventArgs e)
        {
            this.Text = "Please wait";
            ed.EncFile(txtEncInput.Text, txtEncOutput.Text, textBox1.Text + "qlku");
            MessageBox.Show("New File Location  :  '" + txtEncOutput.Text + "'", encfileextention + " file converted successfully");
            this.Text = "Password protect your files here !";
        }

        private void btnDecrypt_Click(object sender, EventArgs e)
        {
            this.Text = "Please wait";
            ed.DecFile(txtDecInput.Text, txtDecOutput.Text, textBox2.Text + "qlku");
            MessageBox.Show("New File Location  :  '" + txtDecOutput.Text + "'", decfileextention + " file converted successfully");
            this.Text = "Password protect your files here !";
        }

    }
class ENC_DEC
    {
        public void DecFile(string inputFile, string outputFile, string Pass)
        {
            try
            {
                string password = Pass; // Your Key Here
                UnicodeEncoding UE = new UnicodeEncoding();
                byte[] key = UE.GetBytes(password);
                FileStream fsCrypt = new FileStream(inputFile, FileMode.Open);
                RijndaelManaged RMCrypto = new RijndaelManaged();
                CryptoStream cs = new CryptoStream(fsCrypt, RMCrypto.CreateDecryptor(key, key), CryptoStreamMode.Read);
                FileStream fsOut = new FileStream(outputFile, FileMode.Create);
                int data;
                while ((data = cs.ReadByte()) != -1)
                {
                    fsOut.WriteByte((byte)data);
                }
                fsOut.Close();
                cs.Close();
                fsCrypt.Close();

            }
            catch
            {
                MessageBox.Show("You have entered wrong password");
            }
        }
        public void EncFile(string inputFile, string outputFile, string Mypassword)
        {
            try
            {
                string password = @Mypassword; // Your Key Here
                UnicodeEncoding UE = new UnicodeEncoding();
                byte[] key = UE.GetBytes(password);
                string cryptFile = outputFile;
                FileStream fsCrypt = new FileStream(cryptFile, FileMode.Create);
                RijndaelManaged RMCrypto = new RijndaelManaged();
                CryptoStream cs = new CryptoStream(fsCrypt, RMCrypto.CreateEncryptor(key, key), CryptoStreamMode.Write);
                FileStream fsIn = new FileStream(inputFile, FileMode.Open);
                int data;


                while ((data = fsIn.ReadByte()) != -1)
                {
                    cs.WriteByte((byte)data);

                }
                fsIn.Close();
                cs.Close();
                fsCrypt.Close();

            }
            catch
            {
                MessageBox.Show("Encryption failed!", "Error");
            }
        }

    }



Please Note:
** Do not Copy & Paste code written here ; instead type it in your Development Environment
** Testing done in .Net Framework 4.5 but code should be very similar for previous versions of .Net Framework
** All Program Codes written here are 100%  tested & running.
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