Bad Data error in Cryptography

Question

Bad Data error in Cryptography

Sanjay Prabhakar Kamath

SSC-Addicted

Points: 441
More actions
April 30, 2005 at 1:51 am

#85880

Using the code given below I am able to encrypt the text using RSA encryption but am not able to decrypt it.
I get error Bad Data.
How to resolve this?
  /// <summary>
  /// The main entry point for the application.
  /// </summary>
  [STAThread]
  static void Main()
  {
   Application.Run(new frmEncryptPass());
  }
  private void btnEncrypt_Click(object sender, System.EventArgs e)
  {

   try

   {
    //Encrypting password. Applying DES Encryption Algo
    Byte[] CypherTextBArray = EncryptingPassword();

    string sCrypt = "";
    for (int i = 0; i <= CypherTextBArray.Length - 1;i+=1)
    {
     sCrypt += Convert.ToChar(CypherTextBArray);
    }

    this.txtEncryptedPassword.Text = sCrypt;
    updatePasswordInDB("Server=Server1; database=CSharpDB; uid=sa; pwd=sa");

   }
   catch(Exception ex)
   {
    throw ex;
   }
  }
  public byte[] EncryptingPassword()
  {
   //Return Encrypted Password
   /*return
   CspParameters cspParams = new CspParameters();
   cspParams.Flags = CspProviderFlags.UseMachineKeyStore;
   RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(cspParams);
            RSAParameters xmlKeys = rsa.ExportParameters(true);
   RSAParameters xmlPublicKey = rsa.ExportParameters(false);


   //RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
   //Hold the public key to be used in the encryption procedure

         //'get the public key so you can encrypt the message:
      //rsa.FromXmlString(xmlPublicKey);
   rsa.ImportParameters(xmlPublicKey);

   byte [] IV = {10, 20, 30, 40, 50, 60, 70, 80};

   byte[] InputByteArray = System.Text.UnicodeEncoding.Default.GetBytes((this.txtPassword.Text.Trim()));

   CypherTextBArray = rsa.Encrypt(InputByteArray,false);

   rsa.PersistKeyInCsp = true;

   return CypherTextBArray;
  }

  public string DecryptingPassword(Byte[] CypherTextBArray)
  {
  CspParameters cspParams = new CspParameters();
   cspParams.Flags = CspProviderFlags.UseMachineKeyStore;
   RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(cspParams);



   rsa.FromXmlString(GetXmlKeys());

   //create a byte array and then put the decrypted plaintext into it
    Byte[] RestoredPlainText = (rsa.Decrypt(CypherTextBArray,false));
   //'Step through the two-byte unicode plaintext, displaying the restored         'plaintext message
   string sCrypt = "";
   for (int i = 0; i <= CypherTextBArray.Length - 1;i+=1)
   {
    sCrypt += Convert.ToChar(RestoredPlainText);
   }

    return sCrypt;
  }
  public void updatePasswordInDB(string connectionString)
  {
   SqlConnection objConn= new SqlConnection(connectionString);
   objConn.Open();
   SqlCommand objcmd = new SqlCommand("update Users set password = '" +
   this.txtEncryptedPassword.Text.Trim() + "' where NTUser_name = 'Samuel'", objConn);
   objcmd.ExecuteNonQuery();
  }

  public string GetPasswordFromDB(string connectionString)
  {
   SqlConnection objConn= new SqlConnection(connectionString);
   objConn.Open();
   SqlCommand objcmd = new SqlCommand("select password from Users where NTUser_name = 'Samuel'", objConn);
   SqlDataAdapter sqlDa = new SqlDataAdapter(objcmd);
   DataSet ds = new DataSet();
   sqlDa.Fill(ds);

   return(ds.Tables[0].Rows[0]["password"].ToString());
  }
  private void btnDecrypt_Click(object sender, System.EventArgs e)
  {

   try

   {
    //Encrypting password. Applying DES Encryption Algo

    String sPwd = GetPasswordFromDB("Server=Server1; database=CSharpDB; uid=sa; pwd=sa");
    byte[] InputByteArray = System.Text.UnicodeEncoding.Default.GetBytes(sPwd.TrimEnd());
    this.txtPassword.Text = DecryptingPassword(InputByteArray);


   }
   catch(Exception ex)
   {

    throw ex;
   }
  }
  public string GetXmlKeys()
  {
   CspParameters cspParams = new CspParameters();
   cspParams.Flags = CspProviderFlags.UseMachineKeyStore;
   RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(cspParams);
   //Hold both keys in a global variable that will be used in the
   //RSAParameters xmlKeys = rsa.ExportParameters(true);
   xmlKeys = rsa.ToXmlString(true);

   return xmlKeys.ToString();

  }
}
}

Viewing 3 posts - 1 through 2 (of 2 total)

You must be logged in to reply to this topic. Login to reply

Antares686 SSC Guru Points: 125444 More actions · Answer 1

Sorry nothing setup to test here. However hav you run in debug and verified which line is failing and stepped thru the process in full?

Sanjay Prabhakar Kamath SSC-Addicted Points: 441 More actions · Answer 2

The line that is failing is :

Byte[] RestoredPlainText = (rsa.Decrypt(CypherTextBArray,false));

I am unable to decrypt the string that I have sucessfully encrypted.