.NET: what are my options for decrypting a passwor

Question

In the UI of my winForm I ask the user for a user name and password. I store this password as text in the Settings (the .settings file) of my project. The app is a visual Studio Add-in

How can I encrypt and decrypt the password before and after I enter it into the Settings file?

I don't really need anything fancy. It's just a little in-house app. But I'd like to know all my options

Thanks Bob

Answer 1

I dd it with this:

    public static string Decrypt(string stringToDecrypt)
    {
        UnicodeEncoding byteConverter = new UnicodeEncoding();
        byte[] dataToEncrypt = byteConverter.GetBytes(stringToDecrypt);
        byte[] decryptedData = null;
        try
        {
            using (RSACryptoServiceProvider rsaCryptoServiceProvider = new RSACryptoServiceProvider())
            {
                rsaCryptoServiceProvider.FromXmlString(_key);
                byte[] decryptBytes = Encoding.Default.GetBytes(Properties.Settings.Default.SqlPassword);

                decryptedData = rsaCryptoServiceProvider.Decrypt(decryptBytes, false);
            }
        }
        catch (Exception ex)
        {
            //TODO Do proper logging
            Console.WriteLine("Decrypt failed: " + ex.Message);
        }

        return byteConverter.GetString(decryptedData);
    }

    public static string Encrypt(string stringToEncrypt)
    {
        try
        {
            UnicodeEncoding byteConverter = new UnicodeEncoding();
            byte[] dataToEncrypt = byteConverter.GetBytes(stringToEncrypt);

            using (RSACryptoServiceProvider rsaCryptoServiceProvider = new RSACryptoServiceProvider())
            {
                rsaCryptoServiceProvider.FromXmlString(_key);
                byte[] encryptedData = rsaCryptoServiceProvider.Encrypt(dataToEncrypt, false);

                return Encoding.Default.GetString(encryptedData);
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine("Encrypt failed: " + ex.Message);
        }
    }

Answer 2

I have my own service (written in one of my project) you can use my codes if you want :) You can Encrypt / Decrypt byte[] and strings

//***********************************************************************
// Assembly         : Common
// Author           : SERKANH
// Created          : 09-27-2009
//
// Last Modified By : SERKANH
// Last Modified On : 09-27-2009
// Description      : 
//
// Copyright        : (c) Microsoft. All rights reserved.
//***********************************************************************
using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;

namespace Common
{
    /// <summary>
    /// This class provides 3DES encryption and decryption routines.
    /// 
    /// Serkan Hekimoglu
    /// </summary>
    public class TripleDes
    {
        readonly byte[] _key = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 };
        readonly byte[] _iv = { 8, 7, 6, 5, 4, 3, 2, 1 };

        // define the triple des provider
        private readonly TripleDESCryptoServiceProvider _mDes = new TripleDESCryptoServiceProvider();

        // define the string handler
        private readonly UTF8Encoding _mUtf8 = new UTF8Encoding();

        // define the local property arrays
        private readonly byte[] _mKey;
        private readonly byte[] _mIv;

        /// <summary>
        /// Default constructor
        /// </summary>
        public TripleDes()
        {
            _mKey = _key;
            _mIv = _iv;
        }

        /// <summary>
        /// Parameterized constructor
        /// </summary>
        /// <param name="key"></param>
        /// <param name="iv"></param>
        public TripleDes(byte[] key, byte[] iv)
        {
            _mKey = key;
            _mIv = iv;
        }

        /// <summary>
        /// Encrypts the given byte array input
        /// </summary>
        /// <param name="input">Input value</param>
        /// <returns>Encrypted result</returns>
        public byte[] Encrypt(byte[] input)
        {
            return Transform(input, _mDes.CreateEncryptor(_mKey, _mIv));
        }

        /// <summary>
        /// Decrypts the given encrypted byte array input
        /// </summary>
        /// <param name="input">Encrypted byte array input</param>
        /// <returns>Decrypted result</returns>
        public byte[] Decrypt(byte[] input)
        {
            return Transform(input, _mDes.CreateDecryptor(_mKey, _mIv));
        }

        /// <summary>
        /// Encrypts the given string input
        /// </summary>
        /// <param name="text">Input value</param>
        /// <returns>Encrypted result</returns>
        public string Encrypt(string text)
        {
            byte[] input = _mUtf8.GetBytes(text);
            byte[] output = Transform(input, _mDes.CreateEncryptor(_mKey, _mIv));
            return Convert.ToBase64String(output);
        }

        /// <summary>
        /// Decrypts the given encrypted string input
        /// </summary>
        /// <param name="text">Encrypted string input</param>
        /// <returns>Decrypted result</returns>
        public string Decrypt(string text)
        {
            byte[] input = Convert.FromBase64String(text);
            byte[] output = Transform(input, _mDes.CreateDecryptor(_mKey, _mIv));
            return _mUtf8.GetString(output);
        }

        private static byte[] Transform(byte[] input, ICryptoTransform cryptoTransform)
        {
            // create the necessary streams
            using (MemoryStream memStream = new MemoryStream())
            {
                using (CryptoStream cryptStream = new CryptoStream(memStream, cryptoTransform, CryptoStreamMode.Write))
                {
                    // transform the bytes as requested
                    cryptStream.Write(input, 0, input.Length);
                    cryptStream.FlushFinalBlock();
                    // Read the memory stream andconvert it back into byte array
                    memStream.Position = 0;
                    byte[] result = memStream.ToArray();
                    // close and release the streams
                    memStream.Close();
                    cryptStream.Close();
                    // hand back the encrypted buffer
                    return result;
                }
            }
        }
    }

}