You may use the standard Rijndael algorithm to encrypt the entire connection string. You only need to keep the algorithm's password and the salt values in the code level (you may consider them as application constants).
App Config:-
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<connectionStrings>
<add name="DbContext" connectionString="7ryM3BFhWTwVGpeMWK0pMMujIwj7j+GvrJf7xewEW4Pd+uq0W8aSq85eaEp6+O2Gom98iVNHcyeuaG/93B2y/uJKyHmSnsBlHT3UtBpnT8Lx3OragLK5EXtIiVl38uq10bMga055qq1dACR6XQQeIQ==" providerName="System.Data.SqlClient" />
</connectionStrings>
</configuration>
Code:-
class Program
{
private static string _password = "0B6854E7-20AA-4B0E-978A-410152AA1B41";
static void Main(string[] args)
{
var connection = System.Configuration.ConfigurationManager.ConnectionStrings["DbContext"].ConnectionString;
var salt = "Pa$$w0rd";
var plainConnection = DecryptRijndael(connection, salt);
//var encrypted = EncryptRijndael(connection, salt);
}
public static string EncryptRijndael(string text, string salt)
{
if (string.IsNullOrEmpty(text))
throw new ArgumentNullException("text");
using(var aesAlg = NewRijndaelManaged(salt))
using(var encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV))
using (var msEncrypt = new MemoryStream())
{
using (var csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
using (var swEncrypt = new StreamWriter(csEncrypt))
swEncrypt.Write(text);
return Convert.ToBase64String(msEncrypt.ToArray());
}
}
public static string DecryptRijndael(string cipherText, string salt)
{
if (string.IsNullOrEmpty(cipherText))
throw new ArgumentNullException("cipherText");
if (!IsBase64String(cipherText))
throw new Exception("The cipherText input parameter is not base64 encoded");
using (var aesAlg = NewRijndaelManaged(salt))
using (var decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV))
{
var cipher = Convert.FromBase64String(cipherText);
using (var msDecrypt = new MemoryStream(cipher))
using (var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
using (var srDecrypt = new StreamReader(csDecrypt))
return srDecrypt.ReadToEnd();
}
}
private static bool IsBase64String(string base64String)
{
base64String = base64String.Trim();
return (base64String.Length % 4 == 0) &&
Regex.IsMatch(base64String, @"^[a-zA-Z0-9\+/]*={0,3}$", RegexOptions.None);
}
private static RijndaelManaged NewRijndaelManaged(string salt)
{
if (salt == null) throw new ArgumentNullException("salt");
var saltBytes = Encoding.ASCII.GetBytes(salt);
using (var key = new Rfc2898DeriveBytes(_password, saltBytes))
{
var aesAlg = new RijndaelManaged();
aesAlg.Key = key.GetBytes(aesAlg.KeySize / 8);
aesAlg.IV = key.GetBytes(aesAlg.BlockSize / 8);
return aesAlg;
}
}
}
Hope this helps.
