please have a look it will help you.
public class TestContext : DbContext
{
// this is wt we use in application we can delete default ctor it is not required
public TestContext(string connectionName)
{
// i m reading a already encrypted connection string from config
// decrpt it and set the connction of db context
var conn = ConfigurationManager.ConnectionStrings["EncryptedConnection"].ConnectionString;
this.Database.Connection.ConnectionString = Encrypt.DecryptString(conn, "myKey");
}
public virtual DbSet<Contact> Contacts { get; set; }
}
config
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<configSections>
<!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
<section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
</configSections>
<connectionStrings>
<add name="EncryptedConnection" connectionString="qIhXH2MDWohYjOPJ3BiA7A4E70kRjRW3aSOMixpASFHu1oyak2YEMO3BTaRr3s5eVtuvi5dY07vK+PUm1xFZ6D1XT/qJjDvrs1SpbTHe45g=" providerName="System.Data.SqlClient" />
</connectionStrings>
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
</startup>
<entityFramework>
<defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
<parameters>
<parameter value="mssqllocaldb" />
</parameters>
</defaultConnectionFactory>
<providers>
<provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
</providers>
</entityFramework>
</configuration>
--- use in appplication
static void Main(string[] args)
{
// here I am using first takes a valid connectionstring from encrypt it.
// this is needed because I am showing it in console application idealy this step is independent of this
// this needs to be done by some build and deployment tool which wil copy this encrypted string to app.config
var encryptString = Encrypt.EncryptString("Data Source=yashssd;Initial Catalog=StackOverFlow1;Integrated Security=True", "myKey");
// this encryped connecton string I will save to th app.config manauly but this can be auutomated with build/ deployment tools
//var decrypt = Encrypt.DecryptString(encryptString, "myKey");
using (var ctx = new TestContext("EncryptedConnection"))
{
// for testing to see al working
//this is important to read the entity first .
var contact = ctx.Contacts.FirstOrDefault(x => x.ContactID == 1);
}
Console.ReadLine();
}
Final-- the logic of encryption / decryption
// this can be a seprate application whosw function is to provide encrypted keys to diffrent application I just took one whichI foundon internet this can be changed or can bemake more secure based on user needs .
public static class Encrypt
{
// This size of the IV (in bytes) must = (keysize / 8). Default keysize is 256, so the IV must be
// 32 bytes long. Using a 16 character string here gives us 32 bytes when converted to a byte array.
private const string initVector = "pemgail9uzpgzl88";
// This constant is used to determine the keysize of the encryption algorithm
private const int keysize = 256;
//Encrypt
public static string EncryptString(string plainText, string passPhrase)
{
byte[] initVectorBytes = Encoding.UTF8.GetBytes(initVector);
byte[] plainTextBytes = Encoding.UTF8.GetBytes(plainText);
PasswordDeriveBytes password = new PasswordDeriveBytes(passPhrase, null);
byte[] keyBytes = password.GetBytes(keysize / 8);
RijndaelManaged symmetricKey = new RijndaelManaged();
symmetricKey.Mode = CipherMode.CBC;
ICryptoTransform encryptor = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes);
MemoryStream memoryStream = new MemoryStream();
CryptoStream cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write);
cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
cryptoStream.FlushFinalBlock();
byte[] cipherTextBytes = memoryStream.ToArray();
memoryStream.Close();
cryptoStream.Close();
return Convert.ToBase64String(cipherTextBytes);
}
//Decrypt
public static string DecryptString(string cipherText, string passPhrase)
{
byte[] initVectorBytes = Encoding.ASCII.GetBytes(initVector);
byte[] cipherTextBytes = Convert.FromBase64String(cipherText);
PasswordDeriveBytes password = new PasswordDeriveBytes(passPhrase, null);
byte[] keyBytes = password.GetBytes(keysize / 8);
RijndaelManaged symmetricKey = new RijndaelManaged();
symmetricKey.Mode = CipherMode.CBC;
ICryptoTransform decryptor = symmetricKey.CreateDecryptor(keyBytes, initVectorBytes);
MemoryStream memoryStream = new MemoryStream(cipherTextBytes);
CryptoStream cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read);
byte[] plainTextBytes = new byte[cipherTextBytes.Length];
int decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
memoryStream.Close();
cryptoStream.Close();
return Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount);
}
}
