using System.Security.Cryptography;
//
private ICryptoTransform encRij;
private ICryptoTransform enc3des;
private ICryptoTransform decRij;
private ICryptoTransform dec3des;
// Helper functions
public static string EncryptAndBase64(string val, ICryptoTransform trans)
{
byte[] buf = UnicodeEncoding.Unicode.GetBytes(val);
MemoryStream memStream = new MemoryStream();
CryptoStream cryptStream = new CryptoStream(memStream, trans, CryptoStreamMode.Write);
cryptStream.Write(buf, 0, buf.Length);
cryptStream.FlushFinalBlock();
cryptStream.Clear();
Array.Clear(buf, 0, buf.Length);
buf = memStream.GetBuffer();
val = Convert.ToBase64String(buf, 0, (int)memStream.Length);
Array.Clear(buf, 0, (int)memStream.Length);
return val;
}
public static string DecryptFromBase64(string base64str, ICryptoTransform trans)
{
byte[] buf = Convert.FromBase64String(base64str);
MemoryStream memStream = new MemoryStream();
CryptoStream cryptStream = new CryptoStream(memStream, trans, CryptoStreamMode.Write);
cryptStream.Write(buf, 0, buf.Length);
cryptStream.FlushFinalBlock();
cryptStream.Clear();
Array.Clear(buf, 0, buf.Length);
buf = memStream.GetBuffer();
string ret = UnicodeEncoding.Unicode.GetString(buf, 0, (int)memStream.Length);
Array.Clear(buf, 0, (int)memStream.Length);
memStream.Close();
return ret;
}
// Save a MemoryStream file with encryption to persistent file
public static void SaveData(MemoryStream memStream, ICryptoTransform ict, string filePath)
{ try{
FileIOPermission perm = new FileIOPermission(FileIOPermissionAccess.Write, filePath);
perm.Demand();
}
catch{
}
Stream fileStream = new FileStream(filePath, FileMode.Create, FileAccess.Write, FileShare.None);
try
{
CryptoStream cryptStream = new CryptoStream(memStream, ict, CryptoStreamMode.Read);
int read = 0;
byte[] buf = new byte[4096];
while (true)
{
read = cryptStream.Read(buf, 0, buf.Length);
if (read == 0)
break;
fileStream.Write(buf, 0, read);
}
cryptStream.Clear();
}
finally
{
fileStream.Close();
}
}
// Load an ecrypted file and process it
private bool LoadData(string filePath, ICryptoTransform ict)
{
bool bReturn = true;
if( FileExists(filePath) )
{
Stream fileStream = new FileStream(filePath, FileMode.OpenOrCreate, FileAccess.Read, FileShare.None);
MemoryStream memStream = new MemoryStream();
try
{
CryptoStream cryptStream = new CryptoStream(fileStream, ict, CryptoStreamMode.Read);
int read = 0;
byte[] buf = new byte[4096];
while (true)
{
read = cryptStream.Read(buf, 0, buf.Length);
if (read == 0)
break;
memStream.Write(buf, 0, read);
}
cryptStream.Clear();
memStream.Position = 0;
//
// Process here the memStream file;
//
buf = memStream.GetBuffer();
Array.Clear(buf, 0, (int)memStream.Length);
xmlr.Close();
memStream.Close();
}
catch(Exception ex)
{
string sMsg = "LoadData:" + ex.GetType() + ex.Message;
//Util.WriteToEventLog(sMsg,enumLogType.Error);
bReturn = false;
}
finally
{
if (fileStream!=null)
fileStream.Close();
}
}
private bool SetEncryptorDecryptor(Key3IV3 k3iv3)
{
bool bReturn = true;
RijndaelManaged aes = null;
TripleDESCryptoServiceProvider des3 = null;
try
{
aes = new RijndaelManaged();
des3 = new TripleDESCryptoServiceProvider();
encRij = aes.CreateEncryptor(k3iv3.KeyRij, k3iv3.IVRij);
enc3des = des3.CreateEncryptor(k3iv3.Key3des, k3iv3.IV3des);
decRij = aes.CreateDecryptor(k3iv3.KeyRij, k3iv3.IVRij);
dec3des = des3.CreateDecryptor(k3iv3.Key3des, k3iv3.IV3des);
}
catch (Exception e)
{
string sMsg = "SetEncryptorDecryptor:" + e.GetType() + e.Message;
//Util.WriteToEventLog(sMsg,enumLogType.Error);
bReturn = false;
}
finally
{
if (des3 != null)
des3.Clear();
if (aes != null)
aes.Clear();
}
return bReturn;
}
// Provides the enc/dec objects from a given key
public class Key3IV3
{
private byte[] keyRij;
private byte[] key3des;
private byte[] ivRij;
private byte[] iv3des;
internal byte[] KeyRij
{
get { return keyRij; }
}
internal byte[] IVRij
{
get { return ivRij; }
}
internal byte[] Key3des
{
get { return key3des; }
}
internal byte[] IV3des
{
get { return iv3des; }
}
public Key3IV3(string txtPlainKey)
{
byte[] salt = System.Text.UTF8Encoding.UTF8.GetBytes(txtPlainKey);
SHA1 hash = new SHA1Managed();
for (int i = 0; i < 200; ++i)
{
salt = hash.ComputeHash(salt, 0, salt.Length);
hash.Initialize();
}
PasswordDeriveBytes pdb = new PasswordDeriveBytes(txtPlainKey, salt, "SHA512", 1000);
Array.Clear(salt, 0, salt.Length);
hash.Clear();
keyRij = pdb.GetBytes(32);
key3des = pdb.GetBytes(24);
ivRij = pdb.GetBytes(16);
iv3des = pdb.GetBytes(8);
}
public void Clear()
{
Array.Clear(keyRij, 0, keyRij.Length);
Array.Clear(ivRij, 0, ivRij.Length);
Array.Clear(key3des, 0, key3des.Length);
Array.Clear(iv3des, 0, iv3des.Length);
}
~Key3IV3()
{
// ...
}
}
