C# İle Şifreleme : Simetrik Şifreleme Algoritmaları

Simetrik şifreleme yöntemlerinde şifrelenen veriye ulaşmak için şifreyi çözen tarafın veriyi şifreleyen tarafla aynı anahtara ihtiyacı vardır. C# Simetrik şifreleme yöntemlerinden 3 tanesini hazır olarak bize sunar. Şimdi bunlar için birer örnek yapalım.

public static byte[] ByteDonustur(string deger)
{
UnicodeEncoding ByteConverter = new UnicodeEncoding();
return ByteConverter.GetBytes(deger);
}

public static byte[] Byte8(string deger)
{
char[] arrayChar = deger.ToCharArray();
byte[] arrayByte = new byte[arrayChar.Length];
for (int i = 0; i < arrayByte.Length; i++)
{
arrayByte[i] = Convert.ToByte(arrayChar[i]);
}
return arrayByte;
}


C# ile DES Şifreleme Yöntemi

public string DESSifrele(string strGiris)
{
string sonuc = "";
if (strGiris == "" || strGiris == null)
{
throw new ArgumentNullException("Şifrelenecek veri yok");
}
else
{
byte[] aryKey = Byte8("12345678"); // BURAYA 8 bit string DEĞER GİRİN
byte[] aryIV = Byte8("12345678"); // BURAYA 8 bit string DEĞER GİRİN
DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
MemoryStream ms = new MemoryStream();
CryptoStream cs = new CryptoStream(ms, cryptoProvider.CreateEncryptor(aryKey, aryIV), CryptoStreamMode.Write);
StreamWriter writer = new StreamWriter(cs);
writer.Write(strGiris);
writer.Flush();
cs.FlushFinalBlock();
writer.Flush();
sonuc = Convert.ToBase64String(ms.GetBuffer(), 0, (int)ms.Length);
writer.Dispose();
cs.Dispose();
ms.Dispose();
}
return sonuc;
}

public string DESCoz(string strGiris)
{
string strSonuc = "";
if (strGiris == "" || strGiris == null)
{
throw new ArgumentNullException("Şifrelenecek veri yok.");
}
else
{
byte[] aryKey = Byte8("12345678");
byte[] aryIV = Byte8("12345678");
DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
MemoryStream ms = new MemoryStream(Convert.FromBase64String(strGiris));
CryptoStream cs = new CryptoStream(ms, cryptoProvider.CreateDecryptor(aryKey, aryIV), CryptoStreamMode.Read);
StreamReader reader = new StreamReader(cs);
strSonuc = reader.ReadToEnd();
reader.Dispose();
cs.Dispose();
ms.Dispose();
}
return strSonuc;
}

C# ile TripleDES Şifreleme Yöntemi
TripleDES algoritması 24 bit anahtar ve 8 bit iv değeri kullanır.

public string Sifrele(string strGiris)
{
string sonuc = "";
if (strGiris == "" || strGiris == null)
{
throw new ArgumentNullException("Şifrelenecek veri yok.");
}
else
{
byte[] aryKey = Byte8("123456781234567812345678");
byte[] aryIV = Byte8("12345678");
TripleDESCryptoServiceProvider dec = new TripleDESCryptoServiceProvider();
MemoryStream ms = new MemoryStream();
CryptoStream cs = new CryptoStream(ms, dec.CreateEncryptor(aryKey, aryIV), CryptoStreamMode.Write);
StreamWriter writer = new StreamWriter(cs);
writer.Write(strGiris);
writer.Flush();
cs.FlushFinalBlock();
writer.Flush();
sonuc = Convert.ToBase64String(ms.GetBuffer(), 0, (int)ms.Length);
writer.Dispose();
cs.Dispose();
ms.Dispose();
}
return sonuc;
}

public string Coz(string strGiris)
{
string strSonuc = "";
if (strGiris == "" || strGiris == null)
{
throw new ArgumentNullException("Şifrelenecek veri yok.");
}
else
{
byte[] aryKey = Byte8("123456781234567812345678");
byte[] aryIV = Byte8("12345678");
TripleDESCryptoServiceProvider cryptoProvider = new TripleDESCryptoServiceProvider();
MemoryStream ms = new MemoryStream(Convert.FromBase64String(strGiris));
CryptoStream cs = new CryptoStream(ms, cryptoProvider.CreateDecryptor(aryKey, aryIV), CryptoStreamMode.Read);
StreamReader reader = new StreamReader(cs);
strSonuc = reader.ReadToEnd();
reader.Dispose();
cs.Dispose();
ms.Dispose();
}
return strSonuc;
}


C# ile RC2 Şifreleme Yöntemi
RC2 algoritması 8 bit anahtar ve 8 bit iv değeri kullanır.

public string Sifrele(string strGiris)
{
string sonuc = "";
if (strGiris == "" || strGiris == null)
{
throw new ArgumentNullException("Şifrelenecek veri yok.");
}
else
{
byte[] aryKey = Byte8("12345678");
byte[] aryIV = Byte8("12345678");
RC2CryptoServiceProvider dec = new RC2CryptoServiceProvider();
MemoryStream ms = new MemoryStream();
CryptoStream cs = new CryptoStream(ms, dec.CreateEncryptor(aryKey, aryIV), CryptoStreamMode.Write);
StreamWriter writer = new StreamWriter(cs);
writer.Write(strGiris);
writer.Flush();
cs.FlushFinalBlock();
writer.Flush();
sonuc = Convert.ToBase64String(ms.GetBuffer(), 0, (int)ms.Length);
writer.Dispose();
cs.Dispose();
ms.Dispose();
}
return sonuc;
}

public string Coz(string strGiris)
{
string strSonuc = "";
if (strGiris == "" || strGiris == null)
{
throw new ArgumentNullException("Şifresi çözülecek veri yok.");
}
else
{
byte[] aryKey = Byte8("12345678");
byte[] aryIV = Byte8("12345678");
RC2CryptoServiceProvider cp = new RC2CryptoServiceProvider();
MemoryStream ms = new MemoryStream(Convert.FromBase64String(strGiris));
CryptoStream cs = new CryptoStream(ms, cp.CreateDecryptor(aryKey, aryIV), CryptoStreamMode.Read);
StreamReader reader = new StreamReader(cs);
strSonuc = reader.ReadToEnd();
reader.Dispose();
cs.Dispose();
ms.Dispose();
}
return strSonuc;
}

C# ile Rijndael Şifreleme Yöntemi
Rijndael algoritması 8 anahtar ve 16 bit iv değeri kullanır.

public string Sifrele(string strGiris)
{
string sonuc = "";
if (strGiris == "" || strGiris == null)
{
throw new ArgumentNullException("Şifrelenecek veri yok.");
}
else
{
byte[] aryKey = Byte8("12345678");
byte[] aryIV = Byte8("1234567812345678");
RijndaelManaged dec = new RijndaelManaged();
dec.Mode = CipherMode.CBC;
MemoryStream ms = new MemoryStream();
CryptoStream cs = new CryptoStream(ms, dec.CreateEncryptor(aryKey, aryIV), CryptoStreamMode.Write);
StreamWriter writer = new StreamWriter(cs);
writer.Write(strGiris);
writer.Flush();
cs.FlushFinalBlock();
writer.Flush();
sonuc = Convert.ToBase64String(ms.GetBuffer(), 0, (int)ms.Length);
writer.Dispose();
cs.Dispose();
ms.Dispose();
}
return sonuc;
}
public string Coz(string strGiris)
{
string strSonuc = "";
if (strGiris == "" || strGiris == null)
{
throw new ArgumentNullException("Şifrezi çözülecek veri yok.");
}
else
{
byte[] aryKey = Byte8("12345678");
byte[] aryIV = Byte8("1234567812345678");
RijndaelManaged cp = new RijndaelManaged();
MemoryStream ms = new MemoryStream(Convert.FromBase64String(strGiris));
CryptoStream cs = new CryptoStream(ms, cp.CreateDecryptor(aryKey, aryIV), CryptoStreamMode.Read);
StreamReader reader = new StreamReader(cs);
strSonuc = reader.ReadToEnd();
reader.Dispose();
cs.Dispose();
ms.Dispose();
}
return strSonuc;
}