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using System.Security.Cryptography;
namespace WindowsFormsApplication9
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
const int keySize = 1024;
string publicAndPrivateKey;
string publicKey;
private void button1_Click(object sender, EventArgs e)
{
Form1.GenerateKeys(keySize, out publicKey, out publicAndPrivateKey);
string text = txt_clear.Text;
string encrypted = Form1.EncryptText(text, keySize, publicKey);
string decrypted = Form1.DecryptText(encrypted, keySize, publicAndPrivateKey);
txt_cipher.Text = encrypted;
}
private void button2_Click(object sender, EventArgs e)
{
Form1.GenerateKeys(keySize, out publicKey, out publicAndPrivateKey);
string text = txt_clear.Text;
// string text = "reza";
string encrypted = Form1.EncryptText(text, keySize, publicKey);
string decrypted = Form1.DecryptText(encrypted, keySize, publicAndPrivateKey);
txt_plain.Text = decrypted;
}
private static bool _optimalAsymmetricEncryptionPadding = false;
public static void GenerateKeys(int keySize, out string publicKey, out string publicAndPrivateKey)
{
using (var provider = new RSACryptoServiceProvider(keySize))
{
publicKey = provider.ToXmlString(false);
publicAndPrivateKey = provider.ToXmlString(true);
}
}
public static string EncryptText(string text, int keySize, string publicKeyXml)
{
var encrypted = Encrypt(Encoding.UTF8.GetBytes(text), keySize, publicKeyXml);
return Convert.ToBase64String(encrypted);
}
public static byte[] Encrypt(byte[] data, int keySize, string publicKeyXml)
{
if (data == null || data.Length == 0) throw new ArgumentException("Data are empty", "data");
int maxLength = GetMaxDataLength(keySize);
if (data.Length > maxLength) throw new ArgumentException(String.Format("Maximum data length is {0}", maxLength), "data");
if (!IsKeySizeValid(keySize)) throw new ArgumentException("Key size is not valid", "keySize");
if (String.IsNullOrEmpty(publicKeyXml)) throw new ArgumentException("Key is null or empty", "publicKeyXml");
using (var provider = new RSACryptoServiceProvider(keySize))
{
provider.FromXmlString(publicKeyXml);
return provider.Encrypt(data, _optimalAsymmetricEncryptionPadding);
}
}
public static string DecryptText(string text, int keySize, string publicAndPrivateKeyXml)
{
var decrypted = Decrypt(Convert.FromBase64String(text), keySize, publicAndPrivateKeyXml);
return Encoding.UTF8.GetString(decrypted);
}
public static byte[] Decrypt(byte[] data, int keySize, string publicAndPrivateKeyXml)
{
if (data == null || data.Length == 0) throw new ArgumentException("Data are empty", "data");
if (!IsKeySizeValid(keySize)) throw new ArgumentException("Key size is not valid", "keySize");
if (String.IsNullOrEmpty(publicAndPrivateKeyXml)) throw new ArgumentException("Key is null or empty", "publicAndPrivateKeyXml");
using (var provider = new RSACryptoServiceProvider(keySize))
{
provider.FromXmlString(publicAndPrivateKeyXml);
return provider.Decrypt(data, _optimalAsymmetricEncryptionPadding);
}
}
public static int GetMaxDataLength(int keySize)
{
if (_optimalAsymmetricEncryptionPadding)
{
return ((keySize - 384) / 8) + 7;
}
return ((keySize - 384) / 8) + 37;
}
public static bool IsKeySizeValid(int keySize)
{
return keySize >= 384 &&
keySize <= 16384 &&
keySize % 8 == 0;
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void button3_Click(object sender, EventArgs e)
{
Application.Exit();
}
}
}
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