public static KeyModel GetKeyByHeader(string header)
{
var keyModel = new KeyModel();
string[] forKey = header.Split('_');
if (forKey.Length < 2)
{
throw new InputFormatException("header");
}
string[] keys = forKey[1].Split(',');
if (keys.Length < 2)
{
throw new InputFormatException("header");
}
try
{
if (DefinedEncrypt(header))
keyModel.E = BigInteger.Parse(keys[0]);
else
keyModel.D = BigInteger.Parse(keys[0]);
keyModel.N = BigInteger.Parse(keys[1]);
}
catch (Exception e)
{
throw new InputFormatException(e.Message);
}
return keyModel;
}
private void Input(out bool forEncode, out string data, out KeyModel key)
{
using (var reader = new StreamReader(_settings.InputFilename, Encoding.UTF8))
{
string firstLine = reader.ReadLine();
bool isEncrypt = RSAHelper.DefinedEncrypt(firstLine);
KeyModel keyModel;
try
{
keyModel = RSAHelper.GetKeyByHeader(firstLine);
}catch(InputFormatException)
{
//need to decrypt secret key to encrypt the public
//if the encrypt key is not specified - it will generate
if (isEncrypt)
keyModel = _cryptService.GenerateKey();
else
throw new InputFormatException("header");
}
string content = reader.ReadLine();
if (string.IsNullOrEmpty(content))
{
throw new InputFormatException("data");
}
key = keyModel;
forEncode = isEncrypt;
data = content;
}
}
public void EncryptDecryptTest()
{
var service = new RSACryptService(1024,_encode);
const string testString = "rsa is complete";
var key = new KeyModel {D = 44273, E = 65537, N = 49163};
var encryptData = service.Encrypt(testString, key);
string decryptString = service.Decrypt(encryptData, key);
Assert.AreEqual(testString,decryptString);
}
public BigInteger[] Encrypt(string data, KeyModel key)
{
byte[] dataBytes = _encoding.GetBytes(data);
var toReturn = new BigInteger[dataBytes.Length];
for (int i = 0; i< dataBytes.Length;i++)
{
toReturn[i] = BigInteger.ModPow(dataBytes[i], key.E, key.N);
}
return toReturn;
}
public string Decrypt(BigInteger[] encryptedData, KeyModel key)
{
var dataBytes = new byte[encryptedData.Length];
for (int i = 0; i < encryptedData.Length; i++)
{
var decodeNum = BigInteger.ModPow(encryptedData[i], key.D, key.N);
dataBytes[i] = decodeNum.ToByteArray()[0];
}
string result = _encoding.GetString(dataBytes);
return result;
}
public static string SecretKeyAsString(KeyModel model)
{
bool isDefined = model.D != default(BigInteger) && model.N != default(BigInteger);
return isDefined ? String.Format("Secret key (d,n): {0},{1}{2}", model.D, model.N, Environment.NewLine) : null;
}
public static string PublicKeyAsString(KeyModel model)
{
bool isDefined = model.E != default(BigInteger) && model.N != default(BigInteger);
return isDefined ? String.Format("Public key (e,n): {0},{1}{2}", model.E, model.N, Environment.NewLine) : null;
}
private void WriteHeader(KeyModel key)
{
string writeData = "";
writeData += RSAHelper.PublicKeyAsString(key);
writeData += RSAHelper.SecretKeyAsString(key);
ToOutput(writeData, false);
}
private void ResultToOutput(string data, KeyModel key)
{
WriteHeader(key);
ToOutput(data, true);
}
