/// <summary>
/// Decrypt a Product Settings string.
/// </summary>
/// <param name="string">The string to decrypt.</param>
/// <returns>The decrypted string.</returns>
public static string Decrypt(string @string)
{
if (String.IsNullOrEmpty(@string))
{
return(@string);
}
string result;
try
{
using (var dataStream = new MemoryStream(Convert.FromBase64String(@string)))
using (var cryptoService = new XorCryptoServiceProvider {
Key = Encoding.UTF8.GetBytes(@"ClearCanvas"), IV = Encoding.UTF8.GetBytes(@"IsSoCool")
})
using (var cryptoStream = new CryptoStream(dataStream, cryptoService.CreateDecryptor(), CryptoStreamMode.Read))
using (var reader = new StreamReader(cryptoStream, Encoding.UTF8))
{
result = reader.ReadToEnd().TrimEnd('\0');
}
}
catch (Exception)
{
result = string.Empty;
}
return(result);
}
private static void TestRoundtripEncryption(string inputText, string key, string iv, Encoding encoding)
{
inputText = inputText.TrimEnd('\0');
var keyBytes = encoding.GetBytes(key);
var ivBytes = encoding.GetBytes(iv);
var inputBytes = encoding.GetBytes(inputText);
Console.WriteLine("=======================================");
Console.WriteLine("{0,12}: {1}", "Input", Convert.ToBase64String(inputBytes));
using (var cryptoServiceProvider = new XorCryptoServiceProvider {
Key = keyBytes, IV = ivBytes
})
{
byte[] cipherBytes;
using (var memoryStream = new MemoryStream())
using (var cryptoStream = new CryptoStream(memoryStream, cryptoServiceProvider.CreateEncryptor(), CryptoStreamMode.Write))
{
cryptoStream.Write(inputBytes, 0, inputBytes.Length);
cryptoStream.FlushFinalBlock();
cipherBytes = memoryStream.ToArray();
Console.WriteLine("{0,12}: {1}", "Encrypted", Convert.ToBase64String(cipherBytes));
Assert.AreNotEqual(inputText, encoding.GetString(cipherBytes), "cipher form should not be same as plaintext form");
Assert.LessOrEqual(inputBytes.Length * 8 / 3, GetBitDelta(inputBytes, cipherBytes), "cipher form should not be similar to plaintext form");
}
using (var memoryStream = new MemoryStream(cipherBytes))
using (var cryptoStream = new CryptoStream(memoryStream, cryptoServiceProvider.CreateDecryptor(), CryptoStreamMode.Read))
using (var streamReader = new StreamReader(cryptoStream, encoding))
{
var outputText = streamReader.ReadToEnd().TrimEnd('\0');
var outputBytes = encoding.GetBytes(outputText);
Console.WriteLine("{0,12}: {1}", "Decrypted", Convert.ToBase64String(outputBytes));
Assert.AreEqual(inputText, outputText, "decrypted plaintext should be equal to original plaintext");
}
}
}
private static void TestRoundtripEncryption(string inputText, string key, string iv, Encoding encoding)
{
inputText = inputText.TrimEnd('\0');
var keyBytes = encoding.GetBytes(key);
var ivBytes = encoding.GetBytes(iv);
var inputBytes = encoding.GetBytes(inputText);
Console.WriteLine("=======================================");
Console.WriteLine("{0,12}: {1}", "Input", Convert.ToBase64String(inputBytes));
using (var cryptoServiceProvider = new XorCryptoServiceProvider {Key = keyBytes, IV = ivBytes})
{
byte[] cipherBytes;
using (var memoryStream = new MemoryStream())
using (var cryptoStream = new CryptoStream(memoryStream, cryptoServiceProvider.CreateEncryptor(), CryptoStreamMode.Write))
{
cryptoStream.Write(inputBytes, 0, inputBytes.Length);
cryptoStream.FlushFinalBlock();
cipherBytes = memoryStream.ToArray();
Console.WriteLine("{0,12}: {1}", "Encrypted", Convert.ToBase64String(cipherBytes));
Assert.AreNotEqual(inputText, encoding.GetString(cipherBytes), "cipher form should not be same as plaintext form");
Assert.LessOrEqual(inputBytes.Length*8/3, GetBitDelta(inputBytes, cipherBytes), "cipher form should not be similar to plaintext form");
}
using (var memoryStream = new MemoryStream(cipherBytes))
using (var cryptoStream = new CryptoStream(memoryStream, cryptoServiceProvider.CreateDecryptor(), CryptoStreamMode.Read))
using (var streamReader = new StreamReader(cryptoStream, encoding))
{
var outputText = streamReader.ReadToEnd().TrimEnd('\0');
var outputBytes = encoding.GetBytes(outputText);
Console.WriteLine("{0,12}: {1}", "Decrypted", Convert.ToBase64String(outputBytes));
Assert.AreEqual(inputText, outputText, "decrypted plaintext should be equal to original plaintext");
}
}
}
