/// <summary>
/// Demonstrates saving a key file using the PackageFactory class
/// </summary>
private void SaveKey()
{
try
{
// add the time/date expiration stamp if key policy is volatile
if (HasPolicy(KeyPolicies.Volatile))
{
if (dtVolatileTime.Value.Ticks > DateTime.Now.Ticks)
_container.Authority.OptionFlag = dtVolatileTime.Value.Ticks;
else
throw new Exception("Invalid Expiry time. If a key is marked as Volatile, the expired time must be greater than the current time.");
}
// get the key tag description
if (!string.IsNullOrEmpty(txtKeyDescription.Text))
{
byte[] data = new byte[32];
byte[] tag = Encoding.ASCII.GetBytes(txtKeyDescription.Text);
Array.Copy(tag, data, tag.Length < 32 ? tag.Length : 32);
_container.Authority.PackageTag = data;
}
// get the number of subkeys to create in this package
int keyCount = 1;
if (!string.IsNullOrEmpty(txtSubKeyCount.Text) && txtSubKeyCount.Text != "0")
int.TryParse(txtSubKeyCount.Text, out keyCount);
// create a PackageKey; a key package can contain 1 or many thousands of 'subkeys'. Each subkey set
// contains one group of unique random keying material; key, iv, and optional hmac key.
// Each key set is used only once for encryption, guaranteeing that a unique set of values is used for every encryption cycle.
PackageKey package = new PackageKey(
_container.Authority, // the KeyAuthority structure
_container.Description, // the CipherDescription structure
keyCount, // the number of subkeys to add to this key package
IdGenerator()); // the file extension encryption key
// create and write the key
using (PackageFactory factory = new PackageFactory(_keyFilePath, _container.Authority))
factory.Create(package);
// store path
_lastKeyPath = Path.GetDirectoryName(_keyFilePath);
Reset();
lblStatus.Text = "The Key has been saved!";
}
catch (Exception ex)
{
if (File.Exists(_keyFilePath))
File.Delete(_keyFilePath);
string message = ex.Message == null ? "" : ex.Message;
MessageBox.Show("An error occured, the key could not be created! " + message);
}
}
/// <summary>
/// Creates a temporary PackageKey on disk, extracts and compares the copy
/// <para>Throws an Exception on failure</</para>
/// </summary>
public static void PackageFactoryTest()
{
string path = GetTempPath();
KeyGenerator kgen = new KeyGenerator();
// populate a KeyAuthority structure
KeyAuthority authority = new KeyAuthority(kgen.GetBytes(16), kgen.GetBytes(16), kgen.GetBytes(16), kgen.GetBytes(32), 0);
// cipher paramaters
CipherDescription desc = new CipherDescription(
SymmetricEngines.RDX, 32,
IVSizes.V128,
CipherModes.CTR,
PaddingModes.X923,
BlockSizes.B128,
RoundCounts.R14,
Digests.Keccak512,
64,
Digests.Keccak512);
// create the package key
PackageKey pkey = new PackageKey(authority, desc, 10);
// write a key file
using (PackageFactory pf = new PackageFactory(path, authority))
pf.Create(pkey);
for (int i = 0; i < pkey.SubKeyCount; i++)
{
CipherDescription desc2;
KeyParams kp1;
KeyParams kp2;
byte[] ext;
byte[] id = pkey.SubKeyID[i];
// get at index
using (FileStream stream = new FileStream(path, FileMode.Open))
kp2 = PackageKey.AtIndex(stream, i);
// read the package from id
using (PackageFactory pf = new PackageFactory(path, authority))
pf.Extract(id, out desc2, out kp1, out ext);
// compare key material
if (!Compare.AreEqual(kp1.Key, kp2.Key))
throw new Exception();
if (!Compare.AreEqual(kp1.IV, kp2.IV))
throw new Exception();
if (!Compare.AreEqual(pkey.ExtensionKey, ext))
throw new Exception();
if (!desc.Equals(desc2))
throw new Exception();
}
if (File.Exists(path))
File.Delete(path);
}