/// <summary>
/// Create a key file using a <see cref="VTDev.Libraries.CEXEngine.Crypto.Processing.Structure.PackageKey"/> structure; containing the cipher description and operating ids and flags.
/// </summary>
///
/// <param name="Package">The PackageKeyKey containing the cipher description and operating ids and flags</param>
/// <param name="SeedEngine">The <see cref="VTDev.Libraries.CEXEngine.Crypto.Common.CipherDescription">Random Generator</see> used to create the stage 1 seed material during key generation.</param>
/// <param name="DigestEngine">The <see cref="VTDev.Libraries.CEXEngine.Crypto.Common.CipherDescription">Digest Engine</see> used in the stage II phase of key generation.</param>
///
/// <exception cref="CryptoProcessingException">Thrown if a key file exists at the path specified, the path is read only, the CipherDescription or KeyAuthority structures are invalid, or
/// number of SubKeys specified is either less than 1 or more than the maximum allowed (100,000)</exception>
public void Create(PackageKey Package, SeedGenerators SeedEngine = SeedGenerators.CSPRsg, Digests DigestEngine = Digests.SHA512)
{
// if you are getting exceptions.. read the docs!
if (!CipherDescription.IsValid(Package.Description))
{
throw new CryptoProcessingException("PackageFactory:Create", "The key package cipher settings are invalid!", new FormatException());
}
if (!KeyAuthority.IsValid(Package.Authority))
{
throw new CryptoProcessingException("PackageFactory:Create", "The key package key authority settings are invalid!", new FormatException());
}
if (Package.SubKeyCount < 1)
{
throw new CryptoProcessingException("PackageFactory:Create", "The key package must contain at least 1 key!", new ArgumentOutOfRangeException());
}
if (Package.SubKeyCount > SUBKEY_MAX)
{
throw new CryptoProcessingException("PackageFactory:Create", String.Format("The key package can not contain more than {0} keys!", SUBKEY_MAX), new ArgumentOutOfRangeException());
}
// get the size of a subkey set
int subKeySize = Package.Description.KeySize + EXTKEY_SIZE;
if (Package.Description.IvSize > 0)
{
subKeySize += Package.Description.IvSize;
}
if (Package.Description.MacKeySize > 0)
{
subKeySize += Package.Description.MacKeySize;
}
if (subKeySize < 1)
{
throw new CryptoProcessingException("PackageFactory:Create", "The key package cipher settings are invalid!", new Exception());
}
try
{
// store the auth struct and policy
m_keyOwner = Package.Authority;
KeyPolicy = Package.KeyPolicy;
// get the serialized header
byte[] header = Package.ToBytes();
// size key buffer
byte[] buffer = new byte[subKeySize * Package.SubKeyCount];
// generate the keying material
using (KeyGenerator keyGen = new KeyGenerator(SeedEngine, DigestEngine))
keyGen.GetBytes(buffer);
BinaryWriter keyWriter = new BinaryWriter(m_keyStream);
// pre-set the size to avoid fragmentation
keyWriter.BaseStream.SetLength(PackageKey.GetHeaderSize(Package) + (subKeySize * Package.SubKeyCount));
if (IsEncrypted(Package.KeyPolicy))
{
// add policy flags, only part of key not encrypted
keyWriter.Write(Package.KeyPolicy);
// get salt, return depends on auth flag settings
byte[] salt = GetSalt();
// create a buffer for encrypted data
int hdrLen = header.Length - PackageKey.GetPolicyOffset();
byte[] data = new byte[buffer.Length + hdrLen];
// copy header and key material
Buffer.BlockCopy(header, PackageKey.GetPolicyOffset(), data, 0, hdrLen);
Buffer.BlockCopy(buffer, 0, data, hdrLen, buffer.Length);
// encrypt the key and header
TransformBuffer(data, salt);
// write to file
keyWriter.Write(data);
// don't wait for gc
Array.Clear(salt, 0, salt.Length);
Array.Clear(data, 0, data.Length);
}
else
{
// write the keypackage header
keyWriter.Write(header, 0, header.Length);
// write the keying material
keyWriter.Write(buffer, 0, buffer.Length);
}
// cleanup
m_keyStream.Seek(0, SeekOrigin.Begin);
Array.Clear(header, 0, header.Length);
Array.Clear(buffer, 0, buffer.Length);
}
catch (Exception)
{
throw;
}
}