/// <summary>
/// Initializes a new instance of the <see cref="FileMeta"/> class and generates missing keys.
/// </summary>
/// <param name="path">The local file path to load the meta data from.</param>
/// <param name="algorithm">The cryptographic algorith to encrypt this <see cref="FileMeta"/>.</param>
/// <param name="hmacKey">256 bit HMAC key to verify integrity of this <see cref="FileMeta"/>.</param>
/// <param name="aesKey">256 bit AES key to encrypt this <see cref="FileMeta"/>.</param>
/// <param name="fileKey">256 bit AES key to encrypt the associated file.</param>
/// <exception cref="ArgumentException"/>
/// <exception cref="ArgumentNullException"/>
/// <exception cref="ArgumentOutOfRangeException"/>
/// <exception cref="FileNotFoundException"/>
public static async Task <FileMeta> FromFileAsync(string path, ContentAlgorithm algorithm, byte[] hmacKey, byte[] aesKey, byte[] fileKey)
{
if (string.IsNullOrWhiteSpace(path))
{
throw new ArgumentNullException(nameof(path));
}
if (algorithm != ContentAlgorithm.None && algorithm != ContentAlgorithm.Aes256CbcHmacSha256)
{
throw new ArgumentException("This content algorithm is not supported.", nameof(algorithm));
}
FileMeta instance = new FileMeta(algorithm, hmacKey, aesKey, fileKey);
await instance.LoadFromFileAsync(path);
instance.Available = true;
return(instance);
}
private FileMeta(ContentAlgorithm algorithm, byte[] hmacKey, byte[] aesKey, byte[] fileKey)
{
Algorithm = algorithm;
AesKey = aesKey;
HmacKey = hmacKey;
FileKey = fileKey;
if (Algorithm == ContentAlgorithm.Aes256CbcHmacSha256)
{
if (AesKey == null)
{
AesKey = AesStatic.GenerateKey();
}
else if (AesKey.Length != 32)
{
throw new ArgumentOutOfRangeException(nameof(aesKey));
}
if (hmacKey == null)
{
HmacKey = AesStatic.GenerateKey();
}
else if (HmacKey.Length != 32)
{
throw new ArgumentOutOfRangeException(nameof(hmacKey));
}
if (fileKey == null)
{
FileKey = AesStatic.GenerateKey();
}
else if (FileKey.Length != 32)
{
throw new ArgumentOutOfRangeException(nameof(fileKey));
}
FileEncryption = ContentAlgorithm.Aes256Cbc; // The file needs no HMAC as we have an SHA256
}
}
private async void BtnSendFile_Click(object sender, EventArgs e)
{
string path;
using (OpenFileDialog fd = new OpenFileDialog())
{
fd.InitialDirectory = Program.TempPath;
if (fd.ShowDialog() == DialogResult.Cancel)
{
return;
}
path = fd.FileName;
}
ContentAlgorithm algorithm = ContentAlgorithm.None;
byte[] aesKey = null;
byte[] hmacKey = null;
if (!string.IsNullOrWhiteSpace(TbFileKey.Text))
{
algorithm = ContentAlgorithm.Aes256CbcHmacSha256;
byte[] keys = Util.GetBytes(TbFileKey.Text);
hmacKey = keys.Take(32);
aesKey = keys.Skip(32);
}
FTEventArgs args = new FTEventArgs(new Identifier(0), await FileMeta.FromFileAsync(path, algorithm, hmacKey, aesKey, null), path);
args.Progress += VslClient_FTProgress;
args.Finished += VslClient_FTFinished;
if (!await vslClient.FileTransfer.StartUploadAsync(args))
{
return;
}
btnReceiveFile.Enabled = false;
btnSendFile.Enabled = false;
}
/// <summary>
/// Initializes a new instance of the <see cref="FileMeta"/> class and generates all required keys.
/// </summary>
/// <param name="path">The local file path to load the meta data from.</param>
/// <param name="algorithm">The cryptographic algorith to encrypt this <see cref="FileMeta"/>.</param>
/// <exception cref="ArgumentNullException"/>
/// <exception cref="FileNotFoundException"/>
/// <exception cref="NotSupportedException"/>
public static Task <FileMeta> FromFileAsync(string path, ContentAlgorithm algorithm)
{
return(FromFileAsync(path, algorithm, null, null, null));
}
