/// <summary>
/// Downloads the message payload referred to by the specified <see cref="PayloadReference"/>.
/// </summary>
/// <param name="notification">The payload reference.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>The task representing the asynchronous operation.</returns>
protected virtual async Task <Payload> DownloadPayloadAsync(PayloadReference notification, CancellationToken cancellationToken)
{
Requires.NotNull(notification, "notification");
var responseMessage = await this.HttpClient.GetAsync(notification.Location, cancellationToken);
var messageBuffer = await responseMessage.Content.ReadAsByteArrayAsync();
// Calculate hash of downloaded message and check that it matches the referenced message hash.
var messageHash = this.CryptoServices.Hash(messageBuffer);
if (!Utilities.AreEquivalent(messageHash, notification.Hash))
{
throw new InvalidMessageException();
}
var encryptedResult = new SymmetricEncryptionResult(
notification.Key,
notification.IV,
messageBuffer);
var plainTextBuffer = this.CryptoServices.Decrypt(encryptedResult);
var plainTextStream = new MemoryStream(plainTextBuffer);
var plainTextReader = new BinaryReader(plainTextStream);
var message = Utilities.DeserializeDataContract <Payload>(plainTextReader);
message.PayloadReferenceUri = notification.ReferenceLocation;
return(message);
}
/// <summary>
/// Symmetrically decrypts a buffer using the specified key.
/// </summary>
/// <param name="data">The encrypted data and the key and IV used to encrypt it.</param>
/// <returns>
/// The decrypted buffer.
/// </returns>
public virtual byte[] Decrypt(SymmetricEncryptionResult data)
{
Requires.NotNull(data, "data");
var plaintext = new MemoryStream();
var ciphertext = new MemoryStream(data.Ciphertext);
this.DecryptAsync(ciphertext, plaintext, data, CancellationToken.None).Wait();
return(plaintext.ToArray());
}
/// <summary>
/// Downloads a <see cref="PayloadReference"/> that is referenced from an incoming inbox item.
/// </summary>
/// <param name="inboxItem">The inbox item that referenced the <see cref="PayloadReference"/>.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>The task representing the asynchronous operation.</returns>
protected virtual async Task <PayloadReference> DownloadPayloadReferenceAsync(IncomingList.IncomingItem inboxItem, CancellationToken cancellationToken)
{
Requires.NotNull(inboxItem, "inboxItem");
var responseMessage = await this.HttpClient.GetAsync(inboxItem.Location, cancellationToken);
if (responseMessage.StatusCode == HttpStatusCode.NotFound)
{
// delete inbox item and move on.
await this.DeletePayloadReferenceAsync(inboxItem.Location, cancellationToken);
this.Log("Missing payload reference.", null);
return(null);
}
responseMessage.EnsureSuccessStatusCode();
var responseStream = await responseMessage.Content.ReadAsStreamAsync();
var responseStreamCopy = new MemoryStream();
await responseStream.CopyToAsync(responseStreamCopy, 4096, cancellationToken);
responseStreamCopy.Position = 0;
var encryptedKey = await responseStreamCopy.ReadSizeAndBufferAsync(cancellationToken);
var key = this.CryptoServices.Decrypt(this.Endpoint.EncryptionKeyPrivateMaterial, encryptedKey);
var iv = await responseStreamCopy.ReadSizeAndBufferAsync(cancellationToken);
var ciphertext = await responseStreamCopy.ReadSizeAndBufferAsync(cancellationToken);
var encryptedPayload = new SymmetricEncryptionResult(key, iv, ciphertext);
var plainTextPayloadBuffer = this.CryptoServices.Decrypt(encryptedPayload);
var plainTextPayloadStream = new MemoryStream(plainTextPayloadBuffer);
var signature = await plainTextPayloadStream.ReadSizeAndBufferAsync(cancellationToken);
long payloadStartPosition = plainTextPayloadStream.Position;
var signedBytes = new byte[plainTextPayloadStream.Length - plainTextPayloadStream.Position];
await plainTextPayloadStream.ReadAsync(signedBytes, 0, signedBytes.Length);
plainTextPayloadStream.Position = payloadStartPosition;
var plainTextPayloadReader = new BinaryReader(plainTextPayloadStream);
var recipientPublicSigningKeyBuffer = plainTextPayloadReader.ReadSizeAndBuffer();
var creationDateUtc = DateTime.FromBinary(plainTextPayloadReader.ReadInt64());
var notificationAuthor = Utilities.DeserializeDataContract <Endpoint>(plainTextPayloadReader);
var messageReference = Utilities.DeserializeDataContract <PayloadReference>(plainTextPayloadReader);
messageReference.ReferenceLocation = inboxItem.Location;
if (!this.CryptoServices.VerifySignature(notificationAuthor.SigningKeyPublicMaterial, signedBytes, signature))
{
throw new InvalidMessageException();
}
if (!Utilities.AreEquivalent(recipientPublicSigningKeyBuffer, this.Endpoint.PublicEndpoint.SigningKeyPublicMaterial))
{
throw new InvalidMessageException(Strings.MisdirectedMessage);
}
return(messageReference);
}
/// <summary>
/// Symmetrically decrypts a buffer using the specified key.
/// </summary>
/// <param name="cryptoProvider">The crypto provider.</param>
/// <param name="data">The encrypted data and the key and IV used to encrypt it.</param>
/// <returns>
/// The decrypted buffer.
/// </returns>
public static byte[] Decrypt(this CryptoSettings cryptoProvider, SymmetricEncryptionResult data)
{
var symmetricKey = CryptoSettings.SymmetricAlgorithm.CreateSymmetricKey(data.Key);
return WinRTCrypto.CryptographicEngine.Decrypt(symmetricKey, data.Ciphertext, data.IV);
}
/// <summary>
/// Downloads the message payload referred to by the specified <see cref="PayloadReference"/>.
/// </summary>
/// <param name="notification">The payload reference.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>The task representing the asynchronous operation.</returns>
protected virtual async Task<Payload> DownloadPayloadAsync(PayloadReference notification, CancellationToken cancellationToken) {
Requires.NotNull(notification, "notification");
var responseMessage = await this.HttpClient.GetAsync(notification.Location, cancellationToken);
var messageBuffer = await responseMessage.Content.ReadAsByteArrayAsync();
// Calculate hash of downloaded message and check that it matches the referenced message hash.
var messageHash = this.CryptoServices.Hash(messageBuffer);
if (!Utilities.AreEquivalent(messageHash, notification.Hash)) {
throw new InvalidMessageException();
}
var encryptedResult = new SymmetricEncryptionResult(
notification.Key,
notification.IV,
messageBuffer);
var plainTextBuffer = this.CryptoServices.Decrypt(encryptedResult);
var plainTextStream = new MemoryStream(plainTextBuffer);
var plainTextReader = new BinaryReader(plainTextStream);
var message = Utilities.DeserializeDataContract<Payload>(plainTextReader);
message.PayloadReferenceUri = notification.ReferenceLocation;
return message;
}
/// <summary>
/// Downloads a <see cref="PayloadReference"/> that is referenced from an incoming inbox item.
/// </summary>
/// <param name="inboxItem">The inbox item that referenced the <see cref="PayloadReference"/>.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>The task representing the asynchronous operation.</returns>
protected virtual async Task<PayloadReference> DownloadPayloadReferenceAsync(IncomingList.IncomingItem inboxItem, CancellationToken cancellationToken) {
Requires.NotNull(inboxItem, "inboxItem");
var responseMessage = await this.HttpClient.GetAsync(inboxItem.Location, cancellationToken);
if (responseMessage.StatusCode == HttpStatusCode.NotFound) {
// delete inbox item and move on.
await this.DeletePayloadReferenceAsync(inboxItem.Location, cancellationToken);
this.Log("Missing payload reference.", null);
return null;
}
responseMessage.EnsureSuccessStatusCode();
var responseStream = await responseMessage.Content.ReadAsStreamAsync();
var responseStreamCopy = new MemoryStream();
await responseStream.CopyToAsync(responseStreamCopy, 4096, cancellationToken);
responseStreamCopy.Position = 0;
var encryptedKey = await responseStreamCopy.ReadSizeAndBufferAsync(cancellationToken);
var key = this.CryptoServices.Decrypt(this.Endpoint.EncryptionKeyPrivateMaterial, encryptedKey);
var iv = await responseStreamCopy.ReadSizeAndBufferAsync(cancellationToken);
var ciphertext = await responseStreamCopy.ReadSizeAndBufferAsync(cancellationToken);
var encryptedPayload = new SymmetricEncryptionResult(key, iv, ciphertext);
var plainTextPayloadBuffer = this.CryptoServices.Decrypt(encryptedPayload);
var plainTextPayloadStream = new MemoryStream(plainTextPayloadBuffer);
var signature = await plainTextPayloadStream.ReadSizeAndBufferAsync(cancellationToken);
long payloadStartPosition = plainTextPayloadStream.Position;
var signedBytes = new byte[plainTextPayloadStream.Length - plainTextPayloadStream.Position];
await plainTextPayloadStream.ReadAsync(signedBytes, 0, signedBytes.Length);
plainTextPayloadStream.Position = payloadStartPosition;
var plainTextPayloadReader = new BinaryReader(plainTextPayloadStream);
var recipientPublicSigningKeyBuffer = plainTextPayloadReader.ReadSizeAndBuffer();
var creationDateUtc = DateTime.FromBinary(plainTextPayloadReader.ReadInt64());
var notificationAuthor = Utilities.DeserializeDataContract<Endpoint>(plainTextPayloadReader);
var messageReference = Utilities.DeserializeDataContract<PayloadReference>(plainTextPayloadReader);
messageReference.ReferenceLocation = inboxItem.Location;
if (!this.CryptoServices.VerifySignature(notificationAuthor.SigningKeyPublicMaterial, signedBytes, signature)) {
throw new InvalidMessageException();
}
if (!Utilities.AreEquivalent(recipientPublicSigningKeyBuffer, this.Endpoint.PublicEndpoint.SigningKeyPublicMaterial)) {
throw new InvalidMessageException(Strings.MisdirectedMessage);
}
return messageReference;
}
/// <summary> /// Symmetrically decrypts a buffer using the specified key. /// </summary> /// <param name="data">The encrypted data and the key and IV used to encrypt it.</param> /// <returns> /// The decrypted buffer. /// </returns> public abstract byte[] Decrypt(SymmetricEncryptionResult data);
/// <summary> /// Symmetrically decrypts a buffer using the specified key. /// </summary> /// <param name="data">The encrypted data and the key and IV used to encrypt it.</param> /// <returns> /// The decrypted buffer. /// </returns> public abstract byte[] Decrypt(SymmetricEncryptionResult data);
