static private VerifySignatureWithTolerantHashAlgorithm ( byte signingPublicKey, byte data, byte signature, AsymmetricAlgorithm signingAlgorithm = null ) : bool | ||
signingPublicKey | byte | The public key used to verify the signature. |
data | byte | The data that was signed. |
signature | byte | The signature. |
signingAlgorithm | AsymmetricAlgorithm | The signing algorithm. |
return | bool |
/// <summary> /// Deserializes an endpoint from an address book entry and validates that the signatures are correct. /// </summary> /// <returns>The deserialized endpoint.</returns> /// <exception cref="BadAddressBookEntryException">Thrown if the signatures are invalid.</exception> public Endpoint ExtractEndpoint() { var reader = new BinaryReader(new MemoryStream(this.SerializedEndpoint)); Endpoint endpoint; try { endpoint = reader.DeserializeDataContract <Endpoint>(); } catch (SerializationException ex) { throw new BadAddressBookEntryException(ex.Message, ex); } try { if (!CryptoProviderExtensions.VerifySignatureWithTolerantHashAlgorithm(endpoint.SigningKeyPublicMaterial, this.SerializedEndpoint, this.Signature, this.HashAlgorithmName != null ? (AsymmetricAlgorithm?)CryptoProviderExtensions.GetSignatureProvider(this.HashAlgorithmName) : null)) { throw new BadAddressBookEntryException(Strings.AddressBookEntrySignatureDoesNotMatch); } } catch (Exception ex) { // all those platform-specific exceptions that aren't available to portable libraries. throw new BadAddressBookEntryException(Strings.AddressBookEntrySignatureDoesNotMatch, ex); } return(endpoint); }
/// <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).ConfigureAwait(false); if (responseMessage.StatusCode == HttpStatusCode.NotFound) { // delete inbox item and move on. await this.DeletePayloadReferenceAsync(inboxItem.Location, cancellationToken).ConfigureAwait(false); this.Log("Missing payload reference.", null); return(null); } responseMessage.EnsureSuccessStatusCode(); var responseStream = await responseMessage.Content.ReadAsStreamAsync().ConfigureAwait(false); var responseStreamCopy = new MemoryStream(); await responseStream.CopyToAsync(responseStreamCopy, 4096, cancellationToken).ConfigureAwait(false); responseStreamCopy.Position = 0; var encryptedKey = await responseStreamCopy.ReadSizeAndBufferAsync(cancellationToken).ConfigureAwait(false); var key = WinRTCrypto.CryptographicEngine.Decrypt(this.Endpoint.EncryptionKey, encryptedKey); var iv = await responseStreamCopy.ReadSizeAndBufferAsync(cancellationToken).ConfigureAwait(false); var ciphertextStream = await responseStreamCopy.ReadSizeAndStreamAsync(cancellationToken).ConfigureAwait(false); var encryptedVariables = new SymmetricEncryptionVariables(key, iv); var plainTextPayloadStream = new MemoryStream(); await this.CryptoServices.DecryptAsync(ciphertextStream, plainTextPayloadStream, encryptedVariables, cancellationToken).ConfigureAwait(false); plainTextPayloadStream.Position = 0; AsymmetricAlgorithm?signingHashAlgorithm = null; //// Encoding.UTF8.GetString(await plainTextPayloadStream.ReadSizeAndBufferAsync(cancellationToken)); byte[] signature = await plainTextPayloadStream.ReadSizeAndBufferAsync(cancellationToken).ConfigureAwait(false); long payloadStartPosition = plainTextPayloadStream.Position; var signedBytes = new byte[plainTextPayloadStream.Length - plainTextPayloadStream.Position]; await plainTextPayloadStream.ReadAsync(signedBytes, 0, signedBytes.Length).ConfigureAwait(false); 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 (messageReference.HashAlgorithmName == null) { messageReference.HashAlgorithmName = Utilities.GuessHashAlgorithmFromLength(messageReference.Hash.Length).GetHashAlgorithmName(); } if (!CryptoProviderExtensions.VerifySignatureWithTolerantHashAlgorithm(notificationAuthor.SigningKeyPublicMaterial, signedBytes, signature, signingHashAlgorithm)) { throw new InvalidMessageException(); } if (!Utilities.AreEquivalent(recipientPublicSigningKeyBuffer, this.Endpoint.PublicEndpoint.SigningKeyPublicMaterial)) { throw new InvalidMessageException(Strings.MisdirectedMessage); } return(messageReference); }