DTLSServer Component

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The DTLSServer component provides server-side functionality of the DTLS protocol.

Syntax

TsbxDTLSServer

Remarks

Use this component to receive data over a protected DTLS channel in your applcation.

Property List

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The following is the full list of the properties of the component with short descriptions. Click on the links for further details.

Method List

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The following is the full list of the methods of the component with short descriptions. Click on the links for further details.

Event List

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The following is the full list of the events fired by the component with short descriptions. Click on the links for further details.

Config Settings

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The following is a list of config settings for the component with short descriptions. Click on the links for further details.

Active Property (DTLSServer Component)

Indicates whether the server is active and is listening to new connections.

Syntax

property Active: Boolean read get_Active;

Default Value

false

Remarks

This read-only property returns True if the server is listening to incoming connections.

This property is read-only and not available at design time.

BoundPort Property (DTLSServer Component)

Indicates the bound listening port.

Syntax

property BoundPort: Integer read get_BoundPort;

Default Value

0

Remarks

Check this property to find out the port that has been allocated to the server by the system. The bound port always equals Port if it is provided, or is allocated dynamically if configured to fall in the range between PortRangeFrom and PortRangeTo constraints.

This property is read-only and not available at design time.

ErrorOrigin Property (DTLSServer Component)

Indicates the endpoint where the error originates from.

Syntax

property ErrorOrigin: TsbxErrorOrigins read get_ErrorOrigin write set_ErrorOrigin;

TsbxErrorOrigins = (
  eoLocal,
  eoRemote
);

Default Value

eoLocal

Remarks

Use this property to establish whether the reported error originates from a local or remote endpoint.

This property is not available at design time.

ErrorSeverity Property (DTLSServer Component)

The severity of the error that happened.

Syntax

property ErrorSeverity: TsbxErrorSeverities read get_ErrorSeverity write set_ErrorSeverity;

TsbxErrorSeverities = (
  esInfo,
  esWarning,
  esFatal
);

Default Value

esWarning

Remarks

Use this property to establish whether the error is fatal.

This property is not available at design time.

ExternalCrypto Property (DTLSServer Component)

Provides access to external signing and DC parameters.

Syntax

property ExternalCrypto: TsbxExternalCrypto read get_ExternalCrypto;

Remarks

Use this property to tune-up remote cryptography settings. SecureBlackbox supports two independent types of external cryptography: synchronous (based on the ExternalSign event) and asynchronous (based on the DC protocol and the DCAuth signing component).

This property is read-only.

Please refer to the ExternalCrypto type for a complete list of fields.

FIPSMode Property (DTLSServer Component)

Reserved.

Syntax

property FIPSMode: Boolean read get_FIPSMode write set_FIPSMode;

Default Value

false

Remarks

This property is reserved for future use.

Host Property (DTLSServer Component)

The host to bind the listening port to.

Syntax

property Host: String read get_Host write set_Host;

Default Value

''

Remarks

Use this property to specify the IP address on which to listen to incoming connections.

PinnedClient Property (DTLSServer Component)

Populates the pinned client details.

Syntax

property PinnedClient: TsbxTLSClientEntry read get_PinnedClient;

Remarks

Use this property to access the details of the client connection previously pinned with PinClient method.

This property is read-only and not available at design time.

Please refer to the TLSClientEntry type for a complete list of fields.

PinnedClientChain Property (DTLSServer Component)

Contains the certificate chain of the pinned client.

Syntax

property PinnedClientChain: TsbxCertificateList read get_PinnedClientChain;

Remarks

Use this property to access the certificate chain of the client connection pinned previously with a PinClient call.

This property is read-only and not available at design time.

Please refer to the Certificate type for a complete list of fields.

Port Property (DTLSServer Component)

Specifies the port number to listen for connections on.

Syntax

property Port: Integer read get_Port write set_Port;

Default Value

80

Remarks

Use this property to specify the port number to listen to connections on. Standard port numbers are 80 for an HTTP server, and 443 for an HTTPS server.

Alternatively, you may specify the acceptable range of listening ports via PortRangeFrom and PortRangeTo properties. In this case the port will be allocated within the requested range by the operating system, and reported in BoundPort.

PortRangeFrom Property (DTLSServer Component)

Specifies the lower limit of the listening port range for incoming connections.

Syntax

property PortRangeFrom: Integer read get_PortRangeFrom write set_PortRangeFrom;

Default Value

0

Remarks

Use this property to specify the lower limit of the port range to listen to connections on. When a port range is used to specify the listening port (as opposed to a fixed value provided via Port), the port will be allocated within the requested range by the operating system, and reported in BoundPort.

Note that this property is ignored if the Port property is set to a non-zero value, in which case the server always aims to listen on that fixed port.

PortRangeTo Property (DTLSServer Component)

Specifies the upper limit of the listening port range for incoming connections.

Syntax

property PortRangeTo: Integer read get_PortRangeTo write set_PortRangeTo;

Default Value

0

Remarks

Use this property to specify the upper limit of the port range to listen to connections on. When a port range is used to specify the listening port (as opposed to a fixed value provided via Port), the port will be allocated within the requested range by the operating system, and reported in BoundPort.

Note that this property is ignored if the Port property is set to a non-zero value, in which case the server always aims to listen on that fixed port.

ServerCertificates Property (DTLSServer Component)

The server's TLS certificates.

Syntax

property ServerCertificates: TsbxCertificateList read get_ServerCertificates write set_ServerCertificates;

Remarks

Use this property to provide a list of TLS certificates for the server endpoint.

A TLS endpoint needs a certificate to be able to accept TLS connections. At least one of the certificates in the collection - the endpoint certificate - must have a private key associated with it.

The collection may include more than one endpoint certificate, and more than one chain. A typical usage scenario is to include two chains (ECDSA and RSA), to cater for clients with different cipher suite preferences.

This property is not available at design time.

Please refer to the Certificate type for a complete list of fields.

SocketSettings Property (DTLSServer Component)

Manages network connection settings.

Syntax

property SocketSettings: TsbxSocketSettings read get_SocketSettings;

Remarks

Use this property to tune up network connection parameters.

This property is read-only.

Please refer to the SocketSettings type for a complete list of fields.

TLSSettings Property (DTLSServer Component)

Manages TLS layer settings.

Syntax

property TLSSettings: TsbxTLSSettings read get_TLSSettings;

Remarks

Use this property to tune up the TLS layer parameters.

This property is read-only.

Please refer to the TLSSettings type for a complete list of fields.

WebsiteName Property (DTLSServer Component)

Specifies the web site name to use in the certificate.

Syntax

property WebsiteName: String read get_WebsiteName write set_WebsiteName;

Default Value

'SecureBlackbox'

Remarks

If using an internally-generated certificate, use this property to specify the web site name to be included as a common name. A typical common name consists of the host name, such as '192.168.10.10' or 'domain.com'.

BroadcastData Method (DTLSServer Component)

Broadcasts data to all connections.

Syntax

procedure BroadcastData(ConnectionID: Int64; Data: TBytes);

Remarks

Call this method to send Data to all active client connections except for ConnectionID. Set ConnectionID to -1 to broadcast to all connections.

BroadcastText Method (DTLSServer Component)

Broadcasts a text string to all connections.

Syntax

procedure BroadcastText(ConnectionId: Int64; Text: String);

Remarks

Call this method to send Text to all active client connections except for ConnectionID. Set ConnectionID to -1 to broadcast to all connections without exceptions.

Config Method (DTLSServer Component)

Sets or retrieves a configuration setting.

Syntax

function Config(ConfigurationString: String): String;

Remarks

Config is a generic method available in every component. It is used to set and retrieve configuration settings for the component.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

DoAction Method (DTLSServer Component)

Performs an additional action.

Syntax

function DoAction(ActionID: String; ActionParams: String): String;

Remarks

DoAction is a generic method available in every component. It is used to perform an additional action introduced after the product major release. The list of actions is not fixed, and may be flexibly extended over time.

The unique identifier (case insensitive) of the action is provided in the ActionID parameter.

ActionParams contains the value of a single parameter, or a list of multiple parameters for the action in the form of PARAM1=VALUE1;PARAM2=VALUE2;....

DropClient Method (DTLSServer Component)

Terminates a client connection.

Syntax

procedure DropClient(ConnectionId: Int64; Forced: Boolean);

Remarks

Call this method to shut down a connected client. Forced indicates whether the connection should be closed in a graceful manner.

ExportKeyMaterial Method (DTLSServer Component)

Derives key material from the session's master key using the TLS exporters scheme.

Syntax

procedure ExportKeyMaterial(ConnectionID: Int64; Lbl: String; Context: TBytes; Len: Integer);

Remarks

Some protocols - for example, SRTP - use the TLS exporters scheme to derive their own session keys from the TLS master key. This method lets you employ exporters to obtain such keys, or to generate secure keys for your own needs from an active TLS session.

The exported keys depend on the master key, and are different for every TLS session. However, a client and server sharing a session will always end up with the same key material, as long as they use the same values of Lbl, Context, and Len.

Use the ConnectionID parameter to specify the session that you would like to derive key material from.

ListClients Method (DTLSServer Component)

Enumerates the connected clients.

Syntax

function ListClients(): String;

Remarks

This method enumerates the connected clients. It returns a list of strings, with each string being of 'ConnectionID|Address|Port' format, and representing a single connection.

PinClient Method (DTLSServer Component)

Takes a snapshot of the connection's properties.

Syntax

procedure PinClient(ConnectionId: Int64);

Remarks

Use this method to take a snapshot of a connected client. The captured properties are populated in PinnedClient and PinnedClientChain properties.

ProcessPlainData Method (DTLSServer Component)

Process a plain data buffer to a connection client.

Syntax

procedure ProcessPlainData(ConnectionID: Int64; Buffer: TBytes);

Remarks

Use this method to process a plain data buffer to a connected client. Use ConnectionID to specify the client.

SendData Method (DTLSServer Component)

Sends a data buffer to a connection client.

Syntax

procedure SendData(ConnectionID: Int64; Buffer: TBytes);

Remarks

Use this method to send a data buffer to a connected client. Use ConnectionID to specify the client.

SendKeepAlive Method (DTLSServer Component)

Sends a keep-alive packet.

Syntax

function SendKeepAlive(ConnectionId: Int64): Boolean;

Remarks

Use this method to send a keep-alive packet to a client. Keep alive is an empty packet; keep-alive signals sent occasionally can be used to keep connection up.

SendPlainData Method (DTLSServer Component)

Sends a data buffer to a connection client.

Syntax

procedure SendPlainData(ConnectionID: Int64; Buffer: TBytes);

Remarks

Use this method to send a data buffer to a connected client. Use ConnectionID to specify the client.

SendText Method (DTLSServer Component)

Sends a text string to a client.

Syntax

procedure SendText(ConnectionId: Int64; Text: String);

Remarks

Use this method to send a text string to a connected client.

Start Method (DTLSServer Component)

Starts the DTLS server.

Syntax

procedure Start();

Remarks

Use this method to start listening for incoming data.

Stop Method (DTLSServer Component)

Stops the DTLS server.

Syntax

procedure Stop();

Remarks

Call this method to stop listening for incoming data.

Accept Event (DTLSServer Component)

Reports an incoming connection.

Syntax

type TAcceptEvent = procedure (
  Sender: TObject;
  const RemoteAddress: String;
  RemotePort: Integer;
  var Accept: Boolean
) of Object;

property OnAccept: TAcceptEvent read FOnAccept write FOnAccept;

Remarks

This event is fired when a new connection from RemoteAddress:RemotePort is ready to be accepted. Use the Accept parameter to accept or decline it.

Subscribe to Connect event to be notified of every connection that has been set up.

Data Event (DTLSServer Component)

Supplies a data chunk received from a client.

Syntax

type TDataEvent = procedure (
  Sender: TObject;
  ConnectionID: Int64;
  Buffer: TBytes
) of Object;

property OnData: TDataEvent read FOnData write FOnData;

Remarks

This event is fired to supply another piece of data received from a client. This event may fire multiple times.

Error Event (DTLSServer Component)

Information about errors during data delivery.

Syntax

type TErrorEvent = procedure (
  Sender: TObject;
  ConnectionID: Int64;
  ErrorCode: Integer;
  const Description: String
) of Object;

property OnError: TErrorEvent read FOnError write FOnError;

Remarks

The event is fired in case of exceptional conditions during message processing.

ErrorCode contains an error code and Description contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the HTTPS section.

ExternalSign Event (DTLSServer Component)

Handles remote or external signing initiated by the server protocol.

Syntax

type TExternalSignEvent = procedure (
  Sender: TObject;
  ConnectionID: Int64;
  const OperationId: String;
  const HashAlgorithm: String;
  const Pars: String;
  const Data: String;
  var SignedData: String
) of Object;

property OnExternalSign: TExternalSignEvent read FOnExternalSign write FOnExternalSign;

Remarks

Assign a handler to this event if you need to delegate a low-level signing operation to an external, remote, or custom signing engine. Depending on the settings, the handler will receive a hashed or unhashed value to be signed.

The event handler must pass the value of Data to the signer, obtain the signature, and pass it back to the component via the SignedData parameter.

OperationId provides a comment about the operation and its origin. It depends on the exact component being used, and may be empty. HashAlgorithm specifies the hash algorithm being used for the operation, and Pars contains algorithm-dependent parameters.

The component uses base16 (hex) encoding for the Data, SignedData, and Pars parameters. If your signing engine uses a different input and output encoding, you may need to decode and/or encode the data before and/or after the signing.

A sample MD5 hash encoded in base16: a0dee2a0382afbb09120ffa7ccd8a152 - lower case base16 A0DEE2A0382AFBB09120FFA7CCD8A152 - upper case base16

A sample event handler that uses the .NET RSACryptoServiceProvider class may look like the following: signer.OnExternalSign += (s, e) => { var cert = new X509Certificate2("cert.pfx", "", X509KeyStorageFlags.Exportable); var key = (RSACryptoServiceProvider)cert.PrivateKey; var dataToSign = e.Data.FromBase16String(); var signedData = key.SignHash(dataToSign, "2.16.840.1.101.3.4.2.1"); e.SignedData = signedData.ToBase16String(); };

Notification Event (DTLSServer Component)

This event notifies the application about an underlying control flow event.

Syntax

type TNotificationEvent = procedure (
  Sender: TObject;
  const EventID: String;
  const EventParam: String
) of Object;

property OnNotification: TNotificationEvent read FOnNotification write FOnNotification;

Remarks

The component fires this event to let the application know about some event, occurrence, or milestone in the component. For example, it may fire to report completion of the document processing. The list of events being reported is not fixed, and may be flexibly extended over time.

The unique identifier of the event is provided in the EventID parameter. EventParam contains any parameters accompanying the occurrence. Depending on the type of the component, the exact action it is performing, or the document being processed, one or both may be omitted.

PlainData Event (DTLSServer Component)

Supplies a plain data chunk received from a client.

Syntax

type TPlainDataEvent = procedure (
  Sender: TObject;
  ConnectionID: Int64;
  Buffer: TBytes
) of Object;

property OnPlainData: TPlainDataEvent read FOnPlainData write FOnPlainData;

Remarks

This event is fired to supply another piece of plain data received from a client. This event may fire multiple times.

TLSCertValidate Event (DTLSServer Component)

Fires when a client certificate needs to be validated.

Syntax

type TTLSCertValidateEvent = procedure (
  Sender: TObject;
  ConnectionID: Int64;
  var Accept: Boolean
) of Object;

property OnTLSCertValidate: TTLSCertValidateEvent read FOnTLSCertValidate write FOnTLSCertValidate;

Remarks

The component fires this event to notify the application of an authenticating client. Use the event handler to validate the certificate and pass your decision back to the server component via the Accept parameter.

TLSEstablished Event (DTLSServer Component)

Reports the setup of a TLS session.

Syntax

type TTLSEstablishedEvent = procedure (
  Sender: TObject;
  ConnectionID: Int64
) of Object;

property OnTLSEstablished: TTLSEstablishedEvent read FOnTLSEstablished write FOnTLSEstablished;

Remarks

Subscribe to this event to be notified about the setup of a TLS connection by a connected client.

TLSHandshake Event (DTLSServer Component)

Fires when a newly established client connection initiates a TLS handshake.

Syntax

type TTLSHandshakeEvent = procedure (
  Sender: TObject;
  ConnectionID: Int64;
  const ServerName: String;
  var Abort: Boolean
) of Object;

property OnTLSHandshake: TTLSHandshakeEvent read FOnTLSHandshake write FOnTLSHandshake;

Remarks

Use this event to get notified about the initiation of the TLS handshake by the remote client. The ServerName parameter specifies the requested host from the client hello message.

TLSPSK Event (DTLSServer Component)

Requests a pre-shared key for TLS-PSK.

Syntax

type TTLSPSKEvent = procedure (
  Sender: TObject;
  ConnectionID: Int64;
  const Identity: String;
  var PSK: String;
  var Ciphersuite: String
) of Object;

property OnTLSPSK: TTLSPSKEvent read FOnTLSPSK write FOnTLSPSK;

Remarks

The component fires this event to report that a client has requested a TLS-PSK negotiation. ConnectionId indicates the unique connection ID that requested the PSK handshake.

Use Identity to look up for the corresponding pre-shared key in the server's database, then assign the key to the PSK parameter. If TLS 1.3 PSK is used, you will also need to assign the Ciphersuite parameter with the cipher suite associated with that identity and their key.

TLSShutdown Event (DTLSServer Component)

Reports closure of a TLS session.

Syntax

type TTLSShutdownEvent = procedure (
  Sender: TObject;
  ConnectionID: Int64
) of Object;

property OnTLSShutdown: TTLSShutdownEvent read FOnTLSShutdown write FOnTLSShutdown;

Remarks

The component fires this event when a connected client closes their TLS session gracefully. This event is typically followed by a Disconnect, which marks the closure of the underlying TCP session.

Certificate Type

Provides details of an individual X.509 certificate.

Remarks

This type provides access to X.509 certificate details.

Fields

Constructors

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constructor Create();

Creates a new object with default field values.

ExternalCrypto Type

Specifies the parameters of external cryptographic calls.

Remarks

External cryptocalls are used in a Distributed Cryptography (DC) subsystem, which allows the delegation of security operations to the remote agent. For instance, it can be used to compute the signature value on the server, while retaining the client's private key locally.

Fields

Constructors

>

constructor Create();

Creates a new ExternalCrypto object with default field values.

SocketSettings Type

A container for the socket settings.

Remarks

This type is a container for socket-layer parameters.

Fields

Constructors

>

constructor Create();

Creates a new SocketSettings object.

TLSClientEntry Type

A container for a connected TLS client's details.

Remarks

Use this property to access the details of a particular connected client.

Fields

Constructors

>

constructor Create();

Creates a new TLSClientEntry object.

TLSSettings Type

A container for TLS connection settings.

Remarks

The TLS (Transport Layer Security) protocol provides security for information exchanged over insecure connections such as TCP/IP.

Fields

Constructors

>

constructor Create();

Creates a new TLSSettings object.

Config Settings (DTLSServer Component)

The component accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these internal properties is provided through the Config method.

DTLSServer Config Settings

Base Config Settings

Trappable Errors (DTLSServer Component)

DTLSServer Errors

	1048577   Invalid parameter value (SB_ERROR_INVALID_PARAMETER)
	1048578   Component is configured incorrectly (SB_ERROR_INVALID_SETUP)
	1048579   Operation cannot be executed in the current state (SB_ERROR_INVALID_STATE)
	1048580   Attempt to set an invalid value to a property (SB_ERROR_INVALID_VALUE)
	1048581   Certificate does not have its private key loaded (SB_ERROR_NO_PRIVATE_KEY)
	1048581   Cancelled by the user (SB_ERROR_CANCELLED_BY_USER)