Node.js v22.0.0-nightly20231031aa4248dc84 documentation
- Node.js v22.0.0-nightly20231031aa4248dc84
-
►
Table of contents
- TLS (SSL)
- Determining if crypto support is unavailable
- TLS/SSL concepts
- Modifying the default TLS cipher suite
- X509 certificate error codes
- Class:
tls.CryptoStream
- Class:
tls.SecurePair
- Class:
tls.Server
- Event:
'connection'
- Event:
'keylog'
- Event:
'newSession'
- Event:
'OCSPRequest'
- Event:
'resumeSession'
- Event:
'secureConnection'
- Event:
'tlsClientError'
server.addContext(hostname, context)
server.address()
server.close([callback])
server.getTicketKeys()
server.listen()
server.setSecureContext(options)
server.setTicketKeys(keys)
- Event:
- Class:
tls.TLSSocket
new tls.TLSSocket(socket[, options])
- Event:
'keylog'
- Event:
'OCSPResponse'
- Event:
'secureConnect'
- Event:
'session'
tlsSocket.address()
tlsSocket.authorizationError
tlsSocket.authorized
tlsSocket.disableRenegotiation()
tlsSocket.enableTrace()
tlsSocket.encrypted
tlsSocket.exportKeyingMaterial(length, label[, context])
tlsSocket.getCertificate()
tlsSocket.getCipher()
tlsSocket.getEphemeralKeyInfo()
tlsSocket.getFinished()
tlsSocket.getPeerCertificate([detailed])
tlsSocket.getPeerFinished()
tlsSocket.getPeerX509Certificate()
tlsSocket.getProtocol()
tlsSocket.getSession()
tlsSocket.getSharedSigalgs()
tlsSocket.getTLSTicket()
tlsSocket.getX509Certificate()
tlsSocket.isSessionReused()
tlsSocket.localAddress
tlsSocket.localPort
tlsSocket.remoteAddress
tlsSocket.remoteFamily
tlsSocket.remotePort
tlsSocket.renegotiate(options, callback)
tlsSocket.setMaxSendFragment(size)
tls.checkServerIdentity(hostname, cert)
tls.connect(options[, callback])
tls.connect(path[, options][, callback])
tls.connect(port[, host][, options][, callback])
tls.createSecureContext([options])
tls.createSecurePair([context][, isServer][, requestCert][, rejectUnauthorized][, options])
tls.createServer([options][, secureConnectionListener])
tls.getCiphers()
tls.rootCertificates
tls.DEFAULT_ECDH_CURVE
tls.DEFAULT_MAX_VERSION
tls.DEFAULT_MIN_VERSION
tls.DEFAULT_CIPHERS
- TLS (SSL)
-
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node:module
API - Modules: Packages
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- ► Other versions
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TLS (SSL)#
Source Code: lib/tls.js
The node:tls
module provides an implementation of the Transport Layer Security
(TLS) and Secure Socket Layer (SSL) protocols that is built on top of OpenSSL.
The module can be accessed using:
const tls = require('node:tls');
Determining if crypto support is unavailable#
It is possible for Node.js to be built without including support for the
node:crypto
module. In such cases, attempting to import
from tls
or
calling require('node:tls')
will result in an error being thrown.
When using CommonJS, the error thrown can be caught using try/catch:
let tls;
try {
tls = require('node:tls');
} catch (err) {
console.error('tls support is disabled!');
}
When using the lexical ESM import
keyword, the error can only be
caught if a handler for process.on('uncaughtException')
is registered
before any attempt to load the module is made (using, for instance,
a preload module).
When using ESM, if there is a chance that the code may be run on a build
of Node.js where crypto support is not enabled, consider using the
import()
function instead of the lexical import
keyword:
let tls;
try {
tls = await import('node:tls');
} catch (err) {
console.error('tls support is disabled!');
}
TLS/SSL concepts#
TLS/SSL is a set of protocols that rely on a public key infrastructure (PKI) to enable secure communication between a client and a server. For most common cases, each server must have a private key.
Private keys can be generated in multiple ways. The example below illustrates use of the OpenSSL command-line interface to generate a 2048-bit RSA private key:
openssl genrsa -out ryans-key.pem 2048
With TLS/SSL, all servers (and some clients) must have a certificate. Certificates are public keys that correspond to a private key, and that are digitally signed either by a Certificate Authority or by the owner of the private key (such certificates are referred to as "self-signed"). The first step to obtaining a certificate is to create a Certificate Signing Request (CSR) file.
The OpenSSL command-line interface can be used to generate a CSR for a private key:
openssl req -new -sha256 -key ryans-key.pem -out ryans-csr.pem
Once the CSR file is generated, it can either be sent to a Certificate Authority for signing or used to generate a self-signed certificate.
Creating a self-signed certificate using the OpenSSL command-line interface is illustrated in the example below:
openssl x509 -req -in ryans-csr.pem -signkey ryans-key.pem -out ryans-cert.pem
Once the certificate is generated, it can be used to generate a .pfx
or
.p12
file:
openssl pkcs12 -export -in ryans-cert.pem -inkey ryans-key.pem \
-certfile ca-cert.pem -out ryans.pfx
Where:
in
: is the signed certificateinkey
: is the associated private keycertfile
: is a concatenation of all Certificate Authority (CA) certs into a single file, e.g.cat ca1-cert.pem ca2-cert.pem > ca-cert.pem
Perfect forward secrecy#
The term forward secrecy or perfect forward secrecy describes a feature of key-agreement (i.e., key-exchange) methods. That is, the server and client keys are used to negotiate new temporary keys that are used specifically and only for the current communication session. Practically, this means that even if the server's private key is compromised, communication can only be decrypted by eavesdroppers if the attacker manages to obtain the key-pair specifically generated for the session.
Perfect forward secrecy is achieved by randomly generating a key pair for key-agreement on every TLS/SSL handshake (in contrast to using the same key for all sessions). Methods implementing this technique are called "ephemeral".
Currently two methods are commonly used to achieve perfect forward secrecy (note the character "E" appended to the traditional abbreviations):
- ECDHE: An ephemeral version of the Elliptic Curve Diffie-Hellman key-agreement protocol.
- DHE: An ephemeral version of the Diffie-Hellman key-agreement protocol.
Perfect forward secrecy using ECDHE is enabled by default. The ecdhCurve
option can be used when creating a TLS server to customize the list of supported
ECDH curves to use. See tls.createServer()
for more info.
DHE is disabled by default but can be enabled alongside ECDHE by setting the
dhparam
option to 'auto'
. Custom DHE parameters are also supported but
discouraged in favor of automatically selected, well-known parameters.
Perfect forward secrecy was optional up to TLSv1.2. As of TLSv1.3, (EC)DHE is always used (with the exception of PSK-only connections).
ALPN and SNI#
ALPN (Application-Layer Protocol Negotiation Extension) and SNI (Server Name Indication) are TLS handshake extensions:
- ALPN: Allows the use of one TLS server for multiple protocols (HTTP, HTTP/2)
- SNI: Allows the use of one TLS server for multiple hostnames with different certificates.
Pre-shared keys#
TLS-PSK support is available as an alternative to normal certificate-based authentication. It uses a pre-shared key instead of certificates to authenticate a TLS connection, providing mutual authentication. TLS-PSK and public key infrastructure are not mutually exclusive. Clients and servers can accommodate both, choosing either of them during the normal cipher negotiation step.
TLS-PSK is only a good choice where means exist to securely share a key with every connecting machine, so it does not replace the public key infrastructure (PKI) for the majority of TLS uses. The TLS-PSK implementation in OpenSSL has seen many security flaws in recent years, mostly because it is used only by a minority of applications. Please consider all alternative solutions before switching to PSK ciphers. Upon generating PSK it is of critical importance to use sufficient entropy as discussed in RFC 4086. Deriving a shared secret from a password or other low-entropy sources is not secure.
PSK ciphers are disabled by default, and using TLS-PSK thus requires explicitly
specifying a cipher suite with the ciphers
option. The list of available
ciphers can be retrieved via openssl ciphers -v 'PSK'
. All TLS 1.3
ciphers are eligible for PSK and can be retrieved via
openssl ciphers -v -s -tls1_3 -psk
.
According to the RFC 4279, PSK identities up to 128 bytes in length and PSKs up to 64 bytes in length must be supported. As of OpenSSL 1.1.0 maximum identity size is 128 bytes, and maximum PSK length is 256 bytes.
The current implementation doesn't support asynchronous PSK callbacks due to the limitations of the underlying OpenSSL API.
Client-initiated renegotiation attack mitigation#
The TLS protocol allows clients to renegotiate certain aspects of the TLS session. Unfortunately, session renegotiation requires a disproportionate amount of server-side resources, making it a potential vector for denial-of-service attacks.
To mitigate the risk, renegotiation is limited to three times every ten minutes.
An 'error'
event is emitted on the tls.TLSSocket
instance when this
threshold is exceeded. The limits are configurable:
tls.CLIENT_RENEG_LIMIT
<number> Specifies the number of renegotiation requests. Default:3
.tls.CLIENT_RENEG_WINDOW
<number> Specifies the time renegotiation window in seconds. Default:600
(10 minutes).
The default renegotiation limits should not be modified without a full understanding of the implications and risks.
TLSv1.3 does not support renegotiation.
Session resumption#
Establishing a TLS session can be relatively slow. The process can be sped up by saving and later reusing the session state. There are several mechanisms to do so, discussed here from oldest to newest (and preferred).
Session identifiers#
Servers generate a unique ID for new connections and send it to the client. Clients and servers save the session state. When reconnecting, clients send the ID of their saved session state and if the server also has the state for that ID, it can agree to use it. Otherwise, the server will create a new session. See RFC 2246 for more information, page 23 and 30.
Resumption using session identifiers is supported by most web browsers when making HTTPS requests.
For Node.js, clients wait for the 'session'
event to get the session data,
and provide the data to the session
option of a subsequent tls.connect()
to reuse the session. Servers must
implement handlers for the 'newSession'
and 'resumeSession'
events
to save and restore the session data using the session ID as the lookup key to
reuse sessions. To reuse sessions across load balancers or cluster workers,
servers must use a shared session cache (such as Redis) in their session
handlers.
Session tickets#
The servers encrypt the entire session state and send it to the client as a "ticket". When reconnecting, the state is sent to the server in the initial connection. This mechanism avoids the need for a server-side session cache. If the server doesn't use the ticket, for any reason (failure to decrypt it, it's too old, etc.), it will create a new session and send a new ticket. See RFC 5077 for more information.
Resumption using session tickets is becoming commonly supported by many web browsers when making HTTPS requests.
For Node.js, clients use the same APIs for resumption with session identifiers
as for resumption with session tickets. For debugging, if
tls.TLSSocket.getTLSTicket()
returns a value, the session data contains a
ticket, otherwise it contains client-side session state.
With TLSv1.3, be aware that multiple tickets may be sent by the server,
resulting in multiple 'session'
events, see 'session'
for more
information.
Single process servers need no specific implementation to use session tickets. To use session tickets across server restarts or load balancers, servers must all have the same ticket keys. There are three 16-byte keys internally, but the tls API exposes them as a single 48-byte buffer for convenience.
It's possible to get the ticket keys by calling server.getTicketKeys()
on
one server instance and then distribute them, but it is more reasonable to
securely generate 48 bytes of secure random data and set them with the
ticketKeys
option of tls.createServer()
. The keys should be regularly
regenerated and server's keys can be reset with
server.setTicketKeys()
.
Session ticket keys are cryptographic keys, and they must be stored securely. With TLS 1.2 and below, if they are compromised all sessions that used tickets encrypted with them can be decrypted. They should not be stored on disk, and they should be regenerated regularly.
If clients advertise support for tickets, the server will send them. The
server can disable tickets by supplying
require('node:constants').SSL_OP_NO_TICKET
in secureOptions
.
Both session identifiers and session tickets timeout, causing the server to
create new sessions. The timeout can be configured with the sessionTimeout
option of tls.createServer()
.
For all the mechanisms, when resumption fails, servers will create new sessions.
Since failing to resume the session does not cause TLS/HTTPS connection
failures, it is easy to not notice unnecessarily poor TLS performance. The
OpenSSL CLI can be used to verify that servers are resuming sessions. Use the
-reconnect
option to openssl s_client
, for example:
openssl s_client -connect localhost:443 -reconnect
Read through the debug output. The first connection should say "New", for example:
New, TLSv1.2, Cipher is ECDHE-RSA-AES128-GCM-SHA256
Subsequent connections should say "Reused", for example:
Reused, TLSv1.2, Cipher is ECDHE-RSA-AES128-GCM-SHA256
Modifying the default TLS cipher suite#
Node.js is built with a default suite of enabled and disabled TLS ciphers. This default cipher list can be configured when building Node.js to allow distributions to provide their own default list.
The following command can be used to show the default cipher suite:
node -p crypto.constants.defaultCoreCipherList | tr ':' '\n'
TLS_AES_256_GCM_SHA384
TLS_CHACHA20_POLY1305_SHA256
TLS_AES_128_GCM_SHA256
ECDHE-RSA-AES128-GCM-SHA256
ECDHE-ECDSA-AES128-GCM-SHA256
ECDHE-RSA-AES256-GCM-SHA384
ECDHE-ECDSA-AES256-GCM-SHA384
DHE-RSA-AES128-GCM-SHA256
ECDHE-RSA-AES128-SHA256
DHE-RSA-AES128-SHA256
ECDHE-RSA-AES256-SHA384
DHE-RSA-AES256-SHA384
ECDHE-RSA-AES256-SHA256
DHE-RSA-AES256-SHA256
HIGH
!aNULL
!eNULL
!EXPORT
!DES
!RC4
!MD5
!PSK
!SRP
!CAMELLIA
This default can be replaced entirely using the --tls-cipher-list
command-line switch (directly, or via the NODE_OPTIONS
environment
variable). For instance, the following makes ECDHE-RSA-AES128-GCM-SHA256:!RC4
the default TLS cipher suite:
node --tls-cipher-list='ECDHE-RSA-AES128-GCM-SHA256:!RC4' server.js
export NODE_OPTIONS=--tls-cipher-list='ECDHE-RSA-AES128-GCM-SHA256:!RC4'
node server.js
To verify, use the following command to show the set cipher list, note the
difference between defaultCoreCipherList
and defaultCipherList
:
node --tls-cipher-list='ECDHE-RSA-AES128-GCM-SHA256:!RC4' -p crypto.constants.defaultCipherList | tr ':' '\n'
ECDHE-RSA-AES128-GCM-SHA256
!RC4
i.e. the defaultCoreCipherList
list is set at compilation time and the
defaultCipherList
is set at runtime.
To modify the default cipher suites from within the runtime, modify the
tls.DEFAULT_CIPHERS
variable, this must be performed before listening on any
sockets, it will not affect sockets already opened. For example:
// Remove Obsolete CBC Ciphers and RSA Key Exchange based Ciphers as they don't provide Forward Secrecy
tls.DEFAULT_CIPHERS +=
':!ECDHE-RSA-AES128-SHA:!ECDHE-RSA-AES128-SHA256:!ECDHE-RSA-AES256-SHA:!ECDHE-RSA-AES256-SHA384' +
':!ECDHE-ECDSA-AES128-SHA:!ECDHE-ECDSA-AES128-SHA256:!ECDHE-ECDSA-AES256-SHA:!ECDHE-ECDSA-AES256-SHA384' +
':!kRSA';
The default can also be replaced on a per client or server basis using the
ciphers
option from tls.createSecureContext()
, which is also available
in tls.createServer()
, tls.connect()
, and when creating new
tls.TLSSocket
s.
The ciphers list can contain a mixture of TLSv1.3 cipher suite names, the ones
that start with 'TLS_'
, and specifications for TLSv1.2 and below cipher
suites. The TLSv1.2 ciphers support a legacy specification format, consult
the OpenSSL cipher list format documentation for details, but those
specifications do not apply to TLSv1.3 ciphers. The TLSv1.3 suites can only
be enabled by including their full name in the cipher list. They cannot, for
example, be enabled or disabled by using the legacy TLSv1.2 'EECDH'
or
'!EECDH'
specification.
Despite the relative order of TLSv1.3 and TLSv1.2 cipher suites, the TLSv1.3 protocol is significantly more secure than TLSv1.2, and will always be chosen over TLSv1.2 if the handshake indicates it is supported, and if any TLSv1.3 cipher suites are enabled.
The default cipher suite included within Node.js has been carefully
selected to reflect current security best practices and risk mitigation.
Changing the default cipher suite can have a significant impact on the security
of an application. The --tls-cipher-list
switch and ciphers
option should by
used only if absolutely necessary.
The default cipher suite prefers GCM ciphers for Chrome's 'modern cryptography' setting and also prefers ECDHE and DHE ciphers for perfect forward secrecy, while offering some backward compatibility.
Old clients that rely on insecure and deprecated RC4 or DES-based ciphers (like Internet Explorer 6) cannot complete the handshaking process with the default configuration. If these clients must be supported, the TLS recommendations may offer a compatible cipher suite. For more details on the format, see the OpenSSL cipher list format documentation.
There are only five TLSv1.3 cipher suites:
'TLS_AES_256_GCM_SHA384'
'TLS_CHACHA20_POLY1305_SHA256'
'TLS_AES_128_GCM_SHA256'
'TLS_AES_128_CCM_SHA256'
'TLS_AES_128_CCM_8_SHA256'
The first three are enabled by default. The two CCM
-based suites are supported
by TLSv1.3 because they may be more performant on constrained systems, but they
are not enabled by default since they offer less security.
X509 certificate error codes#
Multiple functions can fail due to certificate errors that are reported by
OpenSSL. In such a case, the function provides an <Error> via its callback that
has the property code
which can take one of the following values:
'UNABLE_TO_GET_ISSUER_CERT'
: Unable to get issuer certificate.'UNABLE_TO_GET_CRL'
: Unable to get certificate CRL.'UNABLE_TO_DECRYPT_CERT_SIGNATURE'
: Unable to decrypt certificate's signature.'UNABLE_TO_DECRYPT_CRL_SIGNATURE'
: Unable to decrypt CRL's signature.'UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY'
: Unable to decode issuer public key.'CERT_SIGNATURE_FAILURE'
: Certificate signature failure.'CRL_SIGNATURE_FAILURE'
: CRL signature failure.'CERT_NOT_YET_VALID'
: Certificate is not yet valid.'CERT_HAS_EXPIRED'
: Certificate has expired.'CRL_NOT_YET_VALID'
: CRL is not yet valid.'CRL_HAS_EXPIRED'
: CRL has expired.'ERROR_IN_CERT_NOT_BEFORE_FIELD'
: Format error in certificate's notBefore field.'ERROR_IN_CERT_NOT_AFTER_FIELD'
: Format error in certificate's notAfter field.'ERROR_IN_CRL_LAST_UPDATE_FIELD'
: Format error in CRL's lastUpdate field.'ERROR_IN_CRL_NEXT_UPDATE_FIELD'
: Format error in CRL's nextUpdate field.'OUT_OF_MEM'
: Out of memory.'DEPTH_ZERO_SELF_SIGNED_CERT'
: Self signed certificate.'SELF_SIGNED_CERT_IN_CHAIN'
: Self signed certificate in certificate chain.'UNABLE_TO_GET_ISSUER_CERT_LOCALLY'
: Unable to get local issuer certificate.'UNABLE_TO_VERIFY_LEAF_SIGNATURE'
: Unable to verify the first certificate.'CERT_CHAIN_TOO_LONG'
: Certificate chain too long.'CERT_REVOKED'
: Certificate revoked.'INVALID_CA'
: Invalid CA certificate.'PATH_LENGTH_EXCEEDED'
: Path length constraint exceeded.'INVALID_PURPOSE'
: Unsupported certificate purpose.'CERT_UNTRUSTED'
: Certificate not trusted.'CERT_REJECTED'
: Certificate rejected.'HOSTNAME_MISMATCH'
: Hostname mismatch.
Class: tls.CryptoStream
#
tls.TLSSocket
instead.The tls.CryptoStream
class represents a stream of encrypted data. This class
is deprecated and should no longer be used.
cryptoStream.bytesWritten
#
The cryptoStream.bytesWritten
property returns the total number of bytes
written to the underlying socket including the bytes required for the
implementation of the TLS protocol.
Class: tls.SecurePair
#
tls.TLSSocket
instead.Returned by tls.createSecurePair()
.
Event: 'secure'
#
The 'secure'
event is emitted by the SecurePair
object once a secure
connection has been established.
As with checking for the server
'secureConnection'
event, pair.cleartext.authorized
should be inspected to confirm whether the
certificate used is properly authorized.
Class: tls.Server
#
- Extends: <net.Server>
Accepts encrypted connections using TLS or SSL.
Event: 'connection'
#
socket
<stream.Duplex>
This event is emitted when a new TCP stream is established, before the TLS
handshake begins. socket
is typically an object of type net.Socket
but
will not receive events unlike the socket created from the net.Server
'connection'
event. Usually users will not want to access this event.
This event can also be explicitly emitted by users to inject connections
into the TLS server. In that case, any Duplex
stream can be passed.
Event: 'keylog'
#
line
<Buffer> Line of ASCII text, in NSSSSLKEYLOGFILE
format.tlsSocket
<tls.TLSSocket> Thetls.TLSSocket
instance on which it was generated.
The keylog
event is emitted when key material is generated or received by
a connection to this server (typically before handshake has completed, but not
necessarily). This keying material can be stored for debugging, as it allows
captured TLS traffic to be decrypted. It may be emitted multiple times for
each socket.
A typical use case is to append received lines to a common text file, which is later used by software (such as Wireshark) to decrypt the traffic:
const logFile = fs.createWriteStream('/tmp/ssl-keys.log', { flags: 'a' });
// ...
server.on('keylog', (line, tlsSocket) => {
if (tlsSocket.remoteAddress !== '...')
return; // Only log keys for a particular IP
logFile.write(line);
});
Event: 'newSession'
#
The 'newSession'
event is emitted upon creation of a new TLS session. This may
be used to store sessions in external storage. The data should be provided to
the 'resumeSession'
callback.
The listener callback is passed three arguments when called:
sessionId
<Buffer> The TLS session identifiersessionData
<Buffer> The TLS session datacallback
<Function> A callback function taking no arguments that must be invoked in order for data to be sent or received over the secure connection.
Listening for this event will have an effect only on connections established after the addition of the event listener.
Event: 'OCSPRequest'
#
The 'OCSPRequest'
event is emitted when the client sends a certificate status
request. The listener callback is passed three arguments when called:
certificate
<Buffer> The server certificateissuer
<Buffer> The issuer's certificatecallback
<Function> A callback function that must be invoked to provide the results of the OCSP request.
The server's current certificate can be parsed to obtain the OCSP URL
and certificate ID; after obtaining an OCSP response, callback(null, resp)
is
then invoked, where resp
is a Buffer
instance containing the OCSP response.
Both certificate
and issuer
are Buffer
DER-representations of the
primary and issuer's certificates. These can be used to obtain the OCSP
certificate ID and OCSP endpoint URL.
Alternatively, callback(null, null)
may be called, indicating that there was
no OCSP response.
Calling callback(err)
will result in a socket.destroy(err)
call.
The typical flow of an OCSP request is as follows:
- Client connects to the server and sends an
'OCSPRequest'
(via the status info extension in ClientHello). - Server receives the request and emits the
'OCSPRequest'
event, calling the listener if registered. - Server extracts the OCSP URL from either the
certificate
orissuer
and performs an OCSP request to the CA. - Server receives
'OCSPResponse'
from the CA and sends it back to the client via thecallback
argument - Client validates the response and either destroys the socket or performs a handshake.
The issuer
can be null
if the certificate is either self-signed or the
issuer is not in the root certificates list. (An issuer may be provided
via the ca
option when establishing the TLS connection.)
Listening for this event will have an effect only on connections established after the addition of the event listener.
An npm module like asn1.js may be used to parse the certificates.
Event: 'resumeSession'
#
The 'resumeSession'
event is emitted when the client requests to resume a
previous TLS session. The listener callback is passed two arguments when
called:
sessionId
<Buffer> The TLS session identifiercallback
<Function> A callback function to be called when the prior session has been recovered:callback([err[, sessionData]])
The event listener should perform a lookup in external storage for the
sessionData
saved by the 'newSession'
event handler using the given
sessionId
. If found, call callback(null, sessionData)
to resume the session.
If not found, the session cannot be resumed. callback()
must be called
without sessionData
so that the handshake can continue and a new session can
be created. It is possible to call callback(err)
to terminate the incoming
connection and destroy the socket.
Listening for this event will have an effect only on connections established after the addition of the event listener.
The following illustrates resuming a TLS session:
const tlsSessionStore = {};
server.on('newSession', (id, data, cb) => {
tlsSessionStore[id.toString('hex')] = data;
cb();
});
server.on('resumeSession', (id, cb) => {
cb(null, tlsSessionStore[id.toString('hex')] || null);
});
Event: 'secureConnection'
#
The 'secureConnection'
event is emitted after the handshaking process for a
new connection has successfully completed. The listener callback is passed a
single argument when called:
tlsSocket
<tls.TLSSocket> The established TLS socket.
The tlsSocket.authorized
property is a boolean
indicating whether the
client has been verified by one of the supplied Certificate Authorities for the
server. If tlsSocket.authorized
is false
, then socket.authorizationError
is set to describe how authorization failed. Depending on the settings
of the TLS server, unauthorized connections may still be accepted.
The tlsSocket.alpnProtocol
property is a string that contains the selected
ALPN protocol. When ALPN has no selected protocol because the client or the
server did not send an ALPN extension, tlsSocket.alpnProtocol
equals false
.
The tlsSocket.servername
property is a string containing the server name
requested via SNI.
Event: 'tlsClientError'
#
The 'tlsClientError'
event is emitted when an error occurs before a secure
connection is established. The listener callback is passed two arguments when
called:
exception
<Error> TheError
object describing the errortlsSocket
<tls.TLSSocket> Thetls.TLSSocket
instance from which the error originated.
server.addContext(hostname, context)
#
hostname
<string> A SNI host name or wildcard (e.g.'*'
)context
<Object> | <tls.SecureContext> An object containing any of the possible properties from thetls.createSecureContext()
options
arguments (e.g.key
,cert
,ca
, etc), or a TLS context object created withtls.createSecureContext()
itself.
The server.addContext()
method adds a secure context that will be used if
the client request's SNI name matches the supplied hostname
(or wildcard).
When there are multiple matching contexts, the most recently added one is used.
server.address()
#
- Returns: <Object>
Returns the bound address, the address family name, and port of the
server as reported by the operating system. See net.Server.address()
for
more information.
server.close([callback])
#
callback
<Function> A listener callback that will be registered to listen for the server instance's'close'
event.- Returns: <tls.Server>
The server.close()
method stops the server from accepting new connections.
This function operates asynchronously. The 'close'
event will be emitted
when the server has no more open connections.
server.getTicketKeys()
#
- Returns: <Buffer> A 48-byte buffer containing the session ticket keys.
Returns the session ticket keys.
See Session Resumption for more information.
server.listen()
#
Starts the server listening for encrypted connections.
This method is identical to server.listen()
from net.Server
.
server.setSecureContext(options)
#
options
<Object> An object containing any of the possible properties from thetls.createSecureContext()
options
arguments (e.g.key
,cert
,ca
, etc).
The server.setSecureContext()
method replaces the secure context of an
existing server. Existing connections to the server are not interrupted.
server.setTicketKeys(keys)
#
keys
<Buffer> | <TypedArray> | <DataView> A 48-byte buffer containing the session ticket keys.
Sets the session ticket keys.
Changes to the ticket keys are effective only for future server connections. Existing or currently pending server connections will use the previous keys.
See Session Resumption for more information.
Class: tls.TLSSocket
#
- Extends: <net.Socket>
Performs transparent encryption of written data and all required TLS negotiation.
Instances of tls.TLSSocket
implement the duplex Stream interface.
Methods that return TLS connection metadata (e.g.
tls.TLSSocket.getPeerCertificate()
) will only return data while the
connection is open.
new tls.TLSSocket(socket[, options])
#
socket
<net.Socket> | <stream.Duplex> On the server side, anyDuplex
stream. On the client side, any instance ofnet.Socket
(for genericDuplex
stream support on the client side,tls.connect()
must be used).options
<Object>enableTrace
: Seetls.createServer()
isServer
: The SSL/TLS protocol is asymmetrical, TLSSockets must know if they are to behave as a server or a client. Iftrue
the TLS socket will be instantiated as a server. Default:false
.server
<net.Server> Anet.Server
instance.requestCert
: Whether to authenticate the remote peer by requesting a certificate. Clients always request a server certificate. Servers (isServer
is true) may setrequestCert
to true to request a client certificate.rejectUnauthorized
: Seetls.createServer()
ALPNProtocols
: Seetls.createServer()
SNICallback
: Seetls.createServer()
session
<Buffer> ABuffer
instance containing a TLS session.requestOCSP
<boolean> Iftrue
, specifies that the OCSP status request extension will be added to the client hello and an'OCSPResponse'
event will be emitted on the socket before establishing a secure communicationsecureContext
: TLS context object created withtls.createSecureContext()
. If asecureContext
is not provided, one will be created by passing the entireoptions
object totls.createSecureContext()
.- ...:
tls.createSecureContext()
options that are used if thesecureContext
option is missing. Otherwise, they are ignored.
Construct a new tls.TLSSocket
object from an existing TCP socket.
Event: 'keylog'
#
line
<Buffer> Line of ASCII text, in NSSSSLKEYLOGFILE
format.
The keylog
event is emitted on a tls.TLSSocket
when key material
is generated or received by the socket. This keying material can be stored
for debugging, as it allows captured TLS traffic to be decrypted. It may
be emitted multiple times, before or after the handshake completes.
A typical use case is to append received lines to a common text file, which is later used by software (such as Wireshark) to decrypt the traffic:
const logFile = fs.createWriteStream('/tmp/ssl-keys.log', { flags: 'a' });
// ...
tlsSocket.on('keylog', (line) => logFile.write(line));
Event: 'OCSPResponse'
#
The 'OCSPResponse'
event is emitted if the requestOCSP
option was set
when the tls.TLSSocket
was created and an OCSP response has been received.
The listener callback is passed a single argument when called:
response
<Buffer> The server's OCSP response
Typically, the response
is a digitally signed object from the server's CA that
contains information about server's certificate revocation status.
Event: 'secureConnect'
#
The 'secureConnect'
event is emitted after the handshaking process for a new
connection has successfully completed. The listener callback will be called
regardless of whether or not the server's certificate has been authorized. It
is the client's responsibility to check the tlsSocket.authorized
property to
determine if the server certificate was signed by one of the specified CAs. If
tlsSocket.authorized === false
, then the error can be found by examining the
tlsSocket.authorizationError
property. If ALPN was used, the
tlsSocket.alpnProtocol
property can be checked to determine the negotiated
protocol.
The 'secureConnect'
event is not emitted when a <tls.TLSSocket> is created
using the new tls.TLSSocket()
constructor.
Event: 'session'
#
session
<Buffer>
The 'session'
event is emitted on a client tls.TLSSocket
when a new session
or TLS ticket is available. This may or may not be before the handshake is
complete, depending on the TLS protocol version that was negotiated. The event
is not emitted on the server, or if a new session was not created, for example,
when the connection was resumed. For some TLS protocol versions the event may be
emitted multiple times, in which case all the sessions can be used for
resumption.
On the client, the session
can be provided to the session
option of
tls.connect()
to resume the connection.
See Session Resumption for more information.
For TLSv1.2 and below, tls.TLSSocket.getSession()
can be called once
the handshake is complete. For TLSv1.3, only ticket-based resumption is allowed
by the protocol, multiple tickets are sent, and the tickets aren't sent until
after the handshake completes. So it is necessary to wait for the
'session'
event to get a resumable session. Applications
should use the 'session'
event instead of getSession()
to ensure
they will work for all TLS versions. Applications that only expect to
get or use one session should listen for this event only once:
tlsSocket.once('session', (session) => {
// The session can be used immediately or later.
tls.connect({
session: session,
// Other connect options...
});
});
tlsSocket.address()
#
- Returns: <Object>
Returns the bound address
, the address family
name, and port
of the
underlying socket as reported by the operating system:
{ port: 12346, family: 'IPv4', address: '127.0.0.1' }
.
tlsSocket.authorizationError
#
Returns the reason why the peer's certificate was not been verified. This
property is set only when tlsSocket.authorized === false
.
tlsSocket.authorized
#
This property is true
if the peer certificate was signed by one of the CAs
specified when creating the tls.TLSSocket
instance, otherwise false
.
tlsSocket.disableRenegotiation()
#
Disables TLS renegotiation for this TLSSocket
instance. Once called, attempts
to renegotiate will trigger an 'error'
event on the TLSSocket
.
tlsSocket.enableTrace()
#
When enabled, TLS packet trace information is written to stderr
. This can be
used to debug TLS connection problems.
The format of the output is identical to the output of
openssl s_client -trace
or openssl s_server -trace
. While it is produced by
OpenSSL's SSL_trace()
function, the format is undocumented, can change
without notice, and should not be relied on.
tlsSocket.encrypted
#
Always returns true
. This may be used to distinguish TLS sockets from regular
net.Socket
instances.
tlsSocket.exportKeyingMaterial(length, label[, context])
#
-
length
<number> number of bytes to retrieve from keying material -
label
<string> an application specific label, typically this will be a value from the IANA Exporter Label Registry. -
context
<Buffer> Optionally provide a context. -
Returns: <Buffer> requested bytes of the keying material
Keying material is used for validations to prevent different kind of attacks in network protocols, for example in the specifications of IEEE 802.1X.
Example
const keyingMaterial = tlsSocket.exportKeyingMaterial(
128,
'client finished');
/*
Example return value of keyingMaterial:
<Buffer 76 26 af 99 c5 56 8e 42 09 91 ef 9f 93 cb ad 6c 7b 65 f8 53 f1 d8 d9
12 5a 33 b8 b5 25 df 7b 37 9f e0 e2 4f b8 67 83 a3 2f cd 5d 41 42 4c 91
74 ef 2c ... 78 more bytes>
*/
See the OpenSSL SSL_export_keying_material
documentation for more
information.
tlsSocket.getCertificate()
#
- Returns: <Object>
Returns an object representing the local certificate. The returned object has some properties corresponding to the fields of the certificate.
See tls.TLSSocket.getPeerCertificate()
for an example of the certificate
structure.
If there is no local certificate, an empty object will be returned. If the
socket has been destroyed, null
will be returned.
tlsSocket.getCipher()
#
- Returns: <Object>
name
<string> OpenSSL name for the cipher suite.standardName
<string> IETF name for the cipher suite.version
<string> The minimum TLS protocol version supported by this cipher suite. For the actual negotiated protocol, seetls.TLSSocket.getProtocol()
.
Returns an object containing information on the negotiated cipher suite.
For example, a TLSv1.2 protocol with AES256-SHA cipher:
{
"name": "AES256-SHA",
"standardName": "TLS_RSA_WITH_AES_256_CBC_SHA",
"version": "SSLv3"
}
See SSL_CIPHER_get_name for more information.
tlsSocket.getEphemeralKeyInfo()
#
- Returns: <Object>
Returns an object representing the type, name, and size of parameter of
an ephemeral key exchange in perfect forward secrecy on a client
connection. It returns an empty object when the key exchange is not
ephemeral. As this is only supported on a client socket; null
is returned
if called on a server socket. The supported types are 'DH'
and 'ECDH'
. The
name
property is available only when type is 'ECDH'
.
For example: { type: 'ECDH', name: 'prime256v1', size: 256 }
.
tlsSocket.getFinished()
#
- Returns: <Buffer> | <undefined> The latest
Finished
message that has been sent to the socket as part of a SSL/TLS handshake, orundefined
if noFinished
message has been sent yet.
As the Finished
messages are message digests of the complete handshake
(with a total of 192 bits for TLS 1.0 and more for SSL 3.0), they can
be used for external authentication procedures when the authentication
provided by SSL/TLS is not desired or is not enough.
Corresponds to the SSL_get_finished
routine in OpenSSL and may be used
to implement the tls-unique
channel binding from RFC 5929.
tlsSocket.getPeerCertificate([detailed])
#
detailed
<boolean> Include the full certificate chain iftrue
, otherwise include just the peer's certificate.- Returns: <Object> A certificate object.
Returns an object representing the peer's certificate. If the peer does not
provide a certificate, an empty object will be returned. If the socket has been
destroyed, null
will be returned.
If the full certificate chain was requested, each certificate will include an
issuerCertificate
property containing an object representing its issuer's
certificate.
Certificate object#
A certificate object has properties corresponding to the fields of the certificate.
ca
<boolean>true
if a Certificate Authority (CA),false
otherwise.raw
<Buffer> The DER encoded X.509 certificate data.subject
<Object> The certificate subject, described in terms of Country (C
), StateOrProvince (ST
), Locality (L
), Organization (O
), OrganizationalUnit (OU
), and CommonName (CN
). The CommonName is typically a DNS name with TLS certificates. Example:{C: 'UK', ST: 'BC', L: 'Metro', O: 'Node Fans', OU: 'Docs', CN: 'example.com'}
.issuer
<Object> The certificate issuer, described in the same terms as thesubject
.valid_from
<string> The date-time the certificate is valid from.valid_to
<string> The date-time the certificate is valid to.serialNumber
<string> The certificate serial number, as a hex string. Example:'B9B0D332A1AA5635'
.fingerprint
<string> The SHA-1 digest of the DER encoded certificate. It is returned as a:
separated hexadecimal string. Example:'2A:7A:C2:DD:...'
.fingerprint256
<string> The SHA-256 digest of the DER encoded certificate. It is returned as a:
separated hexadecimal string. Example:'2A:7A:C2:DD:...'
.fingerprint512
<string> The SHA-512 digest of the DER encoded certificate. It is returned as a:
separated hexadecimal string. Example:'2A:7A:C2:DD:...'
.ext_key_usage
<Array> (Optional) The extended key usage, a set of OIDs.subjectaltname
<string> (Optional) A string containing concatenated names for the subject, an alternative to thesubject
names.infoAccess
<Array> (Optional) An array describing the AuthorityInfoAccess, used with OCSP.issuerCertificate
<Object> (Optional) The issuer certificate object. For self-signed certificates, this may be a circular reference.
The certificate may contain information about the public key, depending on the key type.
For RSA keys, the following properties may be defined:
bits
<number> The RSA bit size. Example:1024
.exponent
<string> The RSA exponent, as a string in hexadecimal number notation. Example:'0x010001'
.modulus
<string> The RSA modulus, as a hexadecimal string. Example:'B56CE45CB7...'
.pubkey
<Buffer> The public key.
For EC keys, the following properties may be defined:
pubkey
<Buffer> The public key.bits
<number> The key size in bits. Example:256
.asn1Curve
<string> (Optional) The ASN.1 name of the OID of the elliptic curve. Well-known curves are identified by an OID. While it is unusual, it is possible that the curve is identified by its mathematical properties, in which case it will not have an OID. Example:'prime256v1'
.nistCurve
<string> (Optional) The NIST name for the elliptic curve, if it has one (not all well-known curves have been assigned names by NIST). Example:'P-256'
.
Example certificate:
{ subject:
{ OU: [ 'Domain Control Validated', 'PositiveSSL Wildcard' ],
CN: '*.nodejs.org' },
issuer:
{ C: 'GB',
ST: 'Greater Manchester',
L: 'Salford',
O: 'COMODO CA Limited',
CN: 'COMODO RSA Domain Validation Secure Server CA' },
subjectaltname: 'DNS:*.nodejs.org, DNS:nodejs.org',
infoAccess:
{ 'CA Issuers - URI':
[ 'http://crt.comodoca.com/COMODORSADomainValidationSecureServerCA.crt' ],
'OCSP - URI': [ 'http://ocsp.comodoca.com' ] },
modulus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
exponent: '0x10001',
pubkey: <Buffer ... >,
valid_from: 'Aug 14 00:00:00 2017 GMT',
valid_to: 'Nov 20 23:59:59 2019 GMT',
fingerprint: '01:02:59:D9:C3:D2:0D:08:F7:82:4E:44:A4:B4:53:C5:E2:3A:87:4D',
fingerprint256: '69:AE:1A:6A:D4:3D:C6:C1:1B:EA:C6:23:DE:BA:2A:14:62:62:93:5C:7A:EA:06:41:9B:0B:BC:87:CE:48:4E:02',
fingerprint512: '19:2B:3E:C3:B3:5B:32:E8:AE:BB:78:97:27:E4:BA:6C:39:C9:92:79:4F:31:46:39:E2:70:E5:5F:89:42:17:C9:E8:64:CA:FF:BB:72:56:73:6E:28:8A:92:7E:A3:2A:15:8B:C2:E0:45:CA:C3:BC:EA:40:52:EC:CA:A2:68:CB:32',
ext_key_usage: [ '1.3.6.1.5.5.7.3.1', '1.3.6.1.5.5.7.3.2' ],
serialNumber: '66593D57F20CBC573E433381B5FEC280',
raw: <Buffer ... > }
tlsSocket.getPeerFinished()
#
- Returns: <Buffer> | <undefined> The latest
Finished
message that is expected or has actually been received from the socket as part of a SSL/TLS handshake, orundefined
if there is noFinished
message so far.
As the Finished
messages are message digests of the complete handshake
(with a total of 192 bits for TLS 1.0 and more for SSL 3.0), they can
be used for external authentication procedures when the authentication
provided by SSL/TLS is not desired or is not enough.
Corresponds to the SSL_get_peer_finished
routine in OpenSSL and may be used
to implement the tls-unique
channel binding from RFC 5929.
tlsSocket.getPeerX509Certificate()
#
- Returns: <X509Certificate>
Returns the peer certificate as an <X509Certificate> object.
If there is no peer certificate, or the socket has been destroyed,
undefined
will be returned.
tlsSocket.getProtocol()
#
Returns a string containing the negotiated SSL/TLS protocol version of the
current connection. The value 'unknown'
will be returned for connected
sockets that have not completed the handshaking process. The value null
will
be returned for server sockets or disconnected client sockets.
Protocol versions are:
'SSLv3'
'TLSv1'
'TLSv1.1'
'TLSv1.2'
'TLSv1.3'
See the OpenSSL SSL_get_version
documentation for more information.
tlsSocket.getSession()
#
Returns the TLS session data or undefined
if no session was
negotiated. On the client, the data can be provided to the session
option of
tls.connect()
to resume the connection. On the server, it may be useful
for debugging.
See Session Resumption for more information.
Note: getSession()
works only for TLSv1.2 and below. For TLSv1.3, applications
must use the 'session'
event (it also works for TLSv1.2 and below).
tlsSocket.getSharedSigalgs()
#
- Returns: <Array> List of signature algorithms shared between the server and the client in the order of decreasing preference.
See SSL_get_shared_sigalgs for more information.
tlsSocket.getTLSTicket()
#
For a client, returns the TLS session ticket if one is available, or
undefined
. For a server, always returns undefined
.
It may be useful for debugging.
See Session Resumption for more information.
tlsSocket.getX509Certificate()
#
- Returns: <X509Certificate>
Returns the local certificate as an <X509Certificate> object.
If there is no local certificate, or the socket has been destroyed,
undefined
will be returned.
tlsSocket.isSessionReused()
#
- Returns: <boolean>
true
if the session was reused,false
otherwise.
See Session Resumption for more information.
tlsSocket.localAddress
#
Returns the string representation of the local IP address.
tlsSocket.localPort
#
Returns the numeric representation of the local port.
tlsSocket.remoteAddress
#
Returns the string representation of the remote IP address. For example,
'74.125.127.100'
or '2001:4860:a005::68'
.
tlsSocket.remoteFamily
#
Returns the string representation of the remote IP family. 'IPv4'
or 'IPv6'
.
tlsSocket.remotePort
#
Returns the numeric representation of the remote port. For example, 443
.
tlsSocket.renegotiate(options, callback)
#
-
options
<Object>rejectUnauthorized
<boolean> If notfalse
, the server certificate is verified against the list of supplied CAs. An'error'
event is emitted if verification fails;err.code
contains the OpenSSL error code. Default:true
.requestCert
-
callback
<Function> Ifrenegotiate()
returnedtrue
, callback is attached once to the'secure'
event. Ifrenegotiate()
returnedfalse
,callback
will be called in the next tick with an error, unless thetlsSocket
has been destroyed, in which casecallback
will not be called at all. -
Returns: <boolean>
true
if renegotiation was initiated,false
otherwise.
The tlsSocket.renegotiate()
method initiates a TLS renegotiation process.
Upon completion, the callback
function will be passed a single argument
that is either an Error
(if the request failed) or null
.
This method can be used to request a peer's certificate after the secure connection has been established.
When running as the server, the socket will be destroyed with an error after
handshakeTimeout
timeout.
For TLSv1.3, renegotiation cannot be initiated, it is not supported by the protocol.
tlsSocket.setMaxSendFragment(size)
#
size
<number> The maximum TLS fragment size. The maximum value is16384
. Default:16384
.- Returns: <boolean>
The tlsSocket.setMaxSendFragment()
method sets the maximum TLS fragment size.
Returns true
if setting the limit succeeded; false
otherwise.
Smaller fragment sizes decrease the buffering latency on the client: larger fragments are buffered by the TLS layer until the entire fragment is received and its integrity is verified; large fragments can span multiple roundtrips and their processing can be delayed due to packet loss or reordering. However, smaller fragments add extra TLS framing bytes and CPU overhead, which may decrease overall server throughput.
tls.checkServerIdentity(hostname, cert)
#
hostname
<string> The host name or IP address to verify the certificate against.cert
<Object> A certificate object representing the peer's certificate.- Returns: <Error> | <undefined>
Verifies the certificate cert
is issued to hostname
.
Returns <Error> object, populating it with reason
, host
, and cert
on
failure. On success, returns <undefined>.
This function is intended to be used in combination with the
checkServerIdentity
option that can be passed to tls.connect()
and as
such operates on a certificate object. For other purposes, consider using
x509.checkHost()
instead.
This function can be overwritten by providing an alternative function as the
options.checkServerIdentity
option that is passed to tls.connect()
. The
overwriting function can call tls.checkServerIdentity()
of course, to augment
the checks done with additional verification.
This function is only called if the certificate passed all other checks, such as
being issued by trusted CA (options.ca
).
Earlier versions of Node.js incorrectly accepted certificates for a given
hostname
if a matching uniformResourceIdentifier
subject alternative name
was present (see CVE-2021-44531). Applications that wish to accept
uniformResourceIdentifier
subject alternative names can use a custom
options.checkServerIdentity
function that implements the desired behavior.
tls.connect(options[, callback])
#
options
<Object>-
enableTrace
: Seetls.createServer()
-
host
<string> Host the client should connect to. Default:'localhost'
. -
port
<number> Port the client should connect to. -
path
<string> Creates Unix socket connection to path. If this option is specified,host
andport
are ignored. -
socket
<stream.Duplex> Establish secure connection on a given socket rather than creating a new socket. Typically, this is an instance ofnet.Socket
, but anyDuplex
stream is allowed. If this option is specified,path
,host
, andport
are ignored, except for certificate validation. Usually, a socket is already connected when passed totls.connect()
, but it can be connected later. Connection/disconnection/destruction ofsocket
is the user's responsibility; callingtls.connect()
will not causenet.connect()
to be called. -
allowHalfOpen
<boolean> If set tofalse
, then the socket will automatically end the writable side when the readable side ends. If thesocket
option is set, this option has no effect. See theallowHalfOpen
option ofnet.Socket
for details. Default:false
. -
rejectUnauthorized
<boolean> If notfalse
, the server certificate is verified against the list of supplied CAs. An'error'
event is emitted if verification fails;err.code
contains the OpenSSL error code. Default:true
. -
pskCallback
<Function>- hint: <string> optional message sent from the server to help client
decide which identity to use during negotiation.
Always
null
if TLS 1.3 is used. - Returns: <Object> in the form
{ psk: <Buffer|TypedArray|DataView>, identity: <string> }
ornull
to stop the negotiation process.psk
must be compatible with the selected cipher's digest.identity
must use UTF-8 encoding.
When negotiating TLS-PSK (pre-shared keys), this function is called with optional identity
hint
provided by the server ornull
in case of TLS 1.3 wherehint
was removed. It will be necessary to provide a customtls.checkServerIdentity()
for the connection as the default one will try to check host name/IP of the server against the certificate but that's not applicable for PSK because there won't be a certificate present. More information can be found in the RFC 4279. - hint: <string> optional message sent from the server to help client
decide which identity to use during negotiation.
Always
-
ALPNProtocols
: <string[]> | <Buffer[]> | <TypedArray[]> | <DataView[]> | <Buffer> | <TypedArray> | <DataView> An array of strings,Buffer
s,TypedArray
s, orDataView
s, or a singleBuffer
,TypedArray
, orDataView
containing the supported ALPN protocols.Buffer
s should have the format[len][name][len][name]...
e.g.'\x08http/1.1\x08http/1.0'
, where thelen
byte is the length of the next protocol name. Passing an array is usually much simpler, e.g.['http/1.1', 'http/1.0']
. Protocols earlier in the list have higher preference than those later. -
servername
: <string> Server name for the SNI (Server Name Indication) TLS extension. It is the name of the host being connected to, and must be a host name, and not an IP address. It can be used by a multi-homed server to choose the correct certificate to present to the client, see theSNICallback
option totls.createServer()
. -
checkServerIdentity(servername, cert)
<Function> A callback function to be used (instead of the builtintls.checkServerIdentity()
function) when checking the server's host name (or the providedservername
when explicitly set) against the certificate. This should return an <Error> if verification fails. The method should returnundefined
if theservername
andcert
are verified. -
session
<Buffer> ABuffer
instance, containing TLS session. -
minDHSize
<number> Minimum size of the DH parameter in bits to accept a TLS connection. When a server offers a DH parameter with a size less thanminDHSize
, the TLS connection is destroyed and an error is thrown. Default:1024
. -
highWaterMark
: <number> Consistent with the readable streamhighWaterMark
parameter. Default:16 * 1024
. -
secureContext
: TLS context object created withtls.createSecureContext()
. If asecureContext
is not provided, one will be created by passing the entireoptions
object totls.createSecureContext()
. -
onread
<Object> If thesocket
option is missing, incoming data is stored in a singlebuffer
and passed to the suppliedcallback
when data arrives on the socket, otherwise the option is ignored. See theonread
option ofnet.Socket
for details. -
...:
tls.createSecureContext()
options that are used if thesecureContext
option is missing, otherwise they are ignored. -
...: Any
socket.connect()
option not already listed.
-
callback
<Function>- Returns: <tls.TLSSocket>
The callback
function, if specified, will be added as a listener for the
'secureConnect'
event.
tls.connect()
returns a tls.TLSSocket
object.
Unlike the https
API, tls.connect()
does not enable the
SNI (Server Name Indication) extension by default, which may cause some
servers to return an incorrect certificate or reject the connection
altogether. To enable SNI, set the servername
option in addition
to host
.
The following illustrates a client for the echo server example from
tls.createServer()
:
// Assumes an echo server that is listening on port 8000.
const tls = require('node:tls');
const fs = require('node:fs');
const options = {
// Necessary only if the server requires client certificate authentication.
key: fs.readFileSync('client-key.pem'),
cert: fs.readFileSync('client-cert.pem'),
// Necessary only if the server uses a self-signed certificate.
ca: [ fs.readFileSync('server-cert.pem') ],
// Necessary only if the server's cert isn't for "localhost".
checkServerIdentity: () => { return null; },
};
const socket = tls.connect(8000, options, () => {
console.log('client connected',
socket.authorized ? 'authorized' : 'unauthorized');
process.stdin.pipe(socket);
process.stdin.resume();
});
socket.setEncoding('utf8');
socket.on('data', (data) => {
console.log(data);
});
socket.on('end', () => {
console.log('server ends connection');
});
tls.connect(path[, options][, callback])
#
path
<string> Default value foroptions.path
.options
<Object> Seetls.connect()
.callback
<Function> Seetls.connect()
.- Returns: <tls.TLSSocket>
Same as tls.connect()
except that path
can be provided
as an argument instead of an option.
A path option, if specified, will take precedence over the path argument.
tls.connect(port[, host][, options][, callback])
#
port
<number> Default value foroptions.port
.host
<string> Default value foroptions.host
.options
<Object> Seetls.connect()
.callback
<Function> Seetls.connect()
.- Returns: <tls.TLSSocket>
Same as tls.connect()
except that port
and host
can be provided
as arguments instead of options.
A port or host option, if specified, will take precedence over any port or host argument.
tls.createSecureContext([options])
#
options
<Object>ca
<string> | <string[]> | <Buffer> | <Buffer[]> Optionally override the trusted CA certificates. Default is to trust the well-known CAs curated by Mozilla. Mozilla's CAs are completely replaced when CAs are explicitly specified using this option. The value can be a string orBuffer
, or anArray
of strings and/orBuffer
s. Any string orBuffer
can contain multiple PEM CAs concatenated together. The peer's certificate must be chainable to a CA trusted by the server for the connection to be authenticated. When using certificates that are not chainable to a well-known CA, the certificate's CA must be explicitly specified as a trusted or the connection will fail to authenticate. If the peer uses a certificate that doesn't match or chain to one of the default CAs, use theca
option to provide a CA certificate that the peer's certificate can match or chain to. For self-signed certificates, the certificate is its own CA, and must be provided. For PEM encoded certificates, supported types are "TRUSTED CERTIFICATE", "X509 CERTIFICATE", and "CERTIFICATE". See alsotls.rootCertificates
.cert
<string> | <string[]> | <Buffer> | <Buffer[]> Cert chains in PEM format. One cert chain should be provided per private key. Each cert chain should consist of the PEM formatted certificate for a provided privatekey
, followed by the PEM formatted intermediate certificates (if any), in order, and not including the root CA (the root CA must be pre-known to the peer, seeca
). When providing multiple cert chains, they do not have to be in the same order as their private keys inkey
. If the intermediate certificates are not provided, the peer will not be able to validate the certificate, and the handshake will fail.sigalgs
<string> Colon-separated list of supported signature algorithms. The list can contain digest algorithms (SHA256
,MD5
etc.), public key algorithms (RSA-PSS
,ECDSA
etc.), combination of both (e.g 'RSA+SHA384') or TLS v1.3 scheme names (e.g.rsa_pss_pss_sha512
). See OpenSSL man pages for more info.ciphers
<string> Cipher suite specification, replacing the default. For more information, see Modifying the default TLS cipher suite. Permitted ciphers can be obtained viatls.getCiphers()
. Cipher names must be uppercased in order for OpenSSL to accept them.clientCertEngine
<string> Name of an OpenSSL engine which can provide the client certificate.crl
<string> | <string[]> | <Buffer> | <Buffer[]> PEM formatted CRLs (Certificate Revocation Lists).dhparam
<string> | <Buffer>'auto'
or custom Diffie-Hellman parameters, required for non-ECDHE perfect forward secrecy. If omitted or invalid, the parameters are silently discarded and DHE ciphers will not be available. ECDHE-based perfect forward secrecy will still be available.ecdhCurve
<string> A string describing a named curve or a colon separated list of curve NIDs or names, for exampleP-521:P-384:P-256
, to use for ECDH key agreement. Set toauto
to select the curve automatically. Usecrypto.getCurves()
to obtain a list of available curve names. On recent releases,openssl ecparam -list_curves
will also display the name and description of each available elliptic curve. Default:tls.DEFAULT_ECDH_CURVE
.honorCipherOrder
<boolean> Attempt to use the server's cipher suite preferences instead of the client's. Whentrue
, causesSSL_OP_CIPHER_SERVER_PREFERENCE
to be set insecureOptions
, see OpenSSL Options for more information.key
<string> | <string[]> | <Buffer> | <Buffer[]> | <Object[]> Private keys in PEM format. PEM allows the option of private keys being encrypted. Encrypted keys will be decrypted withoptions.passphrase
. Multiple keys using different algorithms can be provided either as an array of unencrypted key strings or buffers, or an array of objects in the form{pem: <string|buffer>[, passphrase: <string>]}
. The object form can only occur in an array.object.passphrase
is optional. Encrypted keys will be decrypted withobject.passphrase
if provided, oroptions.passphrase
if it is not.privateKeyEngine
<string> Name of an OpenSSL engine to get private key from. Should be used together withprivateKeyIdentifier
.privateKeyIdentifier
<string> Identifier of a private key managed by an OpenSSL engine. Should be used together withprivateKeyEngine
. Should not be set together withkey
, because both options define a private key in different ways.maxVersion
<string> Optionally set the maximum TLS version to allow. One of'TLSv1.3'
,'TLSv1.2'
,'TLSv1.1'
, or'TLSv1'
. Cannot be specified along with thesecureProtocol
option; use one or the other. Default:tls.DEFAULT_MAX_VERSION
.minVersion
<string> Optionally set the minimum TLS version to allow. One of'TLSv1.3'
,'TLSv1.2'
,'TLSv1.1'
, or'TLSv1'
. Cannot be specified along with thesecureProtocol
option; use one or the other. Avoid setting to less than TLSv1.2, but it may be required for interoperability. Default:tls.DEFAULT_MIN_VERSION
.passphrase
<string> Shared passphrase used for a single private key and/or a PFX.pfx
<string> | <string[]> | <Buffer> | <Buffer[]> | <Object[]> PFX or PKCS12 encoded private key and certificate chain.pfx
is an alternative to providingkey
andcert
individually. PFX is usually encrypted, if it is,passphrase
will be used to decrypt it. Multiple PFX can be provided either as an array of unencrypted PFX buffers, or an array of objects in the form{buf: <string|buffer>[, passphrase: <string>]}
. The object form can only occur in an array.object.passphrase
is optional. Encrypted PFX will be decrypted withobject.passphrase
if provided, oroptions.passphrase
if it is not.secureOptions
<number> Optionally affect the OpenSSL protocol behavior, which is not usually necessary. This should be used carefully if at all! Value is a numeric bitmask of theSSL_OP_*
options from OpenSSL Options.secureProtocol
<string> Legacy mechanism to select the TLS protocol version to use, it does not support independent control of the minimum and maximum version, and does not support limiting the protocol to TLSv1.3. UseminVersion
andmaxVersion
instead. The possible values are listed as SSL_METHODS, use the function names as strings. For example, use'TLSv1_1_method'
to force TLS version 1.1, or'TLS_method'
to allow any TLS protocol version up to TLSv1.3. It is not recommended to use TLS versions less than 1.2, but it may be required for interoperability. Default: none, seeminVersion
.sessionIdContext
<string> Opaque identifier used by servers to ensure session state is not shared between applications. Unused by clients.ticketKeys
: <Buffer> 48-bytes of cryptographically strong pseudorandom data. See Session Resumption for more information.sessionTimeout
<number> The number of seconds after which a TLS session created by the server will no longer be resumable. See Session Resumption for more information. Default:300
.
tls.createServer()
sets the default value of the honorCipherOrder
option
to true
, other APIs that create secure contexts leave it unset.
tls.createServer()
uses a 128 bit truncated SHA1 hash value generated
from process.argv
as the default value of the sessionIdContext
option, other
APIs that create secure contexts have no default value.
The tls.createSecureContext()
method creates a SecureContext
object. It is
usable as an argument to several tls
APIs, such as server.addContext()
,
but has no public methods. The tls.Server
constructor and the
tls.createServer()
method do not support the secureContext
option.
A key is required for ciphers that use certificates. Either key
or
pfx
can be used to provide it.
If the ca
option is not given, then Node.js will default to using
Mozilla's publicly trusted list of CAs.
Custom DHE parameters are discouraged in favor of the new dhparam: 'auto'
option. When set to 'auto'
, well-known DHE parameters of sufficient strength
will be selected automatically. Otherwise, if necessary, openssl dhparam
can
be used to create custom parameters. The key length must be greater than or
equal to 1024 bits or else an error will be thrown. Although 1024 bits is
permissible, use 2048 bits or larger for stronger security.
tls.createSecurePair([context][, isServer][, requestCert][, rejectUnauthorized][, options])
#
tls.TLSSocket
instead.context
<Object> A secure context object as returned bytls.createSecureContext()
isServer
<boolean>true
to specify that this TLS connection should be opened as a server.requestCert
<boolean>true
to specify whether a server should request a certificate from a connecting client. Only applies whenisServer
istrue
.rejectUnauthorized
<boolean> If notfalse
a server automatically reject clients with invalid certificates. Only applies whenisServer
istrue
.options
enableTrace
: Seetls.createServer()
secureContext
: A TLS context object fromtls.createSecureContext()
isServer
: Iftrue
the TLS socket will be instantiated in server-mode. Default:false
.server
<net.Server> Anet.Server
instancerequestCert
: Seetls.createServer()
rejectUnauthorized
: Seetls.createServer()
ALPNProtocols
: Seetls.createServer()
SNICallback
: Seetls.createServer()
session
<Buffer> ABuffer
instance containing a TLS session.requestOCSP
<boolean> Iftrue
, specifies that the OCSP status request extension will be added to the client hello and an'OCSPResponse'
event will be emitted on the socket before establishing a secure communication.
Creates a new secure pair object with two streams, one of which reads and writes the encrypted data and the other of which reads and writes the cleartext data. Generally, the encrypted stream is piped to/from an incoming encrypted data stream and the cleartext one is used as a replacement for the initial encrypted stream.
tls.createSecurePair()
returns a tls.SecurePair
object with cleartext
and
encrypted
stream properties.
Using cleartext
has the same API as tls.TLSSocket
.
The tls.createSecurePair()
method is now deprecated in favor of
tls.TLSSocket()
. For example, the code:
pair = tls.createSecurePair(/* ... */);
pair.encrypted.pipe(socket);
socket.pipe(pair.encrypted);
can be replaced by:
secureSocket = tls.TLSSocket(socket, options);
where secureSocket
has the same API as pair.cleartext
.
tls.createServer([options][, secureConnectionListener])
#
options
<Object>-
ALPNProtocols
: <string[]> | <Buffer[]> | <TypedArray[]> | <DataView[]> | <Buffer> | <TypedArray> | <DataView> An array of strings,Buffer
s,TypedArray
s, orDataView
s, or a singleBuffer
,TypedArray
, orDataView
containing the supported ALPN protocols.Buffer
s should have the format[len][name][len][name]...
e.g.0x05hello0x05world
, where the first byte is the length of the next protocol name. Passing an array is usually much simpler, e.g.['hello', 'world']
. (Protocols should be ordered by their priority.) -
ALPNCallback
: <Function> If set, this will be called when a client opens a connection using the ALPN extension. One argument will be passed to the callback: an object containingservername
andprotocols
fields, respectively containing the server name from the SNI extension (if any) and an array of ALPN protocol name strings. The callback must return either one of the strings listed inprotocols
, which will be returned to the client as the selected ALPN protocol, orundefined
, to reject the connection with a fatal alert. If a string is returned that does not match one of the client's ALPN protocols, an error will be thrown. This option cannot be used with theALPNProtocols
option, and setting both options will throw an error. -
clientCertEngine
<string> Name of an OpenSSL engine which can provide the client certificate. -
enableTrace
<boolean> Iftrue
,tls.TLSSocket.enableTrace()
will be called on new connections. Tracing can be enabled after the secure connection is established, but this option must be used to trace the secure connection setup. Default:false
. -
handshakeTimeout
<number> Abort the connection if the SSL/TLS handshake does not finish in the specified number of milliseconds. A'tlsClientError'
is emitted on thetls.Server
object whenever a handshake times out. Default:120000
(120 seconds). -
rejectUnauthorized
<boolean> If notfalse
the server will reject any connection which is not authorized with the list of supplied CAs. This option only has an effect ifrequestCert
istrue
. Default:true
. -
requestCert
<boolean> Iftrue
the server will request a certificate from clients that connect and attempt to verify that certificate. Default:false
. -
sessionTimeout
<number> The number of seconds after which a TLS session created by the server will no longer be resumable. See Session Resumption for more information. Default:300
. -
SNICallback(servername, callback)
<Function> A function that will be called if the client supports SNI TLS extension. Two arguments will be passed when called:servername
andcallback
.callback
is an error-first callback that takes two optional arguments:error
andctx
.ctx
, if provided, is aSecureContext
instance.tls.createSecureContext()
can be used to get a properSecureContext
. Ifcallback
is called with a falsyctx
argument, the default secure context of the server will be used. IfSNICallback
wasn't provided the default callback with high-level API will be used (see below). -
ticketKeys
: <Buffer> 48-bytes of cryptographically strong pseudorandom data. See Session Resumption for more information. -
pskCallback
<Function>- socket: <tls.TLSSocket> the server
tls.TLSSocket
instance for this connection. - identity: <string> identity parameter sent from the client.
- Returns: <Buffer> | <TypedArray> | <DataView> pre-shared key that must either be
a buffer or
null
to stop the negotiation process. Returned PSK must be compatible with the selected cipher's digest.
When negotiating TLS-PSK (pre-shared keys), this function is called with the identity provided by the client. If the return value is
null
the negotiation process will stop and an "unknown_psk_identity" alert message will be sent to the other party. If the server wishes to hide the fact that the PSK identity was not known, the callback must provide some random data aspsk
to make the connection fail with "decrypt_error" before negotiation is finished. PSK ciphers are disabled by default, and using TLS-PSK thus requires explicitly specifying a cipher suite with theciphers
option. More information can be found in the RFC 4279. - socket: <tls.TLSSocket> the server
-
pskIdentityHint
<string> optional hint to send to a client to help with selecting the identity during TLS-PSK negotiation. Will be ignored in TLS 1.3. Upon failing to set pskIdentityHint'tlsClientError'
will be emitted with'ERR_TLS_PSK_SET_IDENTIY_HINT_FAILED'
code. -
...: Any
tls.createSecureContext()
option can be provided. For servers, the identity options (pfx
,key
/cert
, orpskCallback
) are usually required. -
...: Any
net.createServer()
option can be provided.
-
secureConnectionListener
<Function>- Returns: <tls.Server>
Creates a new tls.Server
. The secureConnectionListener
, if provided, is
automatically set as a listener for the 'secureConnection'
event.
The ticketKeys
options is automatically shared between node:cluster
module
workers.
The following illustrates a simple echo server:
const tls = require('node:tls');
const fs = require('node:fs');
const options = {
key: fs.readFileSync('server-key.pem'),
cert: fs.readFileSync('server-cert.pem'),
// This is necessary only if using client certificate authentication.
requestCert: true,
// This is necessary only if the client uses a self-signed certificate.
ca: [ fs.readFileSync('client-cert.pem') ],
};
const server = tls.createServer(options, (socket) => {
console.log('server connected',
socket.authorized ? 'authorized' : 'unauthorized');
socket.write('welcome!\n');
socket.setEncoding('utf8');
socket.pipe(socket);
});
server.listen(8000, () => {
console.log('server bound');
});
The server can be tested by connecting to it using the example client from
tls.connect()
.
tls.getCiphers()
#
- Returns: <string[]>
Returns an array with the names of the supported TLS ciphers. The names are
lower-case for historical reasons, but must be uppercased to be used in
the ciphers
option of tls.createSecureContext()
.
Not all supported ciphers are enabled by default. See Modifying the default TLS cipher suite.
Cipher names that start with 'tls_'
are for TLSv1.3, all the others are for
TLSv1.2 and below.
console.log(tls.getCiphers()); // ['aes128-gcm-sha256', 'aes128-sha', ...]
tls.rootCertificates
#
An immutable array of strings representing the root certificates (in PEM format) from the bundled Mozilla CA store as supplied by the current Node.js version.
The bundled CA store, as supplied by Node.js, is a snapshot of Mozilla CA store that is fixed at release time. It is identical on all supported platforms.
tls.DEFAULT_ECDH_CURVE
#
The default curve name to use for ECDH key agreement in a tls server. The
default value is 'auto'
. See tls.createSecureContext()
for further
information.
tls.DEFAULT_MAX_VERSION
#
- <string> The default value of the
maxVersion
option oftls.createSecureContext()
. It can be assigned any of the supported TLS protocol versions,'TLSv1.3'
,'TLSv1.2'
,'TLSv1.1'
, or'TLSv1'
. Default:'TLSv1.3'
, unless changed using CLI options. Using--tls-max-v1.2
sets the default to'TLSv1.2'
. Using--tls-max-v1.3
sets the default to'TLSv1.3'
. If multiple of the options are provided, the highest maximum is used.
tls.DEFAULT_MIN_VERSION
#
- <string> The default value of the
minVersion
option oftls.createSecureContext()
. It can be assigned any of the supported TLS protocol versions,'TLSv1.3'
,'TLSv1.2'
,'TLSv1.1'
, or'TLSv1'
. Default:'TLSv1.2'
, unless changed using CLI options. Using--tls-min-v1.0
sets the default to'TLSv1'
. Using--tls-min-v1.1
sets the default to'TLSv1.1'
. Using--tls-min-v1.3
sets the default to'TLSv1.3'
. If multiple of the options are provided, the lowest minimum is used.
tls.DEFAULT_CIPHERS
#
- <string> The default value of the
ciphers
option oftls.createSecureContext()
. It can be assigned any of the supported OpenSSL ciphers. Defaults to the content ofcrypto.constants.defaultCoreCipherList
, unless changed using CLI options using--tls-default-ciphers
.