TLS (SSL) | Node.js v25.9.0 Documentation
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Table of contents
TLS (SSL)
Determining if crypto support is unavailable
TLS/SSL concepts
Perfect forward secrecy
ALPN and SNI
Pre-shared keys
Client-initiated renegotiation attack mitigation
Session resumption
Session identifiers
Session tickets
Modifying the default TLS cipher suite
OpenSSL security level
Setting security levels
Using
--tls-cipher-list
X509 certificate error codes
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)
Class:
tls.TLSSocket
new tls.TLSSocket(socket[, options])
Event:
'keylog'
Event:
'OCSPResponse'
Event:
'secure'
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])
Certificate object
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.setKeyCert(context)
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.createServer([options][, secureConnectionListener])
tls.setDefaultCACertificates(certs)
tls.getCACertificates([type])
tls.getCiphers()
tls.rootCertificates
tls.DEFAULT_ECDH_CURVE
tls.DEFAULT_MAX_VERSION
tls.DEFAULT_MIN_VERSION
tls.DEFAULT_CIPHERS
TLS (SSL)
Source Code:
lib/tls.js
Stability: 2
- Stable
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:
import
tls
from
'node:tls'
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 certificate
inkey
: is the associated private key
certfile
: 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
On the client connection, a custom
checkServerIdentity
should be passed
because the default one will fail in the absence of a certificate.
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.
To use TLS-PSK, client and server must specify the
pskCallback
option,
a function that returns the PSK to use (which must be compatible with
the selected cipher's digest).
It will be called first on the client:
hint

optional message sent from the server to help the client
decide which identity to use during negotiation.
Always
null
if TLS 1.3 is used.
Returns:

in the form
{ psk: , identity: }
or
null
Then on the server:
socket

the server socket instance, equivalent to
this
identity

identity parameter sent from the client.
Returns:



the PSK (or
null
).
A return value of
null
stops the negotiation process and sends an
unknown_psk_identity
alert message 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 as
psk
to make the connection
fail with
decrypt_error
before negotiation is finished.
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

Specifies the number of renegotiation
requests.
Default:
tls.CLIENT_RENEG_WINDOW

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.
OpenSSL security level
The OpenSSL library enforces security levels to control the minimum acceptable
level of security for cryptographic operations. OpenSSL's security levels range
from 0 to 5, with each level imposing stricter security requirements. The default
security level is 2, which is generally suitable for most modern applications.
However, some legacy features and protocols, such as TLSv1, require a lower
security level (
SECLEVEL=0
) to function properly. For more detailed information,
please refer to the
OpenSSL documentation on security levels
Setting security levels
To adjust the security level in your Node.js application, you can include
@SECLEVEL=X
within a cipher string, where
is the desired security level. For example,
to set the security level to 0 while using the default OpenSSL cipher list, you could use:
import
createServer
connect
from
'node:tls'
const
port
443
createServer
ciphers
'DEFAULT@SECLEVEL=0'
minVersion
'TLSv1'
},
function
socket
console
log
'Client connected with protocol:'
socket
getProtocol
())
socket
end
()
this
close
()
listen
(port
()
=>
connect
(port
ciphers
'DEFAULT@SECLEVEL=0'
maxVersion
'TLSv1'
const
createServer
connect
require
'node:tls'
const
port
443
createServer
ciphers
'DEFAULT@SECLEVEL=0'
minVersion
'TLSv1'
},
function
socket
console
log
'Client connected with protocol:'
socket
getProtocol
())
socket
end
()
this
close
()
listen
(port
()
=>
connect
(port
ciphers
'DEFAULT@SECLEVEL=0'
maxVersion
'TLSv1'
This approach sets the security level to 0, allowing the use of legacy features while still
leveraging the default OpenSSL ciphers.
Using
--tls-cipher-list
You can also set the security level and ciphers from the command line using the
--tls-cipher-list=DEFAULT@SECLEVEL=X
as described in
Modifying the default TLS cipher suite
However, it is generally discouraged to use the command line option for setting ciphers and it is
preferable to configure the ciphers for individual contexts within your application code,
as this approach provides finer control and reduces the risk of globally downgrading the security level.
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

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.
When certificate errors like
UNABLE_TO_VERIFY_LEAF_SIGNATURE
DEPTH_ZERO_SELF_SIGNED_CERT
, or
UNABLE_TO_GET_ISSUER_CERT
occur, Node.js
appends a hint suggesting that if the root CA is installed locally,
try running with the
--use-system-ca
flag to direct developers towards a
secure solution, to prevent unsafe workarounds.
Class:
tls.Server
Added in: v0.3.2
Extends:

Accepts encrypted connections using TLS or SSL.
Event:
'connection'
Added in: v0.3.2
socket

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'
Added in: v12.3.0, v10.20.0
line

Line of ASCII text, in NSS
SSLKEYLOGFILE
format.
tlsSocket

The
tls.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'
Added in: v0.9.2
History
Version
Changes
v0.11.12
The
callback
argument is now supported.
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

The TLS session identifier
sessionData

The TLS session data
callback

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'
Added in: v0.11.13
The
'OCSPRequest'
event is emitted when the client sends a certificate status
request. The listener callback is passed three arguments when called:
certificate

The server certificate
issuer

The issuer's certificate
callback

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
or
issuer
and
performs an
OCSP request
to the CA.
Server receives
'OCSPResponse'
from the CA and sends it back to the client
via the
callback
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'
Added in: v0.9.2
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

The TLS session identifier
callback

A callback function to be called when the prior session
has been recovered:
callback([err[, sessionData]])
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'
Added in: v0.3.2
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

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'
Added in: v6.0.0
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

The
Error
object describing the error
tlsSocket

The
tls.TLSSocket
instance from which the
error originated.
server.addContext(hostname, context)
Added in: v0.5.3
hostname

A SNI host name or wildcard (e.g.
'*'
context


An object containing any of the possible
properties from the
tls.createSecureContext()
options
arguments
(e.g.
key
cert
ca
, etc), or a TLS context object created with
tls.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()
Added in: v0.6.0
Returns:

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])
Added in: v0.3.2
callback

A listener callback that will be registered to listen
for the server instance's
'close'
event.
Returns:

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()
Added in: v3.0.0
Returns:

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)
Added in: v11.0.0
options

An object containing any of the possible properties from
the
tls.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)
Added in: v3.0.0
keys



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
Added in: v0.11.4
Extends:

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])
Added in: v0.11.4
History
Version
Changes
v12.2.0
The
enableTrace
option is now supported.
v5.0.0
ALPN options are supported now.
socket


On the server side, any
Duplex
stream. On the client side, any
instance of
net.Socket
(for generic
Duplex
stream support
on the client side,
tls.connect()
must be used).
options

enableTrace
: See
tls.createServer()
isServer
: The SSL/TLS protocol is asymmetrical, TLSSockets must know if
they are to behave as a server or a client. If
true
the TLS socket will be
instantiated as a server.
Default:
false
server

net.Server
instance.
requestCert
: Whether to authenticate the remote peer by requesting a
certificate. Clients always request a server certificate. Servers
isServer
is true) may set
requestCert
to true to request a client
certificate.
rejectUnauthorized
: See
tls.createServer()
ALPNProtocols
: See
tls.createServer()
SNICallback
: See
tls.createServer()
ALPNCallback
: See
tls.createServer()
session

Buffer
instance containing a TLS session.
requestOCSP

If
true
, 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
secureContext
: TLS context object created with
tls.createSecureContext()
. If a
secureContext
is
not
provided, one
will be created by passing the entire
options
object to
tls.createSecureContext()
...:
tls.createSecureContext()
options that are used if the
secureContext
option is missing. Otherwise, they are ignored.
Construct a new
tls.TLSSocket
object from an existing TCP socket.
Event:
'keylog'
Added in: v12.3.0, v10.20.0
line

Line of ASCII text, in NSS
SSLKEYLOGFILE
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'
Added in: v0.11.13
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

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:
'secure'
Added in: v0.11.4
The
'secure'
event is emitted after the TLS handshake has successfully
completed and a secure connection has been established.
This event is emitted on both client and server

instances,
including sockets created using the
new tls.TLSSocket()
constructor.
Event:
'secureConnect'
Added in: v0.11.4
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

is created
using the
new tls.TLSSocket()
constructor.
Event:
'session'
Added in: v11.10.0
session

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()
Added in: v0.11.4
History
Version
Changes
v18.4.0
The
family
property now returns a string instead of a number.
v18.0.0
The
family
property now returns a number instead of a string.
Returns:

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
Added in: v0.11.4
Returns the reason why the peer's certificate was not been verified. This
property is set only when
tlsSocket.authorized === false
tlsSocket.authorized
Added in: v0.11.4
Type:

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()
Added in: v8.4.0
Disables TLS renegotiation for this
TLSSocket
instance. Once called, attempts
to renegotiate will trigger an
'error'
event on the
TLSSocket
tlsSocket.enableTrace()
Added in: v12.2.0
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
Added in: v0.11.4
Always returns
true
. This may be used to distinguish TLS sockets from regular
net.Socket
instances.
tlsSocket.exportKeyingMaterial(length, label[, context])
Added in: v13.10.0, v12.17.0
length

number of bytes to retrieve from keying material
label

an application specific label, typically this will be a
value from the
IANA Exporter Label Registry
context

Optionally provide a context.
Returns:

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:
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()
Added in: v11.2.0
Returns:

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()
Added in: v0.11.4
History
Version
Changes
v13.4.0, v12.16.0
Return the IETF cipher name as
standardName
v12.0.0
Return the minimum cipher version, instead of a fixed string (
'TLSv1/SSLv3'
).
Returns:

name

OpenSSL name for the cipher suite.
standardName

IETF name for the cipher suite.
version

The minimum TLS protocol version supported by this cipher
suite. For the actual negotiated protocol, see
tls.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()
Added in: v5.0.0
Returns:

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()
Added in: v9.9.0
Returns:


The latest
Finished
message that has been
sent to the socket as part of a SSL/TLS handshake, or
undefined
if
no
Finished
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])
Added in: v0.11.4
detailed

Include the full certificate chain if
true
, otherwise
include just the peer's certificate.
Returns:

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
History
Version
Changes
v19.1.0, v18.13.0
Add "ca" property.
v17.2.0, v16.14.0
Add fingerprint512.
v11.4.0
Support Elliptic Curve public key info.
A certificate object has properties corresponding to the fields of the
certificate.
ca

true
if a Certificate Authority (CA),
false
otherwise.
raw

The DER encoded X.509 certificate data.
subject

The certificate subject, described in terms of
Country (
), StateOrProvince (
ST
), Locality (
), Organization (
),
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

The certificate issuer, described in the same terms as the
subject
valid_from

The date-time the certificate is valid from.
valid_to

The date-time the certificate is valid to.
serialNumber

The certificate serial number, as a hex string.
Example:
'B9B0D332A1AA5635'
fingerprint

The SHA-1 digest of the DER encoded certificate. It is
returned as a
separated hexadecimal string. Example:
'2A:7A:C2:DD:...'
fingerprint256

The SHA-256 digest of the DER encoded certificate.
It is returned as a
separated hexadecimal string. Example:
'2A:7A:C2:DD:...'
fingerprint512

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

(Optional) The extended key usage, a set of OIDs.
subjectaltname

(Optional) A string containing concatenated names
for the subject, an alternative to the
subject
names.
infoAccess

(Optional) An array describing the AuthorityInfoAccess,
used with OCSP.
issuerCertificate

(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

The RSA bit size. Example:
1024
exponent

The RSA exponent, as a string in hexadecimal number
notation. Example:
'0x010001'
modulus

The RSA modulus, as a hexadecimal string. Example:
'B56CE45CB7...'
pubkey

The public key.
For EC keys, the following properties may be defined:
pubkey

The public key.
bits

The key size in bits. Example:
256
asn1Curve

(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

(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
'GB'
ST
'Greater Manchester'
'Salford'
'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()
Added in: v9.9.0
Returns:


The latest
Finished
message that is expected
or has actually been received from the socket as part of a SSL/TLS handshake,
or
undefined
if there is no
Finished
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()
Added in: v15.9.0
Returns:

Returns the peer certificate as an

object.
If there is no peer certificate, or the socket has been destroyed,
undefined
will be returned.
tlsSocket.getProtocol()
Added in: v5.7.0
Returns:


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()
Added in: v0.11.4
Type:

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()
Added in: v12.11.0
Returns:

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()
Added in: v0.11.4
Type:

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()
Added in: v15.9.0
Returns:

Returns the local certificate as an

object.
If there is no local certificate, or the socket has been destroyed,
undefined
will be returned.
tlsSocket.isSessionReused()
Added in: v0.5.6
Returns:

true
if the session was reused,
false
otherwise.
See
Session Resumption
for more information.
tlsSocket.localAddress
Added in: v0.11.4
Type:

Returns the string representation of the local IP address.
tlsSocket.localPort
Added in: v0.11.4
Type:

Returns the numeric representation of the local port.
tlsSocket.remoteAddress
Added in: v0.11.4
Type:

Returns the string representation of the remote IP address. For example,
'74.125.127.100'
or
'2001:4860:a005::68'
tlsSocket.remoteFamily
Added in: v0.11.4
Type:

Returns the string representation of the remote IP family.
'IPv4'
or
'IPv6'
tlsSocket.remotePort
Added in: v0.11.4
Type:

Returns the numeric representation of the remote port. For example,
443
tlsSocket.renegotiate(options, callback)
Added in: v0.11.8
History
Version
Changes
v18.0.0
Passing an invalid callback to the
callback
argument now throws
ERR_INVALID_ARG_TYPE
instead of
ERR_INVALID_CALLBACK
options

rejectUnauthorized

If not
false
, 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

If
renegotiate()
returned
true
, callback is
attached once to the
'secure'
event. If
renegotiate()
returned
false
callback
will be called in the next tick with an error, unless the
tlsSocket
has been destroyed, in which case
callback
will not be called
at all.
Returns:

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.setKeyCert(context)
Added in: v22.5.0, v20.17.0
context


An object containing at least
key
and
cert
properties from the
tls.createSecureContext()
options
, or a
TLS context object created with
tls.createSecureContext()
itself.
The
tlsSocket.setKeyCert()
method sets the private key and certificate to use
for the socket. This is mainly useful if you wish to select a server certificate
from a TLS server's
ALPNCallback
tlsSocket.setMaxSendFragment(size)
Added in: v0.11.11
size

The maximum TLS fragment size. The maximum value is
16384
Default:
16384
Returns:

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)
Added in: v0.8.4
History
Version
Changes
v17.3.1, v16.13.2, v14.18.3, v12.22.9
Support for
uniformResourceIdentifier
subject alternative names has been disabled in response to CVE-2021-44531.
hostname

The host name or IP address to verify the certificate
against.
cert

certificate object
representing the peer's certificate.
Returns:


Verifies the certificate
cert
is issued to
hostname
Returns

object, populating it with
reason
host
, and
cert
on
failure. On success, returns

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])
Added in: v0.11.3
History
Version
Changes
v15.1.0, v14.18.0
Added
onread
option.
v14.1.0, v13.14.0
The
highWaterMark
option is accepted now.
v13.6.0, v12.16.0
The
pskCallback
option is now supported.
v12.9.0
Support the
allowHalfOpen
option.
v12.4.0
The
hints
option is now supported.
v12.2.0
The
enableTrace
option is now supported.
v11.8.0, v10.16.0
The
timeout
option is supported now.
v8.0.0
The
lookup
option is supported now.
v8.0.0
The
ALPNProtocols
option can be a
TypedArray
or
DataView
now.
v5.3.0, v4.7.0
The
secureContext
option is supported now.
v5.0.0
ALPN options are supported now.
options

enableTrace
: See
tls.createServer()
host

Host the client should connect to.
Default:
'localhost'
port

Port the client should connect to.
path

Creates Unix socket connection to path. If this option is
specified,
host
and
port
are ignored.
socket

Establish secure connection on a given socket
rather than creating a new socket. Typically, this is an instance of
net.Socket
, but any
Duplex
stream is allowed.
If this option is specified,
path
host
, and
port
are ignored,
except for certificate validation. Usually, a socket is already connected
when passed to
tls.connect()
, but it can be connected later.
Connection/disconnection/destruction of
socket
is the user's
responsibility; calling
tls.connect()
will not cause
net.connect()
to be
called.
allowHalfOpen

If set to
false
, then the socket will
automatically end the writable side when the readable side ends. If the
socket
option is set, this option has no effect. See the
allowHalfOpen
option of
net.Socket
for details.
Default:
false
rejectUnauthorized

If not
false
, 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

For TLS-PSK negotiation, see
Pre-shared keys
ALPNProtocols




An array of strings,
or a single
Buffer
TypedArray
, or
DataView
containing the supported
ALPN protocols. Buffers should have the format
[len][name][len][name]...
e.g.
'\x08http/1.1\x08http/1.0'
, where the
len
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

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 the
SNICallback
option to
tls.createServer()
checkServerIdentity(servername, cert)

A callback function
to be used (instead of the builtin
tls.checkServerIdentity()
function)
when checking the server's host name (or the provided
servername
when
explicitly set) against the certificate. This should return an

if
verification fails. The method should return
undefined
if the
servername
and
cert
are verified.
session

Buffer
instance, containing TLS session.
requestOCSP

If
true
, 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.
minDHSize

Minimum size of the DH parameter in bits to accept a
TLS connection. When a server offers a DH parameter with a size less
than
minDHSize
, the TLS connection is destroyed and an error is thrown.
Default:
1024
highWaterMark

Consistent with the readable stream
highWaterMark
parameter.
Default:
16 * 1024
timeout

If set and if a socket is created internally, will call
socket.setTimeout(timeout)
after the socket is created, but before it
starts the connection.
secureContext
: TLS context object created with
tls.createSecureContext()
. If a
secureContext
is
not
provided, one
will be created by passing the entire
options
object to
tls.createSecureContext()
onread

If the
socket
option is missing, incoming data is
stored in a single
buffer
and passed to the supplied
callback
when
data arrives on the socket, otherwise the option is ignored. See the
onread
option of
net.Socket
for details.
...:
tls.createSecureContext()
options that are used if the
secureContext
option is missing, otherwise they are ignored.
...: Any
socket.connect()
option not already listed.
callback

Returns:

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.
import
connect
from
'node:tls'
import
readFileSync
from
'node:fs'
import
stdin
from
'node:process'
const
options
// Necessary only if the server requires client certificate authentication.
key
readFileSync
'client-key.pem'
cert
readFileSync
'client-cert.pem'
// Necessary only if the server uses a self-signed certificate.
ca
readFileSync
'server-cert.pem'
) ]
// Necessary only if the server's cert isn't for "localhost".
checkServerIdentity
()
=>
return
null
},
};
const
socket
connect
8000
options
()
=>
console
log
'client connected'
socket
authorized
'authorized'
'unauthorized'
stdin
pipe
(socket)
stdin
resume
()
socket
setEncoding
'utf8'
socket
on
'data'
data
=>
console
log
(data)
socket
on
'end'
()
=>
console
log
'server ends connection'
// Assumes an echo server that is listening on port 8000.
const
connect
require
'node:tls'
const
readFileSync
require
'node:fs'
const
options
// Necessary only if the server requires client certificate authentication.
key
readFileSync
'client-key.pem'
cert
readFileSync
'client-cert.pem'
// Necessary only if the server uses a self-signed certificate.
ca
readFileSync
'server-cert.pem'
) ]
// Necessary only if the server's cert isn't for "localhost".
checkServerIdentity
()
=>
return
null
},
};
const
socket
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'
To generate the certificate and key for this example, run:
openssl
req
-x509
-newkey
rsa:2048
-nodes
-sha256
-subj
'/CN=localhost'
-keyout
client-key.pem
-out
client-cert.pem
Then, to generate the
server-cert.pem
certificate for this example, run:
openssl
pkcs12
-certpbe
AES-256-CBC
-export
-out
server-cert.pem
-inkey
client-key.pem
-in
client-cert.pem
tls.connect(path[, options][, callback])
Added in: v0.11.3
path

Default value for
options.path
options

See
tls.connect()
callback

See
tls.connect()
Returns:

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])
Added in: v0.11.3
port

Default value for
options.port
host

Default value for
options.host
options

See
tls.connect()
callback

See
tls.connect()
Returns:

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])
Added in: v0.11.13
History
Version
Changes
v22.9.0, v20.18.0
The
allowPartialTrustChain
option has been added.
v22.4.0, v20.16.0
The
clientCertEngine
privateKeyEngine
and
privateKeyIdentifier
options depend on custom engine support in OpenSSL which is deprecated in OpenSSL 3.
v19.8.0, v18.16.0
The
dhparam
option can now be set to
'auto'
to enable DHE with appropriate well-known parameters.
v12.12.0
Added
privateKeyIdentifier
and
privateKeyEngine
options to get private key from an OpenSSL engine.
v12.11.0
Added
sigalgs
option to override supported signature algorithms.
v12.0.0
TLSv1.3 support added.
v11.5.0
The
ca:
option now supports
BEGIN TRUSTED CERTIFICATE
v11.4.0, v10.16.0
The
minVersion
and
maxVersion
can be used to restrict the allowed TLS protocol versions.
v10.0.0
The
ecdhCurve
cannot be set to
false
anymore due to a change in OpenSSL.
v9.3.0
The
options
parameter can now include
clientCertEngine
v9.0.0
The
ecdhCurve
option can now be multiple
':'
separated curve names or
'auto'
v7.3.0
If the
key
option is an array, individual entries do not need a
passphrase
property anymore.
Array
entries can also just be
string
s or
Buffer
s now.
v5.2.0
The
ca
option can now be a single string containing multiple CA certificates.
options

allowPartialTrustChain

Treat intermediate (non-self-signed)
certificates in the trust CA certificate list as trusted.
ca




Optionally override the trusted CA
certificates. If not specified, the CA certificates trusted by default are
the same as the ones returned by
tls.getCACertificates()
using the
default
type. If specified, the default list would be completely replaced
(instead of being concatenated) by the certificates in the
ca
option.
Users need to concatenate manually if they wish to add additional certificates
instead of completely overriding the default.
The value can be a string or
Buffer
, or an
Array
of
strings and/or
Buffer
s. Any string or
Buffer
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 the
ca
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".
cert




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 private
key
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,
see
ca
). When providing multiple cert chains, they do not have to be in
the same order as their private keys in
key
. If the intermediate
certificates are not provided, the peer will not be able to validate the
certificate, and the handshake will fail.
sigalgs

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

Cipher suite specification, replacing the default. For
more information, see
Modifying the default TLS cipher suite
. Permitted
ciphers can be obtained via
tls.getCiphers()
. Cipher names must be
uppercased in order for OpenSSL to accept them.
clientCertEngine

Name of an OpenSSL engine which can provide the
client certificate.
Deprecated.
crl




PEM formatted CRLs (Certificate
Revocation Lists).
dhparam


'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

A string describing a named curve or a colon separated
list of curve NIDs or names, for example
P-521:P-384:P-256
, to use for
ECDH key agreement. Set to
auto
to select the
curve automatically. Use
crypto.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

Attempt to use the server's cipher suite
preferences instead of the client's. When
true
, causes
SSL_OP_CIPHER_SERVER_PREFERENCE
to be set in
secureOptions
, see
OpenSSL Options
for more information.
key





Private keys in PEM
format. PEM allows the option of private keys being encrypted. Encrypted
keys will be decrypted with
options.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: [, passphrase: ]}
. The object form can only
occur in an array.
object.passphrase
is optional. Encrypted keys will be
decrypted with
object.passphrase
if provided, or
options.passphrase
if
it is not.
privateKeyEngine

Name of an OpenSSL engine to get private key
from. Should be used together with
privateKeyIdentifier
Deprecated.
privateKeyIdentifier

Identifier of a private key managed by
an OpenSSL engine. Should be used together with
privateKeyEngine
Should not be set together with
key
, because both options define a
private key in different ways.
Deprecated.
maxVersion

Optionally set the maximum TLS version to allow. One
of
'TLSv1.3'
'TLSv1.2'
'TLSv1.1'
, or
'TLSv1'
. Cannot be specified
along with the
secureProtocol
option; use one or the other.
Default:
tls.DEFAULT_MAX_VERSION
minVersion

Optionally set the minimum TLS version to allow. One
of
'TLSv1.3'
'TLSv1.2'
'TLSv1.1'
, or
'TLSv1'
. Cannot be specified
along with the
secureProtocol
option; use one or the other. Avoid
setting to less than TLSv1.2, but it may be required for
interoperability. Versions before TLSv1.2 may require downgrading the
OpenSSL Security Level
Default:
tls.DEFAULT_MIN_VERSION
passphrase

Shared passphrase used for a single private key and/or
a PFX.
pfx





PFX or PKCS12 encoded
private key and certificate chain.
pfx
is an alternative to providing
key
and
cert
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: [, passphrase: ]}
. The object form can only
occur in an array.
object.passphrase
is optional. Encrypted PFX will be
decrypted with
object.passphrase
if provided, or
options.passphrase
if
it is not.
secureOptions

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 the
SSL_OP_*
options from
OpenSSL Options
secureProtocol

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. Use
minVersion
and
maxVersion
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, see
minVersion
sessionIdContext

Opaque identifier used by servers to ensure
session state is not shared between applications. Unused by clients.
ticketKeys

48-bytes of cryptographically strong pseudorandom
data. See
Session Resumption
for more information.
sessionTimeout

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.createServer([options][, secureConnectionListener])
Added in: v0.3.2
History
Version
Changes
v22.4.0, v20.16.0
The
clientCertEngine
option depends on custom engine support in OpenSSL which is deprecated in OpenSSL 3.
v20.4.0, v18.19.0
The
options
parameter can now include
ALPNCallback
v19.0.0
If
ALPNProtocols
is set, incoming connections that send an ALPN extension with no supported protocols are terminated with a fatal
no_application_protocol
alert.
v12.3.0
The
options
parameter now supports
net.createServer()
options.
v9.3.0
The
options
parameter can now include
clientCertEngine
v8.0.0
The
ALPNProtocols
option can be a
TypedArray
or
DataView
now.
v5.0.0
ALPN options are supported now.
options

ALPNProtocols




An array of strings,
or a single
Buffer
TypedArray
, or
DataView
containing the supported
ALPN protocols. Buffers 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

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 containing
servername
and
protocols
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 in
protocols
, which will be returned to the client as the selected
ALPN protocol, or
undefined
, 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 the
ALPNProtocols
option, and setting both options will throw an error.
clientCertEngine

Name of an OpenSSL engine which can provide the
client certificate.
Deprecated.
enableTrace

If
true
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

Abort the connection if the SSL/TLS handshake
does not finish in the specified number of milliseconds.
'tlsClientError'
is emitted on the
tls.Server
object whenever
a handshake times out.
Default:
120000
(120 seconds).
rejectUnauthorized

If not
false
the server will reject any
connection which is not authorized with the list of supplied CAs. This
option only has an effect if
requestCert
is
true
Default:
true
requestCert

If
true
the server will request a certificate from
clients that connect and attempt to verify that certificate.
Default:
false
sessionTimeout

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)

A function that will be
called if the client supports SNI TLS extension. Two arguments will be
passed when called:
servername
and
callback
callback
is an
error-first callback that takes two optional arguments:
error
and
ctx
ctx
, if provided, is a
SecureContext
instance.
tls.createSecureContext()
can be used to get a proper
SecureContext
If
callback
is called with a falsy
ctx
argument, the default secure
context of the server will be used. If
SNICallback
wasn't provided the
default callback with high-level API will be used (see below).
ticketKeys

48-bytes of cryptographically strong pseudorandom
data. See
Session Resumption
for more information.
pskCallback

For TLS-PSK negotiation, see
Pre-shared keys
pskIdentityHint

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_IDENTITY_HINT_FAILED'
code.
...: Any
tls.createSecureContext()
option can be provided. For
servers, the identity options (
pfx
key
cert
, or
pskCallback
are usually required.
...: Any
net.createServer()
option can be provided.
secureConnectionListener

Returns:

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:
import
createServer
from
'node:tls'
import
readFileSync
from
'node:fs'
const
options
key
readFileSync
'server-key.pem'
cert
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
readFileSync
'client-cert.pem'
) ]
};
const
server
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'
const
createServer
require
'node:tls'
const
readFileSync
require
'node:fs'
const
options
key
readFileSync
'server-key.pem'
cert
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
readFileSync
'client-cert.pem'
) ]
};
const
server
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'
To generate the certificate and key for this example, run:
openssl
req
-x509
-newkey
rsa:2048
-nodes
-sha256
-subj
'/CN=localhost'
-keyout
server-key.pem
-out
server-cert.pem
Then, to generate the
client-cert.pem
certificate for this example, run:
openssl
pkcs12
-certpbe
AES-256-CBC
-export
-out
client-cert.pem
-inkey
server-key.pem
-in
server-cert.pem
The server can be tested by connecting to it using the example client from
tls.connect()
tls.setDefaultCACertificates(certs)
Added in: v24.5.0, v22.19.0
certs


An array of CA certificates in PEM format.
Sets the default CA certificates used by Node.js TLS clients. If the provided
certificates are parsed successfully, they will become the default CA
certificate list returned by
tls.getCACertificates()
and used
by subsequent TLS connections that don't specify their own CA certificates.
The certificates will be deduplicated before being set as the default.
This function only affects the current Node.js thread. Previous
sessions cached by the HTTPS agent won't be affected by this change, so
this method should be called before any unwanted cachable TLS connections are
made.
To use system CA certificates as the default:
const
tls
require
'node:tls'
tls
setDefaultCACertificates
(tls
getCACertificates
'system'
))
import
tls
from
'node:tls'
tls
setDefaultCACertificates
(tls
getCACertificates
'system'
))
This function completely replaces the default CA certificate list. To add additional
certificates to the existing defaults, get the current certificates and append to them:
const
tls
require
'node:tls'
const
currentCerts
tls
getCACertificates
'default'
const
additionalCerts
'-----BEGIN CERTIFICATE-----
\n
...'
tls
setDefaultCACertificates
([
...
currentCerts
...
additionalCerts])
import
tls
from
'node:tls'
const
currentCerts
tls
getCACertificates
'default'
const
additionalCerts
'-----BEGIN CERTIFICATE-----
\n
...'
tls
setDefaultCACertificates
([
...
currentCerts
...
additionalCerts])
tls.getCACertificates([type])
Added in: v23.10.0, v22.15.0
type


The type of CA certificates that will be returned. Valid values
are
"default"
"system"
"bundled"
and
"extra"
Default:
"default"
Returns:

An array of PEM-encoded certificates. The array may contain duplicates
if the same certificate is repeatedly stored in multiple sources.
Returns an array containing the CA certificates from various sources, depending on
type
"default"
: return the CA certificates that will be used by the Node.js TLS clients by default.
When
--use-bundled-ca
is enabled (default), or
--use-openssl-ca
is not enabled,
this would include CA certificates from the bundled Mozilla CA store.
When
--use-system-ca
is enabled, this would also include certificates from the system's
trusted store.
When
NODE_EXTRA_CA_CERTS
is used, this would also include certificates loaded from the specified
file.
"system"
: return the CA certificates that are loaded from the system's trusted store, according
to rules set by
--use-system-ca
. This can be used to get the certificates from the system
when
--use-system-ca
is not enabled.
"bundled"
: return the CA certificates from the bundled Mozilla CA store. This would be the same
as
tls.rootCertificates
"extra"
: return the CA certificates loaded from
NODE_EXTRA_CA_CERTS
. It's an empty array if
NODE_EXTRA_CA_CERTS
is not set.
tls.getCiphers()
Added in: v0.10.2
Returns:

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
Added in: v12.3.0
Type:

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.
To get the actual CA certificates used by the current Node.js instance, which
may include certificates loaded from the system store (if
--use-system-ca
is used)
or loaded from a file indicated by
NODE_EXTRA_CA_CERTS
, use
tls.getCACertificates()
tls.DEFAULT_ECDH_CURVE
Added in: v0.11.13
History
Version
Changes
v10.0.0
Default value changed to
'auto'
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
Added in: v11.4.0
Type:

The default value of the
maxVersion
option of
tls.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
Added in: v11.4.0
Type:

The default value of the
minVersion
option of
tls.createSecureContext()
. It can be assigned any of the supported TLS
protocol versions,
'TLSv1.3'
'TLSv1.2'
'TLSv1.1'
, or
'TLSv1'
Versions before TLSv1.2 may require downgrading the
OpenSSL Security Level
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
Added in: v0.11.3
Type:

The default value of the
ciphers
option of
tls.createSecureContext()
. It can be assigned any of the supported
OpenSSL ciphers. Defaults to the content of
crypto.constants.defaultCoreCipherList
, unless changed using CLI options
using
--tls-default-ciphers

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