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Node.js v6.13.0-rc.1 Documentation
Table of Contents
- TLS (SSL)
- TLS/SSL Concepts
- Modifying the Default TLS Cipher suite
- Class: tls.Server
- Event: 'tlsClientError'
- Event: 'newSession'
- Event: 'OCSPRequest'
- Event: 'resumeSession'
- Event: 'secureConnection'
- server.addContext(hostname, context)
- server.address()
- server.close([callback])
- server.connections
- server.getTicketKeys()
- server.listen(port[, hostname][, callback])
- server.setTicketKeys(keys)
- Class: tls.TLSSocket
- new tls.TLSSocket(socket[, options])
- Event: 'OCSPResponse'
- Event: 'secureConnect'
- tlsSocket.address()
- tlsSocket.authorized
- tlsSocket.authorizationError
- tlsSocket.encrypted
- tlsSocket.getCipher()
- tlsSocket.getEphemeralKeyInfo()
- tlsSocket.getPeerCertificate([ detailed ])
- tlsSocket.getProtocol()
- tlsSocket.getSession()
- tlsSocket.getTLSTicket()
- tlsSocket.localAddress
- tlsSocket.localPort
- tlsSocket.remoteAddress
- tlsSocket.remoteFamily
- tlsSocket.remotePort
- tlsSocket.renegotiate(options, callback)
- tlsSocket.setMaxSendFragment(size)
- tls.connect(port[, host][, options][, callback])
- tls.connect(path[, options][, callback])
- tls.connect(options[, callback])
- tls.createSecureContext(options)
- tls.createServer([options][, secureConnectionListener])
- tls.getCiphers()
- tls.DEFAULT_ECDH_CURVE
- Deprecated APIs
TLS (SSL)#
The 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('tls');
TLS/SSL Concepts#
The TLS/SSL is a public/private key infrastructure (PKI). For most common cases, each client and 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):
- DHE - An ephemeral version of the Diffie Hellman key-agreement protocol.
- ECDHE - An ephemeral version of the Elliptic Curve Diffie Hellman key-agreement protocol.
Ephemeral methods may have some performance drawbacks, because key generation is expensive.
To use Perfect Forward Secrecy using DHE
with the tls
module, it is required
to generate Diffie-Hellman parameters and specify them with the dhparam
option to tls.createSecureContext()
. The following illustrates the use of
the OpenSSL command-line interface to generate such parameters:
openssl dhparam -outform PEM -out dhparam.pem 2048
If using Perfect Forward Secrecy using ECDHE
, Diffie-Hellman parameters are
not required and a default ECDHE curve will be used. The ecdhCurve
property
can be used when creating a TLS Server to specify the name of an alternative
curve to use, see tls.createServer()
for more info.
ALPN, NPN and SNI#
ALPN (Application-Layer Protocol Negotiation Extension), NPN (Next Protocol Negotiation) and, SNI (Server Name Indication) are TLS handshake extensions:
- ALPN/NPN - Allows the use of one TLS server for multiple protocols (HTTP, SPDY, HTTP/2)
- SNI - Allows the use of one TLS server for multiple hostnames with different SSL certificates.
Note: Use of ALPN is recommended over NPN. The NPN extension has never been formally defined or documented and generally not recommended for use.
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. Defaults to3
.tls.CLIENT_RENEG_WINDOW
<number> Specifies the time renegotiation window in seconds. Defaults to600
(10 minutes).
Note: The default renegotiation limits should not be modified without a full understanding of the implications and risks.
To test the renegotiation limits on a server, connect to it using the OpenSSL
command-line client (openssl s_client -connect address:port
) then input
R<CR>
(i.e., the letter R
followed by a carriage return) multiple times.
Modifying the Default TLS Cipher suite#
Node.js is built with a default suite of enabled and disabled TLS ciphers. Currently, the default cipher suite is:
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. 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"
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.
Consult OpenSSL cipher list format documentation for details on the format.
Note: 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.
128 bit AES is preferred over 192 and 256 bit AES in light of specific attacks affecting larger AES key sizes.
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.
Class: tls.Server#
The tls.Server
class is a subclass of net.Server
that accepts encrypted
connections using TLS or SSL.
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.
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 listener callback is passed
three arguments when called:
sessionId
- The TLS session identifiersessionData
- 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.
Note: 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.
Note: 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.)
Note: Listening for this event will have an effect only on connections established after the addition of the event listener.
Note: 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
- The TLS/SSL session identifiercallback
<Function> A callback function to be called when the prior session has been recovered.
When called, the event listener may perform a lookup in external storage using
the given sessionId
and invoke callback(null, sessionData)
once finished. If
the session cannot be resumed (i.e., doesn't exist in storage) the callback may
be invoked as callback(null, null)
. Calling callback(err)
will terminate the
incoming connection and destroy the socket.
Note: 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. Note that depending on the settings
of the TLS server, unauthorized connections may still be accepted.
The tlsSocket.npnProtocol
and tlsSocket.alpnProtocol
properties are strings
that contain the selected NPN and ALPN protocols, respectively. When both NPN
and ALPN extensions are received, ALPN takes precedence over NPN and the next
protocol is selected by ALPN.
When ALPN has no selected protocol, tlsSocket.alpnProtocol
returns false
.
The tlsSocket.servername
property is a string containing the server name
requested via SNI.
server.addContext(hostname, context)#
hostname
<string> A SNI hostname or wildcard (e.g.'*'
)context
<Object> An object containing any of the possible properties from thetls.createSecureContext()
options
arguments (e.g.key
,cert
,ca
, etc).
The server.addContext()
method adds a secure context that will be used if
the client request's SNI hostname matches the supplied hostname
(or wildcard).
server.address()#
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> An optional listener callback that will be registered to listen for the server instance's'close'
event.
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.connections#
Returns the current number of concurrent connections on the server.
server.getTicketKeys()#
Returns a Buffer
instance holding the keys currently used for
encryption/decryption of the TLS Session Tickets
server.listen(port[, hostname][, callback])#
port
<number> The TCP/IP port on which to begin listening for connections. A value of0
(zero) will assign a random port.hostname
<string> The hostname, IPv4, or IPv6 address on which to begin listening for connections. Ifundefined
, the server will accept connections on any IPv6 address (::
) when IPv6 is available, or any IPv4 address (0.0.0.0
) otherwise.callback
<Function> A callback function to be invoked when the server has begun listening on theport
andhostname
.
The server.listen()
methods instructs the server to begin accepting
connections on the specified port
and hostname
.
This function operates asynchronously. If the callback
is given, it will be
called when the server has started listening.
See net.Server
for more information.
server.setTicketKeys(keys)#
keys
<Buffer> The keys used for encryption/decryption of the TLS Session Tickets.
Updates the keys for encryption/decryption of the TLS Session Tickets.
Note: The key's Buffer
should be 48 bytes long. See ticketKeys
option in
tls.createServer for
more information on how it is used.
Note: Changes to the ticket keys are effective only for future server connections. Existing or currently pending server connections will use the previous keys.
Class: tls.TLSSocket#
The tls.TLSSocket
is a subclass of net.Socket
that performs transparent
encryption of written data and all required TLS negotiation.
Instances of tls.TLSSocket
implement the duplex Stream interface.
Note: 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> An instance ofnet.Socket
options
<Object>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. Defaults tofalse
.server
<net.Server> An optionalnet.Server
instance.requestCert
: Whether to authenticate the remote peer by requesting a certificate. Clients always request a server certificate. Servers (isServer
is true) may optionally setrequestCert
to true to request a client certificate.rejectUnauthorized
: Optional, seetls.createServer()
NPNProtocols
: Optional, seetls.createServer()
ALPNProtocols
: Optional, seetls.createServer()
SNICallback
: Optional, seetls.createServer()
session
<Buffer> An optionalBuffer
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
: Optional TLS context object created withtls.createSecureContext()
. If asecureContext
is not provided, one will be created by passing the entireoptions
object totls.createSecureContext()
. Note: In effect, alltls.createSecureContext()
options can be provided, but they will be completely ignored unless thesecureContext
option is missing.- ...: Optional
tls.createSecureContext()
options can be provided, see thesecureContext
option for more information.
Construct a new tls.TLSSocket
object from an existing TCP socket.
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 either ALPN or NPN was used,
the tlsSocket.alpnProtocol
or tlsSocket.npnProtocol
properties can be
checked to determine the negotiated protocol.
tlsSocket.address()#
Returns the bound address, the address family name, and port of the
underlying socket as reported by the operating system. Returns an
object with three properties, e.g.,
{ port: 12346, family: 'IPv4', address: '127.0.0.1' }
tlsSocket.authorized#
Returns true
if the peer certificate was signed by one of the CAs specified
when creating the tls.TLSSocket
instance, otherwise false
.
tlsSocket.authorizationError#
Returns the reason why the peer's certificate was not been verified. This
property is set only when tlsSocket.authorized === false
.
tlsSocket.encrypted#
Always returns true
. This may be used to distinguish TLS sockets from regular
net.Socket
instances.
tlsSocket.getCipher()#
Returns an object representing the cipher name and the SSL/TLS protocol version that first defined the cipher.
For example: { name: 'AES256-SHA', version: 'TLSv1/SSLv3' }
See SSL_CIPHER_get_name()
and SSL_CIPHER_get_version()
in
https://www.openssl.org/docs/man1.0.2/ssl/SSL_CIPHER_get_name.html for more
information.
tlsSocket.getEphemeralKeyInfo()#
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.getPeerCertificate([ detailed ])#
detailed
<boolean> Include the full certificate chain iftrue
, otherwise include just the peer's certificate.
Returns an object representing the peer's certificate. The returned object has some properties corresponding to the fields of the certificate.
If the full certificate chain was requested, each certificate will include a
issuerCertificate
property containing an object representing its issuer's
certificate.
For example:
{ subject:
{ C: 'UK',
ST: 'Acknack Ltd',
L: 'Rhys Jones',
O: 'node.js',
OU: 'Test TLS Certificate',
CN: 'localhost' },
issuer:
{ C: 'UK',
ST: 'Acknack Ltd',
L: 'Rhys Jones',
O: 'node.js',
OU: 'Test TLS Certificate',
CN: 'localhost' },
issuerCertificate:
{ ... another certificate, possibly with a .issuerCertificate ... },
raw: < RAW DER buffer >,
valid_from: 'Nov 11 09:52:22 2009 GMT',
valid_to: 'Nov 6 09:52:22 2029 GMT',
fingerprint: '2A:7A:C2:DD:E5:F9:CC:53:72:35:99:7A:02:5A:71:38:52:EC:8A:DF',
serialNumber: 'B9B0D332A1AA5635' }
If the peer does not provide a certificate, an empty object 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.
Example responses include:
SSLv3
TLSv1
TLSv1.1
TLSv1.2
unknown
See https://www.openssl.org/docs/man1.0.2/ssl/SSL_get_version.html for more information.
tlsSocket.getSession()#
Returns the ASN.1 encoded TLS session or undefined
if no session was
negotiated. Can be used to speed up handshake establishment when reconnecting
to the server.
tlsSocket.getTLSTicket()#
Returns the TLS session ticket or undefined
if no session was negotiated.
Note: This only works with client TLS sockets. Useful only for debugging, for
session reuse provide session
option to tls.connect()
.
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>requestCert
callback
<Function> A function that will be called when the renegotiation request has been completed.
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
.
Note: This method can be used to request a peer's certificate after the secure connection has been established.
Note: When running as the server, the socket will be destroyed with an error
after handshakeTimeout
timeout.
tlsSocket.setMaxSendFragment(size)#
size
<number> The maximum TLS fragment size. Defaults to16384
. The maximum value is16384
.
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.connect(port[, host][, options][, callback])#
port
<number> Default value foroptions.port
.host
<string> Optional default value foroptions.host
.options
<Object> Seetls.connect()
.callback
<Function> Seetls.connect()
.
Same as tls.connect()
except that port
and host
can be provided
as arguments instead of options.
Note: A port or host option, if specified, will take precedence over any port or host argument.
tls.connect(path[, options][, callback])#
path
<string> Default value foroptions.path
.options
<Object> Seetls.connect()
.callback
<Function> Seetls.connect()
.
Same as tls.connect()
except that path
can be provided
as an argument instead of an option.
Note: A path option, if specified, will take precedence over the path argument.
tls.connect(options[, callback])#
options
<Object>host
<string> Host the client should connect to, defaults to '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
<net.Socket> Establish secure connection on a given socket rather than creating a new socket. If this option is specified,path
,host
andport
are ignored. Usually, a socket is already connected when passed totls.connect()
, but it can be connected later. Note that connection/disconnection/destruction ofsocket
is the user's responsibility, callingtls.connect()
will not causenet.connect()
to be called.rejectUnauthorized
<boolean> Iftrue
, 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. Defaults totrue
.NPNProtocols
<string[]> | <Buffer[]> An array of strings orBuffer
s containing supported NPN 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']
.ALPNProtocols
: <string[]> | <Buffer[]> An array of strings orBuffer
s 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:['hello', 'world']
.)servername
: <string> Server name for the SNI (Server Name Indication) TLS extension.checkServerIdentity(servername, cert)
<Function> A callback function to be used (instead of the builtintls.checkServerIdentity()
function) when checking the server's hostname 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. Defaults to1024
.secureContext
: Optional TLS context object created withtls.createSecureContext()
. If asecureContext
is not provided, one will be created by passing the entireoptions
object totls.createSecureContext()
. Note: In effect, alltls.createSecureContext()
options can be provided, but they will be completely ignored unless thesecureContext
option is missing.lookup
: <Function> Custom lookup function. Defaults todns.lookup()
.- ...: Optional
tls.createSecureContext()
options can be provided, see thesecureContext
option for more information.
callback
<Function>
The callback
function, if specified, will be added as a listener for the
'secureConnect'
event.
tls.connect()
returns a tls.TLSSocket
object.
The following implements a simple "echo server" example:
const tls = require('tls');
const fs = require('fs');
const options = {
// Necessary only if using the client certificate authentication
key: fs.readFileSync('client-key.pem'),
cert: fs.readFileSync('client-cert.pem'),
// Necessary only if the server uses the self-signed certificate
ca: [ fs.readFileSync('server-cert.pem') ]
};
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', () => {
server.close();
});
Or
const tls = require('tls');
const fs = require('fs');
const options = {
pfx: fs.readFileSync('client.pfx')
};
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', () => {
server.close();
});
tls.createSecureContext(options)#
options
<Object>pfx
<string> | <Buffer> Optional 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.key
<string> | <string[]> | <Buffer> | <Buffer[]> | <Object[]> Optional 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.passphrase
<string> Optional shared passphrase used for a single private key and/or a PFX.cert
<string> | <string[]> | <Buffer> | <Buffer[]> Optional 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.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 or Buffer, or an Array of strings and/or Buffers. 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 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.crl
<string> | <string[]> | <Buffer> | <Buffer[]> Optional PEM formatted CRLs (Certificate Revocation Lists).ciphers
<string> Optional cipher suite specification, replacing the default. For more information, see modifying the default cipher suite.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. Note:tls.createServer()
sets the default value totrue
, other APIs that create secure contexts leave it unset.ecdhCurve
<string> A string describing a named curve to use for ECDH key agreement orfalse
to disable ECDH. Defaults totls.DEFAULT_ECDH_CURVE
. 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.dhparam
<string> | <Buffer> Diffie Hellman parameters, required for Perfect Forward Secrecy. Useopenssl dhparam
to create the parameters. The key length must be greater than or equal to 1024 bits, otherwise an error will be thrown. It is strongly recommended to use 2048 bits or larger for stronger security. If omitted or invalid, the parameters are silently discarded and DHE ciphers will not be available.secureProtocol
<string> Optional SSL method to use, default is"SSLv23_method"
. The possible values are listed as SSL_METHODS, use the function names as strings. For example,"SSLv3_method"
to force SSL version 3.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.sessionIdContext
<string> Optional opaque identifier used by servers to ensure session state is not shared between applications. Unused by clients. Note:tls.createServer()
uses a 128 bit truncated SHA1 hash value generated fromprocess.argv
, other APIs that create secure contexts have no default value.
The tls.createSecureContext()
method creates a credentials object.
A key is required for ciphers that make use of certificates. Either key
or
pfx
can be used to provide it.
If the 'ca' option is not given, then Node.js will use the default publicly trusted list of CAs as given in http://mxr.mozilla.org/mozilla/source/security/nss/lib/ckfw/builtins/certdata.txt.
tls.createServer([options][, secureConnectionListener])#
options
<Object>handshakeTimeout
<number> Abort the connection if the SSL/TLS handshake does not finish in the specified number of milliseconds. Defaults to120
seconds. A'tlsClientError'
is emitted on thetls.Server
object whenever a handshake times out.requestCert
<boolean> Iftrue
the server will request a certificate from clients that connect and attempt to verify that certificate. Defaults tofalse
.rejectUnauthorized
<boolean> Iftrue
the server will reject any connection which is not authorized with the list of supplied CAs. This option only has an effect ifrequestCert
istrue
. Defaults tofalse
.NPNProtocols
<string[]> | <Buffer> An array of strings or aBuffer
naming possible NPN protocols. (Protocols should be ordered by their priority.)ALPNProtocols
<string[]> | <Buffer> An array of strings or aBuffer
naming possible ALPN protocols. (Protocols should be ordered by their priority.) When the server receives both NPN and ALPN extensions from the client, ALPN takes precedence over NPN and the server does not send an NPN extension to the client.SNICallback(servername, cb)
<Function> A function that will be called if the client supports SNI TLS extension. Two arguments will be passed when called:servername
andcb
.SNICallback
should invokecb(null, ctx)
, wherectx
is a SecureContext instance. (tls.createSecureContext(...)
can be used to get a proper SecureContext.) IfSNICallback
wasn't provided the default callback with high-level API will be used (see below).sessionTimeout
<number> An integer specifying the number of seconds after which the TLS session identifiers and TLS session tickets created by the server will time out. See SSL_CTX_set_timeout for more details.ticketKeys
: A 48-byteBuffer
instance consisting of a 16-byte prefix, a 16-byte HMAC key, and a 16-byte AES key. This can be used to accept TLS session tickets on multiple instances of the TLS server. Note that this is automatically shared betweencluster
module workers.- ...: Any
tls.createSecureContext()
options can be provided. For servers, the identity options (pfx
orkey
/cert
) are usually required.
secureConnectionListener
<Function>
Creates a new tls.Server. The secureConnectionListener
, if provided, is
automatically set as a listener for the 'secureConnection'
event.
The following illustrates a simple echo server:
const tls = require('tls');
const fs = require('fs');
const options = {
key: fs.readFileSync('server-key.pem'),
cert: fs.readFileSync('server-cert.pem'),
// This is necessary only if using the client certificate authentication.
requestCert: true,
// This is necessary only if the client uses the 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');
});
Or
const tls = require('tls');
const fs = require('fs');
const options = {
pfx: fs.readFileSync('server.pfx'),
// This is necessary only if using the client certificate authentication.
requestCert: true,
};
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');
});
This server can be tested by connecting to it using openssl s_client
:
openssl s_client -connect 127.0.0.1:8000
tls.getCiphers()#
Returns an array with the names of the supported SSL ciphers.
For example:
console.log(tls.getCiphers()); // ['AES128-SHA', 'AES256-SHA', ...]
tls.DEFAULT_ECDH_CURVE#
The default curve name to use for ECDH key agreement in a tls server. The
default value is 'prime256v1'
(NIST P-256). Consult RFC 4492 and
FIPS.186-4 for more details.
Deprecated APIs#
Class: CryptoStream#
tls.TLSSocket
instead.The tls.CryptoStream
class represents a stream of encrypted data. This class
has been 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: 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.
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>true
to specify whether a server should automatically reject clients with invalid certificates. Only applies whenisServer
istrue
.options
secureContext
: An optional TLS context object fromtls.createSecureContext()
isServer
: Iftrue
the TLS socket will be instantiated in server-mode. Defaults tofalse
.server
<net.Server> An optionalnet.Server
instancerequestCert
: Optional, seetls.createServer()
rejectUnauthorized
: Optional, seetls.createServer()
NPNProtocols
: Optional, seetls.createServer()
ALPNProtocols
: Optional, seetls.createServer()
SNICallback
: Optional, seetls.createServer()
session
<Buffer> An optionalBuffer
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.
Note: cleartext
has the same API as tls.TLSSocket
.
Note: 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:
secure_socket = tls.TLSSocket(socket, options);
where secure_socket
has the same API as pair.cleartext
.