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Node.js v4.4.5-rc.2 Documentation
Table of Contents
- TLS (SSL)
- Client-initiated renegotiation attack mitigation
- Modifying the Default TLS Cipher suite
- NPN and SNI
- Perfect Forward Secrecy
- Class: CryptoStream
- Class: SecurePair
- Class: tls.Server
- Event: 'clientError'
- 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.maxConnections
- 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.getPeerCertificate([ detailed ])
- tlsSocket.getSession()
- tlsSocket.getTLSTicket()
- tlsSocket.localPort
- tlsSocket.localAddress
- tlsSocket.remoteAddress
- tlsSocket.remoteFamily
- tlsSocket.remotePort
- tlsSocket.renegotiate(options, callback)
- tlsSocket.setMaxSendFragment(size)
- tls.connect(options[, callback])
- tls.connect(port[, host][, options][, callback])
- tls.createSecureContext(details)
- tls.createSecurePair([context][, isServer][, requestCert][, rejectUnauthorized][, options])
- tls.createServer(options[, secureConnectionListener])
- tls.getCiphers()
TLS (SSL)#
Stability: 2 - Stable
Use require('tls')
to access this module.
The tls
module uses OpenSSL to provide Transport Layer Security and/or
Secure Socket Layer: encrypted stream communication.
TLS/SSL is a public/private key infrastructure. Each client and each server must have a private key. A private key is created like this:
openssl genrsa -out ryans-key.pem 2048
All servers and some clients need to have a certificate. Certificates are public keys signed by a Certificate Authority or self-signed. The first step to getting a certificate is to create a "Certificate Signing Request" (CSR) file. This is done with:
openssl req -new -sha256 -key ryans-key.pem -out ryans-csr.pem
To create a self-signed certificate with the CSR, do this:
openssl x509 -req -in ryans-csr.pem -signkey ryans-key.pem -out ryans-cert.pem
Alternatively you can send the CSR to a Certificate Authority for signing.
For Perfect Forward Secrecy, it is required to generate Diffie-Hellman parameters:
openssl dhparam -outform PEM -out dhparam.pem 2048
To create .pfx or .p12, do this:
openssl pkcs12 -export -in agent5-cert.pem -inkey agent5-key.pem \
-certfile ca-cert.pem -out agent5.pfx
in
: certificateinkey
: private keycertfile
: all CA certs concatenated in one file likecat ca1-cert.pem ca2-cert.pem > ca-cert.pem
Client-initiated renegotiation attack mitigation#
The TLS protocol lets the client renegotiate certain aspects of the TLS session. Unfortunately, session renegotiation requires a disproportional amount of server-side resources, which makes it a potential vector for denial-of-service attacks.
To mitigate this, renegotiations are limited to three times every 10 minutes. An
error is emitted on the tls.TLSSocket
instance when the threshold is
exceeded. The limits are configurable:
tls.CLIENT_RENEG_LIMIT
: renegotiation limit, default is 3.tls.CLIENT_RENEG_WINDOW
: renegotiation window in seconds, default is 10 minutes.
Don't change the defaults unless you know what you are doing.
To test your server, connect to it with openssl s_client -connect address:port
and tap R<CR>
(that's the letter R
followed by a carriage return) a few
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 overriden 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"
Note that 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 should by used only if
absolutely necessary.
NPN and SNI#
NPN (Next Protocol Negotiation) and SNI (Server Name Indication) are TLS handshake extensions allowing you:
- NPN - to use one TLS server for multiple protocols (HTTP, SPDY)
- SNI - to use one TLS server for multiple hostnames with different SSL certificates.
Perfect Forward Secrecy#
The term "Forward Secrecy" or "Perfect Forward Secrecy" describes a feature of key-agreement (i.e. key-exchange) methods. Practically it means that even if the private key of a (your) server is compromised, communication can only be decrypted by eavesdroppers if they manage to obtain the key-pair specifically generated for each session.
This is achieved by randomly generating a key pair for key-agreement on every handshake (in contrary to the same key for all sessions). Methods implementing this technique, thus offering Perfect Forward Secrecy, 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.
Class: CryptoStream#
Stability: 0 - Deprecated: Use tls.TLSSocket
instead.
This is an encrypted stream.
cryptoStream.bytesWritten#
A proxy to the underlying socket's bytesWritten accessor, this will return the total bytes written to the socket, including the TLS overhead.
Class: SecurePair#
Returned by tls.createSecurePair.
Event: 'secure'#
The event is emitted from the SecurePair once the pair has successfully established a secure connection.
Similarly to the checking for the server 'secureConnection'
event,
pair.cleartext.authorized should be checked to confirm whether the certificate
used properly authorized.
Class: tls.Server#
This class is a subclass of net.Server
and has the same methods on it.
Instead of accepting just raw TCP connections, this accepts encrypted
connections using TLS or SSL.
Event: 'clientError'#
function (exception, tlsSocket) { }
When a client connection emits an 'error'
event before a secure connection is
established it will be forwarded here.
tlsSocket
is the tls.TLSSocket
that the error originated from.
Event: 'newSession'#
function (sessionId, sessionData, callback) { }
Emitted on creation of TLS session. May be used to store sessions in external
storage. callback
must be invoked eventually, otherwise no data will be
sent or received from secure connection.
NOTE: adding this event listener will have an effect only on connections established after addition of event listener.
Event: 'OCSPRequest'#
function (certificate, issuer, callback) { }
Emitted when the client sends a certificate status request. You could parse
server's current certificate to obtain OCSP url and certificate id, and after
obtaining OCSP response invoke callback(null, resp)
, where resp
is a
Buffer
instance. Both certificate
and issuer
are a Buffer
DER-representations of the primary and issuer's certificates. They could be used
to obtain OCSP certificate id and OCSP endpoint url.
Alternatively, callback(null, null)
could be called, meaning that there is no
OCSP response.
Calling callback(err)
will result in a socket.destroy(err)
call.
Typical flow:
- Client connects to server and sends
'OCSPRequest'
to it (via status info extension in ClientHello.) - Server receives request and invokes
'OCSPRequest'
event listener if present - Server grabs OCSP url from either
certificate
orissuer
and performs an OCSP request to the CA - Server receives
OCSPResponse
from CA and sends it back to client viacallback
argument - Client validates the response and either destroys socket or performs a handshake.
NOTE: issuer
could be null, if the certificate is self-signed or if the issuer
is not in the root certificates list. (You could provide an issuer via ca
option.)
NOTE: adding this event listener will have an effect only on connections established after addition of event listener.
NOTE: you may want to use some npm module like asn1.js to parse the certificates.
Event: 'resumeSession'#
function (sessionId, callback) { }
Emitted when client wants to resume previous TLS session. Event listener may
perform lookup in external storage using given sessionId
, and invoke
callback(null, sessionData)
once finished. If session can't be resumed
(i.e. doesn't exist in storage) one may call callback(null, null)
. Calling
callback(err)
will terminate incoming connection and destroy socket.
NOTE: adding this event listener will have an effect only on connections established after addition of event listener.
Here's an example for using TLS session resumption:
var 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'#
function (tlsSocket) {}
This event is emitted after a new connection has been successfully
handshaked. The argument is an instance of tls.TLSSocket
. It has all the
common stream methods and events.
socket.authorized
is a boolean value which indicates if the
client has verified by one of the supplied certificate authorities for the
server. If socket.authorized
is false, then
socket.authorizationError
is set to describe how authorization
failed. Implied but worth mentioning: depending on the settings of the TLS
server, you unauthorized connections may be accepted.
socket.npnProtocol
is a string containing selected NPN protocol.
socket.servername
is a string containing servername requested with
SNI.
server.addContext(hostname, context)#
Add secure context that will be used if client request's SNI hostname is
matching passed hostname
(wildcards can be used). context
can contain
key
, cert
, ca
and/or any other properties from
tls.createSecureContext()
options
argument.
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])#
Stops the server from accepting new connections. This function is
asynchronous, the server is finally closed when the server emits a 'close'
event. Optionally, you can pass a callback to listen for the 'close'
event.
server.connections#
The number of concurrent connections on the server.
server.getTicketKeys()#
Returns Buffer
instance holding the keys currently used for
encryption/decryption of the TLS Session Tickets
server.listen(port[, hostname][, callback])#
Begin accepting connections on the specified port
and hostname
. If the
hostname
is omitted, the server will accept connections on any IPv6 address
(::
) when IPv6 is available, or any IPv4 address (0.0.0.0
) otherwise. A
port value of zero will assign a random port.
This function is asynchronous. The last parameter callback
will be called
when the server has been bound.
See net.Server
for more information.
server.maxConnections#
Set this property to reject connections when the server's connection count gets high.
server.setTicketKeys(keys)#
Updates the keys for encryption/decryption of the TLS Session Tickets.
NOTE: the buffer should be 48 bytes long. See server ticketKeys
option for
more information oh how it is going to be used.
NOTE: the change is effective only for the future server connections. Existing or currently pending server connections will use previous keys.
Class: tls.TLSSocket#
This is a wrapped version of net.Socket
that does transparent encryption
of written data and all required TLS negotiation.
This instance implements a duplex Stream interfaces. It has all the common stream methods and events.
Methods that return TLS connection meta data (e.g.
tls.TLSSocket.getPeerCertificate()
will only return data while the
connection is open.
new tls.TLSSocket(socket[, options])#
Construct a new TLSSocket object from existing TCP socket.
socket
is an instance of net.Socket
options
is an optional object that might contain following properties:
secureContext
: An optional TLS context object fromtls.createSecureContext()
isServer
: Iftrue
the TLS socket will be instantiated in server-mode. Default:false
server
: An optionalnet.Server
instancerequestCert
: Optional, seetls.createSecurePair()
rejectUnauthorized
: Optional, seetls.createSecurePair()
NPNProtocols
: Optional, seetls.createServer()
SNICallback
: Optional, seetls.createServer()
session
: Optional, aBuffer
instance, containing TLS sessionrequestOCSP
: Optional, iftrue
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
Event: 'OCSPResponse'#
function (response) { }
This event will be emitted if requestOCSP
option was set. response
is a
buffer object, containing server's OCSP response.
Traditionally, the response
is a signed object from the server's CA that
contains information about server's certificate revocation status.
Event: 'secureConnect'#
This event is emitted after a new connection has been successfully handshaked.
The listener will be called no matter if the server's certificate was
authorized or not. It is up to the user to test tlsSocket.authorized
to see if the server certificate was signed by one of the specified CAs.
If tlsSocket.authorized === false
then the error can be found in
tlsSocket.authorizationError
. Also if NPN was used you can check
tlsSocket.npnProtocol
for 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#
A boolean that is true
if the peer certificate was signed by one of the
specified CAs, otherwise false
tlsSocket.authorizationError#
The reason why the peer's certificate has not been verified. This property
becomes available only when tlsSocket.authorized === false
.
tlsSocket.encrypted#
Static boolean value, always true
. May be used to distinguish TLS sockets
from regular ones.
tlsSocket.getCipher()#
Returns an object representing the cipher name and the SSL/TLS protocol version of the current connection.
Example: <name: 'AES256-SHA', version: 'TLSv1/SSLv3'>
See SSL_CIPHER_get_name() and SSL_CIPHER_get_version() in https://www.openssl.org/docs/ssl/ssl.html#DEALING-WITH-CIPHERS for more information.
tlsSocket.getPeerCertificate([ detailed ])#
Returns an object representing the peer's certificate. The returned object has
some properties corresponding to the field of the certificate. If detailed
argument is true
the full chain with issuer
property will be returned,
if false
only the top certificate without issuer
property.
Example:
{ subject:
{ C: 'UK',
ST: 'Acknack Ltd',
L: 'Rhys Jones',
O: 'node.js',
OU: 'Test TLS Certificate',
CN: 'localhost' },
issuerInfo:
{ C: 'UK',
ST: 'Acknack Ltd',
L: 'Rhys Jones',
O: 'node.js',
OU: 'Test TLS Certificate',
CN: 'localhost' },
issuer:
{ ... another certificate ... },
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, it returns null
or an empty
object.
tlsSocket.getSession()#
Return ASN.1 encoded TLS session or undefined
if none was negotiated. Could
be used to speed up handshake establishment when reconnecting to the server.
tlsSocket.getTLSTicket()#
NOTE: Works only with client TLS sockets. Useful only for debugging, for
session reuse provide session
option to tls.connect()
.
Return TLS session ticket or undefined
if none was negotiated.
tlsSocket.localPort#
The numeric representation of the local port.
tlsSocket.localAddress#
The string representation of the local IP address.
tlsSocket.remoteAddress#
The string representation of the remote IP address. For example,
'74.125.127.100'
or '2001:4860:a005::68'
.
tlsSocket.remoteFamily#
The string representation of the remote IP family. 'IPv4'
or 'IPv6'
.
tlsSocket.remotePort#
The numeric representation of the remote port. For example, 443
.
tlsSocket.renegotiate(options, callback)#
Initiate TLS renegotiation process. The options
may contain the following
fields: rejectUnauthorized
, requestCert
(See tls.createServer()
for
details). callback(err)
will be executed with null
as err
,
once the renegotiation is successfully completed.
NOTE: Can be used to request peer's certificate after the secure connection has been established.
ANOTHER NOTE: When running as the server, socket will be destroyed
with an error after handshakeTimeout
timeout.
tlsSocket.setMaxSendFragment(size)#
Set maximum TLS fragment size (default and maximum value is: 16384
, minimum
is: 512
). Returns true
on success, false
otherwise.
Smaller fragment size decreases buffering latency on the client: large 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(options[, callback])#
tls.connect(port[, host][, options][, callback])#
Creates a new client connection to the given port
and host
(old API) or
options.port
and options.host
. (If host
is omitted, it defaults to
localhost
.) options
should be an object which specifies:
host
: Host the client should connect toport
: Port the client should connect tosocket
: Establish secure connection on a given socket rather than creating a new socket. If this option is specified,host
andport
are ignored.path
: Creates unix socket connection to path. If this option is specified,host
andport
are ignored.pfx
: A string orBuffer
containing the private key, certificate and CA certs of the client in PFX or PKCS12 format.key
: A string orBuffer
containing the private key of the client in PEM format. (Could be an array of keys).passphrase
: A string of passphrase for the private key or pfx.cert
: A string orBuffer
containing the certificate key of the client in PEM format. (Could be an array of certs).ca
: A string,Buffer
or array of strings orBuffer
s of trusted certificates in PEM format. If this is omitted several well known "root" CAs will be used, like VeriSign. These are used to authorize connections.ciphers
: A string describing the ciphers to use or exclude, separated by:
. Uses the same default cipher suite astls.createServer()
.rejectUnauthorized
: 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. Default:true
.NPNProtocols
: An array of strings orBuffer
s containing supported NPN protocols.Buffer
s should have following format:0x05hello0x05world
, where first byte is next protocol name's length. (Passing array should usually be much simpler:['hello', 'world']
.)servername
: Servername for SNI (Server Name Indication) TLS extension.checkServerIdentity(servername, cert)
: Provide an override for checking server's hostname against the certificate. Should return an error if verification fails. Returnundefined
if passing.secureProtocol
: The SSL method to use, e.g.SSLv3_method
to force SSL version 3. The possible values depend on your installation of OpenSSL and are defined in the constant SSL_METHODS.session
: ABuffer
instance, containing TLS session.
The callback
parameter will be added as a listener for the
'secureConnect'
event.
tls.connect()
returns a tls.TLSSocket
object.
Here is an example of a client of echo server as described previously:
const tls = require('tls');
const fs = require('fs');
const options = {
// These are necessary only if using the client certificate authentication
key: fs.readFileSync('client-key.pem'),
cert: fs.readFileSync('client-cert.pem'),
// This is necessary only if the server uses the self-signed certificate
ca: [ fs.readFileSync('server-cert.pem') ]
};
var 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')
};
var 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(details)#
Creates a credentials object, with the optional details being a dictionary with keys:
pfx
: A string or buffer holding the PFX or PKCS12 encoded private key, certificate and CA certificateskey
: A string orBuffer
containing the private key of the server in PEM format. To support multiple keys using different algorithms, an array can be provided. It can either be a plain array of keys, or an array of objects in the format{pem: key, passphrase: passphrase}
. (Required)passphrase
: A string of passphrase for the private key or pfxcert
: A string holding the PEM encoded certificateca
: A string,Buffer
or array of strings orBuffer
s of trusted certificates in PEM format. If this is omitted several well known "root" CAs will be used, like VeriSign. These are used to authorize connections.crl
: Either a string or list of strings of PEM encoded CRLs (Certificate Revocation List)ciphers
: A string describing the ciphers to use or exclude. Consult https://www.openssl.org/docs/apps/ciphers.html#CIPHER-LIST-FORMAT for details on the format.honorCipherOrder
: When choosing a cipher, use the server's preferences instead of the client preferences. For further details seetls
module documentation.
If no 'ca' details are 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.createSecurePair([context][, isServer][, requestCert][, rejectUnauthorized][, options])#
Creates a new secure pair object with two streams, one of which reads/writes encrypted data, and one reads/writes cleartext data. Generally the encrypted one is piped to/from an incoming encrypted data stream, and the cleartext one is used as a replacement for the initial encrypted stream.
credentials
: A secure context object from tls.createSecureContext( ... )isServer
: A boolean indicating whether this tls connection should be opened as a server or a client.requestCert
: A boolean indicating whether a server should request a certificate from a connecting client. Only applies to server connections.rejectUnauthorized
: A boolean indicating whether a server should automatically reject clients with invalid certificates. Only applies to servers withrequestCert
enabled.options
: An object with common SSL options. Seetls.TLSSocket
.
tls.createSecurePair()
returns a SecurePair object with cleartext
and
encrypted
stream properties.
NOTE: cleartext
has the same APIs as tls.TLSSocket
tls.createServer(options[, secureConnectionListener])#
Creates a new tls.Server. The connectionListener
argument is
automatically set as a listener for the 'secureConnection'
event. The
options
object has these possibilities:
pfx
: A string orBuffer
containing the private key, certificate and CA certs of the server in PFX or PKCS12 format. (Mutually exclusive with thekey
,cert
andca
options.)key
: A string orBuffer
containing the private key of the server in PEM format. To support multiple keys using different algorithms, an array can be provided. It can either be a plain array of keys, or an array of objects in the format{pem: key, passphrase: passphrase}
. (Required)passphrase
: A string of passphrase for the private key or pfx.cert
: A string orBuffer
containing the certificate key of the server in PEM format. (Could be an array of certs). (Required)ca
: A string,Buffer
or array of strings orBuffer
s of trusted certificates in PEM format. If this is omitted several well known "root" CAs will be used, like VeriSign. These are used to authorize connections.crl
: Either a string or list of strings of PEM encoded CRLs (Certificate Revocation List)ciphers
: A string describing the ciphers to use or exclude, separated by:
. 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
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 compatibiltity.
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) aren't able to complete the handshake with the default configuration. If you absolutely must support these clients, the TLS recommendations may offer a compatible cipher suite. For more details on the format, see the OpenSSL cipher list format documentation.
ecdhCurve
: A string describing a named curve to use for ECDH key agreement or false to disable ECDH.Defaults to
prime256v1
(NIST P-256). 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
: A string orBuffer
containing Diffie Hellman parameters, required for Perfect Forward Secrecy. Useopenssl dhparam
to create it. Its key length should be greater than or equal to 1024 bits, otherwise it throws an error. It is strongly recommended to use 2048 bits or more for stronger security. If omitted or invalid, it is silently discarded and DHE ciphers won't be available.handshakeTimeout
: Abort the connection if the SSL/TLS handshake does not finish in this many milliseconds. The default is 120 seconds.A
'clientError'
is emitted on thetls.Server
object whenever a handshake times out.honorCipherOrder
: When choosing a cipher, use the server's preferences instead of the client preferences. Default:true
.requestCert
: Iftrue
the server will request a certificate from clients that connect and attempt to verify that certificate. Default:false
.rejectUnauthorized
: 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
. Default:false
.NPNProtocols
: An array orBuffer
of possible NPN protocols. (Protocols should be ordered by their priority).SNICallback(servername, cb)
: A function that will be called if client supports SNI TLS extension. Two argument will be passed to it:servername
, andcb
.SNICallback
should invokecb(null, ctx)
, wherectx
is a SecureContext instance. (You can usetls.createSecureContext(...)
to get proper SecureContext). IfSNICallback
wasn't provided the default callback with high-level API will be used (see below).sessionTimeout
: An integer specifying the seconds after which TLS session identifiers and TLS session tickets created by the server are timed out. See SSL_CTX_set_timeout for more details.ticketKeys
: A 48-byteBuffer
instance consisting of 16-byte prefix, 16-byte hmac key, 16-byte AES key. You could use it to accept tls session tickets on multiple instances of tls server.NOTE: Automatically shared between
cluster
module workers.sessionIdContext
: A string containing an opaque identifier for session resumption. IfrequestCert
istrue
, the default is MD5 hash value generated from command-line. (In FIPS mode a truncated SHA1 hash is used instead.) Otherwise, the default is not provided.secureProtocol
: The SSL method to use, e.g.SSLv3_method
to force SSL version 3. The possible values depend on your installation of OpenSSL and are defined in the constant SSL_METHODS.
Here is a simple example 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') ]
};
var 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,
};
var 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');
});
You can test this server by connecting to it with 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.
Example:
var ciphers = tls.getCiphers();
console.log(ciphers); // ['AES128-SHA', 'AES256-SHA', ...]