pem

Create private keys and certificates with node.js

Installation

Install with npm

npm install pem

or use yarn

yarn add pem

:warning: Please make sure you have openssl or libressl already installed on your system/container, without
them pem will not work.

TypeScript

TypeScript declaration files are bundled with the package via types/pem.d.ts. The public API, including the legacy promisified helpers and the CA utility, now has precise typings.

Run yarn test:types to execute the lightweight tsd assertions that guard the definitions.

Examples

Here are some examples for creating an SSL key/cert on the fly, and running an HTTPS server on port 443. 443 is the
standard HTTPS port, but requires root permissions on most systems. To get around this, you could use a higher port
number, like 4300, and use https://localhost:4300 to access your server.

Promise support: Every asynchronous function in pem still accepts a Node-style callback and now returns a
Promise when no callback is provided. The legacy pem.promisified helper is deprecated; use the primary exports
directly for both callback and promise flows.

Basic https

javascriptCopy
var https = require('https')
var pem = require('pem')

pem.createCertificate({ days: 1, selfSigned: true }, function (err, keys) {
  if (err) {
    throw err
  }
  https.createServer({ key: keys.clientKey, cert: keys.certificate }, function (req, res) {
    res.end('o hai!')
  }).listen(443)
})

Express

javascriptCopy
var https = require('https')
var pem = require('pem')
var express = require('express')

pem.createCertificate({ days: 1, selfSigned: true }, function (err, keys) {
  if (err) {
    throw err
  }
  var app = express()

  app.get('/', function (req, res) {
    res.send('o hai!')
  })

  https.createServer({ key: keys.clientKey, cert: keys.certificate }, app).listen(443)
})

Basic https with async/await

javascriptCopy
const https = require('https')
const pem = require('pem')

async function main() {
  const keys = await pem.createCertificate({ days: 1, selfSigned: true })

  const server = https.createServer({ key: keys.clientKey, cert: keys.certificate }, (req, res) => {
    res.end('o hai!')
  })

  server.listen(443)
}

main().catch((err) => {
  console.error(err)
  process.exit(1)
})

API

Please have a look into the API documentation.

All asynchronous functions document below support both callback and promise styles. Invoke them without a callback to
receive a Promise that resolves to the same value that would be passed to the callback.

we had to clean up a bit

<!-- ### Create a dhparam key Use `createDhparam` for creating dhparam keys pem.createDhparam(keyBitsize, callback) Where * **keyBitsize** is an optional size of the key, defaults to 512 (bit) * **callback** is a callback function with an error object and `{dhparam}` ### Create a ecparam key Use `createEcparam` for creating ecparam keys pem.createEcparam(keyName, callback) Where * **keyName** is an optional name of the key curves name, defaults to secp256k1 * **callback** is a callback function with an error object and `{ecparam}` ### Create a private key Use `createPrivateKey` for creating private keys pem.createPrivateKey(keyBitsize, [options,] callback) Where * **keyBitsize** is an optional size of the key, defaults to 2048 (bit) * **options** is an optional object of the cipher and password (both required for encryption), defaults {cipher:'',password:''} (ciphers:["aes128", "aes192", "aes256", "camellia128", "camellia192", "camellia256", "des", "des3", "idea"]) * **callback** is a callback function with an error object and `{key}` ### Create a Certificate Signing Request Use `createCSR` for creating certificate signing requests pem.createCSR(options, callback) Where * **options** is an optional options object * **callback** is a callback function with an error object and `{csr, clientKey}` Possible options are the following * **clientKey** is an optional client key to use * **clientKeyPassword** the optional password for `clientKey` * **keyBitsize** - if `clientKey` is undefined, bit size to use for generating a new key (defaults to 2048) * **hash** is a hash function to use (either `md5`, `sha1` or `sha256`, defaults to `sha256`) * **country** is a CSR country field * **state** is a CSR state field * **locality** is a CSR locality field * **organization** is a CSR organization field * **organizationUnit** is a CSR organizational unit field * **commonName** is a CSR common name field (defaults to `localhost`) * **altNames** is a list (`Array`) of subjectAltNames in the subjectAltName field (optional) * **emailAddress** is a CSR email address field * **csrConfigFile** is a CSR config file ### Create a certificate Use `createCertificate` for creating private keys pem.createCertificate(options, callback) Where * **options** is an optional options object * **callback** is a callback function with an error object and `{certificate, csr, clientKey, serviceKey}` Possible options include all the options for `createCSR` - in case `csr` parameter is not defined and a new CSR needs to be generated. In addition, possible options are the following * **serviceKey** is a private key for signing the certificate, if not defined a new one is generated * **serviceKeyPassword** Password of the service key * **serviceCertificate** is the optional certificate for the `serviceKey` * **serial** is the unique serial number for the signed certificate, required if `serviceCertificate` is defined * **selfSigned** - if set to true and `serviceKey` is not defined, use `clientKey` for signing * **csr** is a CSR for the certificate, if not defined a new one is generated * **days** is the certificate expire time in days * **extFile** extension config file - **without** `-extensions v3_req` * **config** extension config file - **with** `-extensions v3_req` ### Export a public key Use `getPublicKey` for exporting a public key from a private key, CSR or certificate pem.getPublicKey(certificate, callback) Where * **certificate** is a PEM encoded private key, CSR or certificate * **callback** is a callback function with an error object and `{publicKey}` ### Read certificate info Use `readCertificateInfo` for reading subject data from a certificate or a CSR pem.readCertificateInfo(certificate, callback) Where * **certificate** is a PEM encoded CSR or a certificate * **callback** is a callback function with an error object and `{serial, country, state, locality, organization, organizationUnit, commonName, emailAddress, validity{start, end}, san{dns, ip, email}?, issuer{country, state, locality, organization, organizationUnit}, signatureAlgorithm, publicKeyAlgorithm, publicKeySize }` ? *san* is only present if the CSR or certificate has SAN entries. *signatureAlgorithm, publicKeyAlgorithm and publicKeySize* only available if supportet and can parsed form openssl output ### Get fingerprint Use `getFingerprint` to get the default SHA1 fingerprint for a certificate pem.getFingerprint(certificate, [hash], callback) Where * **certificate** is a PEM encoded certificate * **hash** is a hash function to use (either `md5`, `sha1` or `sha256`, defaults to `sha1`) * **callback** is a callback function with an error object and `{fingerprint}` ### Get modulus Use `getModulus` to get the modulus for a certificate, a CSR or a private key. Modulus can be useful to check that a Private Key Matches a Certificate pem.getModulus(certificate, [password], [hash], callback) Where * **certificate** is a PEM encoded certificate, CSR or private key * **password** is an optional passphrase for passpharse protected certificates * **hash** is an optional hash function to use (up to now `md5` supported) (default: none) * **callback** is a callback function with an error object and `{modulus}` ### Get DH parameter information Use `getDhparamInfo` to get the size and prime of DH parameters. pem.getDhparamInfo(dhparam, callback) Where * **dhparam** is a PEM encoded DH parameters string * **callback** is a callback function with an error object and `{size, prime}` ### Export to a PKCS12 keystore Use `createPkcs12` to export a certificate, the private key and optionally any signing or intermediate CA certificates to a PKCS12 keystore. pem.createPkcs12(clientKey, certificate, p12Password, [options], callback) Where * **clientKey** is a PEM encoded private key * **certificate** is a PEM encoded certificate * **p12Password** is the password of the exported keystore * **options** is an optional options object with `cipher`, (one of "aes128", "aes192", "aes256", "camellia128", "camellia192", "camellia256", "des", "des3" or "idea"), `clientKeyPassword` and `certFiles` (an array of additional certificates to include - e.g. CA certificates) * **callback** is a callback function with an error object and `{pkcs12}` (binary) ### Read a PKCS12 keystore Use `readPkcs12` to read a certificate, private key and CA certificates from a PKCS12 keystore. pem.readPkcs12(bufferOrPath, [options], callback) Where * **bufferOrPath** is a PKCS12 keystore as a [Buffer](https://nodejs.org/api/buffer.html) or the path to a file * **options** is an optional options object with `clientKeyPassword` which will be used to encrypt the stored key and `p12Password` which will be used to open the keystore * **callback** is a callback function with an error object and `{key: String, cert: String, ca: Array}` ### Check a PKCS12 keystore Use `checkPkcs12` to check a PKCS12 keystore. pem.checkPkcs12(bufferOrPath, [passphrase], callback) Where * **bufferOrPath** is a PKCS12 keystore as a [Buffer](https://nodejs.org/api/buffer.html) or the path to a file * **passphrase** is an optional passphrase which will be used to open the keystore * **callback** is a callback function with an error object and a boolean as arguments ### Verify a certificate signing chain Use `verifySigningChain` to assert that a given certificate has a valid signing chain. pem.verifySigningChain(certificate, ca, callback) Where * **certificate** is a PEM encoded certificate string * **ca** is a PEM encoded CA certificate string or an array of certificate strings * **callback** is a callback function with an error object and a boolean as arguments ### Check a certificate file Use `checkCertificate` to check / verify consistency of a certificate. pem.checkCertificate(certificate, callback) Where * **certificate** is a PEM encoded certificate string * **callback** is a callback function with an error object and a boolean as arguments -->

Issue certificates with an existing Certificate Authority

Use the CA helper when you already have a certificate authority key pair and want to issue new certificates without rebuilding the PKI state on your own.

javascriptCopy
const fs = require('fs')
const pem = require('pem')

async function main () {
  const ca = new pem.CA({
    key: fs.readFileSync('intermediate-ca-key.pem'),
    certificate: fs.readFileSync('intermediate-ca-cert.pem'),
    chain: [fs.readFileSync('root-ca-cert.pem')]
  })

  const certificate = await ca.issueCertificate({
    commonName: 'service.internal',
    altNames: ['service.internal', '10.0.0.5']
  })

  console.log(certificate.certificate)
}

main().catch(console.error)

Where

• key is a PEM encoded private key for your certificate authority (required)
• certificate is the PEM encoded certificate matching key (required)
• chain is an optional array of PEM encoded certificates that should accompany issued certificates (for example a root certificate)
• keyPassword/password is an optional passphrase used to decrypt an encrypted private key
• defaultDays sets a default validity window (in days) that is applied when no custom dates are provided (defaults to 7)

issueCertificate accepts the same options that createCertificate does for CSR generation (for example commonName, altNames, or a custom config). When no csr is supplied a fresh CSR and key pair are created automatically and included in the response.

By default issued certificates are valid starting "now" and expire after defaultDays. You can override this by supplying startDate, endDate, or days. Dates can be JavaScript Date objects, timestamps, ISO strings, or ASN.1 date strings (e.g. 20240101000000Z).

The returned object contains the issued certificate, the CSR that was used, any generated private key, the CA certificate and chain, the serial number used for issuance, and the resolved validity window.

Custom extensions config file

You can specify custom OpenSSL extensions using the config or extFile options for createCertificate (or using csrConfigFile with createCSR).

extFile and csrConfigFile should be paths to the extension files. While config will generate a temporary file from the supplied file contents.

If you specify config then the v3_req section of your config file will be used.

The following would be an example of a Certificate Authority extensions file:

[req]
req_extensions = v3_req
distinguished_name = req_distinguished_name

[req_distinguished_name]
commonName = Common Name
commonName_max = 64

[v3_req]
basicConstraints = critical,CA:TRUE

While the following would specify subjectAltNames in the resulting certificate:

[req]
req_extensions = v3_req

[ v3_req ]
basicConstraints = CA:FALSE
keyUsage = nonRepudiation, digitalSignature, keyEncipherment
subjectAltName = @alt_names

[alt_names]
DNS.1 = host1.example.com
DNS.2 = host2.example.com
DNS.3 = host3.example.com

Note that createCertificate and createCSR supports the altNames option which would be easier to use in most cases.

:warning: Warning: If you specify altNames the custom extensions file will not be passed to OpenSSL.

Setting openssl location

In some systems the openssl executable might not be available by the default name or it is not included in $PATH. In this case you can define the location of the executable yourself as a one time action after you have loaded the pem module:

javascriptCopy
var pem = require('pem')
pem.config({
  pathOpenSSL: '/usr/local/bin/openssl'
})
// do something with the pem module

:warning: CSR/Certificates with special chars

For more details, search in test/pem.spec.js: Create CSR with specialchars config file

If you use special chars like:

-!$%^&*()_+|~=`{}[]:/;<>?,.@#

You should know that the result mey have escaped characters when you read it in your application.
Will try to fix this in the future, but not sure.

Special thanks to

• Andris Reinman (@andris9) - Initiator of pem

License

MIT