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This module will create a signature container object according to the specifications in the SDMP protocol.

Three important things to note:

  1. This module requires you to pass in a node-rsa object. This means that you will need to specify the signing schema in the options when you create it. (See below for more details.)
  2. Although the specs require the signature payload to be a valid SDMP container. This module does not validate the data in any way prior to signing.
  3. You must pass in a key fingerprint and private key to generate the signature. However, this module does not validate the key fingerprint to the private key.


This module is made to use npm. Install the normal npm way:

npm install sdmp-create-signature

use it

Pass in the payload to be signed as a buffer, and an array of objects containing node-rsa private key objects of 2048 bits, and the key fingerprint (an SDMP specified string, which is the hash of the identity public key):

var create = require('sdmp-create-encrypted')
var listOfNodeRsaPrivateKeys = [{
	fingerprint: fingerprintOfThisKey,
	key: myNodeRsaPrivateKey
var container = create(payload, listOfNodeRsaPrivateKeys)
// container is a valid identity container object, e,g,
console.log(container.signature.payload) // base64url encoded string


The node-rsa module is an RSA crypto module implemented in pure JavaScript. This gives maximum portability, but generating keys in JS is not as fast as system-native libraries.

You can create a node-rsa private key object any of the following ways:

new key

var NodeRSA = require('node-rsa')
var nodeRsaPrivateKey = new NodeRSA({ b: 2048 })

from PEM encoded string

var NodeRSA = require('node-rsa')
var pemKey = '-----BEGIN RSA PRIVATE KEY-----\n...'
var nodeRsaPrivateKey = new NodeRSA(pemKey)

node-rsa signing schema

Note that the node-rsa module does not use the correct signing schema by default. You will need to set the signing schema manually in the following manner:

	signingScheme: {
		hash: 'sha512'

payload, listOfKeyObjects

listOfKeyObjects[].fingerprint listOfKeyObjects[].key

api create(payload, listOfKeyObjects)

In all cases, calling the function will either return a new container object, or throw an exception.

payload (Buffer, required)

The parameter payload must be a buffer.

The SDMP specs require the payload to be a valid container object, so you will likely do something like:

var container = { /* a valid container object */ }
var payload = new Buffer(JSON.stringify(container), 'utf8')

Note: The payload is not verified to be a valid container object.

listOfKeyObjects (array, required)

An array of objects containing a key and fingerprint.

listOfKeyObjects[].key (object, required)

A node-rsa equivalent object, containing a public key of 2048 bytes.

listOfKeyObjects[].fingerprint (string, required)

The key fingerprint of the key used to generate the signature.

Note: The fingerprint is not verified against the key.


Published and released under the Very Open License.