post-e-voting/source-code/scytl-cryptolib/cryptolib-js-pbkdf/README.md

PBKDF Module

This module defines the password based key derivation function (PBKDF) API for Scytl's JavaScript cryptographic library. The starting point for using this module is the instantiation of a PBKDF service.

How to view, build and test the source code of this module

Start by git cloning the project comm/scytl-cryptolib from Stash.

The source code of this module will be found in the directory scytl-cryptolib/cryptolib-js-pbkdf/lib.

To build this module, change to the directory scytl-cryptolib/cryptolib-js-pbkdf and do the following:

npm install
--or--
mvn clean install -DskipTests

The unit tests of this module will be found in the directory scytl-cryptolib/cryptolib-js-pbkdf/spec. To run the tests, change to the directory scytl-cryptolib/cryptolib-js-pbkdf and do the following:

karma test
--or--
mvn test

To only run a chosen test suite, add an f in front of the corresponding describe statement. For example:

fdescribe('create a PBKDF deriver that should be able to', function()
...

To only run a chosen test, add an f in front of the corresponding it statement. For example:

fit('derive a key of the expected length, when using the default cryptographic policy.',
...

Note: To build and test the entire scytl-cryptolib project, change to the directory scytl-cryptolib and do the following:

mvn clean install

How to generate the JSDoc for this module

To generate the JSDoc for this module, change to the directory scytl-cryptolib/cryptolib-js-pbkdf, build the module (if not already done) and do the following:

node_modules/.bin/jsdoc lib

This will generate a file called out. Double click on the file out/index.html to view the JSDoc.

How to npm install this module

To npm install this module in standalone mode, do the following:

npm install --registry https://nexus.scytl.net/content/groups/public-npm/ scytl-pbkdf

To npm install this module as a dependency of your own module, do the following:

1. Add the following lines to the dependencies section of your module's package.json file.

   "scytl-codec": "^2.1.0",
   "scytl-cryptopolicy": "^2.1.0",
   "scytl-pbkdf": "^2.1.0",
   

2. Make sure that the .npmrc file of your module contains the following line.

   registry=https://nexus.scytl.net/content/groups/public-npm/
   

3. Install all dependencies.

   npm install
   

   How to instantiate a PBKDF service

The following example shows the default way to create a new instance of a PBKDF service.

var pbkdf = require('scytl-pbkdf');

var pbkdfService = pbkdf.newService();

The PBKDF service accepts an optional input argument that can be used to override the default cryptographic policy used for PBKDF operations. For example, to set the length of the derived key to 16 bytes, one could do the following:

var cryptoPolicy = require('scytl-cryptopolicy');
var pbkdf = require('scytl-pbkdf');

var myPolicy = cryptoPolicy.newInstance();

myPolicy.primitives.keyDerivation.pbkdf.keyLengthBytes =
  cryptoPolicy.options.primitives.keyDerivation.pbkdf.keyLengthBytes.KL_16;

var pbkdfService = pbkdf.newService({policy: myPolicy});

Note It is desirable to use the property CryptographicPolicy.options to override the default policy, as shown above, in order to ensure that one is using an option that is allowed by the cryptographic policy.

How to instantiate a PBKDF deriver

The following example shows how to create a new PBKDF deriver object.

var deriver = pbkdfService.newDeriver();

How to derive a PBKDF key

The following examples show how to derive a PBKDF key from a given password and salt. The password is provided as a string and the salt can be provided as a string or as a byte array, wrapped in a Uint8Array object). The output will be in the form of a byte array, wrapped in a Uint8Array object.

var codec = require('scytl-codec');
...

var derivedKey = deriver.derive('myPassword', 'mySalt');
var derivedKey = deriver.derive('myPassword', new Uint8Array([0x01, 0x02, 0x03]));