/*!
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* csrf
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* Copyright(c) 2014 Jonathan Ong
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* Copyright(c) 2015 Douglas Christopher Wilson
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* MIT Licensed
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*/
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'use strict'
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/**
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* Module dependencies.
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* @private
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*/
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var rndm = require('rndm')
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var uid = require('uid-safe')
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var compare = require('tsscmp')
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var crypto = require('crypto')
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/**
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* Module variables.
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* @private
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*/
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var EQUAL_GLOBAL_REGEXP = /=/g
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var PLUS_GLOBAL_REGEXP = /\+/g
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var SLASH_GLOBAL_REGEXP = /\//g
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/**
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* Module exports.
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* @public
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*/
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module.exports = Tokens
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/**
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* Token generation/verification class.
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*
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* @param {object} [options]
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* @param {number} [options.saltLength=8] The string length of the salt
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* @param {number} [options.secretLength=18] The byte length of the secret key
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* @public
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*/
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function Tokens (options) {
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if (!(this instanceof Tokens)) {
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return new Tokens(options)
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}
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var opts = options || {}
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var saltLength = opts.saltLength !== undefined
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? opts.saltLength
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: 8
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if (typeof saltLength !== 'number' || !isFinite(saltLength) || saltLength < 1) {
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throw new TypeError('option saltLength must be finite number > 1')
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}
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var secretLength = opts.secretLength !== undefined
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? opts.secretLength
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: 18
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if (typeof secretLength !== 'number' || !isFinite(secretLength) || secretLength < 1) {
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throw new TypeError('option secretLength must be finite number > 1')
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}
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this.saltLength = saltLength
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this.secretLength = secretLength
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}
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/**
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* Create a new CSRF token.
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*
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* @param {string} secret The secret for the token.
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* @public
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*/
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Tokens.prototype.create = function create (secret) {
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if (!secret || typeof secret !== 'string') {
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throw new TypeError('argument secret is required')
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}
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return this._tokenize(secret, rndm(this.saltLength))
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}
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/**
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* Create a new secret key.
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*
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* @param {function} [callback]
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* @public
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*/
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Tokens.prototype.secret = function secret (callback) {
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return uid(this.secretLength, callback)
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}
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/**
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* Create a new secret key synchronously.
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* @public
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*/
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Tokens.prototype.secretSync = function secretSync () {
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return uid.sync(this.secretLength)
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}
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/**
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* Tokenize a secret and salt.
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* @private
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*/
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Tokens.prototype._tokenize = function tokenize (secret, salt) {
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return salt + '-' + hash(salt + '-' + secret)
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}
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/**
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* Verify if a given token is valid for a given secret.
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*
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* @param {string} secret
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* @param {string} token
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* @public
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*/
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Tokens.prototype.verify = function verify (secret, token) {
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if (!secret || typeof secret !== 'string') {
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return false
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}
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if (!token || typeof token !== 'string') {
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return false
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}
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var index = token.indexOf('-')
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if (index === -1) {
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return false
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}
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var salt = token.substr(0, index)
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var expected = this._tokenize(secret, salt)
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return compare(token, expected)
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}
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/**
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* Hash a string with SHA1, returning url-safe base64
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* @param {string} str
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* @private
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*/
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function hash (str) {
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return crypto
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.createHash('sha1')
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.update(str, 'ascii')
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.digest('base64')
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.replace(PLUS_GLOBAL_REGEXP, '-')
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.replace(SLASH_GLOBAL_REGEXP, '_')
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.replace(EQUAL_GLOBAL_REGEXP, '')
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}
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