0.2.0 - Mid migration

web/node_modules/hmac-drbg/lib/hmac-drbg.js

@@ -0,0 +1,113 @@
+'use strict';
+
+var hash = require('hash.js');
+var utils = require('minimalistic-crypto-utils');
+var assert = require('minimalistic-assert');
+
+function HmacDRBG(options) {
+  if (!(this instanceof HmacDRBG))
+    return new HmacDRBG(options);
+  this.hash = options.hash;
+  this.predResist = !!options.predResist;
+
+  this.outLen = this.hash.outSize;
+  this.minEntropy = options.minEntropy || this.hash.hmacStrength;
+
+  this._reseed = null;
+  this.reseedInterval = null;
+  this.K = null;
+  this.V = null;
+
+  var entropy = utils.toArray(options.entropy, options.entropyEnc || 'hex');
+  var nonce = utils.toArray(options.nonce, options.nonceEnc || 'hex');
+  var pers = utils.toArray(options.pers, options.persEnc || 'hex');
+  assert(entropy.length >= (this.minEntropy / 8),
+         'Not enough entropy. Minimum is: ' + this.minEntropy + ' bits');
+  this._init(entropy, nonce, pers);
+}
+module.exports = HmacDRBG;
+
+HmacDRBG.prototype._init = function init(entropy, nonce, pers) {
+  var seed = entropy.concat(nonce).concat(pers);
+
+  this.K = new Array(this.outLen / 8);
+  this.V = new Array(this.outLen / 8);
+  for (var i = 0; i < this.V.length; i++) {
+    this.K[i] = 0x00;
+    this.V[i] = 0x01;
+  }
+
+  this._update(seed);
+  this._reseed = 1;
+  this.reseedInterval = 0x1000000000000;  // 2^48
+};
+
+HmacDRBG.prototype._hmac = function hmac() {
+  return new hash.hmac(this.hash, this.K);
+};
+
+HmacDRBG.prototype._update = function update(seed) {
+  var kmac = this._hmac()
+                 .update(this.V)
+                 .update([ 0x00 ]);
+  if (seed)
+    kmac = kmac.update(seed);
+  this.K = kmac.digest();
+  this.V = this._hmac().update(this.V).digest();
+  if (!seed)
+    return;
+
+  this.K = this._hmac()
+               .update(this.V)
+               .update([ 0x01 ])
+               .update(seed)
+               .digest();
+  this.V = this._hmac().update(this.V).digest();
+};
+
+HmacDRBG.prototype.reseed = function reseed(entropy, entropyEnc, add, addEnc) {
+  // Optional entropy enc
+  if (typeof entropyEnc !== 'string') {
+    addEnc = add;
+    add = entropyEnc;
+    entropyEnc = null;
+  }
+
+  entropy = utils.toArray(entropy, entropyEnc);
+  add = utils.toArray(add, addEnc);
+
+  assert(entropy.length >= (this.minEntropy / 8),
+         'Not enough entropy. Minimum is: ' + this.minEntropy + ' bits');
+
+  this._update(entropy.concat(add || []));
+  this._reseed = 1;
+};
+
+HmacDRBG.prototype.generate = function generate(len, enc, add, addEnc) {
+  if (this._reseed > this.reseedInterval)
+    throw new Error('Reseed is required');
+
+  // Optional encoding
+  if (typeof enc !== 'string') {
+    addEnc = add;
+    add = enc;
+    enc = null;
+  }
+
+  // Optional additional data
+  if (add) {
+    add = utils.toArray(add, addEnc || 'hex');
+    this._update(add);
+  }
+
+  var temp = [];
+  while (temp.length < len) {
+    this.V = this._hmac().update(this.V).digest();
+    temp = temp.concat(this.V);
+  }
+
+  var res = temp.slice(0, len);
+  this._update(add);
+  this._reseed++;
+  return utils.encode(res, enc);
+};