source: trip-planner-front/node_modules/node-forge/lib/mgf1.js@ 6fe77af

Last change on this file since 6fe77af was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

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1/**
2 * Javascript implementation of mask generation function MGF1.
3 *
4 * @author Stefan Siegl
5 * @author Dave Longley
6 *
7 * Copyright (c) 2012 Stefan Siegl <stesie@brokenpipe.de>
8 * Copyright (c) 2014 Digital Bazaar, Inc.
9 */
10var forge = require('./forge');
11require('./util');
12
13forge.mgf = forge.mgf || {};
14var mgf1 = module.exports = forge.mgf.mgf1 = forge.mgf1 = forge.mgf1 || {};
15
16/**
17 * Creates a MGF1 mask generation function object.
18 *
19 * @param md the message digest API to use (eg: forge.md.sha1.create()).
20 *
21 * @return a mask generation function object.
22 */
23mgf1.create = function(md) {
24 var mgf = {
25 /**
26 * Generate mask of specified length.
27 *
28 * @param {String} seed The seed for mask generation.
29 * @param maskLen Number of bytes to generate.
30 * @return {String} The generated mask.
31 */
32 generate: function(seed, maskLen) {
33 /* 2. Let T be the empty octet string. */
34 var t = new forge.util.ByteBuffer();
35
36 /* 3. For counter from 0 to ceil(maskLen / hLen), do the following: */
37 var len = Math.ceil(maskLen / md.digestLength);
38 for(var i = 0; i < len; i++) {
39 /* a. Convert counter to an octet string C of length 4 octets */
40 var c = new forge.util.ByteBuffer();
41 c.putInt32(i);
42
43 /* b. Concatenate the hash of the seed mgfSeed and C to the octet
44 * string T: */
45 md.start();
46 md.update(seed + c.getBytes());
47 t.putBuffer(md.digest());
48 }
49
50 /* Output the leading maskLen octets of T as the octet string mask. */
51 t.truncate(t.length() - maskLen);
52 return t.getBytes();
53 }
54 };
55
56 return mgf;
57};
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