mirror of https://github.com/moparisthebest/mail
101 lines
2.6 KiB
JavaScript
101 lines
2.6 KiB
JavaScript
/**
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* Javascript implementation of mask generation function MGF1.
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*
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* @author Stefan Siegl
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*
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* Copyright (c) 2012 Stefan Siegl <stesie@brokenpipe.de>
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*/
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(function() {
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/* ########## Begin module implementation ########## */
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function initModule(forge) {
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forge.mgf = forge.mgf || {};
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var mgf1 = forge.mgf.mgf1 = forge.mgf1 = forge.mgf1 || {};
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/**
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* Creates a MGF1 mask generation function object.
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*
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* @return a mask generation function object.
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*/
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mgf1.create = function(md) {
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var mgf = {
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/**
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* Generate mask of specified length.
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*
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* @param {String} seed The seed for mask generation.
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* @param maskLen Number of bytes to generate.
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* @return {String} The generated mask.
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*/
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generate: function(seed, maskLen) {
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/* 2. Let T be the empty octet string. */
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var t = new forge.util.ByteBuffer();
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/* 3. For counter from 0 to ceil(maskLen / hLen), do the following: */
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var len = Math.ceil(maskLen / md.digestLength);
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for(var i = 0; i < len; i++) {
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/* a. Convert counter to an octet string C of length 4 octets */
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var c = new forge.util.ByteBuffer();
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c.putInt32(i);
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/* b. Concatenate the hash of the seed mgfSeed and C to the octet
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* string T: */
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md.start();
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md.update(seed + c.getBytes());
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t.putBuffer(md.digest());
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}
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/* Output the leading maskLen octets of T as the octet string mask. */
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t.truncate(t.length() - maskLen);
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return t.getBytes();
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}
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};
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return mgf;
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};
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} // end module implementation
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/* ########## Begin module wrapper ########## */
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var name = 'mgf1';
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var deps = ['./util'];
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var nodeDefine = null;
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if(typeof define !== 'function') {
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// NodeJS -> AMD
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if(typeof module === 'object' && module.exports) {
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nodeDefine = function(ids, factory) {
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factory(require, module);
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};
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}
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// <script>
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else {
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if(typeof forge === 'undefined') {
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forge = {};
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}
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initModule(forge);
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}
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}
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// AMD
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if(nodeDefine || typeof define === 'function') {
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// define module AMD style
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(nodeDefine || define)(['require', 'module'].concat(deps),
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function(require, module) {
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module.exports = function(forge) {
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var mods = deps.map(function(dep) {
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return require(dep);
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}).concat(initModule);
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// handle circular dependencies
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forge = forge || {};
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forge.defined = forge.defined || {};
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if(forge.defined[name]) {
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return forge[name];
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}
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forge.defined[name] = true;
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for(var i = 0; i < mods.length; ++i) {
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mods[i](forge);
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}
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return forge[name];
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};
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});
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}
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})();
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