data-provider-temporary
Version:
Library that helps with server-to-client synchronization of data
113 lines (104 loc) • 3.07 kB
JavaScript
/**
* Javascript implementation of mask generation function MGF1.
*
* @author Stefan Siegl
* @author Dave Longley
*
* Copyright (c) 2012 Stefan Siegl <stesie@brokenpipe.de>
* Copyright (c) 2014 Digital Bazaar, Inc.
*/
(function() {
/* ########## Begin module implementation ########## */
function initModule(forge) {
forge.mgf = forge.mgf || {};
var mgf1 = forge.mgf.mgf1 = forge.mgf1 = forge.mgf1 || {};
/**
* Creates a MGF1 mask generation function object.
*
* @param md the message digest API to use (eg: forge.md.sha1.create()).
*
* @return a mask generation function object.
*/
mgf1.create = function(md) {
var mgf = {
/**
* Generate mask of specified length.
*
* @param {String} seed The seed for mask generation.
* @param maskLen Number of bytes to generate.
* @return {String} The generated mask.
*/
generate: function(seed, maskLen) {
/* 2. Let T be the empty octet string. */
var t = new forge.util.ByteBuffer();
/* 3. For counter from 0 to ceil(maskLen / hLen), do the following: */
var len = Math.ceil(maskLen / md.digestLength);
for(var i = 0; i < len; i++) {
/* a. Convert counter to an octet string C of length 4 octets */
var c = new forge.util.ByteBuffer();
c.putInt32(i);
/* b. Concatenate the hash of the seed mgfSeed and C to the octet
* string T: */
md.start();
md.update(seed + c.getBytes());
t.putBuffer(md.digest());
}
/* Output the leading maskLen octets of T as the octet string mask. */
t.truncate(t.length() - maskLen);
return t.getBytes();
}
};
return mgf;
};
} // end module implementation
/* ########## Begin module wrapper ########## */
var name = 'mgf1';
if(typeof define !== 'function') {
// NodeJS -> AMD
if(typeof module === 'object' && module.exports) {
var nodeJS = true;
define = function(ids, factory) {
factory(require, module);
};
} else {
// <script>
if(typeof forge === 'undefined') {
forge = {};
}
return initModule(forge);
}
}
// AMD
var deps;
var defineFunc = function(require, module) {
module.exports = function(forge) {
var mods = deps.map(function(dep) {
return require(dep);
}).concat(initModule);
// handle circular dependencies
forge = forge || {};
forge.defined = forge.defined || {};
if(forge.defined[name]) {
return forge[name];
}
forge.defined[name] = true;
for(var i = 0; i < mods.length; ++i) {
mods[i](forge);
}
return forge[name];
};
};
var tmpDefine = define;
define = function(ids, factory) {
deps = (typeof ids === 'string') ? factory.slice(2) : ids.slice(2);
if(nodeJS) {
delete define;
return tmpDefine.apply(null, Array.prototype.slice.call(arguments, 0));
}
define = tmpDefine;
return define.apply(null, Array.prototype.slice.call(arguments, 0));
};
define(['require', 'module', './util'], function() {
defineFunc.apply(null, Array.prototype.slice.call(arguments, 0));
});
})();