tra-analysis/website/functions/node_modules/buffer-equal-constant-time/index.js

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2019-01-06 19:14:45 +00:00
/*jshint node:true */
'use strict';
var Buffer = require('buffer').Buffer; // browserify
var SlowBuffer = require('buffer').SlowBuffer;
module.exports = bufferEq;
function bufferEq(a, b) {
// shortcutting on type is necessary for correctness
if (!Buffer.isBuffer(a) || !Buffer.isBuffer(b)) {
return false;
}
// buffer sizes should be well-known information, so despite this
// shortcutting, it doesn't leak any information about the *contents* of the
// buffers.
if (a.length !== b.length) {
return false;
}
var c = 0;
for (var i = 0; i < a.length; i++) {
/*jshint bitwise:false */
c |= a[i] ^ b[i]; // XOR
}
return c === 0;
}
bufferEq.install = function() {
Buffer.prototype.equal = SlowBuffer.prototype.equal = function equal(that) {
return bufferEq(this, that);
};
};
var origBufEqual = Buffer.prototype.equal;
var origSlowBufEqual = SlowBuffer.prototype.equal;
bufferEq.restore = function() {
Buffer.prototype.equal = origBufEqual;
SlowBuffer.prototype.equal = origSlowBufEqual;
};