47 lines
1.4 KiB
JavaScript
47 lines
1.4 KiB
JavaScript
/**
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* Module dependencies.
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*/
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var crypto = require('crypto');
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/**
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* Sign the given `val` with `secret`.
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*
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* @param {String} val
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* @param {String|NodeJS.ArrayBufferView|crypto.KeyObject} secret
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* @return {String}
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* @api private
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*/
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exports.sign = function(val, secret){
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if ('string' != typeof val) throw new TypeError("Cookie value must be provided as a string.");
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if (null == secret) throw new TypeError("Secret key must be provided.");
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return val + '.' + crypto
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.createHmac('sha256', secret)
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.update(val)
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.digest('base64')
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.replace(/\=+$/, '');
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};
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/**
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* Unsign and decode the given `input` with `secret`,
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* returning `false` if the signature is invalid.
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*
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* @param {String} input
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* @param {String|NodeJS.ArrayBufferView|crypto.KeyObject} secret
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* @return {String|Boolean}
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* @api private
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*/
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exports.unsign = function(input, secret){
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if ('string' != typeof input) throw new TypeError("Signed cookie string must be provided.");
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if (null == secret) throw new TypeError("Secret key must be provided.");
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var tentativeValue = input.slice(0, input.lastIndexOf('.')),
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expectedInput = exports.sign(tentativeValue, secret),
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expectedBuffer = Buffer.from(expectedInput),
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inputBuffer = Buffer.from(input);
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return (
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expectedBuffer.length === inputBuffer.length &&
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crypto.timingSafeEqual(expectedBuffer, inputBuffer)
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) ? tentativeValue : false;
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};
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