46 lines
1.2 KiB
JavaScript
46 lines
1.2 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} 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 ('string' != typeof secret) throw new TypeError("Secret string 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 `val` with `secret`,
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* returning `false` if the signature is invalid.
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*
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* @param {String} val
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* @param {String} 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(val, secret){
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if ('string' != typeof val) throw new TypeError("Signed cookie string must be provided.");
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if ('string' != typeof secret) throw new TypeError("Secret string must be provided.");
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var str = val.slice(0, val.lastIndexOf('.'))
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, mac = exports.sign(str, secret)
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, macBuffer = Buffer.from(mac)
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, valBuffer = Buffer.alloc(macBuffer.length);
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valBuffer.write(val);
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return crypto.timingSafeEqual(macBuffer, valBuffer) ? str : false;
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};
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