node.js stream 加解密

var crypto = require('crypto'),    algorithm = 'aes-256-ctr',    password = 'testpassword';var fs = require('fs');function encryptStream(input,output){var encrypt = crypto.createCipher(algorithm, password);var inStream = fs.createReadStream(input);var outputStream = fs.createWriteStream(output);inStream.pipe(encrypt).pipe(outputStream);}function decryptStream(input,output){var decrypt = crypto.createDecipher(algorithm, password);var inStream = fs.createReadStream(input);var outputStream = fs.createWriteStream(output);inStream.pipe(decrypt).pipe(outputStream);}//input pathvar intext = '';//output pathvar outtext= '';encryptStream(intext,outtext);//decryptStream(intext,outtext);