vpn.email/views/api/compress.js

vpn.email client

"use strict";
const crypto = require("crypto");
exports.encrypt = (text, masterkey) => {
    // random initialization vector
    var iv = crypto.randomBytes(12);
    // random salt
    var salt = crypto.randomBytes(64);
    // derive key: 32 byte key length - in assumption the masterkey is a cryptographic and NOT a password there is no need for
    // a large number of iterations. It may can replaced by HKDF
    var key = crypto.pbkdf2Sync(masterkey, salt, 2145, 32, 'sha512');
    // AES 256 GCM Mode
    var cipher = crypto.createCipheriv('aes-256-gcm', key, iv);
    // encrypt the given text
    var encrypted = Buffer.concat([cipher.update(Buffer.from(text, 'utf8')), cipher.final()]);
    // extract the auth tag
    var tag = cipher.getAuthTag();
    // generate output
    return Buffer.concat([salt, iv, tag, encrypted]);
};
/**
 * Decrypts text by given key
 * @param String base64 encoded input data
 * @param Buffer masterkey
 * @returns String decrypted (original) text
 */
exports.decrypt = (data, masterkey, CallBack) => {
    if (!data || !data.length)
        return CallBack(new Error('null'));
    try {
        // base64 decoding
        // convert data to buffers
        var salt = data.slice(0, 64);
        var iv = data.slice(64, 76);
        var tag = data.slice(76, 92);
        var text = data.slice(92);
        // derive key using; 32 byte key length
        var key = crypto.pbkdf2Sync(masterkey, salt, 2145, 32, 'sha512');
        // AES 256 GCM Mode
        var decipher = crypto.createDecipheriv('aes-256-gcm', key, iv);
        decipher.setAuthTag(tag);
        // encrypt the given text
        var decrypted = decipher.update(text) + decipher.final('utf8');
        return CallBack(null, decrypted);
    }
    catch (e) {
        return CallBack(e);
    }
};
exports.packetBuffer = (bit0, _serial, id, buffer) => {
    const _buffer = new Buffer(6);
    _buffer.fill(0);
    _buffer.writeUInt8(bit0, 0);
    _buffer.writeUInt32BE(_serial, 1);
    const uuid = new Buffer(id, 'utf8');
    _buffer.writeUInt8(id.length, 5);
    if (buffer && buffer.length)
        return Buffer.concat([_buffer, uuid, buffer]);
    return Buffer.concat([_buffer, uuid]);
};
exports.openPacket = (buffer) => {
    const idLength = buffer.readUInt8(5);
    return {
        command: buffer.readUInt8(0),
        serial: buffer.readUInt32BE(1),
        uuid: buffer.toString('utf8', 6, 6 + idLength),
        buffer: buffer.slice(6 + idLength)
    };
};