nodejs.10+.RSA.js

const path            = require('path');
const fs              = require('fs');
const crypto          = require('crypto');
const logger          = require('mii-logger.js');

const RSA_BITS        = 2048 * 2;
const LOCATION        = __dirname+'/rsa_keys';
const SEC_KEY         = 'sec_key.pem';
const PUB_KEY         = 'pub_key.pem';

module.exports = RSA = class{

  constructor(){

    this.isReady = false;
    this.createNewRSAKeys();

    if( this.isReady )
      console.ok(' #RSA: ready ...');
  }

  decrypt( payload ){
    try{

      if( !this.isReady )
        return {code: 400, msg: 'RSA: is not ready ...'};

      const sec_key = fs.readFileSync( LOCATION+'/'+SEC_KEY,'utf-8' );
      const dec_data = crypto.privateDecrypt( sec_key, Buffer.from(payload, 'hex'));
      return {code: 200, msg: 'OK', data: dec_data.toString('utf-8')};

    }catch(e){
      console.warn(' #RSA: decrypt: '+e.message );
      console.error( e  );
      return {code: 500, msg: e.message};
    }
  }

  encrypt( payload ){
    try{

      if( !this.isReady )
        return {code: 400, msg: 'RSA: is not ready ...'};

      const pub_key = fs.readFileSync( LOCATION+'/'+PUB_KEY, 'utf-8' );
      const enc_data = crypto.publicEncrypt( pub_key, Buffer.from(payload,'utf-8'));
      return {code: 200, msg: 'OK', data: enc_data.toString('hex')};

    }catch(e){
      console.warn(' #RSA: encrypt: '+e.message );
      console.error( e  );
      return {code: 500, msg: e.message};
    }
  }

  createNewRSAKeys(){

    if( console.isFile( LOCATION+'/'+SEC_KEY ) || console.isFile( LOCATION+'/'+PUB_KEY ) ){
      // console.warn(' #RSA: Keys already generated. Aborting ...');
      this.isReady = true;
      return;
    }

    try{

      console.log(' #RSA: Generating new keys');

      const RSAKeys = crypto.generateKeyPairSync('rsa', {
        modulusLength: RSA_BITS,
        publicKeyEncoding: { type: 'spki', format: 'pem' },
        privateKeyEncoding: { type: 'pkcs8', format: 'pem', }
      });

      const sec_key_file = path.join( LOCATION, 'sec_key.pem');
      const pub_ke_filey = path.join( LOCATION, 'pub_key.pem');
      fs.writeFileSync( sec_key_file, RSAKeys.privateKey, 'ascii' );
      fs.writeFileSync( pub_ke_filey, RSAKeys.publicKey, 'ascii' );
      this.isReady = true;
      console.ok(' #RSA: Generating new keys: done ...');

    }catch(e){
      console.error(' #RSA: createNewRSAKeys: '+e.message);
      console.error( e );
    }

  }

}