index.js

var program = require('commander'),
    request = require('request'),
    fs = require('fs'),
    ursa = require('ursa');

program.on('--help', function() {
  console.log('  Alternative to https://gist.github.com/fbb99b638e9da27fe24d (generate secure environment variables)');
  console.log('  Example:');
  console.log('');
  console.log('    $ node index -r github-user/user-repo -v SECURE=value');
  console.log('    $ secure: "<travis-ci base64>"');
  console.log('');
});

program
  .version('0.0.1')
  .option('-r, --repository <string>', 'github username/repo')
  .option('-v, --variable <string>', 'variable to protect')
  .parse(process.argv);

program.prompt('Github username: ', function(username) {
  program.password('Password: ', '*', function(password) {
    process.stdin.destroy();

    githubAuthorization(username, password, function(err, token) {
      if (err) {
        console.log(err);
        process.exit(1);
      }

      console.log('Getting travis-ci github auth');
      travisGithubAuth(token, function(err, accessToken) {
        console.log('Getting travis-ci token');
        travisToken(accessToken, function(err, publicKey) {
          var fixedKey = publicKey.replace(new RegExp('RSA PUBLIC KEY', 'gm'), 'PUBLIC KEY');
          var key = ursa.createPublicKey(fixedKey);
          var encoded = key.encrypt(program.variable, 'utf8', 'base64', ursa.RSA_PKCS1_PADDING);
          console.log('\nsecure: "' + encoded + '"');
        });
      });
    });
  });
});

var githubAuthorization = function(username, password, callback) {
  var data = {
    scopes: ['repo'],
    note: 'temporary token to prove that I am me.'
  };

  request({
    method: 'POST',
    uri: 'https://' + username + ':' + password + '@api.github.com/authorizations',
    json: data,
    headers: {
      'Accept': 'application/vnd.github.beta+json'
    }
  },function(err, response, body) {
    if (err) {
      return callback(new Error('Invalid username/password'));
    }

    return callback(null, body.token);
  });
};

var travisGithubAuth = function(token, callback) {
  request({
    method: 'POST',
    uri: 'https://api.travis-ci.com/auth/github',
    body: 'github_token=' + token
  },function(err, response, body) {
    callback(null, JSON.parse(body).access_token);
  });
};

var travisToken = function(token, callback) {
  request({
    method: 'GET',
    uri: 'https://api.travis-ci.com/repos/' + program.repository + '/key',
    headers: {
      'Authorization': 'token ' + token
    }
  },function(err, response, body) {
    callback(null, JSON.parse(body).key);
  });
};