index.js

var crypto    = require("crypto");
var fs        = require("fs");
var prompt    = require("prompt");
var path      = require("path");

module.exports = function(fn) {
  var from = path.join(process.cwd(), process.argv[2]);
  var to   = path.join(process.cwd(), process.argv[3]);

  prompt.start();

  var schema = {
    description: "Enter the config password (" + path.basename(to) + "):\n",
    name: "password",
    type: "string",
    hidden: true,
    replace: "*",
    required: false
  };

  var getSchema = [];

  if (!process.env.CONFIG_LEAF_PASSWORD) {
    getSchema.push(schema);
  }

  prompt.get(getSchema, function (err, result) {
    if (err) {
      console.log(err);
    } else {
      from = fs.createReadStream(from);
      to   = fs.createWriteStream(to);
      fn   = fn("cast5-cbc", result.password || process.env.CONFIG_LEAF_PASSWORD);

      from.pipe(fn).pipe(to);
      from.on("end", function () {
        console.log("done");
        prompt.stop();
      });
    }
  });
};