Bcrypt-bench NPM

bcrypt-bench

Get optimal bcrypt salt rounds for your hardware and hash time tolerance.

This module will test your hardware to find the optimal bcrypt salt rounds given a max hash time (default is 250ms). This can allow your apps to automatically adapt to hardware changes without manual intervention.

The optimal value is a compromise between speed and security. The higher it is set, the better the security, however the operation time grows exponentially. It should be set as high as is tolerable for your particular application.

For more information see the bcrypt module documentation.

Usage

The module exports a single function that will return the optimal salt value as an integer and also set process.env.BCRYPT_SALT.

Configuration

There are some optional configuration values which may be supplied by environment variables and/or by passing an object to the function.

The precedent is as follows:

The function will first look in the object optionally supplied as the first function parameter.
If not present, it will check for an environment variable (if applicable).
If neither are present, it will use the default value.

Option	Env. Variable	Default	Description
`minSalt`	`BCRYPT_SALT`	10	The absolute minimum salt to use, regardless of maxHashTime. The tests will increment from this level. The env. variable will be set or overwritten during the tests.
`maxHashTime`	`BCRYPT_MAXHASHTIME`	250	Target time-per-hash in milliseconds. Different applications have different requirements, so set this to the maximum yours should tolerate.
`epochs`		3	Number of hash operations to perform for each salt value. The higher the number, the more thorough the test will be - but it will take longer.
`quick`		true	Applies techniques to speed up the process. If set to false the salt value will be painstakingly incremented during the test.
`quickFactor`		100	Set between 0 - 100. Controls how aggressive the "quick" feature is. If you are getting funky outcomes, try reducing this.
`quiet`		false	Prevents console logging.

Basic example

const {hashSync} = require("bcrypt");
const bcryptBench = require("bcrypt-bench");

const options = {
  minSalt: 12,
  maxHashTime: 500
};

const salt = bcryptTest(options);

hashSync("abcdef", salt);

Example with .env

.env

BCRYPT_SALT        = 12
BCRYPT_MAXHASHTIME = 250

index.js

const dotenv = require("dotenv");
const {hashSync} = require("bcrypt");
const bcryptBench = require("bcrypt-bench");

dotenv.config();

if (process.env.NODE_ENV === "production") {

  const options = {
    maxHashTime: 500 // Overrides value from .env
  };

  bcryptTest(options);
}

hashSync("abcdef", Number(process.env.BCRYPT_SALT)); // Env. vars are strings and will upset bcrypt

4 years ago

4 years ago