RandomPassword

Efficiently generate cryptographically strong random passwords using alpha (including Unicode), decimal and symbol characters.

Build Status   Hex Version   License: MIT

TOC

Usage

Create a module for generating random passwords:

  iex> defmodule(DefaultPassword, do: use(RandomPassword))

  iex> DefaultPassword.generate()

  "Uip5jNV%X6hEvRIgE"

By default, RandomPassword modules generate passwords comprised of 14 alpha, 2 decimal, and 1 symbol. To specify different character counts, supply any combination of alpha, decimal or symbol during module creation:

  iex> defmodule(StrongPassword, do: use(RandomPassword, alpha: 16, decimal: 4, symbol: 2))

  iex> StrongPassword.generate()

  "ghp0?HQ5|tl6AIbXSwGR7D"

Default alpha characters are uppercase (A-Z) and lowercase (a-z) ascii. Any set of unique characters (including Unicode) can be specified:

  iex> alphas = "dđiînñgğoøsşkķyŷ"

  iex> defmodule(CustomAlphaPassword, do: use(RandomPassword, alpha: 12, symbol: 3, alphas: alphas))

  iex> CustomAlphaPassword.generate()

  "#ñđdğdo_ŷ}oîiñķ"

Symbol characters can also be explicitly specified:

  iex> defmodule(CustomSymbolsPassword, do: use(RandomPassword, alpha: 10, decimal: 3, symbol: 3, symbols: "@#$%&!"))

  iex> CustomSymbolsPassword.generate()

  "2e5@jfB&@sw4wvCF"

Each created module includes an info/0 function to display module parameterization:

  iex> defmodule(StrongPassword, do: use(RandomPassword, alpha: 17, decimal: 3, symbol: 3))

  iex> StrongPassword.generate()

  "d{ItIFZ76ads;u8cQbhPjg#"

  iex> StrongPassword.info()

  %RandomPassword.Info{

    alpha: 17,

    alphas: "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz",

    decimal: 3,

    decimals: "0123456789",

    entropy_bits: 121.3,

    length: 23,

    symbol: 3,

    symbols: "!#$%&()*+,-./:;<=>?@[]^_{|}~"

  }

Installation

Add random_password to mix.exs dependencies:

def deps,

  do: [ 

    {:random_password, "~> 1.1"}

  ]

Update dependencies

mix deps.get

TOC

Strategy

RandomPassword uses Puid to generate random strings. Puid is extremely fast, and by default using cryptographically strong random bytes for random string generation.

Three random strings are generated, one from each of alphas, decimal and symbols characters of length specified by the alpha, decimal and symbol options. These three strings are concatenated and shuffled to form the final random password.

Since RandomPassword restricts the optional setting of alphas and symbols characters to not overlap with either each other or the fixed decimal characters, the resulting entropy of the random password is the sum of the entropy for the three separate random strings. The RandomPassword module function info/0 lists the total entropy bits of the generated random passwords.