Hashids

Hashids lets you obfuscate numerical identifiers via reversible mapping.

This is a port of Hashids from JavaScript.

Installation

Add Hashids as a dependency to your Mix project:

defp deps do
  [
    {:hashids, "~> 2.0"}
  ]
end

Usage

Hashids encodes a list of integers into a string (technically, iodata). Some of the encoding parameters can be customized.

s = Hashids.new([
  salt: "123",  # using a custom salt helps producing unique cipher text
  min_len: 2,   # minimum length of the cipher text (1 by default)
])

cipher1 = Hashids.encode(s, 129)
#=> "pE6"

cipher2 = Hashids.encode(s, [1,2,3,4])
#=> "4bSwImsd"

# decode() always returns a list of numbers

Hashids.decode(s, cipher1)
#=> {:ok, [129]}

Hashids.decode!(s, cipher2)
#=> [1, 2, 3, 4]

It is also possible to customize the character set used for the cipher text by providing a custom alphabet. It has to be at least 16 characters long.

defmodule MyAccessToken do
  @cyrillic_alphabet "123456789абвгґдеєжзиіїйклмнопрстуфцчшщьюяАБВГҐДЕЄЖЗИІЇЙКЛМНОПРСТУФЦЧШЩЬЮЯ"
  @coder Hashids.new(alphabet: @cyrillic_alphabet)

  def encode(token_ids) do
    Hashids.encode(@coder, token_ids)
  end

  def decode(data) do
    Hashids.decode(@coder, data)
  end
end

data = MyAccessToken.encode([1234, 786, 21, 0])
#=> "ЦфюєИНаЛ1И"

MyAccessToken.decode(data)
#=> {:ok, [1234, 786, 21, 0]}

Migrating from 1.0

See the changelog.

License

This software is licensed under the MIT license.