A compliant and complete implementation of PASETO and PASERK.

PASETO is everything you love about JOSE (JWT, JWE, JWS) without any of the many design deficits that plague the JOSE standards.

PASETO (Platform-Agnostic SEcurity TOkens) is a specification and reference implementation for secure stateless tokens.

Paseto is pronounced paw-set-oh (pɔːsɛtəʊ).

Key Differences between Paseto and JWT

Unlike JSON Web Tokens (JWT), which gives developers more than enough rope with which to hang themselves, PASETO only allows secure operations. JWT gives you "algorithm agility", PASETO gives you "versioned protocols". It's incredibly unlikely that you'll be able to use Paseto in an insecure way.

Caution: Neither JWT nor PASETO were designed for stateless session management. Paseto is suitable for tamper-proof cookies, but cannot prevent replay attacks by itself.

PASETO

PASETO expects a version and a purpose in order to build and parse tokens. The version is a string that represents the current version of the protocol. The purpose is a short string describing the purpose of the token, where the accepted values are:

• local: shared-key authenticated encryption

• public: public-key digital signatures; not encrypted

Tokens can be built and parsed like so:

iex> key = Pasexto.Key.new(:v4, :local)
iex> claims = %{"hello" => "world"}
iex> footer = <<>>
iex> {:ok, paseto, claims} = Pasexto.build(:v4, :local, key, claims, footer)
iex> {:ok, ^claims, ^footer} = Pasexto.parse(:v4, :local, key, paseto)

iex> key = Pasexto.Key.new(:v4, :public)
iex> claims = %{"hello" => "world"}
iex> footer = <<>>
iex> {:ok, paseto, claims} = Pasexto.build(:v4, :public, key, claims, footer)
iex> {:ok, ^claims, ^footer} = Pasexto.parse(:v4, :public, key, paseto)

Keyring

This library also supports keyrings making it easier to manage a group of keys. It can be used like so:

iex> key = Pasexto.Key.new(:v4, :local)
iex> keyring = Pasexto.Keyring.new(:v4, :local) |> Pasexto.Keyring.put("key1", key)
iex> claims = %{"hello" => "world"}
iex> footer = %{"kid" => "key1"}
iex> {:ok, paseto, claims} = Pasexto.build(:v4, :local, keyring, claims, footer)
iex> {:ok, ^claims, ^footer} = Pasexto.parse(:v4, :local, keyring, paseto)

PASERK

PASERK is an extension to PASETO that provides key-wrapping and serialization. It can be used like so:

iex> key = Pasexto.Key.new(:v4, :local)
iex> {:ok, kid} = Pasexto.Paserk.build(:k4, :lid, key)
iex> keyring = Pasexto.Keyring.new(:v4, :local) |> Pasexto.Keyring.put(kid, key)
iex> claims = %{"hello" => "world"}
iex> footer = %{"kid" => kid}
iex> {:ok, paseto, claims} = Pasexto.build(:v4, :local, keyring, claims, footer)
iex> {:ok, ^claims, ^footer} = Pasexto.parse(:v4, :local, keyring, paseto)