JSON Object Signing and Encryption (JOSE) for Erlang and Elixir
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potatosalad Version 1.8.4
* Enhancements
  * Add support for reading and writing PEM files for Ed25519, Ed448, X25519, and X448 keys based on https://tools.ietf.org/html/draft-ietf-curdle-pkix.
  * Add support for https://github.com/potatosalad/erlang-json adapter for encoding/decoding JSON.
Latest commit f8f97fb May 19, 2017

README.md

JOSE

Build Status Hex.pm

JSON Object Signing and Encryption (JOSE) for Erlang and Elixir.

Installation

Add jose to your project's dependencies in mix.exs

defp deps do
  [
    {:jose, "~> 1.8"}
  ]
end

If you are using deployment tools (exrm, etc.) and your app depends on jose directly, you will need to include jose in your applications list in mix.exs to ensure they get compiled into your release:

def application do
  [mod: {YourApp, []},
   applications: [:jose]]
end

Add jose to your project's dependencies in your Makefile for erlang.mk or the following to your rebar.config

{deps, [
  {jose, ".*", {git, "git://github.com/potatosalad/erlang-jose.git", {branch, "master"}}}
]}.

JSON Encoder/Decoder

You will also need to specify either jiffy, jsone, jsx, ojson, or Poison as a dependency.

For example, with Elixir and mix.exs

defp deps do
  [
    {:jose, "~> 1.8"},
    {:ojson, "~> 1.0"}
  ]
end

Or with Erlang and rebar.config

{deps, [
  {jose, ".*", {git, "git://github.com/potatosalad/erlang-jose.git", {branch, "master"}}},
  {ojson, ".*", {git, "git://github.com/potatosalad/erlang-ojson.git", {branch, "master"}}}
]}.

jose will attempt to find a suitable JSON encoder/decoder and will try to use (in order) ojson, Poison, jiffy, jsone, or jsx.

You may also specify a different json_module as an application environment variable to jose or by using jose:json_module/1 or JOSE.json_module/1.

ChaCha20/Poly1305 Support

ChaCha20/Poly1305 encryption and one-time message authentication functions are experimentally supported based on RFC 7539.

Fallback support for ChaCha20/Poly1305 encryption and Poly1305 signing is also provided. See crypto_fallback below.

External support is also provided by the following libraries:

  • libsodium - ChaCha20/Poly1305 encryption and Poly1305 signing

Other modules which implement the jose_chacha20_poly1305 behavior may also be used as follows:

# ChaCha20/Poly1305
JOSE.chacha20_poly1305_module(:libsodium)                  # uses a fast Erlang port driver for libsodium
JOSE.chacha20_poly1305_module(:jose_jwa_chacha20_poly1305) # uses the pure Erlang implementation (slow)

Curve25519 and Curve448 Support

Curve25519 and Curve448 and their associated signing/key exchange functions are experimentally supported while CFRG ECDH and signatures in JOSE is still a draft.

Fallback support for Ed25519, Ed25519ph, Ed448, Ed448ph, X25519, and X448 is provided. See crypto_fallback below.

External support is also provided by the following libraries:

  • libdecaf - Ed25519, Ed25519ph, Ed448, Ed448ph, X25519, X448
  • libsodium - Ed25519, Ed25519ph, X25519

If both libraries are present, libdecaf will be used by default. Other modules which implement the jose_curve25519 or jose_curve448 behaviors may also be used as follows:

# Curve25519
JOSE.curve25519_module(:libdecaf)            # uses a fast Erlang NIF for libdecaf
JOSE.curve25519_module(:jose_jwa_curve25519) # uses the pure Erlang implementation (slow)

# Curve448
JOSE.curve448_module(:libdecaf)          # uses a fast Erlang NIF for libdecaf
JOSE.curve448_module(:jose_jwa_curve448) # uses the pure Erlang implementation (slow)

SHA-3 Support

SHA-3 is experimentally supported for use with Ed448 and Ed448ph signing functions.

Fallback support for SHA-3 is provided. See crypto_fallback below.

External support for SHA-3 is provided by the keccakf1600 and libdecaf libraries. If present, keccakf1600 will be used by default. Other modules which implement the jose_sha3 behaviors may also be used as follows:

JOSE.sha3_module(:keccakf1600)   # uses a NIF written in C with timeslice reductions
JOSE.sha3_module(:jose_jwa_sha3) # uses the pure Erlang implementation (slow)

Cryptographic Algorithm Fallback

jose strives to support all of the cryptographic algorithms specified in the JOSE RFCs.

However, not all of the required algorithms are supported natively by Erlang/Elixir. For algorithms unsupported by the native crypto and public_key, jose has a pure Erlang implementation that may be used as a fallback.

See ALGORITHMS.md for more information about algorithm support for specific OTP versions.

By default, the algorithm fallback is disabled, but can be enabled by setting the crypto_fallback application environment variable for jose to true or by calling jose:crypto_fallback/1 or JOSE.crypto_fallback/1 with true.

You may also review which algorithms are currently supported with the jose_jwa:supports/0 or JOSE.JWA.supports/0 functions. For example, on Elixir 1.0.5 and OTP 18:

# crypto_fallback defaults to false
JOSE.JWA.supports

[{:jwe,
  {:alg,
   ["A128GCMKW", "A128KW", "A192GCMKW", "A192KW", "A256GCMKW", "A256KW",
    "ECDH-ES", "ECDH-ES+A128KW", "ECDH-ES+A192KW", "ECDH-ES+A256KW",
    "PBES2-HS256+A128KW", "PBES2-HS384+A192KW", "PBES2-HS512+A256KW",
    "RSA-OAEP", "RSA1_5", "dir"]},
  {:enc,
   ["A128CBC-HS256", "A128GCM", "A192CBC-HS384", "A192GCM", "A256CBC-HS512",
    "A256GCM"]}, {:zip, ["DEF"]}},
 {:jwk, {:kty, ["EC", "OKP", "RSA", "oct"]}, {:kty_OKP_crv, []}},
 {:jws,
  {:alg,
   ["ES256", "ES384", "ES512", "HS256", "HS384", "HS512", "RS256", "RS384",
    "RS512"]}}]

# setting crypto_fallback to true
JOSE.crypto_fallback(true)

# additional algorithms are now available for use
JOSE.JWA.supports

[{:jwe,
  {:alg,
   ["A128GCMKW", "A128KW", "A192GCMKW", "A192KW", "A256GCMKW", "A256KW",
    "ECDH-ES", "ECDH-ES+A128KW", "ECDH-ES+A192KW", "ECDH-ES+A256KW",
    "PBES2-HS256+A128KW", "PBES2-HS384+A192KW", "PBES2-HS512+A256KW",
    "RSA-OAEP", "RSA-OAEP-256", "RSA1_5", "dir"]},
  {:enc,
   ["A128CBC-HS256", "A128GCM", "A192CBC-HS384", "A192GCM", "A256CBC-HS512",
    "A256GCM", "ChaCha20/Poly1305"]}, {:zip, ["DEF"]}},
 {:jwk, {:kty, ["EC", "OKP", "RSA", "oct"]},
  {:kty_OKP_crv,
   ["Ed25519", "Ed25519ph", "Ed448", "Ed448ph", "X25519", "X448"]}},
 {:jws,
  {:alg,
   ["ES256", "ES384", "ES512", "Ed25519", "Ed25519ph", "Ed448", "Ed448ph",
    "HS256", "HS384", "HS512", "PS256", "PS384", "PS512", "Poly1305", "RS256",
    "RS384", "RS512"]}}]

Unsecured Signing Vulnerability

The "none" signing algorithm is disabled by default to prevent accidental verification of empty signatures (read about the vulnerability here).

If you want to further restrict the signature algorithms allowed for a token, use JOSE.JWT.verify_strict/3:

# Signed Compact JSON Web Token (JWT) with HS256
token = "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjEzMDA4MTkzODAsImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlLCJpc3MiOiJqb2UifQ.shLcxOl_HBBsOTvPnskfIlxHUibPN7Y9T4LhPB-iBwM"

# JSON Web Key (JWK)
jwk = %{
  "kty" => "oct",
  "k" => :base64url.encode("symmetric key")
}

{verified, _, _} = JOSE.JWT.verify_strict(jwk, ["HS256"], token)
# {true, _, _}

{verified, _, _} = JOSE.JWT.verify_strict(jwk, ["RS256"], token)
# {false, _, _}

If you need to inspect the contents of a JSON Web token (JWT) prior to verifying it, use JOSE.JWT.peek_payload/1 or JOSE.JWT.peek_protected/1:

token = "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjEzMDA4MTkzODAsImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlLCJpc3MiOiJqb2UifQ.shLcxOl_HBBsOTvPnskfIlxHUibPN7Y9T4LhPB-iBwM"

payload = JOSE.JWT.peek_payload(token)
# %JOSE.JWT{fields: %{"exp" => 1300819380, "http://example.com/is_root" => true,
#    "iss" => "joe"}}

protected = JOSE.JWT.peek_protected(token)
# %JOSE.JWS{alg: {:jose_jws_alg_hmac, {:jose_jws_alg_hmac, :sha256}},
#  b64: :undefined, fields: %{"typ" => "JWT"}}

# If you want to inspect the JSON, you can convert it back to a regular map:
{_, protected_map} = JOSE.JWS.to_map(protected)
# {_, %{"alg" => "HS256", "typ" => "JWT"}}

You may also enable the "none" algorithm as an application environment variable for jose or by using jose:unsecured_signing/1 or JOSE.unsecured_signing/1.

# unsecured_signing defaults to false
JOSE.JWA.supports[:jws]

{:alg,
 ["ES256", "ES384", "ES512", "Ed25519", "Ed25519ph", "Ed448", "Ed448ph",
  "HS256", "HS384", "HS512", "PS256", "PS384", "PS512", "Poly1305", "RS256",
  "RS384", "RS512"]}

# setting unsecured_signing to true
JOSE.unsecured_signing(true)

# the "none" algorithm is now available for use
JOSE.JWA.supports[:jws]

{:alg,
 ["ES256", "ES384", "ES512", "Ed25519", "Ed25519ph", "Ed448", "Ed448ph",
  "HS256", "HS384", "HS512", "PS256", "PS384", "PS512", "Poly1305", "RS256",
  "RS384", "RS512", "none"]}

Usage

JSON Web Signature (JWS) of JSON Web Token (JWT) using HMAC using SHA-256 (HS256) with JSON Web Key (JWK)

Elixir

# JSON Web Key (JWK)
jwk = %{
  "kty" => "oct",
  "k" => :base64url.encode("symmetric key")
}

# JSON Web Signature (JWS)
jws = %{
  "alg" => "HS256"
}

# JSON Web Token (JWT)
jwt = %{
  "iss" => "joe",
  "exp" => 1300819380,
  "http://example.com/is_root" => true
}

signed = JOSE.JWT.sign(jwk, jws, jwt)
# {%{alg: :jose_jws_alg_hmac},
#  %{"payload" => "eyJleHAiOjEzMDA4MTkzODAsImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlLCJpc3MiOiJqb2UifQ",
#    "protected" => "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9",
#    "signature" => "shLcxOl_HBBsOTvPnskfIlxHUibPN7Y9T4LhPB-iBwM"}}

compact_signed = JOSE.JWS.compact(signed)
# {%{alg: :jose_jws_alg_hmac},
#  "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjEzMDA4MTkzODAsImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlLCJpc3MiOiJqb2UifQ.shLcxOl_HBBsOTvPnskfIlxHUibPN7Y9T4LhPB-iBwM"}

verified = JOSE.JWT.verify(jwk, compact_signed)
# {true,
#  %JOSE.JWT{fields: %{"exp" => 1300819380, "http://example.com/is_root" => true,
#     "iss" => "joe"}},
#  %JOSE.JWS{alg: {:jose_jws_alg_hmac, :HS256}, b64: :undefined,
#   fields: %{"typ" => "JWT"}}}

verified == JOSE.JWT.verify(jwk, signed)
# true

Erlang

% JSON Web Key (JWK)
JWK = #{
  <<"kty">> => <<"oct">>,
  <<"k">> => base64url:encode(<<"symmetric key">>)
}.

% JSON Web Signature (JWS)
JWS = #{
  <<"alg">> => <<"HS256">>
}.

% JSON Web Token (JWT)
JWT = #{
  <<"iss">> => <<"joe">>,
  <<"exp">> => 1300819380,
  <<"http://example.com/is_root">> => true
}.

Signed = jose_jwt:sign(JWK, JWS, JWT).
% {#{alg => jose_jws_alg_hmac},
%  #{<<"payload">> => <<"eyJleHAiOjEzMDA4MTkzODAsImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlLCJpc3MiOiJqb2UifQ">>,
%    <<"protected">> => <<"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9">>,
%    <<"signature">> => <<"shLcxOl_HBBsOTvPnskfIlxHUibPN7Y9T4LhPB-iBwM">>}}

CompactSigned = jose_jws:compact(Signed).
% {#{alg => jose_jws_alg_hmac},
%  <<"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjEzMDA4MTkzODAsImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlLCJpc3MiOiJqb2UifQ.shLcxOl_HBBsOTvPnskfIlxHUibPN7Y9T4LhPB-iBwM">>}

Verified = jose_jwt:verify(JWK, CompactSigned).
% {true,
%     #jose_jwt{
%         fields =
%             #{<<"exp">> => 1300819380,
%               <<"http://example.com/is_root">> => true,
%               <<"iss">> => <<"joe">>}},
%     #jose_jws{
%         alg = {jose_jws_alg_hmac,'HS256'},
%         b64 = undefined,
%         fields = #{<<"typ">> => <<"JWT">>}}}

Verified =:= jose_jwt:verify(JWK, Signed).
% true
Reading JSON Web Keys (JWK) from PEM files

The examples below use three keys created with openssl:

# RSA Private Key
openssl genrsa -out rsa-2048.pem 2048

# EC Private Key (Alice)
openssl ecparam -name secp256r1 -genkey -noout -out ec-secp256r1-alice.pem

# EC Private Key (Bob)
openssl ecparam -name secp256r1 -genkey -noout -out ec-secp256r1-bob.pem

Elixir

# RSA examples
rsa_private_jwk = JOSE.JWK.from_pem_file("rsa-2048.pem")
rsa_public_jwk  = JOSE.JWK.to_public(rsa_private_jwk)

## Sign and Verify (defaults to PS256)
message = "my message"
signed = JOSE.JWK.sign(message, rsa_private_jwk)
{true, ^message, _} = JOSE.JWK.verify(signed, rsa_public_jwk)

## Sign and Verify (specify RS256)
signed = JOSE.JWK.sign(message, %{ "alg" => "RS256" }, rsa_private_jwk)
{true, ^message, _} = JOSE.JWK.verify(signed, rsa_public_jwk)

## Encrypt and Decrypt (defaults to RSA-OAEP with A128CBC-HS256)
plain_text = "my plain text"
encrypted = JOSE.JWK.block_encrypt(plain_text, rsa_public_jwk)
{^plain_text, _} = JOSE.JWK.block_decrypt(encrypted, rsa_private_jwk)

## Encrypt and Decrypt (specify RSA-OAEP-256 with A128GCM)
encrypted = JOSE.JWK.block_encrypt(plain_text, %{ "alg" => "RSA-OAEP-256", "enc" => "A128GCM" }, rsa_public_jwk)
{^plain_text, _} = JOSE.JWK.block_decrypt(encrypted, rsa_private_jwk)

# EC examples
alice_private_jwk = JOSE.JWK.from_pem_file("ec-secp256r1-alice.pem")
alice_public_jwk  = JOSE.JWK.to_public(alice_private_jwk)
bob_private_jwk   = JOSE.JWK.from_pem_file("ec-secp256r1-bob.pem")
bob_public_jwk    = JOSE.JWK.to_public(bob_private_jwk)

## Sign and Verify (defaults to ES256)
message = "my message"
signed = JOSE.JWK.sign(message, alice_private_jwk)
{true, ^message, _} = JOSE.JWK.verify(signed, alice_public_jwk)

## Encrypt and Decrypt (defaults to ECDH-ES with A128GCM)
### Alice sends Bob a secret message using Bob's public key and Alice's private key
alice_to_bob = "For Bob's eyes only."
encrypted = JOSE.JWK.box_encrypt(alice_to_bob, bob_public_jwk, alice_private_jwk)
### Only Bob can decrypt the message using his private key (Alice's public key is embedded in the JWE header)
{^alice_to_bob, _} = JOSE.JWK.box_decrypt(encrypted, bob_private_jwk)

Erlang

% RSA examples
RSAPrivateJWK = jose_jwk:from_pem_file("rsa-2048.pem"),
RSAPublicJWK  = jose_jwk:to_public(RSAPrivateJWK).

%% Sign and Verify (defaults to PS256)
Message = <<"my message">>,
SignedPS256 = jose_jwk:sign(Message, RSAPrivateJWK),
{true, Message, _} = jose_jwk:verify(SignedPS256, RSAPublicJWK).

%% Sign and Verify (specify RS256)
SignedRS256 = jose_jwk:sign(Message, #{ <<"alg">> => <<"RS256">> }, RSAPrivateJWK),
{true, Message, _} = jose_jwk:verify(SignedRS256, RSAPublicJWK).

%% Encrypt and Decrypt (defaults to RSA-OAEP with A128CBC-HS256)
PlainText = <<"my plain text">>,
EncryptedRSAOAEP = jose_jwk:block_encrypt(PlainText, RSAPublicJWK),
{PlainText, _} = jose_jwk:block_decrypt(EncryptedRSAOAEP, RSAPrivateJWK).

%% Encrypt and Decrypt (specify RSA-OAEP-256 with A128GCM)
EncryptedRSAOAEP256 = jose_jwk:block_encrypt(PlainText, #{ <<"alg">> => <<"RSA-OAEP-256">>, <<"enc">> => <<"A128GCM">> }, RSAPublicJWK),
{PlainText, _} = jose_jwk:block_decrypt(EncryptedRSAOAEP256, RSAPrivateJWK).

% EC examples
AlicePrivateJWK = jose_jwk:from_pem_file("ec-secp256r1-alice.pem"),
AlicePublicJWK  = jose_jwk:to_public(AlicePrivateJWK),
BobPrivateJWK   = jose_jwk:from_pem_file("ec-secp256r1-bob.pem"),
BobPublicJWK    = jose_jwk:to_public(BobPrivateJWK).

%% Sign and Verify (defaults to ES256)
Message = <<"my message">>,
SignedES256 = jose_jwk:sign(Message, AlicePrivateJWK),
{true, Message, _} = jose_jwk:verify(SignedES256, AlicePublicJWK).

%% Encrypt and Decrypt (defaults to ECDH-ES with A128GCM)
%%% Alice sends Bob a secret message using Bob's public key and Alice's private key
AliceToBob = <<"For Bob's eyes only.">>,
EncryptedECDHES = jose_jwk:box_encrypt(AliceToBob, BobPublicJWK, AlicePrivateJWK),
%%% Only Bob can decrypt the message using his private key (Alice's public key is embedded in the JWE header)
{AliceToBob, _} = jose_jwk:box_decrypt(EncryptedECDHES, BobPrivateJWK).

Algorithm Support

JSON Web Encryption (JWE) RFC 7516

"alg" RFC 7518 Section 4

"enc" RFC 7518 Section 5

"zip" RFC 7518 Section 7.3

  • DEF

JSON Web Key (JWK) RFC 7517

"alg" RFC 7518 Section 6

JSON Web Signature (JWS) RFC 7515

"alg" RFC 7518 Section 3

Additional Specifications

OTP-17 Native algorithm not supported by OTP-17. Use the crypto_fallback setting to enable the non-native implementation. See ALGORITHMS.md for more information about algorithm support for specific OTP versions.

OTP-18 Native algorithm not supported by OTP-18. Use the crypto_fallback setting to enable the non-native implementation. See ALGORITHMS.md for more information about algorithm support for specific OTP versions.

OTP-19 Native algorithm not supported by OTP-19. Use the crypto_fallback setting to enable the non-native implementation. See ALGORITHMS.md for more information about algorithm support for specific OTP versions.

unsecured This algorithm is disabled by default due to the unsecured signing vulnerability. Use the unsecured_signing setting to enable this algorithm.