NaCerl

An implementation of NaCl for Erlang that can be compiled on Windows and Linux.

NaCl is an easy-to-use high-speed software library for network communication, encryption, decryption, signatures etc. For more information see nacl.cr.yp.to.

This project takes parts from various sources to ensure that the software can be compiled on a Windows system. It should also compile on a Linux system, but if you are using a Linux system you should probably opt for an Erlang implementation that uses libsodium, such as enacl.

This project is based on parts from various sources:

• Most of the C code comes from TweetNaCL . This is the actual implementation of the cryptographic functions.

• Some additional C code to generate random bytes comes from https://github.com/ultramancool/tweetnacl-usable.

• The Erlang code to create a NIF that uses the C implementation comes from https://github.com/tonyg/erlang-nacl. Nacerl is essentially a version of Tony Garnock-Jones' project, but using TweetNaCl in stead of libsodium to facilitate the compilation.

Example

1> rr("nacl.hrl").
[nacl_box_keypair,nacl_envelope]

2> #nacl_box_keypair{pk = PublicKey, sk = SecretKey} = nacl:box_keypair().
#nacl_box_keypair{pk = <<91,231,73,96,227,2,29,109,216,
                         185,247,252,203,223,128,51,194,
                         170,57,210,188,136,145,143,241,
                         19,6,...>>,
                  sk = <<30,193,12,53,65,254,33,83,210,116,42,182,7,97,73,
                         35,123,241,11,251,199,50,127,186,25,202,...>>}

3> Message = <<"this is a secret">>.
<<"this is a secret">>

4> Nonce = crypto:strong_rand_bytes(24). %% Nonce must be 24 bytes
<<201,16,213,16,7,166,221,39,0,47,251,186,164,141,57,92,
  152,218,43,176,243,223,126,16>>

5> #nacl_envelope{ciphertext = Encrypted} = nacl:box(Message, Nonce, PublicKey, SecretKey).
#nacl_envelope{nonce = <<201,16,213,16,7,166,221,39,0,47,
                         251,186,164,141,57,92,152,218,43,
                         176,243,223,126,16>>,
               ciphertext = <<164,122,249,242,77,152,181,74,124,83,197,
                              190,118,29,0,186,162,163,133,185,217,197,
                              150,66,96,134,...>>}

6> {ok, Message} = nacl:box_open(Encrypted, Nonce, PublicKey, SecretKey).
{ok,<<"this is a secret">>}