erlang-scrypt: Port driver for Colin Percival's "scrypt" function

scrypt, a Password-Based Key Derivation Function from Colin Percival, from version 1.1.6 of his library.

For general background on what scrypt is, and why it's useful, see these slides (PDF) and Colin Percival's page on scrypt.

Depending on this library from rebar

Include it as a dep:

{deps_dir, ["deps"]}.
{deps,
 [
  ...
  {scrypt, "1.1.6:0",
   {git, "git://github.com/tonyg/erlang-scrypt.git", "master"}}
 ]}.

Using the library

Include it in your application's applications key in its .app file:

{application, your_app,
 [
  {applications, [
                  ...
                  scrypt
                 ]},
  ...
 ]}.

The only entry point is scrypt:scrypt/6.

scrypt:scrypt(Passwd, Salt, N, R, P, Buflen)

Both Passwd and Salt must be binaries. N, R, and P control the complexity of the password-derivation process. Buflen is the number of bytes of key material to generate.

For some good choices for N, R and P, see the paper.

Example:

Eshell V5.9.1  (abort with ^G)
1> scrypt:scrypt(<<"pleaseletmein">>, <<"SodiumChloride">>, 16384, 8, 1, 64).
<<112,35,189,203,58,253,115,72,70,28,6,205,129,253,56,235,
  253,168,251,186,144,79,142,62,169,181,67,246,84,...>>

License

erlang-scrypt is written by Tony Garnock-Jones [email protected] and is licensed under the 2-clause BSD license:

Copyright © 2013, Tony Garnock-Jones
All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

erlang-scrypt relies on scrypt itself, which is written by Colin Percival and licensed as follows:

Copyright 2009 Colin Percival
All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.