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erlang-bcrypt

erlang-bcrypt is a wrapper around the OpenBSD Blowfish password hashing algorithm, as described in "A Future-Adaptable Password Scheme" by Niels Provos and David Mazieres.

Basic build instructions

  1. Build it (project uses rebar, but I've included a Makefile):

    make

  2. Run it (simple way, starting sasl, crypto and bcrypt):

    erl -pa ebin -boot start_sasl -s crypto -s bcrypt

Basic usage instructions

  1. Hash a password using a salt with the default number of rounds:

    1> {ok, Salt} = bcrypt:gen_salt(),
{ok,"$2a$12$sSS8Eg.ovVzaHzi1nUHYK."}
2> {ok, Hash} = bcrypt:hashpw("foo", Salt),
{ok,"$2a$12$sSS8Eg.ovVzaHzi1nUHYK.HbUIOdlQI0iS22Q5rd5z.JVVYH6sfm6"}

  1. Verify the password:

    3> {ok, Hash} =:= bcrypt:hashpw("foo", Hash).
true
4> {ok, Hash} =:= bcrypt:hashpw("bar", Hash).
false

Configuration

The bcrypt application is configured by changing values in the application's environment:

default_log_rounds
Sets the default number of rounds which define the complexity of the hash function. Defaults to 12.
mechanism

Specifies whether to use the NIF implementation ('nif') or a pool of port programs ('port'). Defaults to 'nif'.

Note: the NIF implementation no longer blocks the Erlang VM scheduler threads

pool_size
Specifies the size of the port program pool. Defaults to 4.

Authors