ksha3 is a NIF wrapper around the pre-NIST KECCAK cryptographic hashing function
You must have Erlang/OTP R14B or later and a GNU-style build system to compile and run ksha3.
git clone git://github.com/onyxrev/ksha3.git
cd ksha3
make
Start up an Erlang shell with the path to ksha3 included.
cd path/to/ksha3/_build/default/lib/ksha3/ebin
erl
Hash a binary by calling ksha3:hash/2 with the desired number of bits for the resulting hash:
1> Bits = 256.
256
2> Data = <<"foobarbazquux">>.
<<"foobarbazquux">>
3> {ok, Hash} = ksha3:hash(Bits, Data).
{ok,<<44,116,195,124,154,54,203,192,209,31,49,133,80,8,
197,88,60,97,25,146,40,128,231,75,121,226,1,...>>}
4> bit_size(Hash).
256
Supported hash bit lengths are 224, 256, 384, and 512.
You may find ksha3:hexhash/2 more useful, as it returns a hexadecimal-encoded string representing the hash:
5> HexHash = ksha3:hexhash(Bits, Data).
<<"2C74C37C9A36CBC0D11F31855008C5583C6119922880E74B79E2014A28F862DA">>
Alternatively, you might want to incrementally hash a longer message:
6> Bits = 256.
256
7> Data1 = <<"foobar">>.
<<"foobar">>
8> Data2 = <<"bazquux">>.
<<"bazquux">>
9> {ok, Handle} = ksha3:init(Bits).
{ok,<<>>}
10> {ok, Handle} = ksha3:update(Handle, Data1).
{ok,<<>>}
11> {ok, Handle} = ksha3:update(Handle, Data2).
{ok,<<>>}
12> {ok, Hash} = ksha3:final(Handle).
{ok,<<44,116,195,124,154,54,203,192,209,31,49,133,80,8,
197,88,60,97,25,146,40,128,231,75,121,226,1,...>>}
13> bit_size(Hash).
256
The underlying hashing code in ksha3 is the reference implementation of KECCAK. SHA-3 from NIST is ever so slightly different from KECCAK. The main reason you might want to use this implementation is if you have code that expects the pre-NIST reference implementation (Ethereum is one example of a major project that uses this hash algo).
Details on the algorithm as submitted and known analysis can be found at http://keccak.noekeon.org/.