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https://github.com/marianoguerra/erlang-pbkdf2-no-history

basho/erlang-pbkdf2 repo withouth couchdb history to reduce repo size
https://github.com/marianoguerra/erlang-pbkdf2-no-history

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basho/erlang-pbkdf2 repo withouth couchdb history to reduce repo size

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README 

        
erlang-pbkdf2

=============



A [PBKDF2][] implementation for [Erlang][] extracted from [Apache CouchDB][].



[Full erlang-pbkdf2 repo (see note below)]: https://github.com/basho/erlang-pbkdf2

[PBKDF2]: http://en.wikipedia.org/wiki/PBKDF2

[Erlang]: http://www.erlang.org

[Apache CouchDB]: http://couchdb.apache.org



NOTE:



    this repo is a clean import of the pbkdf2 module without the couchdb git

    history to avoid downloading 14MBs of history for a library with ~200 lines

    of code, if you want the full history use this repository:

    https://github.com/basho/erlang-pbkdf2



Building

--------



`erlang-pbkdf2` uses [rebar][] to manage the build process. To build the project, run:



	./rebar compile



You can then run the `xref` and `eunit` tests:



	./rebar xref eunit



If you want to remove all generated files, run:



	./rebar clean



[rebar]: https://github.com/rebar/rebar/wiki



Usage

-----



```erlang

OriginalPassword = <<"password">>.



% Settings

{Salt, Iterations, DerivedLength} = {<<"salt">>, 4096, 20}.



% Hash the original password.

{ok, Key} = pbkdf2:pbkdf2(OriginalPassword, Salt, Iterations, DerivedLength).



% At this point, Key = <<"4b007901b765489abead49d926f721d065a429c1">>.



% Get the password from the user.

EnteredPassword = getpass().



% Ensure that the entered password is the same as the original.

{ok, Key} = pbkdf2:pbkdf2(EnteredPassword, Salt, Iterations, DerivedLength).

```



If you're curious what `getpass/0` would look like, here's a sample implementation:



```erlang

% Get the password from the user.

getpass() ->

	% Store current options for stdio.

	InitialIOOpts = io:getopts(),

	% Disable input character echo.

	ok = io:setopts([{echo, false}]),

	% Prompt the user for a password.

	EnteredPassword = io:get_line("Password: "),

	% Restore original options for stdio.

	ok = io:setopts(InitialIOOpts),

	% Print a newline, since we had local echo disabled above.

	io:format("\n"),

	% Remove trailing newline character, if present.

	case lists:reverse(EnteredPassword) of

		[$\n | Rest] ->

			lists:reverse(Rest);

		_ ->

			EnteredPassword

	end.

```



Cryptographic Software Notice

-----------------------------



This distribution includes cryptographic software. The country in which you

currently reside may have restrictions on the import, possession, use, and/or

re-export to another country, of encryption software. BEFORE using any

encryption software, please check your country's laws, regulations and policies

concerning the import, possession, or use, and re-export of encryption software,

to see if this is permitted. See  for more

information.



The U.S. Government Department of Commerce, Bureau of Industry and Security

(BIS), has classified this software as Export Commodity Control Number (ECCN)

5D002.C.1, which includes information security software using or performing

cryptographic functions with asymmetric algorithms. The form and manner of this

Apache Software Foundation distribution makes it eligible for export under the

License Exception ENC Technology Software Unrestricted (TSU) exception (see the

BIS Export Administration Regulations, Section 740.13) for both object code and

source code.



The following provides more details on the included cryptographic software:



`erlang-pbkdf2` implements the PBKDF2 key derivation function.