[erlang-questions] Compiling Erlang without RC4?

Alexander Færøy <>
Tue Sep 13 20:42:33 CEST 2016


On 13 September 2016 at 17:16, Oliver Korpilla <> wrote:
> We currently have to work with a system where somebody thought removing rc4.h would solve the security issues involved with this weak algorithm...
>
> Is there any way to build Erlang without RC4 (but still with crypto functionality)?

It doesn't look like the RC4 functionality is hidden behind a guard in
the C source code, but I don't think you should be overly worried
about using an Erlang release that contains RC4 support.

If you take a look at the ciphers that the SSL application will use by
default, you will see that there's no RC4 ciphers included (at least
not in my OTP-18 installation locally):

    lists:foreach(fun (Suite) -> io:format("~p~n", [Suite]) end,
ssl:cipher_suites()).

You could consider filtering out the 3DES ciphers that are enabled by
default though[1] using the {ciphers, [...]} option for SSL
connections.

Cheers,
Alex.

[1]: https://sweet32.info


-- 
Alexander Færøy


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