Interoperability

[vincenzoml]

Hi,

how can data encrypted in SJCL be decrypted using other languages? How difficult it is to get openSSL compatibility? 

thanks

Vincenzo

[Mike Hamburg]

Hi,

It's trickier than I'd like. You'll need a JSON parser, a base64 decoder, and a crypto suite capable of PBKDF2 (with SHA256), AES and CCM mode, and you'll have to more or less re-implement SJCL's dataflow. Parse the JSON; send the salt and password through PBKDF2 with the right number of iterations; pass the key and IV into CCM; decrypt the ciphertext.

Cheers,
-- Mike

[Maarten Bodewes]

On Sat, Sep 1, 2012 at 6:06 AM, Mike Hamburg <mi...@shiftleft.org> wrote:
> It's trickier than I'd like. You'll need a JSON parser, a base64 decoder, and a crypto suite capable of PBKDF2 (with SHA256), AES and CCM mode, and you'll have to more or less re-implement SJCL's dataflow. Parse the JSON; send the salt and password through PBKDF2 with the right number of iterations; pass the key and IV into CCM; decrypt the ciphertext.

Besides that you need to take care that you follow SJCL conventions. I
know since I created an (unfinished) SJCL compatible Java library. For
instance, binary data is not directly supported by JSON, and SJCL does
not use the '=' padding character for base64 encoding.

CCM mode encryption is also something that is not so commonly
available, and it is a bit of a pain to work with, certainly much
worse in that regard than GCM.

That said, as the main functionality of my Java code is there, it is
certainly possible.

Regards,
Maarten

[Shlomi Cohen-Ganor]

Could you by any chance share your unfinished SJCL compatible Java library?

I need to encrypt something in javascript and then decrypt it in Java.

Many thanks

[Pablo Nussembaum]

Since I haven't any proper solution to encrypt/decrypt in plain java.
I'm using nashorn to run the sjcl.js directly.
Here is a snippet:
    private static void test() throws ScriptException {
        ScriptEngine engine = new ScriptEngineManager().getEngineByName("nashorn");
        engine.eval(new InputStreamReader(Crypto.class.getResourceAsStream("sjcl.js")));

        Object eval = engine.eval("sjcl.encrypt('password', 'Hello World')");
        System.out.println(eval);

        eval = engine.eval("sjcl.decrypt('password', '" + eval + "')");
        System.out.println(eval);
    }