PKCS1 encryption in Flutter won't work without reflection

Question

I'm writing some code to encrypt data from a flutter client and send it to our servers. We are using PKCS1 padded RSA but i get the error below when attempting to encrypt the data.

I/flutter (12394): Bad state: Reflectable has not been initialized.
I/flutter (12394): Please make sure that the first action taken by your program
I/flutter (12394): in `main` is to call `initializeReflectable()`.

The code responsible for this is as follows.

static String encrypt(String text, RSAPublicKey pubKey) {
    var cipher = PKCS1Encoding(RSAEngine());
    cipher.init(true, PublicKeyParameter<RSAPublicKey>(pubKey));
    Uint8List output1 = cipher.process(utf8.encode(text));
    return base64Encode(output1);
}

I've managed to get a non padded sample running fine but the PKCS1 padded encryption requires a random generator that is initialized through reflection and flutter is saying no.

Any help would be appreciated.

That's probably because you are using a package that uses mirrors. You can't use such a package with Flutter. — Günter Zöchbauer, Sep 11 '18 at 07:44
@GünterZöchbauer They have flutter compat. [pointycastle](https://github.com/PointyCastle/pointycastle#without-dartmirrors-or-packagereflectable-flutter) — Duncan Hoggan, Sep 11 '18 at 08:40
What version are you using? `1.0.0-rc2` is the only one that might work. — Günter Zöchbauer, Sep 11 '18 at 08:42
@GünterZöchbauer Yeah on `1.0.0-rc2` An un-padded RSA encrypt works fine. — Duncan Hoggan, Sep 11 '18 at 08:57
And you import it like explained in the link you posted above? In this case I'd create an issue in the plugins GitHub repo. — Günter Zöchbauer, Sep 11 '18 at 08:58
Yes the import is used correctly. I've forked and done a quick patch for now [here](https://github.com/duncanhoggan/pointycastle/commit/95bf515709202904beda9b71ae9a3770d3653710), would I raise it on the flutter/plugins repo? — Duncan Hoggan, Sep 11 '18 at 09:05
No, pointycastle is a 3rd-party plugin. Ideally you'd create a Pull Request in the pointycastle repo. — Günter Zöchbauer, Sep 11 '18 at 09:09

Duncan Hoggan · Answer 1 · 2018-12-06T11:08:14.190

1

The reflection based Random constructor has been replaced with FortunaRandom and seeded.

_random = new FortunaRandom();
_random.seed(KeyParameter(_seed()));

The PR has been approved and is in master now so no one should have this issue ever again!

edited Dec 06 '18 at 11:08

answered Sep 11 '18 at 09:30

Duncan Hoggan

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PKCS1 encryption in Flutter won't work without reflection

1 Answers1