TypeError:null is not an object(evaluating 'RNRdandomBytes.seed')

[leeeverest]

Error:Requiring module "node_modules\react-native-crypto\index.js",which threw an exception:TypeError:null is not an object(evaluating 'RNRdandomBytes.seed')

[pcowgill]

I have the same issue, but there's a small typo in the text @leeeverest included in the issue name and description:

RNRdandomBytes.seed -> RNRandomBytes.seed

[pcowgill]

The advice to get RNRandomBytes working seems to be that you should link the react native package react-native-randombytes (a peer dep of react-native-crypto) (see the docs here).

Of course, if your project doesn't need a shim for the crypto node core module, leaving the crypto polyfill out in your metro.config.js is a better solution than doing a react-native link, especially now that autolinking is the new way of doing things.

const nodelibs = require("node-libs-react-native");

nodelibs.crypto = null;

module.exports = {
  resolver: {
    extraNodeModules: nodelibs
  }
};

[parshap]

Perhaps we should remove this polyfill and just mention it in the docs instead of automatically including it since it requires a manual build. This has been my strategy with other modules that require react-native link: https://github.com/parshap/node-libs-react-native#other-react-native-modules

[pcowgill]

@parshap Yep, that seems like a good change to make!

[leeeverest]

Sorry for the typo @pcowgill ,i try react-native link ,but it did't work(EXPO bare flow,SDK 36,RN version 0.61.4),using react-native-crypto-js instead,it works,my fork: https://github.com/leeeverest/node-libs-react-native @parshap

[pcowgill]

@leeeverest Thanks for the updated. You might want to update the README in your fork too to reflect the library you're using now.

Looks like the package you're using instead, react-native-crypto-js, doesn't have many crypto functions implemented. I guess it covered the ones you needed to use for your app?

[leeeverest]

No,you are exactly right! @pcowgill ,i need ecdsa-secp256k1 or ed25519 algorithm,but this package didn't have these functions,i got new error in my app:not implemented yet,so sad.

[noahhayespluto]

@leeeverest did you ever get it to work? I'm encountering the same issue.

[quybeans]

If I understand correctly, the react-native-crypto & react-native-randombytes require rn-nodeify to work. Because there is a require('crypto') in their code. This will lead to require cycle error. But we want to avoid rn-nodeify.

I end up a solution making custom crypto.js file within my app.

The only function I need for my crypto is randomBytes function which return a Buffer, and I need a native implementation without resulting require cycle error. This looks like what I need.

yarn add react-native-get-random-values

// metro.config.js
const nodelibs = require("node-libs-react-native");

nodelibs.crypto = `${__dirname}/src/crypto.js`;

module.exports = {
  resolver: {
    extraNodeModules: nodelibs,
  },
};

// src/crypto.js
'use strict'
import { Buffer } from 'buffer';
const { NativeModules } = require('react-native');

const randomBytes = (size) => {
  if (NativeModules.RNGetRandomValues) {
    return Buffer(NativeModules.RNGetRandomValues.getRandomBase64(size));
  } else {
    throw new Error('Native module not found')
  }
};

exports.randomBytes = exports.rng = exports.pseudoRandomBytes = exports.prng = randomBytes;

This solves my need for crypto module. Until there is a 100% compatible crypto package for React Native.

[jfamousket]

Following @quybeans suggestion and code, I was able to patch the react-native-crypto package, replacing the randomBytes function, removing all require cycles and still having all the react-native-crypto functions by doing the following:

• Add react-native-get-random-values and patch-package package:

$ yarn add react-native-get-random-values patch-package

• Create a patches directory in your project root to patch react-native-crypto using patch-package.
• Create a file in the patches directory name react-native-crypto+2.2.0.patch. Note that the 2.2.0 depends on your react-native-crypto version, so the patch might not work if you have a different version. But this should be due to differences like new lines, spaces etc which can manually correct.
• Add the following contents to the file

diff --git a/node_modules/react-native-crypto/index.js b/node_modules/react-native-crypto/index.js
index f644543..e2ff55a 100644
--- a/node_modules/react-native-crypto/index.js
+++ b/node_modules/react-native-crypto/index.js
@@ -1,7 +1,17 @@
 'use strict'
 
-import { randomBytes } from 'react-native-randombytes'
-exports.randomBytes = exports.rng = exports.pseudoRandomBytes = exports.prng = randomBytes
+import { Buffer } from 'buffer';
+const { NativeModules } = require('react-native');
+
+const randomBytes = (size) => {
+  if (NativeModules.RNGetRandomValues) {
+    return Buffer(NativeModules.RNGetRandomValues.getRandomBase64(size));
+  } else {
+    throw new Error('Native module not found')
+  }
+};
+
+exports.randomBytes = exports.rng = exports.pseudoRandomBytes = exports.prng = randomBytes;
 
 // implement window.getRandomValues(), for packages that rely on it
 if (typeof window === 'object') {

• Finally run

$ yarn patch-package

• Also add a postinstall script to you package.json so the changes are re-applied after you install other packages

"scripts": {
// other scripts
"postinstall": "patch-package"
}

[mellertson]

Here is a package written for Expo projects, which fixed this issue for me. I have been running into this issue for some time now, but following the instructions to define crypto globally in expo-standard-web-crypto fixed it.

If you are not running an Expo project you could easily apply the same technique to fix this issue. The "magic" can be found in index.js, provided here for convenience.

/*global crypto*/
import getRandomValues from './getRandomValues';

class Crypto {
  getRandomValues<TArray extends ArrayBufferView>(values: TArray): TArray {
    return getRandomValues(values);
  }
}

const webCrypto = typeof crypto !== 'undefined' ? crypto : new Crypto();

export default webCrypto;

export function polyfillWebCrypto(): void {
  if (typeof crypto === 'undefined') {
    Object.defineProperty(window, 'crypto', {
      configurable: true,
      enumerable: true,
      get: () => webCrypto,
    });
  }
}

[Tjerk-Haaye-Henricus]

Hey there 👋

I'm running in this error too. Will this been solved one day or should we do the workaround ?