Remove insecure Math.random() fallback - #70
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The fallback existed because remote debugging in Chrome ran the JS bundle in the browser's V8, where synchronous native module calls are not supported. Remote debugging in Chrome was removed from React Native before 0.81, the minimum version this package supports, and the bridgeless check already made this path dead code on the new architecture. Removing it guarantees that crypto.getRandomValues can never silently return predictable values from Math.random(), which is the correct failure mode for code generating key material. If the native module is unavailable, TurboModuleRegistry.getEnforcing throws instead.
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Why
The
Math.random()fallback existed because the old "Debug JS Remotely" mode ran the JS bundle in desktop Chrome's V8, where synchronous native module calls are impossible (nativeCallSyncHookis undefined), so callinggetRandomBase64would throw. The fallback kept apps from crashing while debugging — at the cost ofcrypto.getRandomValuessilently returning predictable values.That rationale no longer applies:
RN$Bridgelesscheck already made the fallback dead code.What
Removes
insecureRandomValues,isRemoteDebuggingInChrome, and the branch that invoked them.getRandomValuesnow always uses a real CSPRNG (ExpoCrypto if present, otherwise the native module). If the native module were ever unavailable,TurboModuleRegistry.getEnforcingthrows instead of silently degrading — the right failure mode for a polyfill that applications use to generate key material (e.g. wallet private keys), where a silently weak RNG is a catastrophic failure. This class of bug has caused real-world thefts (e.g. the BitcoinJS "Randstorm" disclosures).