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fix(secure-storage): make the ios simulator NSUserDefaults fallback opt-in #670

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Merged
NathanWalker merged 1 commit into from
Aug 4, 2026
Merged

fix(secure-storage): make the ios simulator NSUserDefaults fallback opt-in #670

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12 changes: 9 additions & 3 deletions packages/secure-storage/README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -113,9 +113,15 @@ const secureStorage = new SecureStorage(kSecAttrAccessibleWhenUnlockedThisDevice

## iOS Simulator

Currently this plugin defaults to using `NSUserDefaults` on **iOS Simulators**. You can change this behaviour by providing `disableFallbackToUserDefaults` to the constructor of `SecureStorage`. This then uses the keychain instead of `NSUserDefaults` on simulators.
The plugin uses the keychain on **iOS Simulators** just like it does on device, so no configuration is needed.

If you're running into issues similar to [issue_10](https://github.com/EddyVerbruggen/nativescript-secure-storage/issues/10), consider using the default behaviour again.
An opt-in fallback to `NSUserDefaults` on the simulator is still available for toolchains old enough that `SecItemAdd` fails there with `-34018` (`errSecMissingEntitlement`), see [issue_10](https://github.com/EddyVerbruggen/nativescript-secure-storage/issues/10). Enable it by passing `disableFallbackToUserDefaults: false` as the second constructor argument:

```ts
const secureStorage = new SecureStorage(kSecAttrAccessibleAfterFirstUnlockThisDeviceOnly, false);
```

Note that the fallback stores values **unencrypted**, under the raw key, in the same `NSUserDefaults` domain that `ApplicationSettings` writes to, so those keys can collide with plain application settings. Only turn it on if the simulator keychain is genuinely unavailable to you.

## iOS Keychain Access/App Groups

Expand Down Expand Up @@ -152,7 +158,7 @@ To setup:
```

## Credits
* On __iOS__ we're leveraging the KeyChain using the [SAMKeychain](https://github.com/soffes/SAMKeychain) library (on the Simulator `NSUserDefaults`),
* On __iOS__ we're leveraging the KeyChain using the [SAMKeychain](https://github.com/soffes/SAMKeychain) library,
* On __Android__ we're using [Hawk](https://github.com/orhanobut/hawk) library which internally uses [Facebook conceal](https://github.com/facebook/conceal).
* Thanks, [Prabu Devarrajan](https://github.com/prabudevarrajan) for [adding the `deleteAll` function](https://github.com/EddyVerbruggen/nativescript-secure-storage/pull/11)!
* Thank you [Eddy Verbruggen](https://github.com/EddyVerbruggen) for all the years of service and great work!
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16 changes: 4 additions & 12 deletions packages/secure-storage/index.ios.ts
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Expand Up @@ -11,23 +11,15 @@ export class SecureStorage extends SecureStorageCommon {
// This is a copy of 'kSSKeychainAccountKey_copy' which is not exposed from SSKeychain.h by {N}
private static kSSKeychainAccountKey_copy: string = 'acct';

constructor(accessibilityType: string = kSecAttrAccessibleAfterFirstUnlockThisDeviceOnly, disableFallbackToUserDefaults = false) {
constructor(accessibilityType: string = kSecAttrAccessibleAfterFirstUnlockThisDeviceOnly, disableFallbackToUserDefaults = true) {
super();

if (disableFallbackToUserDefaults) {
this.isSimulator = false;
} else {
const isMinIOS9 = NSProcessInfo.processInfo.isOperatingSystemAtLeastVersion({
majorVersion: 9,
minorVersion: 0,
patchVersion: 0,
});
if (isMinIOS9) {
const simDeviceName = NSProcessInfo.processInfo.environment.objectForKey('SIMULATOR_DEVICE_NAME');
this.isSimulator = simDeviceName !== null;
} else {
this.isSimulator = UIDevice.currentDevice.name.toLowerCase().indexOf('simulator') > -1;
}
// Only the simulator runtime sets this; anything derived from the device name can be spoofed by renaming a real device.
const simDeviceName = NSProcessInfo.processInfo.environment.objectForKey('SIMULATOR_DEVICE_NAME');
this.isSimulator = simDeviceName !== null;
}

this.accessibilityType = accessibilityType;
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