Capacitor Secure Key Storage Plugin

Reusable Capacitor plugin for secure key/value storage using:

• Android Keystore-backed EncryptedSharedPreferences
• iOS Keychain

This package is useful when multiple Capacitor apps need the same secure-storage native implementation instead of copying plugin code into each repo.

What It Supports

• Android secure storage via EncryptedSharedPreferences
• iOS secure storage via Keychain
• Simple key/value API:
  • set
  • get
  • remove

Current Platform Scope

• Android: implemented
• iOS: implemented

Install

npm install @khadarvsk/capacitor-secure-storage
npx cap sync

Usage

import SecureKeyStorage from "@khadarvsk/capacitor-secure-storage";

await SecureKeyStorage.set({
  key: "nostr_nsec",
  value: "nsec1example",
});

const { value } = await SecureKeyStorage.get({
  key: "nostr_nsec",
});

await SecureKeyStorage.remove({
  key: "nostr_nsec",
});

Example Wrapper

In an app, it is usually nicer to wrap the raw plugin methods:

import SecureKeyStorage from "@khadarvsk/capacitor-secure-storage";

const NSEC_KEY = "nostr_nsec";

export async function saveNsec(nsec: string) {
  await SecureKeyStorage.set({ key: NSEC_KEY, value: nsec });
}

export async function getNsec() {
  const { value } = await SecureKeyStorage.get({ key: NSEC_KEY });
  return value;
}

export async function removeNsec() {
  await SecureKeyStorage.remove({ key: NSEC_KEY });
}

Notes

• This package stores data securely on Android and iOS native platforms.
• If an app also supports web, it should provide its own fallback outside this package.
• On iOS, values are stored in the Keychain as generic-password items keyed by the provided key.