Swift 4 Xcode项目上架App Store后，用户可访问哪些文件与数据？

Great question—this is a critical topic for anyone building iOS apps that handle sensitive or proprietary data. Let’s break down exactly what a motivated user can get their hands on once your app is live on the App Store, and what steps you can take to protect your assets.

What a determined user can access #

• Sandbox files (databases, CSVs, plists, etc.): If a user jailbreaks their device, they can navigate directly to your app’s sandbox directory (typically under /var/mobile/Containers/Data/Application/<random-UUID>/) and access all files stored there—your core SQLite database, bundled CSV parsers, cached data, plaintext plists, and more. Even without jailbreaking, if you enabled file sharing via the UIFileSharingEnabled flag in your Info.plist, tools like iExplorer let users pull data off the device through a USB connection.
• Compiled binary & embedded strings: The app’s main binary (inside the .app bundle) can be extracted and disassembled with tools like Hopper or IDA Pro. Basic obfuscation won’t stop a dedicated reverse-engineer from picking apart your logic, and any hardcoded strings (like forgotten API keys or secret constants) are trivial to extract using the strings terminal command.
• Bundled resources: Any images, localized text files, bundled CSV/JSON data, or other assets in your app bundle are completely accessible. Once someone extracts your IPA file, these resources are sitting in plain sight to copy.

What’s harder (or nearly impossible) for users to access #

• Keychain data: Items stored in the iOS Keychain are encrypted and tied to your app’s bundle ID plus the user’s device security (passcode/Touch ID/Face ID). Even on a jailbroken device, accessing Keychain data requires the user to know the device’s passcode or exploit a serious system vulnerability—this is far more work than grabbing sandbox files.
• Encrypted files: If you encrypt your core database (using tools like SQLCipher) or proprietary CSV files with a strong encryption key (that’s not hardcoded in the binary!), a user who gets the file won’t be able to read its contents without the key. Derive the key from user input (like their passcode) or store it securely in the Keychain for best results.

Quick tips to secure your app’s data #

• Avoid plaintext storage: Never put sensitive data (API keys, user credentials, proprietary logic) in plists, plaintext files, or hardcoded into your binary.
• Encrypt critical files: Use strong encryption for databases and proprietary data files, and avoid hardcoding encryption keys.
• Disable unnecessary file sharing: If your app doesn’t require users to transfer files to/from it, turn off UIFileSharingEnabled in your Info.plist.
• Obfuscate and thin: Use Apple’s app thinning to reduce binary size, and consider obfuscation tools to make reverse-engineering more tedious (though it’s never 100% foolproof).
• Shift logic to the backend: For ultra-sensitive logic or data, keep it on your server instead of the client app. That way, users never get direct access to it.

内容的提问来源于stack exchange，提问作者Adam S.