The practical comparison
| Question | Android Keystore | Apple Keychain |
|---|---|---|
| Primary role | Generate, store, or use app cryptographic keys under platform policy | Store small secrets, keys, certificates, and identities |
| Hardware protection | Available on supported devices and configurations | Device security and Secure Enclave integration depend on item and API design |
| Stores an entire photo library | No | No |
| Replaces authenticated file encryption | No | No |
| Survives every uninstall, reset, or migration | No universal promise | Depends on accessibility and migration attributes |
Android explains that Keystore can keep key material non-exportable and, on supported devices, bind it to secure hardware. Apple describes Keychain as an encrypted database for small pieces of sensitive data. Read the Android Keystore documentation and Apple Keychain Services overview.
Example: A vault stores encrypted photo files in private app storage and uses platform-protected material to help unwrap a vault key. Copying only the ciphertext to another phone should not automatically reproduce the original device’s protected key context. A portable backup therefore needs a separate, intentionally designed recovery path.
Why a vault needs both layers
The platform service protects compact key material and enforces device policy. Authenticated encryption protects the much larger content and metadata. Key derivation handles the human pattern. Backup design handles device loss. Treating any one layer as the whole system leaves gaps.
Availability in NullVault
NullVault for Android uses Android Keystore-protected key material as part of local vault access. The released iOS app uses Apple CryptoKit and libsodium with encrypted private app storage. These are platform-specific trust boundaries and should not be described as identical implementations.
Limits
Platform key storage cannot stop someone who observes a legitimately unlocked screen. A rooted, jailbroken, debugged, or otherwise compromised live device can exceed normal assumptions. Hardware backing also does not create a backup; losing device-bound material without a separate recovery design can make ciphertext permanently inaccessible.
Guide reviewed: 28 August 2026.