Encrypt a Realm¶
On this page
You can encrypt the realm database file on disk with AES-256 + SHA-2 by supplying a 64-byte encryption key when opening a realm.
Realm transparently encrypts and decrypts data with standard AES-256 encryption using the first 256 bits of the given 512-bit encryption key. Realm uses the other 256 bits of the 512-bit encryption key to validate integrity using a hash-based message authentication code (HMAC).
Storing & Reusing Keys¶
You must pass the same encryption key when opening the encrypted realm again. Apps should store the encryption key in the Android KeyStore so that other apps cannot read the key.
Typically, reads and writes on encrypted realms can be up to 10% slower than unencrypted realms.
Encryption and Realm Sync¶
The following code demonstrates how to generate an encryption key and open an encrypted realm:
// Generate a key // IMPORTANT! This is a silly way to generate a key. It is also never stored. // For proper key handling please consult: // * https://developer.android.com/training/articles/keystore.html // * http://nelenkov.blogspot.dk/2012/05/storing-application-secrets-in-androids.html val key = ByteArray(64) SecureRandom().nextBytes(key) val config = RealmConfiguration.Builder() .encryptionKey(key) .build() // Open the encrypted realm val realm = Realm.getInstance(config)