Error after Fingerprint touched on Samsung phones: android.security.KeyStoreException: Key user not authenticated

Question

My app uses Android 6.0 Fingerprint API to protect AES key in the Android KeyStore. The stored key can be used only when user is authenticated by fingerprint sensor because

Answer 1

I also had this issue when using RSA and could solve it by creating a copy of the public key as soon as i want to encrypt some data.

// create a copy of the public key -> workaround for android.security.KeyStoreException: Key user not authenticated
val publicKey = KeyFactory
    .getInstance("RSA")
    .generatePublic(X509EncodedKeySpec(keyPair.public.encoded))

// encrypt with the public key
val cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding")
cipher.init(Cipher.ENCRYPT_MODE, publicKey)
val encryptedData = cipher.doFinal(data)