Re-encrypt the DB key with the stored key.

bramble-api/src/main/java/org/briarproject/bramble/api/crypto/CryptoComponent.java

@@ -153,6 +153,13 @@ public interface CryptoComponent {
 	byte[] decryptWithPassword(byte[] ciphertext, String password,
 			@Nullable KeyStoreConfig keyStoreConfig);
 
+	/**
+	 * Returns true if the given ciphertext was encrypted using a stored key
+	 * to strengthen the password-based key. The validity of the ciphertext is
+	 * not checked.
+	 */
+	boolean isEncryptedWithStoredKey(byte[] ciphertext);
+
 	/**
 	 * Encrypts the given plaintext to the given public key.
 	 */