@Override
    public void setKey(@NonNull final byte[] key) {
        super.setKey(key);
        identityKey = SecureUtils.calculateIdentityKey(key);
        derivatives = SecureUtils.calculateK2(key, SecureUtils.K2_MASTER_INPUT);
    }
Returns the key refresh phase of the network key

@return int phase
mesh/src/main/java/no/nordicsemi/android/mesh/NetworkKey.java