@Override
    public List<MultifactorAuthenticationRegisteredDevice> findRegisteredDevices(final Principal principal) {
        val registrations = yubiKeyAccountRegistry.getAccount(principal.getId());
        return registrations
            .stream()
            .map(this::mapAccount)
            .flatMap(List::stream)
            .collect(Collectors.toList());
    }
This is {@link YubiKeyMultifactorAuthenticatorDeviceManager}.

@author Misagh Moayyed
@since 7.1.0
support/cas-server-support-yubikey-core-mfa/src/main/java/org/apereo/cas/adaptors/yubikey/YubiKeyMultifactorAuthenticatorDeviceManager.java