throw new InvalidUserDataException("Unable to read secret key from " + sourceDescription + " (it may not be a PGP secret key ring)", e);
        }
        return readSecretKey(keyRingCollection, normalizeKeyId(keyId), sourceDescription);
    }

    protected PGPSecretKey readSecretKey(PGPSecretKeyRingCollection keyRings, final PgpKeyId keyId, String sourceDescription) {
        PGPSecretKey key = findSecretKey(keyRings, keyId);