return unionTransformers{gcm, aestransformer.NewCBCTransformer(block)}, nil
	}

	return storagevalue.PrefixTransformer{
		Transformer: envelope.NewEnvelopeTransformer(envelopeService, int(*config.CacheSize), baseTransformerFunc),
		Prefix:      []byte(prefix + config.Name + ":"),
	}
}

type unionTransformers []storagevalue.Transformer