Transform (sign) artifact before publication to maven artifactory

I would like to sign all jar files before its publication to maven artifactory.
I found that it is very easy to write custom signer, but signing plugin is sadly not designed to modify existing artifacts before publications. I found a possible way how to do it by signing plugin (mentioned in the link above) but it is too hacky. Is there any official way how to transform artifacts just before publication? Or immediately after they are created. But in some general way which will be working with jar, war or with an android AAR.