Looking for repo and package for opendkim on debian 8 (Jessie)

I know that debian 8 (Jessie) is deprecated, but I have a debian 8 server that cannot be upgraded in the near future. I'm keeping that server running, and for the most part, so far, so good. However ... I'd like to install the opendkim and opendkim-tools packages on this server, and I can't find those packages in any apt repos. Does anyone know of any 3rd-party apt repo from which I could obtain the debian 8 packages for opendkim and opendkim-tools? Thank you very much in advance.