Dear Benny
Thanks for the great work reviving the S/MIME Util library! One of the features you were requesting from the previous maintainer was to make the cryptographic algorithms configurable. I do have the same need for some projects I am working on. Therefore, I added support for this type of configuration, without breaking the existing API. To check that configuration is indeed working, I added several tests. I hope my changes are helpful and fit with your architectural ideas for the library.

Your parent POM did not quite work out for my setup; therefore I removed the upstream dependence; I hope it is not too much of an issue to reintroduce it and make it work for your build pipelines.