Although probably not well-known, http://crackmes.de/ http://crackmes.de/ is a site I've been using to create / upload and also work on challenges for various R

Although probably not well-known, http://crackmes.de/ http://crackmes.de/ is a site I've been using to create / upload and also work on challenges for various RE applications for about 10 years now. I'd definitely recommend it to newcomers wanting to learn more about RE in general.