Doorway Pages are web pages designed and built specifically to draw search engine visitors to your website. They are standalone pages designed only to act as doorways to your site. For Clocking refer this thread: https://forums.digitalpoint.com/threads/what-is-clocking-in-seo.1657470/
I hope you are aware about both of that are black hat SEO techniques. But both are used in different ways. The doorway pages are used to manipulate users where the submission has been done with attracting keywords or information and the user will redirect to some other page. For e.g. The link is given for sports and when you click on it you will redirect to some other page such as medical equipments or etc. The cloaking is used to manipulate search engine robots where the hidden contents are used on the web site. The site owner using hidden content in the coding as well in the body of the site where the font are used same color as the theme and so that the user cannot able to see it but the robots will crawl it.
agreed! With The Dharmik opinion. Google takes doorway and cloaking very seriously and consider it as a black hat techniques which will artificially increase your site ranking. If you get caught by Google then you will surely hit by their webspam department.
The search engines takes doorway and cloaking very seriously and ponder over it as a black hat techniques that may artificially increase your web site ranking.