The thread is not asking for the definition improving the SE rankings of a website or site page but for the difference between black and white hat SEO. Also the thread is not asking you to choose what to use.
White hat SEO is
using proper keywords
showing the relevancy of content to the user
usage of optimization technique
Black Hat SEO
showing duplicate content
Meta keyword stuffing
Difference between White Hat SEO & Black Hat SEO:
White Hat SEO is safe & it gives result organically in SERP & Black Hat SEO is unsafe & it gives result Quickly but it's a spam so I prefer WhiteHat SEO.
There is difference between blackhat techniques and white hat techniques.
1. Blackhat Techniques : A technique or way to force or cheat search engines that violates their guidelines to rank on the top of the SERPS. For Ex : Keyword stuffing, Link Baiting, Content Duplicacy etc.
2. White Hat Techniques : Technique which follows the search engine guideline to rank on top follow all declared procedures and factors to rank. Like. Good, long and relevant content, no content duplicacy, no link baiting, no cloaking etc.