According to the web search results, there are nine countries that have placed an absolute ban on cryptocurrencies, meaning that it is completely illegal to use, trade, or mine them. These countries are Algeria, Bangladesh, China, Egypt, Iraq, Morocco, Nepal, Qatar, and Tunisia.
Some of the reasons for these bans include concerns about money laundering, terrorism financing, tax evasion, fraud, speculation, and environmental impact. However, some experts argue that these bans are ineffective and counterproductive, as they limit the potential benefits of cryptocurrencies for innovation, inclusion, and development.
Cryptocurrencies are a complex and controversial topic that have different legal and regulatory implications in different jurisdictions. If you are interested in learning more about the legality of cryptocurrencies by country or territory, you can check out this Wikipedia article or this report by the Library of Congress.