Wie kann ich Bitcoins kaufen ohne Anmeldung?

Could you elaborate on the process of purchasing Bitcoins without the need for registration? I'm interested in understanding the various methods that allow for anonymous or semi-anonymous transactions in the cryptocurrency market. Specifically, I'm wondering if there are any trusted platforms or services that facilitate this kind of purchase, perhaps through the use of decentralized exchanges or peer-to-peer networks. Additionally, I'm curious about the potential risks and limitations that might be associated with such transactions, such as security concerns, transaction speeds, and potential legal implications. Could you provide me with a comprehensive overview of the steps involved in making such a purchase?