Purists may tear this explanation apart as its simplified and some people get REALLY mental about this stuff, but cryptocurrencies like Bitcoin are just a cryptographic code generated by lots of difficult math (a math problem that is impossible/nearly impossible to undo/reverse and gives a unique "answer"). This code represents the Bitcoin itself. To buy or sell it more math is done using bits from your side and the other person's side to make another new answer that is specific to you two and shows who now "owns" the answer (The Bitcoin) It's math and secret codes all the way down. It only has value because people choose to say so and is not backed by anything physical.
There are Exchanges (sites where you exchange real money for various cryptocurnencies) and Wallets (where you store the cryptocurrency as a digital code on your computer/hard drive/the cloud). Some Exchanges offer Wallets as a part of their site services, but it's not smart to have them store your cryptocurrency because they are unregulated like banks and people have lost it all when an Exchange closed down or someone (employee or hacker) stole everything. Once someone else gets your secret code that represents the Bitcoin...they own it. There is no way to get it back unless they choose to give it. There is no chargeback service or way to "undo". It's like mailing someone cash...it's now in their hands and they can do what they want with it, so it needs to be guarded and backups kept (Note this isn't a duplicate of the Bitcoin...its just a copy of all the math and a secret code to show you still own it)...so in case you accidentally delete your hard drive or have some digital issues...you can "recreate" the wallet as long as you have the codes. If you left your backup unprotected, with no passwords and laying in a cafe, someone could take that and recreate your wallet and take the Bitcoin. So everything you do needs to be kept secure with passwords and backups.
Another option is to buy directly from someone who has Bitcoin in their wallet where you hand them cash and they send the secret codes/math from their wallet to yours using the address (another bunch of math that looks like random numbers and letters) you give them. At the end of the day you have to trade someone or some service real money for that cryptographic code that represents the Bitcoin, and then have a place to keep that code safely until you use it. You can even print all the codes off on paper and put them in a safe so they aren't online or on a computer anywhere. But to use them you have to enter those codes back into a digital wallet...like putting cash in your bank account to be able to use your debit card.
There really is no way to do this TRULY anonymously for 99% of people since these purchases and sales are all recorded in a ledger called the "blockchain" which is a history of all the math and codes exchanged. You CAN do a sort of "money laundering" thing called "mixing" or "tumbling" where you pay someone else to try and hide your math in a bunch of other math, but then you are trusting a stranger not to just steal it all. Really nobody is going to be tracing the Bitcoin of a single person buying drugs online though, especially not a one time purchase. So fear of being found out this way is unwarranted.
There are ways where you don't need to trust strangers (except the exchange) but it's annoying and costly.
You need
- Accounts on multiple exchanges. (which know your identity to due intrusive spy laws thanks to our governments)
- A physical location that has people trading in real life (there are many sites for this, just meet in a public place for safety)
- Real wallets aka full nodes for both Bitcoin and coins like XMR which feature privacy by design. (this can be a real pain because of the insane disk space requirement and download time but anything else is not 100% trustworthy)
- An internet connection that is not traceable to you. You're recorded forever after all.
Then "simply" trade the BTC for XMR (or a similarly useful coin of choice, but I'm not sure if there are others with such extensive research), move the XMR from a real wallet you control to another, trade them again for BTC via an exchange that does not require you to give up your identity (very few left, hence physical trades).
Advantages:
- you now have fully private BTC to do with as you please
Disadvantages:
- effort
- cost. This is huge. Crypto exchanges demand INSANE fees. Unheard of in the real world. And real world trades with physical people usually have enormous markups that are even higher. If you want to have $100 in BTC you will have maybe $70 after all of this if you're efficient.
But if you want to buy N that is not really required since A is the one who has to make sure he stays secret. And since he's a massively wealthy multimillionaire he probably has people who do all of this in the best possible manner. If you want to cut the link to A then you can use real wallets between the exchange and A, without the additional XMR in between. Since nobody can prove who this middle one belongs to you cannot be held liable.
