Ik vermoed dat je toch beter wat uitleg kan geven waarom je deze data nodig zou kunnen hebben, anders is de kans op een positief antwoord zéér laag.

Als ik véél BTC in m'n bezit zou hebben zou ik héél ver weg blijven van een anonieme persoon die graag zou willen weten wie er allemaal véél crypto in huis heeft. Een $5 wrench attack zou ik écht niet willen meemaken.

BTW: mijn wallet is bijna leeg, bij mij moet je niet voor de deur komen staan met een baseballbat, ik doe toch niet open, en als ik zou open doen kan je maximaal 50 euro buit maken

The OP is talking about bitcoin, you need a sha256d asic. If you have a sha256d asic, you can mine other coins with sha256d as their POW algo without downloading and installing drivers or modules. As a matter of fact, if you run into an altcoin that claims to use sha256d as it's POW algo, but tries to make you download modules or drivers to mine said coin: walk away, it's a trap...

Or, if you're not that technically inclined, but still want a sneak preview of epochtalk, i have a reasonably recent version running here:
https://blog.mocacinno.com/

It'll only stay online for as long as i don't need the resources, and if a decent vulnerability is found it'll be taken offline in a heartbeat

About mining different coins with the same ASIC, i agree with pooya87 but wanted to elaborate.

Mining bitcoin is basically:

• Collecting and verifying broadcasted, unconfirmed transactions
• Building a merkle tree
• using the hash of the previous block header + merkle tree + nonce + extra data as a new block header
• Using an ASIC to iterate trough the nonces, each time creating a sha256d hash of the "new" header with the "new" nonce
• If the miner finds a nonce for which the sha256d hash of the complete header is  under the current target, he has found a valid block, and he's allowed to broadcast said block

So, as long as the coin uses sha256d as it's POW algorithm, you can mine said coin with a sha256d ASIC. IF the coin uses (for example) scypt as it's POW algorithm, it can be mined with a scrypt ASIC, just like all the other coins with scrypt as it's POW

Eventough btcpay is great, i'd probably recommand either electrum daemon or just plain bitcoind (bitcoin core daemon), and use json-rpc.

Your requirements talk about not having to include a checkout page, and working completely "behind the scenes", so i'm not sure if the overhead of btcpay would actually be worth it for you.
For core, you could take a look at -alertnotify=,  -blocknotify=, -txindex

If you're talking about bitcoin, it's just called double spending, and the fee is just called the miner's fee (not gas).
This being said, double spending unspent outputs on the bitcoin network is not that easy. Most nodes will reject a double spending transaction as long as the original transaction is still in their mempool. Sometimes scammers use a fee that's so low the transaction never confirms, and once it's dropped from the mempool of most nodes, double spending is not that hard. Other times the scammed person is just out of luck and the double spending transaction reaches a miner before the original one does, in which case the scammer "wins".
Offcourse, opt-in RBF is also a possibility

The security deposit always throws me off... I have been following the development for a long time, i've compiled bisq on my server and i open it up every time i want to do an exchange. But then i remember the security deposit and i use binance or some on-the-fly exchange instead.

I don't think it's illegal to buy something on the darknet, as long as the product itself is legal both in the seller's and the buyer's country. However, the odds of the seller actually having a legit business, and him/her paying taxes on the product he/she is selling is small.

The problem was that i did my homework, and i wanted one specific kind of hempseed: a seed that grew well in my climate, was relatively cheap, was relatively resistant to fungi and rot and that had both <0.2% THC and a high percentage of CBD. I ended up with one specific "brand" of hempseed, and for that specific "brand" i only found a handfull of sellers.

Some of these sellers no longer had the product on stock, some of the sellers only did B2B (business to business) sales, some had very poor trustpilot reviews... So i basically ended up with 1 seller that had the seeds on stock, sold to private persons, had a reasonable price and a reasonable trustpilot review.
I really did not like talking to him. So far, i've payed him allmost 2 weeks ago, and i still don't have the seeds in hand either,... And like i said before: he's not living on the other side of the planet, if i get in my car tomorrow morning i can be at his shop's door before nightfall. I do plan on leaving him a review on trustpilot, and it'll most likely won't be all that positive. However, if i do finally get the seeds in hand, it'll probably be 2 or 3 stars. If i don't get the product it'll be the minimum amount (i think that's 1 star).
I don't think the client is king, a client can be a pain in th *ss and a seller doens't have to bend over backwards whenever a client asks something completely absurd... However, a client is still a client, and a basic notion of professionality on the seller's side is the least i'd expect, especially if a client inquires about a payment that has been made 4 days ago and still doesn't registers.

Lightning:
you'll need a lightning wallet for this task.
You send your funds, on-chain to the lightning wallet, then your lightning wallet uses this unspent output to create an on-chain transaction opening a lightning channel with an other node. From this point on, you can pay lightning invoices offchain using this channel. Once no more funds are left on your side of the channel, you can either leave it open or close it using an on-chain transaction. This closing transaction will distribute the funds between you and the node you had an open channel with, how much each partner gets depends on the state the offchain transactions left the channel in.

I've used zap wallet in the past, and on my mobile i use eclair. To be 100% honest, i found eclair more user-friendly than zap.

I'd urge you to use zap or eclair on the TESTnet before trying it out on the mainnet... Eclair defenately has a testnet version, there are testnet lightning nodes, and even a testnet lightning store.

Wasabi & CoinJoin
Wasabi is a wallet that has built-in support for coinjoining. Coinjoining is usually fine privacy and security-wise. Other options are mixing or exchanging your BTC for a privacy-centered coin, and after moving those funds around for a bit back to BTC.
Each of these methods has pro's and con's, but they depend on your point of view... If you really want the highest level of anonimity, you'll probably need more than one method.

To be honest, i've never had my deposit flagged (so far), but i've heared horror stories aswell. Apparently, some companies actually do some data mining and follow the unspent-outputs-trace several transactions deep. So, if you want to be certain your deposit won't get flagged, you might even move it around several times before spending it... I'm not an expert about this tough, somebody else might have something more usefull to say.

Using Bitcoin Core offline:
yes, you can create an address while being offline. An address is a hash of a public key belonging to the private key stored in your wallet. Your address is not "registered" with a central authority. If you create a private key, you can derive a public key, and you can hash this public key to generate an address. This address exists because you created a private key, not because it was broadcasted or registered.
It is possible to create 2 exactly thesame private keys, this is called key collision... The odds of creating a key collising when using a proper RNG are incredibly, incredibly small (allmost nonexistant).
When i say: "allmost nonexistant", i actually mean "allmost nonexistant"... Not like: you have 1% chance of having a key collision in your lifetime... No, those odds are waaaaaay smaller.

I actually did the math a while back: https://bitcointalk.org/index.php?topic=5240403.msg54220088#msg54220088
The actual discussion was about generating a private key whose public key hash was a predetermined address that was funded by somebody else, and this was the end conclusion:

Thanks for the feedback guys, and especially about the seedsman tip... At the moment, i'm waiting for seeds from a strain called kompotli, it's flowers should have less than 0.2% THC and up to 25% CBD (altough that's really the maximum, most fenotypes should have around 9%). The <0.2% THC was very important for us, since my wife does not want to be faced with the effects of THC, nor does she want to risk getting pulled over by the police and lose her drivers licence (driving under the influence of THC is illegal, you can lose your drivers licence if you get caught).

If i was informed correctly, the seeds should remain viable for 2 years in my fridge and up to 5 years in my freezer, so i hope i'm all set for the next couple of years... I have enough to plant 7 seeds/year for the next 3 years, ~50% female, 1 or 2 that die, so i should have at least 1 or 2 female plants/year, and i can put most of the flowers in the freezer for up to 5 years anyways.

I have no idear if the seller used the international transfer as an excuse and he was actually out of stock, but the main point is that even if he did this, it was still because of the FIAT transfer. If i would have used crypto, he had no option to hide behind the excuse he did not yet receive my money, since i could have proved  he received my funds without a shadow of a doubt.
I must say that i did not like the seller's attitude at all, he was rather smug and almost made fun of my question, but he was the only one with reasonable trustpilot reviews, selling this particular strain for a decent price to an enduser in the EU while having them on stock to.

This ^^ seems the most logical interpretation of the OP's question AND the answer is correct

However, i'd like to ask the OP for the reason wanting to "change the password". Is it because the initial password was weak and the bip38 encrypted key was exposed? In that case, just decrypting and re-encrypting won't help him at all (since the exposed encrypted key can still be decrypted with the weak password, and the resulting private key is equal to the private key from the bip38 key that was encrypted with a strong password)

I haven't heared the podcast (yet), i'm happy i don't have to go to the darknet to buy something that actually helps my wife tough. I'm not a pothead, eventough i did smoke some weed when i was (much) younger... But medicine is medicine. This plant contains allmost no THC, the amounts of THC you'd ingest are lower than if you'd sit in a room with somebody smoking a joint for just a couple of minutes.
My wife takes a cocktail of painkillers and NSAID's, and with CBD she's able to use less of the other drugs... Studies have shown CBD to be safer than most of the other things she takes, and it works... So why not. I'd imagine i'd also go to the darknet if this stuff was illegal in my country.

If these seeds actually arrive, and they sprout allright, next year i'll buy seeds from this bloke using crypto as a payment, and i'll do so on friday so he can send my package on monday. You live and learn... Stay away from international wire transfers and use crypto if it's available and you trust the seller

Any non-custodial wallet will do. There is no central authority in the bitcoin ecosystem. Teenagers are not prohibited, my 11 year old daughter has a wallet.

But, if you want names:

• Bitcoin core
• Electrum
• Wasabi
• Armory
• Knots
• Eclair

Or, you can create a properly generated, bip38 encrypted paper wallet, and give these to your winners (together with the password). This way you can even tell them to sweep the wallet, and add a disclaimer you'll sweep any leftover funds after x months... If they're not interested in the cryptocurrency ecosystem and just throw the paper wallet away, there is no use letting the funds dissapear...

Just make sure you stay away from any custodial wallets: web wallets (even non-custodial ones), freewallet, exchange wallets,... If you use those ones, underage people might get into troubles because custodial wallets have a habit of imposing their own rule-set onto their users.

Not an important discussion, but i need to vent  

Sooo... Prepare for a long story that has nothing to do with bitcoin, EXCEPT the conclusion.

My wife has a chronic disease that results in (amongst other things) a lot of pain. At the advice of our MD, she started taking CBD oil drops (which are legal in my country).
These drops work, but they cost like 25€/10 ml 3% CBD drops. You can get cheaper brands, but they taste like crap.

So, instead of paying a ludicrous amount to a shop, i decided to look around online, and i found a reseller that asked a reasonable price for cannabis seeds from a landrace that was tested and has >9% CBD and <0.1% THC. I say reasonable price, but if i would have been a reseller, i could have bought a full kilo of seeds for about 3 times more than he's asking for 20 measly seeds... But hey, that's economics right?

I bought some seeds from him. While checking out, there was an option to use bitcoin OR use a credit card. Because i'm convinced the btc price will go up (so hodling is a good strategy) AND because i didn't trust the seller 100%, i decided to go for a creditcard payment (so i didn't have to start a discussion with the vendor wether or not he got payed... CC's are older, these guys have better knowledge on how to verify payments in FIAT, so i decided to make his life easyer).

Payed him right away. Waited 4 days, status still "pending". Contacted the bloke via email... Got a snubby mail back where the guy basically started making fun of me: did i really think an international (within the EU, within SEPA) wiretransfer would be completed in 4 freaking days? Stupid me...
It took 8 freaking days to transfer my hard-earned money from my bank account to a bank account of a guy that still lives within driving distance... That's right, i can get in my car early in the morning and actually drive to this guy and arrive before nightfall.
The bank charges me allmost 3€/month plus a lot of additional costs, and they take more than a full week to do an electronic transfer. Bloody hell, what are they doing... Do they still write all transactions for foreign banks on a floppydisk and drive them around by horse and carriage?

After 8 days, the seller finally admitted he got my money, but at that time it was thursday, and he only sends items on monday and wednesday.
My seeds got shipped on the 20th, but the post is slooooow as hell.
In a little while, i'll have missed the planting window.

If i would have used bitcoin as a payment system, i would have won 8 freaking days. I would have payed the bloke, and 1 hour later he would have had a funding transaction that was confirmed several times, and he could have sent me the stuff i bought.
I don't like banks.

Possible...
The only way to find out is by doing a lot of grunt work...

• If a transaction uses multiple unspent outputs funding multiple addresses, the odds are big that the addresses belong to the same wallet
• If an address is funded with coinbase transactions, sometimes you can look at the OP_RETURN's of the coinbase transactions and see if they belong to the same pool as other addresses that were funded with coinbase transactions
• https://www.walletexplorer.com/
• google.com
• sometimes people admit owning the private key for a certain address
• or, if the last transactions funding a certain address were confirmed in very, very early blocks (2009-2010) and if those unspent outputs remained untouched ever since, odds are they belong to satoshi

No, not exactly, not a pool, an exchange... And there are defenatly people that can spend from this address. Ideally only employees of huobi.

These funds were sent to huobi by people having an account with huobi. They keep their funds on this exchange because they're either not familiar with the many, many, many risks of using an exchange as a wallet... Or because they use their balance to trade on a daily basis.

If an employee that has full access to this wallet decides to rob his/her employer, he can defenately do so. If a hacker or a physical thief can get his/her hands on these funds, they're gone. These are not mining rewards, they're the lifesavings of hundreds (maybe thousands) of customers.

I was still editing my previous post, adding more info... But it's an exchange... It's not this company's money, it's the money of the customers of this company (read my first post )

Well, it seems you've tracked huobi's coldwallet
 https://bitinfocharts.com/bitcoin/address/35hK24tcLEWcgNA4JxpvbkNkoAcDGqQPsP

Huobi is an exchange, this is their wallet. The funds funding that address do not belong to the person that has access to it's private key, but to the customers of the exchange.
This is a prime example why you should not keep your funds in an exchange wallet. If the private key holder goes scam, or gets robbed, hundreds, maybe thousands of people will lose their funds.

I doubt that the chinese mining pools pay more than 1 or 2 cents/kwh.

I've heared rumours that a lot of those mining companies are located near hydroelectric power plants, with a production cost of less than 1 cent/Kwh.

Also, this calculation is based on S9's, maybe they're running more performant hardware?

And last (but not least), you didn't include the fees... Only the block rewards.

On the other hand, you need to substract costs for the server room, labour costs,...

If you drop the average power price to 1 cents/kwh, you'll end up with something like ~$1500/BTC, and the current preev rate is $7100.
If you drop the average power price to 2 cents/kwh, you'll end up with something like ~$3000/BTC, and the current preev rate is $7100.
If you drop the average power price to 3 cents/kwh, you'll end up with something like ~$4500/BTC, and the current preev rate is $7100.
If you drop the average power price to 4 cents/kwh, you'll end up with something like ~$6000/BTC, and the current preev rate is $7100.
If you drop the average power price to 5 cents/kwh, you'll end up with something like ~$7500/BTC, and the current preev rate is $7100.

@iasenko : Apparently, my memory looks like a swiss cheese, full of holes

What i was thinking about was the server compromise in 2015 where Theymos explicitly asked everybody to disable their secret questions
https://bitcointalk.org/index.php?topic=1067985.msg11445725#msg11445725


However, you are 100% correct, the secret question isn't technically disabled... But using it will lead to a locked account.