It doesn't matter in terms of fees, but it still creates blockchain bloat and still results in blocks filling up more quickly, delaying the confirmation of other transactions.

Perhaps. If I make a transaction with three outputs (two payments and one change), then it is obvious that is the same person paying both those third parties. However, I can make a transaction with two outputs and completely obfuscate which one of those outputs is the change output, then when I send that change output to another third party there would be no way for an outside observer to be sure that it was me making that transaction. There is no requirement for such transactions to be in the same block, though.

I think the most likely reason you will find chains of unconfirmed transaction in the same block are either a centralized service with poor automated systems as HCP has outlined, or a user spending unconfirmed change without understanding what they are doing.

The max limit is 25 unconfirmed parent transactions.

Sure. In these cases it is probably a big centralized exchange or service processing multiple withdrawals in a row or something similar. As an aside, it's a very inefficient way to use bitcoin, since one transaction with 20 outputs is significantly cheaper than 20 transactions with 2 outputs each all chained together.

It is trivial to create a thousand new addresses, but yes, long chains like the one you have quoted above probably point to an automated process.

More or less:

You are looking for any wallet which will let you spend unconfirmed outputs. Most good wallets will let you do this, including the most popular wallets of Bitcoin Core and Electrum. You would simply sign and broadcast a transaction which has at least one change output back to your own wallet, and then immediately spend that unconfirmed change output in a new transaction. You can repeat this several times, up to a chain of 25 unconfirmed transactions.

Depending on the fees you choose for each transaction would depend on when they all get mined. If you keep the fees very low for all but the last transaction, and then pay a much higher fee for the last one, there is a good chance of them all being confirmed together in the same block.

It's not odd at all. This is normal behavior and occurs quite frequently.

Essentially, yes.

T2 cannot be confirmed until T1 is confirmed. T2 will wait in the mempool until T1 is confirmed, and will be confirmed either at the same time as T1, or in a later block than T1.

What you have described - T2 paying a much higher fee than T1 - is what is known as a "child pays for parent" transaction. If T1 is currently stuck in the mempool with too low a fee, you can make T2 with a much higher fee to effectively "boost" the fee of T1. A miner which wants to mine T2 to claim the high fee will also have to include T1 in the same block. Both transactions will then be mined in the same block, with the T2 child transaction incentivizing the miner to mine the T1 parent transaction, hence, "child pays for parent".

That guy says he worked on the project for a while. Don't see what his motivation would be to make something like that up.

On further examination, there is indeed an entire page on their GitHub which codes for this Tetris game: https://github.com/Foundation-Devices/passport-firmware/blob/b26d45bdeb240a7f631037b71c149f57f1d8c5fc/ports/stm32/boards/Passport/modules/stacking_sats.py

It also screams of unprofessionalism to me. You want people to store thousands or even millions of dollars worth of cryptocurrency on your device, but then you say "Lol, we made it play Snake and Tetris! Next update we'll add Frogger too!" Get that bloatware off the device, get the code down to the minimum required to function to minimize any attack surface, and focus on developing your security features instead of implementing stupid games.

What other stupid "hidden features" have they included?

Those kind of posts are easily covered by rule 1 - zero/low value, pointless, or uninteresting. I've reported thousands of posts like that (literally) with the simple comment "Low value spam", and my 100% accuracy suggests that the mods don't often disagree with my assessment of these posts. The problem is I could spend all day reporting such posts, and sometimes did, and by the time I woke up the next day there would be twice as many new spam posts to work through. Reporting the same user 100+ times and seeing no action taken against them is a pretty strong indication that you are wasting your time playing a never ending game of whac-a-mole.

What a hugely unfortunate boating formatting accident. I can confirm though, I was there at the time and this person also deleted all of my keys too.

This is not a flaw with bitcoin - this is a flaw with the user. If you can lose all your coins following one simple mistake, then your security set up sucks and you should take immediate steps to fix it. If your entire holdings are stored on one hard drive with no offsite back ups, no written down seed phrases, no redundancy at all, then you really have no one to blame but yourself when you lose everything because that hard drive becomes lost, damaged, stolen, fails, gets water spilled on it, or anything else.

No need to stop there. Your derivation path can have 255 additional levels to it after the master key m, and each level can support 2³² - 1 values if you are including hardened values. There are more valid derivation paths than there are private keys or seed phrases, by many many orders of magnitude. You could pick a derivation path made up of 255 randomly chosen numbers between 0 and 2³² - 1, and no attacker would ever be able to find your coins even if you told them your seed phrase.

The reason people don't do this is because it provides no additional security. Just as an attacker couldn't steal your coins in my made up scenario without knowing your derivation path, an attacker can't steal your coins in a real life scenario without knowing your seed phrase. Why choose to back up something in which it is easy to make a mistake with (long strings of random numbers) when you can back up something much harder to make a mistake with (seed phrases). In both scenarios you end up with the same amount of security and a back up you need to keep secure, but with seed phrases you also are far less likely to make an error and far less likely to lock yourself out of your own wallets.

If you are concerned about someone stealing your seed phrase, then either use an additional passphrase, encrypt it before backing it up, or use a multi-sig wallet. All are far preferable to rolling your own "security".

It sounds like OP is referring to making a purchase from a merchant who is using Coinbase Commerce as a payment processor. If that is the case, then you must send the amount of bitcoin which is displayed in the invoice. Do not try to do any conversions between bitcoin and fiat yourself, as you will end up with a slightly different result. Just pay what you are asked.

You do not need to pay any additional fees to Coinbase Commerce, but you will obviously need to pay the usual transaction fee for your transaction. Most wallets, if you try to send x BTC to an address, will send x BTC and take the fee from other coins in your wallet. If you are trying to pay direct from an exchange or other centralized service though, then most of these will deduct the withdrawal fee from your payment, so instead of sending x BTC it will send x-fee BTC.

Be aware of this so that your payment matches exactly the amount you have been quoted.

But this bill would give the government reason and permission to shake them down, if they want to. Running a service they don't like, or perhaps working on a project they don't like? Then you must now present thr tax records of all your users, and if you can't, then you are acting illegally.

If you want to run a service, and have to choose between a country which forces you to collect unnecessary KYC or risk a criminal charge and a country which does not do this, it's obvious which one you'd choose.

Sure. So if you use Ctrl+F and then manually type the address in to the search bar while reading it directly from the source to see if it matches what you have copy and pasted, then that is effectively the same as manually comparing the two addresses and is a good checking method. But using Ctrl+F followed by Ctrl+V is not, since it simply duplicates the same method you used to enter the address in the first place and does nothing to protect against clipboard malware.

I put my hardware wallet next to my computer screen for every transaction to make double checking easier. I got a 6 foot long USB cable from Best Buy for like $5.

All centralized exchanges. If you don't want the government spying on you and your transactions, then use decentralized exchanges such as Bisq or LocalCryptos instead.

In the US, we already spend more on our military than the next 11 countries combined, while also bankrupting people for getting cancer. Our taxes are already spent in the most moronic of ways, but almost everyone just pays them for fear of retribution. The government already knows they can do pretty much anything they like with your taxes, since they can just arrest you if you stop paying.

I still think the solution is the one I've outlined above - ban the spammers, punish the campaigns, punish the managers.

Deleting individual posts in isolation does nothing. A sig spammer is always incentivized to make more, and can churn them out just as fast as we can report them. If you start doing something which will actually affect their income - temp bans - then they may be motivated to change. If after multiple temp bans they are still not motivated to change, then a permanent ban provides no loss to the forum.

Most managers similarly have no incentive to clean up their act. Properly moderating their participants and monitoring post quality takes time and effort. Why bother doing that when you can just put in the minimum amount of effort and get paid the same amount? There is literally no downside at present to them doing this, since they are never punished for promoting spam. Start handing out temp bans to managers not doing their job properly, and they become incentivized to weed out spam and spammers.

And the worst of the worst campaigns, such as Yobit, can be banned from the forum directly.

---

Has anyone got a blank copy of my cryptohunter bingo card? I'm travelling away from home right now. This post might be our best result yet!

But why? Every extra piece of code has the potential to cause a bug or present a vulnerability. Why add in gimmicks like a snake game which no one is ever going to use?

Which is what you should be doing. The Ctrl+F method does not provide any protection against clipboard malware. If you are going to manually check the address from the source, then the Ctrl+F method is unnecessary. If you are not going to manually check the address from the source, then the Ctrl+F method alone does not prevent your coins from being stolen.

Either way, it is a bad method. Copy and paste to enter the address, then manually check. There is no point using the same method (copy and paste) to both enter and check the address.

Actually, more often than you might think. Mining blocks is a Poisson process, and so the probability of finding a block within the next x seconds can be given by the equation:

1-e^(-x/600)

I you set x to be 2 minutes (120 seconds), then you'll find that 18.1% of blocks, almost one fifth, are found within 2 minutes of the last block. To drop below the "1% of blocks" range, you have to lower your time limit to only 6 seconds.

This is a bad method. Let's say I copy an address to my clipboard I want to send some coins to. As soon as I do, some clipboard malware I am unaware of changes it to a malicious address. I then go to my browser and paste the address in, which has now been changed to a malicious address. I now want to double check the address. I hit "Find in page", I go and copy my original address again, the malware again changes it to the malicious address, and I paste the malicious address in to the search box. The malicious address in the search box matches the malicious address in my browser, I hit send, and I lose all my coins.

That's not correct. Whenever you purchase anything with bitcoin, the IRS treats that as you selling bitcoin for fiat. You are expected to work out the fair market price of your bitcoin at the time of the trade, and declare a capital gain (or loss) on any difference between that price and your cost basis. It doesn't matter how many other taxes you have already been hit with. It doesn't matter if you already paid tax on the USD you earned to buy the bitcoin in the first place, and you are paying sales tax on the goods, and the merchant is paying business tax, and all the rest of it. See Question 8 on this page: https://www.irs.gov/individuals/international-taxpayers/frequently-asked-questions-on-virtual-currency-transactions

Pretty easy given most people use centralized exchanges which report to the government. Let's say you buy 0.1 bitcoin on Coinbase and withdraw to your own wallet. Coinbase then tell the IRS that you are holding 0.1 bitcoin, what address you are holding it on, and how much you paid for it. At that point, you can mix or coinjoin your coins to obfuscate what you are doing with them, but the IRS still know you bought 0.1 BTC at a price of $xx,xxx.

Have you clicked on "This Tor Browser" on the left hand side on the about:debugging page?