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.

In that case, look here:

https://en.bitcoin.it/wiki/Difficulty

This is the formula to estimate the hashrate (in hashes/second) based on the difficulty.
At this moment
hashrate = 15958652328578 * 2^32 /600

So, the estimation of the networks hashrate is 114.236.483.065.794.593.641 hashes/second

That's 114.236.483 Th/s

Now, let's take a reasonably recent version of bitmain's antminer, the S9... Some will use a better asic, some will use the S9, some will use older hardware... But for this estimation, i'd guess that the "average" ASIC is about an S9... If the actual average ASIC is more recent than the S9, the total power draw will be lower than what i estimate, if the actual average ASIC is older than the S9, i'll underestimate the power draw.
Hashrate of the S9 = 14 Th/s, power consumption is 1375 Watt.

So, you'd need about 8.16 million S9's running to provide the current estimated hashrate.
This many antminers would draw 11.219.654.580 Watt (11.22 Gigawatt)
The daily power consumption would be ~270 Gwh

The estimated power price is something you have to figure out for yourself, cause this is where the math stops...
If you estimate most of the mining power to be located in countries with cheap power, you'd have to estimate a lower power price than the global average, otherwise a higher one... If you estimate most of the mining power to be located in low wage countries vs high wage countries... If you estimate most of the ASIC's running in a server room vs at home (with no extra shelves, ups's , network infrastructure, cooling, security,...)

It has been disabled for many, many years IIRC, it was because of a vulnerability in SMF that allowed hackers to obtain a database dump with the unencrypted security questions.. So if these questions were left as they were, the hackers could have used them to attack accounts, so Theymos disabled the feature.

Sure, you can send them to whatever address you want, but why? You'll use gas for no good reason... I have about 10 dead tokens, i really don't care. I just ignore them.

If it was a targeted attack, the attacker must have known about cwwang's crypto holdings, otherwise it wouldn't have been a targeted attack.
This being said, there's plenty of malware that's included into many real and fake programs, usually tools that have something to do with crypto, meanth to infect as many people as possible in the hope of finding a wallet, or copy/pasting keys, or copying the thief's address whenever a btc address is placed in the clipboard.

Don't know about the classification, but sure, if your wallet is compromised, it's usually all keys that get stolen at once.


Hardware wallets.
There is no other procedure that can give you > 99% protection while spending from an ONLINE pc. There are plenty of really good procedures for airgapped wallets and paper wallets that are at least as safe as hardware wallets tough.

I'm not a windows admin, i don't really like windows OS, but to the best of my knowledge, not all malware can be seen from the taskmanager... Rootkits, taskmanager vulnerability's, replacing the name of system components,...

If you would use an S17 and solve a block and getting the coinbase reward (12,5 BTC, but going to be 6.25 BTC pretty soon) + the fees, the cost would still be different based on many factors.

There are places near hydroelectric dams where you pay 1 cent / Kwh (vs 30 cents/Kwh in some places in the EU), there are places where you can rent a building for a couple hundred dollars a month (vs several thousand dollars in some places), there are places where the basic income is just a couple dollars a day (vs > 1500 euro/month in some places).

IF you would want to calculate the average cost of 1 BTC, you would have to know:
- How much ASICs, which type and which batchnumber are currently mining on the main net
- Where they are running their ASIC's
- What the power cost is for each of these places
- How much the worker are payed in each mining facility
- How much the buildings cost for each place where an ASIC is running


Bottom line is: there is no information in the block as to who solved it, which hardware was used, where the miner was located... Sometimes you can find which pool the miner was using, but that's about it.
If you really wanted to solve this equation, you'd have to get a list of every buyer of every piece of hardware from all the ASIC vendors, then contact each buyer, find out where his ASIC is currently running (if it wasn't turned off), and get all the variables from each buyer (power price, labour cost, mining room cost,..)

Since this is impossible, the best you can do is work with averages... Get the specs of a reasonably new ASIC, look at the network difficulty, calculate how many of those reasonably new ASIC's are needed to push the diff to the current level... Then find out the average power cost, the average income, the average serverroom cost,... Apply those average to the number of ASIC's (and their specs: power draw, number of U's needed, amount of maintenance needed, average income,...) and you have an estimation... Not a real number, just an estimation...

Thanks for the word of mouth advertising, it's certainly appreciated

As for the price: my daughter is just a kid, the quality isn't professional, so i don't think her price will be that high. It'll probably depend on the amount of materials she needs and the difficulty of the project.

It's basically pocket money for her, and a way to get her interested in crypto... Basically, if you have a project, post the description here and make an offer as to what you'd be willing to pay her. It's up to her if she accepts the offer, but the odds are pretty big she'll accept if you don't offer an absolute low amount.

To give you an idear, the demo video isn't her best work (she made much higher quality videos, but they showed identifiable features, so i didn't want to upload them) , it was watermarked afterwards (hence the 2 watermarks). This video is 13 seconds and it took her about ~20 minutes to make. I guess for the demo video, somewhere around ~$5  would probably have made make her happy, so for a 20 second video i guess somewhere between $10 and $25 (depending on the requirements) + cost of the materials?

No worries about dev time, i'm currently working on a very small-scale semi-automated exchange script commissioned by a thirth party, so i'm happy to get a break from time to time

At the moment, all bingocards are final, there is no way to reshuffle the excuses. IIRC, i did this to level the playingfield (if you could change/reshuffle the options, it would be to easy to win the bingo ).

But, since this excuse wasn't in the bingopool when you created a bingocard, i have cheated and sneaked this excuse in just for once... It took like 30 seconds of my time to run a single update-query, so it wasn't a problem at all. It's not like the bingo is provably-fair anyways

btw, just for the record, i can't take credit for being a ln dev. I'm a fan, i run bleeding edge versions of ln daemons i recompile at least once a week and i try to submit all bugs i find, but i'm not nearly smart enough to be a ln dev

Wow, this is an old one, i'm happy to see it's still being used.

I added the string, altough 24 excuses are picked randomly out of the 33 potential excuses, so there's always a chance this excuse won't be picked when generating a new bingo card.

The current content of the excuselist:

I have something i have to get off my chest after re-reading some of the comments in this topic.

It's not because YOU have used an unreliable wallet for years and didn't have a single problem, that it's a good idea to recommend said unreliable wallet to others.

For example, coinomi only sent the seed to google's online spellchecker when restoring a wallet from seed (IIRC). It's perfectly possible YOU created a new wallet and your seed wasn't sent to google... Or maybe it was sent to google, but nobody malicious parsed the logs and they were truncated after a while. But the bloke you recommend this wallet to restores his wallet from seed aaaaaand poooof => a couple days later he's robbed blind.

Same goes for about any online wallet. Sure, loads of people use blockchain.info, but it's still an online wallet. They store your private key in THEIR database. Sure they claim it's encrypted, but it's still stored with them... I've seen dozens of people lose their lifesavings because they used blockchain.info. They fall victim to phising, they fall victim to plugins, they lose their access code,... But the major problem is: they're not the only one in controll of their own private keys, so they're not the only ones in controll of their funds.

Same goes for new wallets that aren't community vetted

Always use your own due diligence... Airgapped wallets using latest version of community vetted binaries are usually safest; properly generated paper wallets and popular (community vetted) hardware wallets are secure aswell.
From that point on, you really have to be carefull. Stay away from online wallets, and before using a desktop wallet: read and learn (even "good" community vetted, open source wallets can have vulnerabilitys... For example: electrum had a major one a couple years ago). Don't take any post on any forum at face value, there are lots of people that use some kind of unsafe wallet but by sheer luck never got robbed, and they'll recommend the wallet of their choice to anybody and their mother's... I've seen newbies, juniors, members, full members, seniors, hero's and even legendary's push unreliable wallets. They do so because they believe they provide a service and guidance to new members, but in reality they make those new members make unsafe choices.

It's nice and all, and i realise that if you've chosen a strong password the odds of anybody bruteforcing this hash is very, very, very close to 0.

This being said, i'm always a bit sceptical if a newbie enters the forum with an account that can be thrown away in a heartbeat and offers a very big reward for about any task... IF somebody actually succeeds, and by doing so helps you improve your security, what's stopping you from just logging out never to return to bitcointalk using the same account without paying the "winner"? After all, you don't have a reputation you can lose, nobody knows who you are, you're just an anonymous new member that can do whatever he/she wants and walk away without real consequences.

If you offer a reward, it should be helt in escrow by a trusted forum member... At very least you should give proof of funds (altough this is not sufficient imho)

No idear... Maybe some malware/virus/keylogger. Maybe phishing. Maybe physical access. Maybe an accidental backup in the cloud. Maybe a physical vulnerability on the OS level.
But the fact remains that if you were cleaned out, somebody must have had the opportunity to get to your private keys... This makes your complete setup compromised. You can never be 100% sure you are safe unless you start over with a clean install, clean wallets, ...

I personally have 4: a ledger HW.1 (discontinued ages ago), a ledger nano S, a trezor one and a trezor model T... I must say that i personally prefer ledger hardware, but that's just my personal taste. Both ledger and trezor make quality products. There are other vendors out there, most of them are legit, but those two brands are the most popular... And a large usebase is a good thing when it comes to discovering vulnerability's and longtime support.

But if you need a sollution right now, you can either find an old laptop/desktop and completely disable all networking hardware (or plain remove the networking cards) then setup bitcoin core or electrum as an airgapped wallet.

walktroughs:
https://en.bitcoin.it/wiki/How_to_set_up_a_secure_offline_savings_wallet
https://electrum.readthedocs.io/en/latest/coldstorage.html

An other possibility is making a paper wallet in a secure way... Basically, use a community vetted, trusted wallet generator to create a bip38 encrypted paper wallet on an OFFLINE pc (at least reboot it after the paper wallet has been generated), print on a locally connected printer (reboot the printer afterwards). Make several copys, laminate...

BEFORE actually using your new (secure) setup, i'd recommand a testnet setup first... Basically, run the airgapped setup in testnet mode, or create a testnet paper wallet... Fund the airgapped wallet/paper wallet with some tBTC and test if you are able to spend the funds afterwards. Only when you are confident you have a working procedure to access your funds later on, move on to the mainnet...

So, after reading your log, and looking up that address on a block explorer, i can pretty much say you were indeed robbed.
He used all unspent outputs completely, no change address was used. He overspent on the fee aswell, so he'd be sure the transaction would get confirmed quickly.

Since your wallet wasn't online at the time of the robbery, you can be certain the robber has indeed all private keys belonging to this wallet... Consider the wallet to be compromised, consider your computer to be compromised. If you hold any more funds on any other wallet, DO NOT open that wallet on that compromised PC... Buy a hardware wallet, create a paper wallet,.... Do whatever you need to do, but you should move any funds on any wallet that was on the compromised computer to a wallet that never touched the compromised machine as soon as you can without acting so hastely you make other mistakes.

But i cannot stress this enough: any funds on any wallet that was on your compromised machine is at risk. Just moving the wallet files to a clean PC is not sufficient, you need to create brand new wallets on a clean pc and move all funds from the old wallets (on the compromised pc) to the brand new wallets (that never touch the compromised machine)

I hate to be the barer of bad news, but those 8+ BTC are gone i'm afraid... +150 confirmations... I feel sorry for you.

I know it doesn't mean anything to you, but i gave your post a merit. You seem like the kind of person i'd like hanging around on bitcointalk. I hope this robbery didn't scare you away from crypto currencies (altough i would completely understand if it did). It's all hindsight now, but a hardware wallet or an airgapped setup would probably have been the way to go when holding >8 BTC...

Well, a compromised computer would do the trick... If somebody has access to your wallet.dat AND is able to capture your keystrokes when entering the passphrase, he can rob you blind.

Could you post (part of) your debug.log? If the log entry was generated on 02:39 , it means your wallet was running at that point in time... However, like i said before: it's perfectly possible to spend your funds while your wallet is not running, the only thing a thief needs is the private key(s)... When he has the key(s) he can spend your unspent outputs at any time he wishes, he does not need your wallet to be online.

PS: posting your log can decrease your anonimity, but it does not contain information that will allow anybody to steal from you again.

Well, somebody must have had access to your wallet.dat (since you're using bitcoin-qt). There are some other possibility's, but they're really far-fetched (like somebody using the json-rpc interface, but that would require access to your computer from within the same network, an unlocked wallet,a weak password).

Did you lock your wallet using a strong password?
Did you save your wallet.dat on the cloud?
Did you give your wallet.dat to somebody else (a spouse, somebody unknown,...)?
Does anybody you don't trust 100% have access to your computer?
Do you run a virusscanner?
Is there a firewall?
Do you install any programs from untrusted sources?
Did you import private keys yourself?

If somebody has access to your wallet.dat, or is able to export your private key(s) while bitcoin-qt was running, he can spend your funds whenever he/she likes, your wallet doesn't have to be online for this... He can just sign the spending transactions with the key(s) he stole earlyer.

Thanks for the pointers, especially the background and the amount of pictures she needs to take... I'll pass it on to her, or she can read your post when she checks this thread
She does have a tripod, but i think she sometimes bumps into it when making pictures. As for the watermark: the original video didn't have one, but we decided to use a free tool to watermark the endresult so she has copyright in case somebody decides to steal her work (so the final video ended up with her watermark AND the watermark of the tool we used to watermark the video). If any videos are commissioned on this forum, they won't have any watermarks on them