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I would appreciate any contribution but the experiment will take almost 50 testnet BTC.
It will obviously not be destroying those coins so if you would like I could return it to you or to a faucet of your choice.

The address is mk8NxMJEPE8F1K2o9Z3QzJLQbnPHdML9mn. Let me know if you've any questions.

Thank you.

What would you need 50 testnet coins for, that 0.50 or 0.05, or 0.005 will not suffice? I don't have that much either, but you can always get from the many faucets a small amount. It's for testing, the amount should not matter.

But I'd like to also know if there are any other ways of acquiring such amount of testnet coins other than mining them.

Nope, you either run in regtest mode, or you mine tBTC...

Sometimes 0.5 tBTC does not suffice, for example: if you're designing a mixer... You'll need a lot of tBTC in order to do a proper taint analysis.

@OP: I run a faucet: https://tbtc.mocacinno.com and i've given tBTC as a loan in the past. I have > 50 tBTC (but most are on my hardware wallet at home, so i can't access them for another 3 hours)
However : since you're a newbie, i would require sufficient collateral for such a loan. The collateral should be sufficient to rent hashrate from miningrigrentals and mine >50 tBTC in case your run off.
To tell you the truth, the diff on the testnet is still very high and the block reward is ~0.39 tBTC, so i'm afraid it'll be a lot of collateral to loan 50 tBTC.

IF you're interested: i'm willing to use a trusted forum escrow to hold the collateral, no intrest, but ALL fees are payed by you (including the fees to transfer the collateral to me or the escrow, and the fees to transfer the collateral back to you). Please do not PM me, but post anything on this very thread... I don't like to hide in PM's, telegram, mails,...

What and why you are going to mine? And why you are asking to people to donate something to you? What are the benefits if I am going to do this?

testnet BTC are not supposed to have any value ... ... but ... yeah.

That's true, they don't have any value... But that doesn't mean you can mine them for free anymore...

I would give a tBTC loan to anybody who wants one, but for people i don't know i still request collateral so i get the tBTC back and i don't have to rent hashrate to mine new tBTC for my faucet out of my own pocket.

I know it kind of defeats the purpose, and i really wonder why there are people that insist on pushing the difficulty on the testnet so incredibly high by mining on the testnet with relatively new ASIC's... I'd love to mine on the testnet with my cpu, but if i did this i'd mine close to nothing  :(

I did a VERY raw calculation, based on prices i found on miningrigrentals:
You can rent an S9 with 16,5 Th hashrate for  0.00002/hour.
The diff is 10.5M
The block reward is 0.39 tBTC

So, if you run this S9 for a full day, it would mine:
 (((((16500000000000 * 0.39 * 600 * 65535) / 2^48) / 10500000) * 6 * 24) = 12.3 tBTC/day

A day of mining with this rented S9 would cost 0.00002 * 24 = 0.00048

So, mining 1 tBTC with rented hashrate would cost ~0.00004 BTC, NOT including the transaction fees, not including the fact that you'd end up with change on miningrigrentals, not including the time i'd need to setup everything, not paying for my efforts, not including the odds that i'm unlucky and hit less blocks than average,...

I understand completely. I wonder why the block reward is so small though, shouldn't it match mainnet, more or less.

This just means there are people mining something worthless. Or, mining not for profit, since one does not sell testnet coins.

It's much "cheaper" to just run the faucets every day to get more coins than you can mining with a single S9. That's so strange to me, but I wouldn't know, I don't hang around the testnet often. I have some on a Lightning wallet, but I also got those from a faucet. So I "test" them by buying starblocks or something like that.

Seriously, what could the rational be for the mining difficulty to be so high, or does it simply not cost some rich miner to unleash a few machines on the testnet ... maybe they are old equipment running on solar or something.

I don't follow Bitcoin's testnet closely, but I assume it's because the difficulty drops back to 1 whenever no block has been found for 20 minutes [1]? At least that would explain testnet's block height of beyond 1.6M [2] which means it already went through 7 halvings which would correspond with the block subsidy mocacinno mentioned.

[1] https://en.bitcoin.it/wiki/Testnet
[2] https://live.blockcypher.com/btc-testnet/

Wait i dont get it. I thought there are some online site which is even mention on bitcoin.org site and on this forum for getting the testnet bitcoin for free, i mean site like
https://tpfaucet.appspot.com/
https://bitcointalk.org/index.php?topic=950331.0

Are the site not working again?

There are indeed a couple of working testnet faucets. (I used to google for them.) But the amounts they give are usually small. You'll need a huge effort to gather big amounts like the 50 tBTC OP was asking.
I find mocacinno's offer reasonable. Basically OP would only lose the tx fees for the collateral, since he will return the loaned tBTC (and if any tBTC is lost for fees, that can be recovered from faucets).

^^ This ^^ is correct :)

It's a tad bit more elaborate tough...
If a block hasn't been found for 20 minutes, the diff indeed drops to 1.

Now, let's assume we've just had a diff adjustment at height x
at height x + 1980, the guy running a couple of ASIC's on the testnet decides to turn them off, block @ height x + 1981 isn't found for 20 minutes (diff = 1), block @ height x + 1982 idem...

Now, when we finally arrivate at x + 2016, the average time between 2 blocks > 10 min and the current diff is 1....
Sooooo... At the retarget, the diff will once again be 1 (the minimum), but it'll stay 1 for the next 2016 blocks.
After another 2016 blocks, the average time between 2 blocks is just mere seconds, so the diff is adjusted to 2.
After another 2016 blocks, the average time between 2 blocks is just mere seconds, so the diff is adjusted to 4.
After another 2016 blocks, the average time between 2 blocks is just mere seconds, so the diff is adjusted to 8.

Sooo, in this case, if the ASIC guy turned his ASIC's off @ height x + 1982, and turned them back on @ x + 2017, he'd be able to mine thousands and thousands of blocks in MINUTES... It would take a ton of retargets before the diff was adjusted to a height that would bring the average time between 2 blocks to ~10 minutes.

However, since he's the ASIC guy, he'd still be able to mine most of the blocks compared to a CPU miner.

Let's say the ASIC miner only has 5 Th of hashrate, while a cpu miner has 5 Mh => the ASIC guy produces a whopping 1000000 times more hashes per second than the CPU guy, so the odds of him finding a block at diff 1 is 1.000.000 times higher... Offcourse, at this point, things like other factors come into play (network speed, network hashrate, which nodes you're connected to, time needed to verify a block, IO ,...) but still...

Soooo.... to get a lot of testnet coins, just run a bunch of asics, or wait for diff to drop to 1 and then run the asics. But that's what everyone with an ASIC miner will do. I guess just keep it on for awhile, eventually you'll get at least a few blocks in when difficulty drops to 1.

You'd need to rent hashrate for a much longer time period if you don't own the mining hardware, whereas anyone with previous generation miners would be able to get something in.

7 halvings ... maybe testnet should be reset again and block rewards not get half, .. or maybe .. well, then how do we test the future, LOL.. id' like to see what happens in testnet if it's like the year 2140 or something equivalent (but only people with current day hardware can mine) where block reward is just transaction fees.

Or something like after every 2 or 3 halvings, it goes back up to 50 per block.

Alternatively, one can just use an altcoin or make your own fork, since it's for testing purposes. You'll get as many whole coins as you need. But, yeah, it's an altcoin ... (go fork and make Bitcoin Test Fork ABC XYZ BSV Gold Platinum Diamond Need It for Mixing Something...)

Hi, sorry for the late response.
I  would like to build a crypto exchange and a mixer.
And just like you say. I need enough coins to test stability.
I think I can give the collateral, but not sure what is it...
Please tell me the detail, thanks.

I'm currently on vacation for the rest of this week. On Monday I'll try to come up with a reasonable collateral estimation to cover 50 tbtc.

Speaking of the testnet bitcoins, the wallet address posted by the OP start with "mk" not even 1. Does this mean there's a particular wallet which are use for the testnet bitcoin or every BTC wallet are good to go?

You'll need to simply run bitcoin core with testnet=1 (edit bitcoin.conf), and then it'll generate testnet adresses, (which have a different prefix.)

With electrum you also simply add --testnet as a parameter and it should start in testnet mode. (Newer versions of electrum automatically come with a shortcut for testnet, on windows at least.)

it is not "mk" it is "m" and it is the well known initial character of a testnet address equivalant to mainnet addresses that start with "1". https://en.bitcoin.it/wiki/List_of_address_prefixes
as for wallet, usually it is developers who need testnet coins to "test" their own system so most don't need a wallet and instead use their own code.


you can run core with -testnet argument through command line too.
and you can create the shortcut of both on your system by adding the argument at the end of the location of the executable. on windows right click on the shortcut and select properties. in shortcut tab there is a box called "target" which has the directory like c:\.... at the end of it you can add that argument:
[/code]

Sooo... I'm taking a raw stab at this... To be perfectly honest from the start: THIS IS NOT A SALE... In the end, my estimation will include the price for renting premium hashrate, adjusted for bad luck, including fees, including rounding margins, some beer money for my time to setup tBTC mining... If you want to have tBTC to OWN, you'd better mine it yourself. As a matter of fact, i'd be happy to give you a cost estimation to help you setup a tBTC node, p2pool and teach you how to setup an ASIC in order to mine on the testnet p2pool node, i can basically guarantee that if you want to OWN a lot of tBTC it'll be cheaper (and more honest) to do it this way.
tBTC is completely worthless, and there is no need to hoard it, the dev's can decide to reset the testnet at any time!!!

The collateral will be high, but it's exactly this: collateral... If you give me the 50 tBTC back, you'll get your collateral back (minus the transaction fees!!!).... If you decide to run, i'll keep the collateral and use it to mine more tBTC to fund my faucet, and i'll end up with some pocketchange aswell.


So here we go... Cost estimation of what it'll cost me if you decide not to repay the loan and i want to get the 50 tBTC back so my faucet doesn't run dry.

Miningrigrentals
This is the cheapest: https://www.miningrigrentals.com/rigs/151500/?currency=BTC
0.00001800 BTC/THASH/DAY * 17 Th = 0.000306 BTC/Day

The formula to estimate the daily income:
(((((Hashrate (hashes/sec) * average block reward * 600 * 65535) / 2^48) / Difficulty) * 6 * 24)

The variables
Hashrate = 17 Th = 17000000000000 Hashes/sec
average block reward = 0.39 tBTC
Difficulty = 10.5M = 10.500.000

The result
((((( 17000000000000  * 0.39  * 600 * 65535) / 2^48) / 10500000) * 6 * 24) = 12.7 tBTC/day
50 tBTC / 12.7 tBTC/day = 3.94 days =~ 4days

The time i'll need to mine 50 tBTC
getting the escrow to release the collateral: 30 minutes
Setting up p2pool on my testnet node: 1 hours
setting up miningrigrentals: 30 minutes
Total: 2 hours @ $25/hour @ 8641 $/BTC = 0.005781

The total costs
4 days of mining  @ 0.000306 BTC/day = 0.001224 BTC to rent the hashrate
I'll have to fund mininrigrentals with a tiny bit extra (10%), since it's not guaranteed that i'll get the cheapest miner: 0.0001224 BTC
Transaction cost (2 inputs, 2 outputs, 10 sat/byte: 0.0000374
Labour cost: 0.005781BTC

Grand total: 0.0071648... So 0.0072 BTC would be acceptable collateral for a 50 tBTC loan.



As said before, the terms are simple:

• 1 month time to repay the 50 tBTC, after exactly 1 month i'll use the collateral to buy hashrate from miningrigrentals, so there'll be no way to get your funds back
• i want 50 tBTC back, you can use the 6 free, working faucets to claim the fees you've spend while testing
• i accept a couple altcoins or bitcoin as collateral, collateral can be helt by a trusted forum escrow if you want to
• all fees are payed by you (escrow fees, transaction fees to move collateral,...)

It will obviously not be destroying those coins so if you would like I could return it to you or to a faucet of your choice.

you can contact mocacinno (https://bitcointalk.org/index.php?action=profile;u=405464) and see if he can help you with some larger amounts of TBTC. he also has a faucet you may visit: https://bitcointalk.org/index.php?topic=5223320.0

meanwhile there are 3 active faucets that i use whenever i want to test something and they are enough for me:
https://testnet-faucet.mempool.co/
https://bitcoinfaucet.uo1.net/
https://coinfaucet.eu/en/btc-testnet/

If this is not a sale, you should not be involving money in any way in any transaction involving tBTC.

It would probably also be a good idea to tell the people who are posting nonsense that they need xx tBTC instead of 0.00xx tBTC that faucets give out, that there is no reason to need a specific amount of tBTC. Frankly, if you are unable to adjust the code in your application you are testing to account for the difference between 50 tBTC and 0.0005 tBTC, then your application is not ready.

I make the assumption that anyone asking for large amounts of testnet coins is a scammer looking to rip someone off who does not understand the diffidence between mainnet and testnet. It's also a somewhat trivial programming change to mask the fact that the reference client is running on testenet. Probably other clients also can be changed somewhat easily not to show that it's on testnet.

But yeah for programming 10=1=.1=.01 should not matter how many coins you have.

And if you are any kind of non scammer you can just rent hashrate be it at nicehash / mining rig rentals / wherever and for a few bucks get them yourself.
If you have a real project it's just the cost of startup.

-Dave

If i wouldn't request COLLATERAL, i wouldn't get anything back... Simple as that... If an established member would ask me to borrow some tBTC for tests, i'd give it to them without collateral, if it's somebody with a throwaway account, i request collateral because, eventough tBTC is WORTHLESS, it's still not FREE to mine tBTC... As a matter of fact, it's quite costly.

A real-world example, i really don't like art... I just don't get it... But, if my daughter makes a clay pot, colors it with those special ceramic (expensive) colors, then bakes it, it has a certain function for her (she decorates her room with them, for example).
The effective net worth of the artwork is $0, but that pot actually cost me $20 in raw materials. Eventough it's worth $0, my daughter still needs it to decorate her room, and if it's gone she'll need to make a new pot, worth $0 but costing $20 in raw materials.

If, one day, somebody bumps in to me in the street, i've never seen the guy, i don't know where he's from, but he asks for my daughter's pot and pinky promises to give it back... I'd request him to pay at least $20 in collateral. If he gives the pot back, he'll get his $20 back... If he runs, at least i have the cost of the raw material and my daughter can use the stranger's $20 to buy new clay, ceramic paint and power for my oven, so she can make a new pot (with an effective worth of $0, but costing $20 in raw materials) to decorate her room.

Same with these tBTC... They're worth $0, but i need to rent hashpower, setup a pool, do a lot of setup work and monitoring to mine them... So the cost to mine them is not $0, they're just worth $0, but their cost is a LOT higher...

As for your second remark... There are tons of things you'd need higher amounts of tBTC for. Sure, you can adjust your code to work with smaller amounts, but you shouldn't need to... Every adjustment you make results in a difference between your tests and your final production code. Also, as a simple example, i've written a mixer in the past, if you're going to create thousands and thousands of tumbling transaction to analyse the taint, you're not going to get very far with 0.0005 tBTC, especially since eacht transaction will cost you about 200 tSat in fees...






I personally don't think it's that easy to scam somebody with tBTC...

You either have to guide them to a fake wallet that you've compiled yourself to make it look like the testnet is actually the main net, get them to download said wallet and use it. Sure, the reference (non-gui) wallet is easyer to change, but i don't think you'll get any complete novice to run a cli wallet.
Or you have to get them to execute a cli command including --testnet or get them to execute a startup script where you've hidden the --testnet parameter, then convince them everything is normal while the wallet's gui is filled with the word "testnet".
On top of that, if they want to confirm the transaction on any thirth party tracker, you'd have to convince them the fact the tracker clearly says "testnet" is normal for the main net.

I don't say this kind of scam is impossible, i'm just saying that (for a scammer with these kinds of convincing strategies) it would be easyer to let your victim download a completely 100% fake wallet that isn't even on the testnet, and just shows whatever balance you've hardcoded, or whatever balance it gets from your command an controll server... Or, for sheer simplicity, sell them BCH or BCG for the price of BTC. These strategies would be far easyer than procurring tBTC and scamming someone with it.
Case in point: i've seen dozens of people getting scammed with BCH, i've seen people getting scammed by double spending, i've seen people getting scammed with 100% fake wallets... But i've never met somebody that was scammed with tBTC, and i've been around for a while. Once again, it IS possible to scam with tBTC, but there are far easyer methods around (or so it seems).

Personally, i've met situation where i needed vast amounts of tBTC, and i believe other people can run into the same problems... I could turn a blind eye because somebody *might* try to scam (since it's not impossible), but i try to think that people might actually need tBTC for real life tests.

BTW, mining tBTC, especially in vast quantities is NOT that easy as you'd think... The block reward is 0.39 tBTC/block and the diff (last time i checked) was >13M. Next to the high diff and the low block reward, you'd have to setup a full node and setup a pool, or at least find a way to solo mine using rented hashrate using your own node. It's just not that simple. You've quoted PART of my post calculating how much work goes into 1 tBTC, you just snipped the part where the actual calculations took place. Since then the diff has even gone up, so those calculations are an underestimation...

I have seen 2 demo instances of clients that were on testnet that gave no indication of it.
Yes, it's probably easier to guide someone to a flake client that does something else or works another way, but yeah they are out there. Never saw someone scammed but lets face it, we are probably a small sample set.

I would also like to make the point that just about every person lately asking for testnet coins is a newbie. So it just looks really off. "Hi, I am new user, I need these to do some magical new project, gimme some"


I never quoted the cost, you were a quoted as part of another quote.
But, yeah there is a cost involved both in time and effort, if you have a great new project show it to us or tell us about it. Don't just come in and ask.

If you or Coding Enthusiast or OmegaStarScream or others came in and asked it would probably be a different story.
But the OP came in and posted 1 thing in 2017 in Chinese and then came back 3 years later asking for 50 testnet coins to build a mixer and exchange.
There are plenty of crap alt-coins trading for fractions of a penny to test the exchange with. And you know what, you can also test the mixer with any alt that has a newer codebase.

Just my view. I do also see your points, I just have less trust of humanity.

As for the 1 vs .1 vs 10 vs .001 there might be a few instances that it does matter but I don't think they come up that often.

Keep safe out there.

-Dave

Posted here already https://bitcointalk.org/index.php?topic=5200440.msg55175621#msg55175621

We are looking for 15-30 Testnet Bitcoin for a new application. Happy to make a donation!

Thanks!

Got them, thanks everyone!

Whats the point? Could you not just change the Genesis Block, hardcode it into your bitcoin core and basically create your own blockchain?

Then mine for few hours... you will have your own block chain with hundreds of your own tBTC. For free.

You don't have to change Genesis block or change the code even. All you have to do is to change network by running bitcoin core in RegTest or the new SigNet network and mine there. In RegTest the difficulty will not change so it won't take hours to mine, you can mine hundreds of blocks in seconds.

Yeah, definitely be better off using RegTest... you don't need to change/recompile anything... it's basically an "instamine" and you can freely test whatever you want. Refer: https://developer.bitcoin.org/examples/testing.html#regtest-mode

I learn something new every day... This was the first time i heared about the SigNet... It seems like a "better" testnet. I have no idear how i missed this info :)
https://en.bitcoin.it/wiki/Signet

Regtest is great for small scale tests, but the lack of a real "network" has stopped me from using it for large scale tests... It is, after all, a network in a single box...

Yeah, not that many seem to be aware of SigNet maybe because the addition to core is only a little over a year old. I myself wouldn't have known about it if I weren't looking at chainparams.cpp (https://github.com/bitcoin/bitcoin/blob/master/src/chainparams.cpp#L275).