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June 18, 2021, 12:41:40 AM *
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1  Bitcoin / Project Development / [pre-alpha] new version of transaction fee checker on: April 23, 2021, 12:45:07 PM
The main functionality of my website ( was written back in 2017. IIRC, i was running core version ~0.12~ish (i don't update my node all that often).
Since then, loads has happened in our ecosystem... And my "usefull" tools became outdated and no longer functional.
I've been thinking about rewriting my site, but over the years so many things were "added on".... So i needed a radical new way of working, changing just a little bit won't do, it needs to rewritten completely and all the sub-tools need to be moved manually...

I'm currently in the process of rewriting the TOOLS section of my site in go... I'm thinking about using a small footprint webserver in go next to my main webserver, i'll then redirect all requests going to my tools to said go daemon. That way i can fix my tools while i'm in the process of thinking about how to move all that data without breaking stuff.

Because of the current state of the mempool, i'm releasing the first tool, eventough it's currently in pre-pre-pre-alpha stage. => Non-TLS had no added value, so i no longer run a service on this port, use the TLS version instead
TLS version =>

With this tool, you can check wether or not your transaction is in my mempool AND if you added a sufficient fee. You can POST the txid directly to if you don't want to use the form.

Bug reports are welcome BUT you'll have to realise this is pre-pre-pre alpha...
my immediate TO-DO list:
  • I'll defenately add TLS (https)
  • input sanitation
  • fix the menu... At the moment, clicking any link other than "using the feechecker tool" will send you on a wild goose-chase over one of my many ip's and open ports... Also, images and layout WILL break if you do something else than testing the feechecker
  • add more functionality

Also, this is not a linux service (yet). If it crashes, it crashes and it'll only start when I start it again... When i go to a beta phase, i'll make sure the service restarts if it crashes Smiley

In case you want to fix bugs yourself (or steal my code) =>

EDIT: just a little sidenote: i'll be gone during the weekend, i'll be back on monday morning to read potential bug reports Smiley
2  Other / Serious discussion / is it ok to give out testnet loans for collateral on: January 05, 2021, 05:56:03 AM
Since i started running a testnet faucet, i receive messages asking for bigger amounts of tBTC in my mail, my bitcointalk messages, my twitter account on a daily basis.

Because i was getting tired of keeping track of everything, i decided to open up a tBTC loan thread...
Since i want to keep any discussion seperate of the actual loan thread, i decided to open this "meta" thread instead... If you have arguments pro or contra tbtc loans, you're free to discuss them here...

The first post comes directly from my loan thread:
This sounds a lot like you are trying to profit from your testnet coin. In other words, it sounds like you are trying to assign value to your testnet coin. You should not do this.

tBTC is intended to aid the development of bitcoin and bitcoin services. By requiring transaction fees to be paid, you are effectively receiving value in exchange for your tBTC. You are also creating a market for tBTC.

Most tBTC faucets allow people to receive small amounts of tBTC, and ask that users return unused tBTC once their testing is complete. IMO this is how tBTC should be distributed to devs wanting to build/test bitcoin-related services.

What's the alternative?
I run a testnet faucet, I do my part in distributing tBTC freely... But from time to time i do get valid requests, people that actually make a good case as to why they need more than the tiny fraction of a tBTC that's been distributed by tBTC faucets (including mine).
What should i do with those cases? Just give them 100 tBTC and pray they return the funds eventough it's the first time i've talked to them, and they're using a throwaway email... I don't have an endless supply of tBTC, if i run out i can either close my faucet and stop helping people, or i can setup a mining node and rent a lot of expensive hashrate and pay out of my own pocket. People seem to think it's easy to mine tBTC, let me tell you: it's not... In my loan thread you see my calculation proving the testnet has a combined hashrate of over 1 Petahash, and the block reward is smaller than 0.1 tBTC/block... Mining on the testnet is HARD... It's shouldn't be, but it IS.. It's not fair, but it's a fact...

I've given quite a few tBTC loans over the last year, and allmost all of them return the tBTC BECAUSE i asked for collateral... If you count the hours and effort i put into mining the tBTC in the first place and setting up these loans, i'm defenatly not getting rich by handing out loans...
3  Other / Off-topic / building a NAS, need HW advice on: January 04, 2021, 05:52:38 PM
This topic has nothing to do with bitcoin, but this is about the only forum I frequent, and I know some of you guys are running full nodes on self-assembled small form-factor machines, so you guys might have something to add to this topic Smiley

Bottom line: I'm looking for a cheap NAS... I have a zyxel NAS325 at home, but they have a couple of serious vulnerability's and the vendor is no longer pushing out patches for this machine. Initially I tought about buying a zyxel NAS326, or an other low-end (cheap) NAS from WD or synology... However, none of these NAS'es really caught my fancy... They were either missing features, to limited, to expensive, to old, not enough updates, to much power draw, not enough drive bays (do you know they sell NAS's with one drive Roll Eyes )....

So, i tought to myself: why not build my own machine, or (even better) buy a cheap pre-built configuration and add one or two extra 2,5" disks. That way i have full controll over the hardware, and i can easily install centos or bsd and have full controll over the os aswell (including regular patches).

The problem isn't that i cannot build a small pc, but rather that i have no clue where to get the best bang for my bucks... I'm used to looking at server configs at work, but i don't have to pay the bill when i pick a suitable config Smiley
Also, at work, it's either POWER hardware or i get a list of approved hardware from SAP and i basically have to fill in the very limited amount of gaps...

So far, i had 2 idears:
buy a raspberry... But then i'd have to buy an rpi, a psu (if i want to use 3,5" disks), a NAS HAT, cables, heat sinks, screws, fans, cables....
The end result is rather pricey, looks very "artisanal", and i end up with a Cortex-A72 (which uses very little power, but isn't all that performant in case i want to use my build for other stuff.... like controll my smart plugs, or record my security camera's)

build a small pc... I had something like this in my mind:
GIGABYTE H410M S2, socket 1200 motherboard , µATX
Intel Celeron G5900, 3,4 GHz socket 1200 processor
cpu cooler
Kingston ValueRAM 4 GB DDR4-2666 Mhz
SilentiumPC Elementum E2 350W 80Plus
a case
1x 1Tb Harddisk, 2,5" (for OS)
2x 3Tb Harddisks, 2,5" (maybe add one more for RAID5)
This way i have a small pc that uses relatively little power due to the celeron (which should be relatively efficient) and the 2,5" disks.... But still, prices do add up after a while (about 400-500€).

My main question: am i missing something here? Should i be looking at something completely different? AMD? pre-made machines? Complete rPi kits? Stick to a certain out-of-the-box NAS i missed completely?

4  Bitcoin / Development & Technical Discussion / tBTC loans on: January 04, 2021, 08:10:40 AM
This thread is meant for tBTC loan applications... I know some people disagree to lending out tBTC (especially for collateral), but this is NOT the place to discuss this. It's true that regtest exists, it's true that most tests only require a very small amount of tBTC, it's true there are loads of 1 sat altcoins you can use... But there are still instances where larger amounts of tBTC can be useful for testing purposes, and this is the thread to request a larger amount... If you want to discuss why i'm wrong when giving out loans, open a new thread and send me a PM with the link... I'll be happy to join your discussion

Since the current bull market, I get more and more PM's from people that want to borrow tBTC.
I have no idear if a bull market sparks innovation, thus the need for tBTC rises, or if these people are scammers that want to scam gullible newbies that enter the market.
I strongly believe that it's quite hard to scam somebody with tBTC compared to all the other scam methods around (and i believe most scammers will take the path of least resistance), so i hope the ratio of scammers vs developers is in favor of the developers...

This being said, I do think that developers of new services are a crucial part of the ecosystem, and since some developments NEED tBTC, I still believe in giving out tBTC loans to those that qualify.

Because i'm tired of individually handle PM's and mails, i'll just point borrowers to this thread instead in the future

So, from now on, the procedure for borrowing tBTC from me is as follows:
  • 1) You post in this thread to introduce yourself (especially if you're a member or lower)
  • 2) in the same post, you explain what you want to do with the tBTC
  • 3) in the same post, you tell me how much you want to borrow and for how long. Tell me which (alt)coin you'll be giving as collateral. Don't offer some unknown coin tough, if the coin you want to use isn't in the top-20 of the odds of me accepting it are low. If you want to use an escrow: no problem... Find one we both trust... Also: post your tBTC address you want me to fund
  • 4) i'll reply by give you a collateral quote or by denying the loan (for example, if no proper explanation as to why you need tBTC is given, or if i'm out of tBTC). Expect the required collateral/tBTC to be higher for long-term loans, higher if you give an altcoin as collateral, higher for people i don't know (people i trust completely won't have to give any collateral for smaller loans),... I'll also post an address for you to send the collateral to (unless an escrow is to be used).
  • 5) AFTER i receive the collateral (or AFTER the escrow confirms he/she is holding the collateral), i'll fund the address you posted in step 3
  • 6) There are no extensions... This service is 100% interest-free (tips are appreciated tough), i don't want to bother keeping a long list of exceptions and extensions, it's free, just make sure you ask enough time to begin with. You will have to repay me before the loanterm is over. The term starts at the moment i funded your tBTC address, and ends exactly after the agreed upon number of days/weeks stipulated in point 3. I WILL sell your collateral when the time is up... Also, I will probably leave negative trust on loan defaulters...
  • 7) The tBTC lost as mining fees has to be replenished by using a faucet... Incomplete repayments are possible, but i'll keep some of the collateral (a share equal to the amount of tBTC you're short + 50%)
  • Cool it's a free service, you pay ALL the fees!!! This includes, but is not limited to: the transaction fees to transfer the tBTC to you, the transaction fees associated with the collateral, the escrow fees,... No exceptions, i'm doing this for free, so i won't be paying anything out of my own pocket.

Collateral? Why? Why so much? Is it fair?

Whenever i give a loan to somebody i don't trust 100% i require collateral. Why? Because even-tough tBTC is completely worthless, mining it is far from free... Let me compare it to a real life situation: let's assume my daughter is great at art (she isn't, but let's assume she is). She loves painting oil on canvas, and her masterpieces are used all over my house because i love having paintings to decorate my rooms. These paintings are not worth anything (my daughter is only 12 years old, she isn't famous), but each masterpiece costs 100€ in raw materials.
One day, a complete stranger i have never seen before takes a peek trough my window and sees my daughter's paintings. He knocks on the door and asks to borrow 5 of them. He pinky promises to bring them back in 2 weeks. Mind you: i don't know the stranger, i can't trust him to even carry a valid passport, and i use the paintings to cover my walls... This means that if the stranger doesn't keep his word, my daughter has to paint 5 new "worthless" paintings to fill my walls, and it'll cost me another 500€ in raw materials.
Should i let the stranger walk away with 5 worthless paintings that cost me 500€ out of pocket? I personally wouldn't do this... I'd ask the stranger to give me 600€ for the paintings, and promise him he'll get his money back if he returns them after 2 weeks... And i would expect him to give my daughter a decent tip because she lent him her art...

Same with tBTC... It's worthless, but I do have a use for it (i'm running a faucet). If somebody wants to borrow tBTC, i'm willing to help them out (intrest free), but i'm not willing to let somebody I don't know walk away with tBTC i do need without any form of collateral.

The collateral should be sufficient to cover my "raw materials" + something extra for my troubles in case the borrower runs off without returning my tBTC. The extra collateral should incentivise the borrower to return my tBTC

Now, for the boring stuff:
How much does it cost to mine 1 tBTC?Huh?

The current block reward on the testnet is 0.097 tBTC/block
I'll have to mine 11 testnet blocks to earn 1 tBTC
The current difficulty is 157M
The formula's you can find on
network hashrate = D * 2**32 / 600
time to find one block = difficulty * 2**32 / hashrate

So, in our case
network hashrate = 157.000.000 * 2**32 / 600
network hashrate = 1.123.849.775.786.666 hashes/second
network hashrate = 1.123.849.775.787 kh/second
network hashrate = 1.123.849.776 Mh/second
network hashrate = 1.123.850 Gh/second
network hashrate = 1.124 Th/second
network hashrate = 1 Ph/second

Wow, 1 Ph??? Yup... 1 Peta-hash...
In order to mine a couple of blocks, we'll have to rent a semi-decent rig...
At the moment, a rig like this one comes with a good price/quality ratio:
It'll cost 0.00056916 BTC per 12 hours running @ 124 Th/s

with such a machine:
time to find one block = difficulty * 2**32 / hashrate
time to find one block = 157.000.000 * 2**32 / 12400000000
time to find one block = 5438 seconds

But we need 11 blocks...
11*5438 =~60.000 seconds

That's about 17 hours

So, if we rent the rig on miningrigrentals:
0.00056916 => 12 hours
0.00004743 => 1 hour
0.00080631 => 17 hours

Given that I would have to do all the grunt work (setting up a solo mining operation, renting the hashrate,..) and i would have to take all the risks, i'd round this up to 0.001 BTC/tBTC (this is just a ballpark figure, the actual collateral/tBTC will depend on a lot of factors)

Is this amount fair? Well, like i said, tBTC is worthless, but it's not free to mine... If i wouldn't ask for collateral, people would just borrow and forget... or run away... and no, the word of somebody i don't know doesn't count (i'm not that naive)... I'd be left with an empty wallet and no tBTC for my faucet... That doesn't sound fair either doesn't it?

5  Other / Beginners & Help / [TUTORIAL]getting a low-fee transaction unstuck by creating a CPFP with electrum on: October 29, 2020, 09:31:38 AM
Since the mempool is filling up nicely the last couple of days and i see loads of new and longtime members struggeling getting their transactions confirmed after paying a fee that's to low for the current status of the mempool, i decided to dedicate a long post to executing a Child Pays For Parent (CPFP).

What is a CPFP?
Well, if you create a transaction, you use one or more unspent outputs as an input for your new transaction, and your transaction creates one or more new unspent outputs funding an address created by the receiver and USUALLY the leftover funds (the change) funds an address created by your own wallet (the change address).
If the fee (in sat/vbyte) you chose when creating your transaction was to low (sometimes the wallet set a low fee in your place), miners won't have an incentive to add your transaction to the block they're currently trying to solve (yep, the fees go to the miner, NOT to the creator of the wallet), so the odds of getting your transaction confirmed are low.

A CPFP fixes this problem. A CPFP is taking one new unspent output created by your unconfirmed transaction and using it as an input for a new transaction. This new transaction should have a fee that is at least enough to cover the fee of your stuck transaction + the fee of your new transaction (minus the fee already payed for the stuck transaction).

If i miner wants to collect this big fee of the second transaction, he also has to put the stuck transaction into the block he's trying to solve.

A theoretical example
unspent output aaa with a value of 1 BTC funds address 1MyWalletAddress
you use unspent output aaa as an input for a new transaction funding address 1ReceiverAddress with unspent output bbb (value 0.5 BTC) and change address 1ChangeAddress with unspent output ccc (value 0.499999). The fee payed by this transaction is 1 - (0.5+0.499999) => 0.000001 (100 sats). Waaaay to low... This transaction is stuck in the mempool for ages if we don't do something...

Well, luckily both you and the receiver have access to an address that was funded by this stuck transaction:
you have address 1ChangeAddress funded by unspent output ccc
the receiver has address 1ReceiverAddress funded by unspent output bbb

Soooo.... Either you create a new transaction using unspent output ccc as an input or the receiver creates a new transaction using unspent output bbb as an input.
The fee you should pay for this new is:
(the optimal fee of the first transaction) + (the optimal fee of the second transaction) - (the fee already payed for the first transaction => 100 sat) + (something extra since you don't want both transactions to get stuck if there's a sudden influx of tx's in the mempool).

For newbies, it might be usefull to use tools like, together with block explorers like to get a hold of the sizes of transactions (yes, it's the size of the transaction that matters, not it's value... It's perfectly possible to transfer $1.000.000 in value and pay a smaller fee than transferring $50 in value... It all depends on the amount of unspent outputs used as an input, the amount of new unspent outputs created, and the type of wallet).

A little boilerplate background info before i start posting screenshots:
  • CPFP is NOT the only tool in your toolbox when being faced with stuck transactions. Ideally you should have enabled opt-in RBF so you can just bump the fee.. Or you could pay viabtc or use their free accelerator, or you could just wait it out...
  • I'm giving demos on the TESTNET... Yeah, at current feerates i'm not going to do a demo on the main net Smiley
  • I take no responsability if you follow this walktrough and things go wrong... DYOR before executing following steps
  • I'm using electrum... Why electrum? Well, to begin with, electrum is a popular wallet by itself... But, it also allows you to use many popular hardware wallets together with electrum without compromising your xprv. It also allows you restore wallets from many other popular vendors, and last but not least: it allows you to easily import multiple private keys... So many situations can be solved by using electrum, even if the initial problem wasn't "created" using electrum. Oh yeah, electrum runs on linux, windows, mac and android Wink
  • Do be carefull when downloading electrum: only download from AND verify ThomasV's signature!!!

Now, let's get to it... Creating a CPFP for newbies (the easy version):
Right click on the stuck transaction and see if there's a menu: child pays for parent... Follow the wizard Smiley

you'll be presented with a nice gui:

and what do we learn from this gui?
  • the sum of the sizes of the stuck tx + the cpfp tx is 417 bytes
  • since the testnet only requires 1 sat/byte, the gui proposes a fee of 417 sats...
  • since the stuck tx already had a fee of 226 sats, this makes the total fee for child + parent 643 sats

If presented with the following screen, just click on "sign", sometimes you have to enter your password or use your hardware wallet to sign

if presented with the following screen, click on "broadcast"

Now, let's get to it... Creating a CPFP for newbies (the hard version where you'll actually learn what you're doing and have full controll):
i started my electrum client on the testnet... But everything should work the same on the main net!

I "accidentally" created a tx with a fee of 1 sat/byte... For the testnet, that's actually sufficient... But we're going to pretend we're on the main net, and our  sat/byte tx will be stuck for days/weeks

if i copy the tx id and look it up on an explorer like blockstream, or blockchair, or blockchain,...

you can see the following things:
  • the status is unconfirmed... that's the big problem isn't it Smiley
  • the ETA is one block because we're on the testnet... You'll probably see a much larger number, otherwise you wouldn't be reading this walktrough
  • you see a fee of 1 sat/vbyte
  • you see i opted in RBF... If you see the same for YOUR transaction, there's a much easyer way to solve your stuck transaction... Just increase the fee with electrum's gui... But for this tutorial, i wanted to show a CPFP, so that's what we're going to do (eventough i can get this tx unstuck in an easyer way)
  • but the most interesting thing to see on this screenshot is: there are 2 unspent outputs created: one funding address 2MyMu3v5U7P7Ri2gThigxRn9VmandyepBVG with an unspent output with value 0.005 (this is the "payment"), and one funding address mjUxPsHYbn9rrs9c8bqNr4WFKCoeWCatmw with an unspent output with value 0.04499776 (this is the change)... Remember address mjUxPsHYbn9rrs9c8bqNr4WFKCoeWCatmw it's going to come back to haunt us

we want to show our unspent outputs in electrum

go to the "coins" tab, and you'll see a list of unspent outputs funding your addresses:

Do you see the unspent output funding my change address? mjUxPsHYbn9rrs9c8bqNr4WFKCoeWCatmw? That's the one we need!!! You could verify this by looking in the same "coins" tab to the "output point" column. This should be the tx id of the stuck transaction!!!
This tutorial is written from the sender's point of view... HOWEVER, it works exactly the same way if you're the receiver. In this case, you'll also see an unspent output funding the address you gave to the sender, this is the unspent output you want to use Smiley

once you've found the unspent output funding the change address created by the stuck transaction, do the following:

go to "preferences"

the transactions tab:

  • use replace by fee => check if you never want to create another CPFP
  • check advanced preview
  • the rest are my personal settings, you can do with them what you want after reading the help info

go to the "addresses" tab (wich you might have to activate by clicking "view" => "show addresses" and pick an unused address (or a used one, i don't care)

copy it

click on the send tab, paste it, click on "max"

since you enabled "advanced preview" in the settings, you'll end up on this page:

As you can see, you can manually set the fee for your CPFP tx... Remember, you need the fee to cover the fee for your stuck transaction AND your cpfp transaction... Calculating an appropriate fee is a completely different discussion... And since this post is already huge i'll skip it... As a rule of thumb, you should at least double the current fee, unless the stuck transaction is big (in that case doubling it won't do the trick).

click on sign

enter your password (or sign using your hardware wallet)

click on "broadcast"

here's the block explorer's view of the address i'm using to receive the change from my CPFP:

Now, this is concludes creating a CPFP... Now let's see on my node what we actually did... This step cannot be executed by you, and it's not something that's necessary to create a CPFP... It's just my way of showing what actually happened:

This is the mempool view of my CPFP tx: do you see the fee? It's much higher than the 1 sat/vbyte fee we used for our stuck transaction isn't it? What's even more important is to see the tx id of the stuck transaction in the section "depends". This actually means that a miner cannot claim the fee of the CPFP tx without also including the stuck transaction... The CPFP tx depends on the stuck transaction.
Once a miner mines a block that includes the CPFP tx, he also has to include the stuck tx, solving your problem Smiley

6  Economy / Service Discussion / My Bitcoin? on: September 21, 2020, 06:44:18 AM
I just noticed a new tab on

Does anybody have any info on this? I don't see any bitcoin logo or deposit address anywhere?
7  Other / Meta / Merit giveaway: is it a good idear? on: September 16, 2020, 10:53:43 AM
I'm writing this topic after responding in this thread:

The OP of this thread is giving away merit to newbies that promise to abide by the forum rules and copy/paste their favorite rule in said thread. I can only imagine it takes a newbie less than 30 seconds to rank up this way, 0 effort needed. I quickly noticed two of the recipients were on my ignorelist. These 2 ignored members have now ranked up, and can add a signature and have more lenient posting restrictions in general.

This means they now have an opportunity to partake in sigspamming, or they can now make money by selling the ranked-up account. Neither of these options is very appealing to me.

People that know me a little bit probably know i'm not a big fan of ignoring people. I always try to stay friendly and helpfull. I don't ignore people all that often. I value opinions and try to stay away from drama as much as possible (sure, we're on bitcointalk... 100% drama avoidance is very, very, very hard... If not, impossible). As a matter of fact, i basically have to notice a certain username multiple times when they're actively posting crap before i'm tempted to read their post history. And only if their posthistory shows they continuously post utter garbage they'll end up on my ignorelist. Just to say that today, 2 crapposters got ranked up...

This topic is NOT pointed towards the OP in the linked thread, but merely to discuss the general stance of other members towards merit giveaways. AFAIK, the OP in above thread is trying to do some good for newbies, and others have done merit giveaways long before he started his thread.

I think there's a fine line between merit giveaways that are beneficial, and merit giveaways that are toxic.

I've seen OgNasty give away merit to people that have mastered the technical details of signing a message. I've seen people that allow newbies to highlight merit-worthy posts... I think these forms of merit-giveaway are fine, since they at least require a minimum amount of effort of the participant.
But on the other hand, any giveaway that can be claimed with less than 15 minutes of work might do more harm than good (IMHO).

I'm sure we'll see a lot of different opinions on this subject tough Smiley

8  Economy / Goods / group buy => handmade BTC facemasks on: August 15, 2020, 08:25:58 AM
I'm working together with the owner of to start a group buy of

"custom, hand-made, bitcoin-themed facemasks"!

The masks are made of washable materials bought in the EU, and handmade by the store's owner.

These masks do not exist yet, there is no stock, they'll only be produced if i succeed in getting downpayments for >10 masks. Why? Because obtaining custom-printed, high-quality cotton is quite expensive. If i can't find 10 people that want a bitcoin facemask on Bitcointalk, the owner won't be able to ROI after having to buy the fabric.

The theme used for the masks will be very basic and look like this:

IF you own the rights to an other bitcoin-theme, we could defenately have a look at it, and see if we can get it custom-printed aswell!

This is how the facemasks will look (but using bitcoin-themed fabric)

It's perfectly fine to resell these items, or if you're from a big geographic area you can pool together to save on portage costs.

What's the price?
€12,5 + shipping & handling . Sending from Belgium, either tracked (and insured) or untracked (at receiver's risk)

preffered payment method = Bitcoin (on-chain or via the LN). LTC or ETH are also accepted.

How to get your own bitcoin-themed facemask?
  • contact me on this thread, or via PM. Tell me you country (not your address), the coin you'd like to use and the amount of masks you would like to buy
  • i'll be in rather close contact with the owner, so you'll get a quote in < 2 working days
  • if you accept the quoted amount, i'll send you an address or a lightning invoice (i can provide a signature with an address i staked back in 2016)
  • the owner wants a downpayment of at least 40% of the total quoted amount. The downpayment will be kept by me OR by a trusted thirth party bitcointalk escrow (buyer pays the escrow's fee). The downpayment is non-refundable in case you decide to get out of the deal. It is meant to cover part of the costs of the fabric the owner will buy.
  • as soon as 10 people have pre-ordered their facemask, the owner will order the custom-printed material and create the facemasks. There is no 100% guarantee the fabric will be 100% the same as the one in the picture (it'll depend on the printing company)
  • you'll have to send the rest of the money either to me or to a trusted escrow (exceptions can be made for highly trusted accounts). At this point, you'll also have to give me your address (can be encrypted using my private key, via email, via PM, or via privnote)
  • the masks will be shipped to you

If i don't succeed in finding 10 candidates before the end of september, all downpayments will be reimbursed 100%. Make sure i can contact you to exchange reimbursement details (either via PM or via e-mail).

If i do find at least 10 interested candidates, the first masks will probably be shipped around the end of September-first weeks of October.
9  Local / Markt / Belgische webshop voor mondkapjes on: July 30, 2020, 02:17:12 PM
Een vriend van me is begonnen met een kleine webwinkel. De BTW-nummer is nog in aanvraag.
Er worden mondkapjes verkocht, tassen om mondkapjes hygienisch op te bergen, netjes om wespen uit je bierglas te houden, kinderkledij, sjaaltjes,... (nog niet alles staat online op dit moment).

Ik werd gevraagd om de webshop helpen op te zetten (wordpress en woocommerce).

Omdat ik de eigenaar ken vanuit de crypto-community word crypto natuurlijk geacepteerd (naast paypal, overschrijving en creditcards via paypal). De eigenaar is momenteel aan het aanmelden bij om ook andere betalingsmogelijkheden kunnen aan te bieden. We hebben momenteel nog geen goeie plugin voor coins als ETH en dergelijke, maar op simpele aanvraag worden ook deze geacepteerd.

De crypto-payments lopen over mijn btcpay server. De eigenaar heeft me een xpub gegeven dewelke gebruikt zal worden om payment addresses van te deriven, en er worden ook lightning payments geacepteerd (deze gaan naar mijn wallet, en ik betaal dan een gelijkwaardige hoeveelheid aan de eigenaar).

Er is een fallback mechanisme voor crypto-payments indien mijn btcpay server zou timeouten: de "Nomiddleman Crypto Payments" plugin. Je kan deze ook gebruiken om met LTC te betalen.

Dit is een pre-release, dus geef me een gil als je iets ziet mislopen.

Ik ben niet de eigenaar, maar de échte eigenaar wenst niet langer aanwezig te zijn op bitcointalk, dus je kan mij aanzien als het officiële aanspreekpunt. Als ik vragen of problemen doorkrijg zal ik deze zo vlug mogelijk melden aan de eigenaar (meestal in minder dan 48 uur).

Ik ga ook proberen wat kortingscodes vast te krijgen voor deze community. Ik hoop dat ik een akkoord hierover krijg van de eignaar.
Here it is:
10  Economy / Service Announcements / [ANN]: buy handmade facemasks, pouches, scarf's with bitcoin on: July 30, 2020, 02:05:32 PM
A friend of mine setup a small home-business selling handmade facemasks, pouches to store facemasks during the day, devices to keep wasps out of your beer, baby clothes, scarfs,... and is currently in the process of making all legal arrangements.

I was asked to help setup a webshop... Just wordpress and woocommerce with some plugins.
I know this person from the crypto community, so offcourse bitcoin payments are accepted... Sadly, the world isn't ready for a crypto-only shop, so next to crypto, also paypal, wire transfer and CC's via paypal are accepted (the owner is in the process of getting accepted with more payment providers).

Bitcoin payments happen trough my btcpay server, either on-chain or via the lightning network! (on-chain addresses get derived from an xpub given by the owner, offchain payments go to me, and i'll foreward an equal amount of BTC to the owner).

Since my btcpay server is a tad bit slow, i also used the "Nomiddleman Crypto Payments" plugin, which derives legacy addresses from an xpub and shows the QR code... This is basically a failover when the connection to my server times out.

Like i said, it's a pre-release... It's in dutch, but the automatic google translate menu can be found in the right bottom corner.

I'm not the owner, but the real owner does not visit bitcointalk anymore and has no intention of coming back in the near future, so you can look at me as this store's representative. If you have problems with this store: send them to me and i'll foreward them to the owner (usually within 1 or 2 days...).

I'll ask the owner for some bitcointalk-only discount codes and post them (if I get my hands on them)

Here it is:
11  Bitcoin / Electrum / 4.0.2 => edit fee => change address on: July 15, 2020, 09:52:23 AM
I've searched a bit, but couldn't find this "missing feature" being described in an other topic (yet).

My environment:
Electrum 4.0.2 (downloaded from, verified the sig)
Windows 10 (my employer forces me to use windows  Roll Eyes)

Following settings:

Some background info: i try to empty out a wallet of mine... Completely empty it out (funds go to a safer hardware wallet).
So i want to use all unspent outputs funding addresses in my electrum wallet, create a transaction with a low fee (transfer between my own wallets, i do not need a confirmation that urgently) and the output of this transaction has to fund an address generated by my hardware wallet.

Step 1:

1) clicked the "send" tab
2) pasted the address generated by my hardware wallet
3) clicked on "max" (i want to empty out this wallet)
4) clicked on "pay"

Step 2:

That's nice and all... But i don't want to pay the 3.9 sat/byte fee that was proposed... I want to pay 1.1 sat/vbyte

step 3:

OOOOOPS... If i manually decrease the fee, a change address gets generated... That's not what i wanted... I clicked on "max", i want my wallet empty AND i don't want to overspend on fees... I don't want a change address...

Now, before i get all kinds of suggestions... They're not needed... I have plenty of workaround and technical knowledge to solve this one all by myself... I just wanted to notify ThomasV (or other dev's that are working on electrum) there was a usecase that isn't completely covered with the 4.0.2 UI

In case somebody wants the workarounds:
  • downgrade to 3.3.8, this glitch did not exist, since the fee slider is placed earlyer in the tx creating process
  • use the console
  • export the private keys, use core or to create the transaction
12  Bitcoin / Bitcoin Discussion / What's up with the need for tBTC? on: July 09, 2020, 06:00:46 AM
I run a tBTC (testnet Bitcoin) faucet, and i've publicly stated i would loan out tBTC to anybody who needs it in the past... Usually i get 2-3 messages per month requesting "random" amount of tBTC from newbies...

After I explain the collateral I estimated a couple months ago will no longer suffice because the difficulty on the testnet rose from 10M to >16M, the block reward went from <0.4 to <0.2 tBTC/block and the price per Th on miningrigrentals rose aswell since my posts about loaning out tBTC, they drop the subject never to be heared off again.

However, yesterday i received 16!!! messages asking for loads of tBTC (most of them in the ~100 tBTC range). The messages were evenly spread between bitcointalk PM's, my 2 public email addresses and my twitter inbox.

This night, 2 more messages, resulting in 18 requests in little over 24 hours...

I'm missing something here... Anybody knows some secret I don't?

I mean, electrum has released version 4... I could understand people asking for tBTC to test out the LN on testnet... But you wouldn't need 100 tBTC for this. Other than that, i'm drawing blanks...
13  Other / Off-topic / cheap storage on: July 01, 2020, 09:49:49 AM
Hi guys,

A bit offtopic, but since this is more or less the only forum i'm using, i still hope to get some non-spam replies.

I'm going to upgrade the proxmox environment on my dedicated host. Since i'm moving from proxmox 4.x to 6.x, odds are i'll break something and i'll have to restart from scratch.
It's pretty easy for me to backup my containers as a tarball, so in case something goes wrong, i can scratch the host and restore my containers.

This is where it's becoming problematic: my biggest container is > 400 Gb and i only have about 200 Gb free space on my device.

I was thinking about getting some free or payed cloud storage that supports mounting on my linux server, mounting said storage, defining the mointpoint as directory storage within proxmox, then create backups of my vm's using this storage. My proxmox instance will think it's back-upping to a local store but in reality it'll be back-upping to external storage.

I can then download the backups to a local disk on my nfs at home.

However, i'm struggeling to find a suitable storage provider. These guys charge an arm and a leg... I need ~0.5 Tb storage for one or two days, i'm not going to pay $50 to transfer 1 or 2 Tb while actually using ~0.5 Tb for one or two days...

Does anybody know a storage provider that provides nfs, sftp, ftps,... >0.5 Tb, short term contracts for a reasonable price?
A VPS provider with >0.5Tb HDD would also be perfectly fine, as long as the price is very reasonable.

Or does anybody have any other idears of how to solve this problem? If this was a machine from work, it would have been a 10 minute task, since i would have created a netapp volume, mounted it, and got everything done... At home, for private use, it seems everything is more difficult.
14  Economy / Service Discussion / Mixers using cloudflare's SSL certificates on: May 12, 2020, 09:19:59 AM
This post was written with a couple encounters with new mixer operators in mind... I won't point fingers, since i had several of these encounters over the last couple of years, so names don't really matter. It serves as a reference post i can point new mixers to when they implement a MITM in their workflow and show no intrest in fixing this.

In my experience dealing with new mixer operators, a discussion between the mixing operator and myself usually falls in this pattern:

  • Mixing owner: Look what a nice mixer i have, look at the nice pictures, look at all the bells and wistles, look at the fancy colors.... I even have moving images to keep you entertained while using my perfect service that is 100% anonymous in every way imaginable!
  • Me: hey OP, your mixer uses cloudflare's SSL certificates as a MITM and google analytics
  • Mixing owner: everybody is doing it, just have a look at our competitors
  • Me: It's not because everybody else is wrong, you have to be too
  • Mixing owner: some other lame excuse
  • Me: That's a lame excuse (but worded politely)
  • Mixing owner: we have a hidden service on tor
  • Me: most users wouldn't even know you're using cloudflare, so they won't switch to the tor mirror (if they even know how to do this)
  • Mixing owner: I'll put it on my todo list (under the section: "things to do when hell freezes over")

These discussions are defenately not limited to mixers, but should extend to any site that handles information you're not willing to share with law enforcement. It's perfectly fine to use cloudflare on your blog, your forum or on your site selling mouth masks.
It's not fine to use cloudflare on banking apps, ammo stores, mixers,...
I realise the irony that my own site is using cloudflare's ssl, but i don't handle any sensitive materials...

The following posts are grossly simplified. I tried to explain what's happening in terms so simple everybody could follow them. This, offcourse, means that if a tech-savvy person looks at the following posts, he'll say: "that's not completely correct, hey dude, you missed an important step". This is by design...

In order to show you what a bad idear implementing an MITM is, i'm going to work my way up from:
Part 1: A non-https site
Part 2: A https site using it's own certificate (aka, best case scenario)
Part 3: A https site behind cloudflare (where security goes wrong)

Last but not least
Part 4: A fictional example of somebody in a country where crypto is banned, using a cloudflare-ssl-using mixer with google analytics included,  and some general conclusions

You're probably best off if you read the parts in their correct sequence part 1 => part 2 => part 3 => part 4. This is because i sometimes skipped steps i already explained in a previous part.

I'll be splitting this post into 5 different posts, so i have some wiggle room for editing the content later on. If a mod thinks these posts should be joined, he/she is completely free to do so

Disclaimer: don't use mixers for mixing coins you received for providing illegal goods or services. That's not what the crypto ecosphere is all about. As a matter of fact, if you got your coins in an unethical way, i honestly hope you get caught...
15  Bitcoin / Bitcoin Discussion / this is why the world needs bitcoin on: April 24, 2020, 06:25:11 AM
Not an important discussion, but i need to vent  Grin

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?Huh 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.
16  Economy / Services / personalised stop-motion videos to promote your product/service/announcement on: April 15, 2020, 01:01:16 PM
My daughter is in lockdown, as is the rest of our country. Her teacher sends over some homework from time to time, and she gets some extra assignments from my wife and myself.
However, she has significantly more free time now than she had before, so she got bored.

As a hobby, she started doing stop-motion animations... She's not really experienced (yet) so it's not that professional (also, she's 11 years old)... However, I do think they look funny.

So, in order to learn a bit about the crypto ecosystem (and earn some crypto pocket money), i created an account for her (MenMs => she loves M&M candies Smiley ) and she's taking non-offensive requests for stop-motion animations. She is a minor, so this thread is self-moderated, and all offensive replies will be deleted. I'm an advocate for free speach, but keep over the top vulgarity out of this thread please.

A sample:

If you want a stick figure doing an unboxing video of your product, a lego figurine spelling out your product's name, a playmobil doll dancing to your company's themesong, an original wedding invitation stop-motion video, a physical "bit"coin rolling over your screen as a screensaver... Post in this thread with the description and  reasonable compensation of her time. I'll let her pick which projects she accepts (so there is no guarantee she'll take a project, only when she's interested and has spare time).

Last but not least, she has her own account, I take financial responsability. If you send her funds, and she does not complete her project, i'll reimburse you in full. Since she's my daughter, I will not act as an escrow since i'm not unprejudiced. However, a trusted thirth party escrow is accepted.
17  Economy / Games and rounds / [FREE PRIVATE GIVEAWAY] Bitcoin keychain on: February 18, 2020, 06:42:16 AM
Free Private Giveaway of a CHEAP, CHINESE, dropshipped keychain.

I'm trying out Themos's new feature:

Basically, in order to join this giveaway, you have to be at least a full member without negative trust from DT1. If you are elegible for the giveaway, follow these steps:

  • Visit to get a giveaway code
  • send an email to with this giveaway code AND a unfunded BITCOIN address you can use to sign a message to prove your identity (you don't have to use your real email addy, just create a free one on gmail, yahoo, gmx, protonmail, guerillamail, 10minutemail,... No link between your bitcointalk account and your email addy)

If you are one of the first 16 mails with a VALID giveaway code i receive, i'll put the sha256 hash of your giveaway code next to your slot (0-f) and announce a future block whose hash's last character is used to announce the winner.
Once the giveaway is finished the winner has 48 hours to send a mail to including his/her physical address (signed with the address in their original email) (including a phone number, so basically: your name, your street + number, your zipcode, your country, your phonenumber). The winner can also include his/her giveaway code for extra verification. You are allowed to PGP encrypt your reply email using my key that can be found on
I'll then proceed to dropship the cheap keychain to the address i have received for the winning giveaway code.

This way, there is no relation between the address receiving the keychain and your bitcointalk account. I have no idear if i'm giving a keychain to my best friend or my worst enemy... I have no idear if the receiver has been boasting about how many BTC he/she holds, or if he/she doesn't own a single satoshi... The only thing i know is that the receiver is full member (or higher) and doesn't have negative trust from DT1.

Since this is my first time dropshipping anything, i really hope everything works as it should... It's dropshipping from china, so it could potentially take a long time before you receive the package (normally 4 to 6 weeks, however, with the corona virus it might even take longer).

disclaimer: i'm testing out a new feature of the forum AND it's my first time dropshipping anything. IF, for some reason, there is a bug in the feature OR if something goes wrong with the dropshipping (including, but not limited to: not receiving the package, incurring extra custom charges,...) i take no responsability, i will not reimburse you, you cannot start a trial against me Smiley.
Full disclosure, to test out the system, i'll probably enter my own hash into the table aswell this time. Won't happen next time tough...

Also, if something goes wrong with the dropshipping, and any identifying information about me gets included in the box, i count on your discretion... Don't dox me for giving away a present!

Self-moderated topic because i want to be able to remove anybody posting identifying info about him/herself or me.

Let the games begin Smiley
18  Bitcoin / Development & Technical Discussion / Testnet Faucet on: February 05, 2020, 09:06:31 AM
I recently tried to help a couple guys that were in need of some tBTC, and i found out there are only a handfull of relatively stable tBTC faucets out there... That's why i decided to take a stab at making one myself:

Following things are "features", not bugs:
  • it has a lot of ads: i'll use part of the ad income and/or tips to rent some hashrate (or buy an old ASIC) an mine some tBTC to fill the faucet's wallet. The rest of the tips will go to hosting costs and electricity costs while mining... If the faucet ever runs completely dry, and there is no income or tBTC donations, the project will stop...
  • it's behind cloudflare: it's only tBTC... Don't use it to do anything illegal because big brother might be watching
  • it's ugly: i'm not a designer
  • it only pays once per hour: i'm trying not to waste tBTC in fees since the hashrate on the testnet is relatively high, so tBTC isn't that easy to mine
  • it's missing some security headers: it's only a tbtc faucet... I didn't put much effort into securing it
  • it's loading external content: it's only a tbtc faucet... I didn't put much effort into securing it

If you run into any other bugs or potential weaknesses, let me know Smiley

What could you do with tBTC?
  • Use it when you develop a new script/app/...
  • Use it to test the lightning network
  • Use it as a learning tool: there are loads of tBTC wallets (including, but not limited to: hardware wallets, desktop wallets, mobile wallets and paper wallets). Point newbies towards these when they have the need to learn how to perform certain actions in a risk-free environment
19  Other / Beginners & Help / scam spam on: January 23, 2020, 01:26:54 PM
Just a quick heads-up for any newbies that are likely to fall for this new scam method i just got confronted with.

Somebody got his hands on my private email and sent me a message that was not stopped by gmail's filters, nor did it look like any of that bulk scam crap you get every day. The pretense of this scammer is that he mistakenly sent an email containing login details to a server that is running some kind of "wallet". If you log in trough ssh, you are shown some kind of menu and you immediately see the wallet contains +3BTC. Offcourse, in order to withdraw the 3 BTC you need to "activate" a withdrawal address by sending the scammer a couple bucks...  Roll Eyes
He's hiding a classic scam behind something that might be technically difficult for unexperienced users. This way, i think he hopes the unexperienced user will stare at the technical difficult task and doesn't notice it's just an old scam method with a new coat of paint.

Anybody reading this post after receiving such an email: if you send any money to "activate" your address, you'll get robbed... It might seem like a good deal to send somebody a couple bucks in order to receive ~$12000, but in reality you'll just lose a couple bucks. Don't get scammed!

I got a mail in my mailbox with following text:
Hi James

We have just talked on Skype.

We have setup access point to your private Bitcoin wallet.
You can now access it via SSH. I recommend Putty to access remote wallet.

Here are the details:
username: james75
password: <snipped>

Don't hesitate to reach out to us, if you have any questions.

Private Bitcoin Vault  

btw: my name isn't James Wink

I have the full mail headers aswell, in case somebody wants to try to track this scammer down.

A simple nslookup already pointed to as hosting company. However, this host's page doesn't have an english, dutch or french translation (only russian?), so if somebody speaks russian, it would be nice if they could open a complaint to the hosting company... One of their users is scamming people using their services.
20  Bitcoin / Development & Technical Discussion / bitcoind, c-lightning and RTL on centos 7 (walktrough) on: January 13, 2020, 12:33:11 PM
bitcoind, c-lightning and RTL on centos 7 (walktrough)

I decided to write down some documentation on how to rebuild some of my services in case i ever faced a system crash, and because i more or less had all documentation on my system, i decided to update everything and publish it on this forum AND my blog... This way everybody could use my documentation to setup their own services of they ever wanted to.

some remaks:
  • I'm not taking any political stance here... The lightning network has pro's and con's, it's not completely mature (yet). This thread is NOT for discussing LN merits or shortcomings, but merely a technical walk-trough on how to get things up and running
  • my system specs: Centos 7, KVM VPS, 3 Gb RAM, 3vCPU's... The most important spec, however, is the disksize... A full node requires 278G at this moment, and there is a (theoritical) growth potential of ~17 Gb/month. Add some space for binaries, updates, builds, logs,... So you'll need at very least 350 Gb of free space on your filesystem
  • not all VPS providers will deliver a VPS that has the same configuration... It's possible some prereqs were already met in my basic image, while you have to install them yourself (or vice-versa)
  • i didn't document the firewall rules, because there are several possible firewall-implementations, and basically, if i'd have to go into the details of setting up firewallrules, i'd need a completely seperate firewall tutorial alltogether. If you have a clean (unused) VPS or you're installing a server in your HOME network (behind your own firewall), you *might* want to disable the firewall for testing puposes (re-enable it afterwards tough!!!)
  • i didn't document the backup procedures. Always make sure you backup wallets, seeds,...
  • no guarantee... If you follow these steps and lose money: don't blame me
  • no help... Sure, i might try to help you out if you run into problems, but i'm under no obligation to do so. Best effort only, and only when i have time to help you
  • no docker. Sure, docker is great, but if you run docker containers, you'll never know what's under the hood Smiley. It's easy to download and spin up a docker container, but you'll learn little (or nothing). Don't get me wrong, if you're building your own containers or if you don't want to learn how to setup your service, docker is great... Just not if you want to get your hands dirty Smiley
  • bitcoin core, c-lightning and RTL are built from source in this walktrough... It's up to you to periodically perform updates (not only for these binaries, but for all packages on your system)
  • this tutorial is a work in progress... There are many other steps (hardening, cleanup,...) that could happen. I'll probably edit these steps when i get input, or when i think about something myself. This is also why i split up this thread, this way every step has the chance/space to grow in the future...

Overview Of what we'll be installing
Bitcoin Core: a full node implementation and wallet, sometimes called the reference client. This node fetches all blocks and unconfirmed transactions from the peers it's connected to, parses and verifies everything and has a full wallet functionality
C-lightning: a Lightning Network implementation in C. Create lightning channels, create or pay lightning invoices.
RTL: Ride the lightning: one of the best GUI's that can be used on top of an existing c-lightning daemon. No extra functionality, but a lot easyer to use than using lightning-cli
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