Sounds great! I know the old one probably would be good enough for most people but somehow you will always run into a few slower ones like me

This might sound a bit stupid but in your thread there are a couple of links and the text (offline!!) following those links. At first I thought you meant those links weren't available at the moment. But I realize you mean you should never enter sensitive stuff like seeds or private keys in an online environment. Maybe you could make the warning a bit clearer?

Nice list/start btw

Am I right to assume when the response of a the bitcoin-cli request for decoderawtransaction contains at least one txinwitness in the input section ("vin") the transaction is a segwit transaction? And the other way around: when there is no txinwitness in the vin-section it should not be considered a segwit transaction?

Any input is appreciated!

This indicates  your private key is in the format of a WIF (Wallet Import Format) for a compressed private key. Since all the signs (correct length, starting with either L or K) indicate you have a valid key chances are big you made a typo in entering the key.

Since the WIF you are trying to enter is encoded in Base-58 certain characters can not be in the address like the number 0 (zero), capital O, lower l.
Please check if the key (WIF) you entered) only consists of these characters:

If you don't want to be scammed out of 0.2 btc I really wouldn't do that!

You can accomplish this if you save some data as response from the "getblock" rpc call. Afaik there is no direct way of doing this by only using one of more rpc calls.

For each block in a 24-hour time frame you store the block along with it's timestamp. When you have those two it shouldn't be hard to calculate the average blocks per day when you do this over a longer period of time. Based on the interval between stored block times it should also be easy to calculate the average time per block.

But, just a reminder: On average Bitcoin aims for a block time of 10 minutes. So even without calculation the numbers you are looking for are:

• Average blocks per day: 6*24= 144
• Average block time: 10 minutes

If you want to see the real numbers for a period of time you can obviously calculate them as I explained in the first part. Otherwise just stick with the already known and aimed for averages.

Well in my opinion it is for public blockchains, the ones where everybody can run a node. However if you are looking at private blockchains you could also store the files itself onchain. It all depends on the use case if you ask me.

Confirmations mean the number of blocks written after a transaction was included in a block. So, in this case, another 100 blocks have been added to the blockchain. If someone somehow wanted to change the block your transaction was in they not only need to have enough hashpower to change that single block but also the 100 blocks afterwards. The number of confirmations only will go up which is a way of expressing how secure the transaction is.

Plenty of posts here referring to sites which can "double your investments" in a couple of hours.

Most of them claiming:

• You will receive 200% of your investment in a couple of hours;
• Some kind of limit on deposits;
• But also claiming you can make as many deposits as you like.

The following is an example of an investment of 5 BTC and doubling at the rate of every six hours:
You start with an "investment" of 5 BTC, get 10 BTC after six hours. Reinvest those 10BTC (as in 2x5BTC transactions) and get 20 BTC after 12 hours. Following this logic here is an overview of how much you would make after the initial investment of 5 BTC in a certain time frame:


So in a little under 6 days I could turn my initial investment into 419 million BTC. Unfortunately, that's a bit more BTC in existence at this time. Even more: it's roughly 20 times the amount of btc which will ever be in existence. So claims like these are proven false.

Please don't fall for these obvious scams!

Obvious scam. Don't you ever get tired of scamming people?

I have a database of all addresses used on the BTC blockchain and can tell you there is not a used address starting with "1eXZ5VsqHa".

There is no massive database (or something like that) which holds all possible private keys and a new address is taken from there. Instead an address is generated at random, something which you could/should do locally.

In short and a bit simplified:
Truly Random Input -> SHA-256 -> Private Key
Private Key -> ECDSA ->Public Key
Public Key ->Add some  checks -> Encode with Base58 -> Bitcoin Address

If the input is truly random there is no way two of the same Private Keys will be generated. So go ahead, you can literally generate million of keys/addresses yourself to use without even a slight risk of finding one which has been found/used before.

Where did you get that information from?

I'm not going to repeat what a lot of others have said in this thread already but chances are real if those coins were indeed bought early on he might have sold them again sometime in the past. A lot of early adapters sold coins from a long time ago so you might be chasing something which isn't there anymore. 

Is that because your on a slow connection? Or do you use a slow drive? Did you try to set the -dbcache parameter to a higher value because in my experience this makes a hugh difference when rebuilding the entire blockchain.

I can recreate the entire blockchain in a couple of hours even with -txindex when setting -dbache to 16384 and storing the result on an SSD.

Backups off the public data are literally everywhere, I would worry most about your personal data: the wallet.dat file.

Then you get a new hard drive and sync the entire blockchain again. All full nodes have a copy of the entire chain so there are plenty of backups!

Sure you can do this. But given the size of the entire thing it would be hard to find a USB stick which can hold the entire blockchain! But you can store the data everywhere and then reference it to bitcoind on startop (or at the bitcoin.conf file):

You mean the WIF's for all uncompressed private keys?

This post is going to be long but it is needed to out these 'double your input' scams. I'm going to proof the claims of this site are not possible.

So this means I can start with an investment of 5 BTC, get 10 BTC after six hours. Reinvest those 10BTC (as in 2x5BTC transactions) and get 20 BTC after 12 hours. Following this logic here is an overview how much you would make after the initial investment of 5 BTC in a certain time frame:

So in a little under 6 days I could turn my initial investment into 419 million BTC. Unfortunately that's a bit more BTC in existence at this time. Even more: it's roughly 20 times the amount of btc which will ever be in existence. So these claims are proven false

Some more excellent points are made in this article: http://www.binaryoptionsarmy.com/2018/06/btc2double-scam-review/.These are the most important conclusions/findings:

BTC2Double Scam
BTC2Double Scam AN ANONYMOUS & FAKE BUSINESS!
The first thing that stood out to us about this BTC2Double system is that it is completely anonymous. First off, there is nowhere on the website where we are told who is in charge here. There is a total lack of transparency and no clear leadership. Are you really going to send your Bitcoin stash to a bunch of anonymous crooks that won’t bother telling you who they are?

The only reason they won’t tell you who they are is because their plan is to steal your coins from you. They obviously won’t reveal their real identities to us because they would end up serving prison time for fraud.

Next, we also know that the BTC2Double company itself is totally fake. It claims to be registered in the UK, and even provides an address and contact details. Well, the contact details are totally fake, the address is made up, and the company does not actually exist as far as we can tell. BTC2Double is neither registered nor licensed. It simply is not a legit business at all. This is more than we can handle and it should be more than enough to send you running for the hills.

BTC2Double Software – How Does It Work?
This is truly a totally ridiculous system. The claim here is that BTC2Double software can double your money in just 6 hours. Apparently, it is a fully automated trading program. However, as the story goes, we do not even have access to this software. We simply deposit our Bitcoin into the system, and it will do all of the work for us.

This is very suspicious, especially considering that we are never told how this program actually works. Since it is supposedly an automated Bitcoin trading program, we want to know exactly how it works. What trading strategies, algorithms, indicators, and analysis tools are used to execute these highly successful trades?

We are provided with absolutely no information in terms of the inner workings of this BTC2Double scam software. We are just expected to believe that it can double our investment every 6 hours without any proof of such. This is extremely suspicious and it is just way too good to be true.

200% ROI IN 6 HOURS???
Do you really think that you can double your Bitcoin investment in 6 hours. This would mean that you can technically double your money 4 times over in a 24 hour period. If our math is correct, this would mean that your initial investment would be multiplied by a factor of 16 in a single day. A $1,000 investment would therefore result in a total return of $16,000 per day.

This is absolutely ludicrous, it is unrealistic, unheard of, and it just cannot be done. For one, we aren’t told how this actually works, which is already suspicious enough. Seriously folks, there is no way that this is possible, not with any amount of programming out there. It just cannot be done.

It is a get rich quick scheme, but the only people getting rich are the anonymous crooks behind this BTC2Double app. They would literally be giving away free money if this were real. The sad reality is that this is just an easy way for these crooks to get their hands on your Bitcoins. To use this BTC2Double system, you have to deposit Bitcoin and give these criminals your Bitcoin wallet address.

They simply steal whatever you deposit, then they hack into your wallet and steal whatever is left in there. This is a scam and it is meant to steal all of your Bitcoin. We have been in contact with several people that have been scammed by this BTC2Double scam system. They have all had their Bitcoin wallets hacked and emptied. Make sure that you are not the next victim!

ILLEGAL FINANCIAL ADVICE!
Yet another telltale sign that there is a scam afoot here has to do with the so called financial planning advice that BTC2Double software provides. Did you know that providing financial advice is a legally regulated financial activity? In other words, a company needs to be licensed in order to provide financial advice.

The BTC2Double system consists of a fake company and anonymous leadership, so there is no way in hell that it is licensed to provide you with financial advice. If there is any financial advice being provided here, it is totally illegal, and probably a load of crap anyway. Don’t trust these scammers!

PONZI & PYRAMID SCHEME!
The other surefire way of telling that BTC2Double software is a scam, is by taking a closer look at the affiliate program. These clowns promise a full 10% in commissions to you if you get your friends to sign up. In other words, these guys are trying to get you to actively screw your own friends and family out of their hard earned money.

Simply put, this is both a pyramid scheme and a Ponzi scheme. The BTC2Double scam app is just trying to steal as many Bitcoins from as many people as they can trick. There is also the point that these clowns never actually pay out any affiliate commission bonuses, which is another big indicator that this is indeed a complete rip off.

Conclusion
There is not a single chance that this BTC2Double app is anything but a scam. Hundreds of people have already had their Bitcoin wallets emptied because of this terrible rip off. Folks, just stay away from it because you won’t accomplish anything but financial ruin if you come into contact with it.

What you are trying to do in your example is not possible. You cannot "deduct" 1 btc from an address and then sent the remaining btc. You always need to spent the entire output from a previous transaction. To follow up on your example:


Now when you want to spent from the above 2 addresses you need to reference them as input in your transaction. Those two transactions add up to 4 btc so the remaining 1 btc has to go to a change address which you control. The address can either be a total new one or could be an existing address you control. So for instance when you sent the 1 btc back to your 1xxxx address the transaction would be made up the following components:
In general: The sum of all inputs should be at least equal to the sum of all outputs. If sum(inputs) > sum(outputs) the remainder is considered the transaction fee.
 

It's still a guessing game as the BitMEX article itself states:

And later on in the article:

So both Sergio's estimate as BitMEX's estimate are educated guesses. More certainty could only come when coins get spent..

Can you check the debug.log file because it seems your bitcoind is not running based on the error message you gave.


The output of the debug.log could help a lot to see what's your problem. But there is a good chance the directory bitcoind is trying to access either doesn't exist or is doesn't have access right to read/write there. Or you are having errors in your confguration file. In the last case delete your bitcoin.conf file all together and try again.