texts: Why do two different fully synced Bitcoin Core nodes differ in the blockchain size?

texts:
The size_on_disk printed when executing getblockchaininfo is 1.2 GB smaller than other nodes are reporting at the same time/block.

txindex=1

What could it be??
I've asked to other peers on twitter to check if anyone else experiencing the same and everyone has more data in their ledger than me. (https://twitter.com/bitdov/status/1231915231368163328)

Here's all the info printed with getblockchaininfo on my node:

{
  "chain": "main",
  "blocks": 618824,
  "headers": 618824,
  "bestblockhash": "0000000000000000000a1fb0ec42e380215bb58698a1321d2953ee5d1b7b                                                                                685d",
  "difficulty": 15546745765529.37,
  "mediantime": 1582569829,
  "verificationprogress": 0.9999950821417113,
  "initialblockdownload": false,
  "chainwork": "00000000000000000000000000000000000000000cfea65b1b3c9262e87778b8                                                                                ",
  "size_on_disk": 299006763199,
  "pruned": false,
  "softforks": {
    "bip34": {
      "type": "buried",
      "active": true,
      "height": 227931
    },
    "bip66": {
      "type": "buried",
      "active": true,
      "height": 363725
    },
    "bip65": {
      "type": "buried",
      "active": true,
      "height": 388381
    },
    "csv": {
      "type": "buried",
      "active": true,
      "height": 419328
    },
    "segwit": {
      "type": "buried",
      "active": true,
      "height": 481824
    }
  },
  "warnings": ""
}


texts: Bitcoin's cryptographic protocol allows for leakage of information about one's Private Key, making recalculation of the private key possible?

texts:
Is it true that the cryptography which is used in bitcoin allows for leakage of information which could be used to recalculate the private key - IF you are continuously reusing the same public address for transactions?
I think there were faulty client implementations in the past which have mishandled the protocol and leaked the keys when reusing same address.
If that is correct, is it possible to make any kind of mathematical assumption, how many times of reusing the same address could practically enable the reengineering of the private key?

After how many times of reusage would you strictly advice a user to
migrate to another wallet with a new private key? Two times reusage is enough to break the key?


texts: Is there a way to generate new addresses for someone else's wallet?

texts:
I thought I saw this feature existed somewhere but I can't find the reference.

Use Case: Alice needs to keep sending multiple bitcoin transactions to Bob, and wants to use a different payment address each time, but neither Alice nor Bob wants to trouble Bob with having to send over a new address for Alice to use. Neither Alice nor Bob want Alice to have Bob's private key.

Any service that sends bitcoins in multiple transactions to a client could make use of this feature. Current services that I've seen, like mining, just reuse the same address over and over, which is not recommended.

What is this feature called?

What bitcoin api (if any) facilitates it, or how would I get started using this api feature?

EDIT

With help from the answer, I was able to do this by adding bitwasp/bitcoin to my php project and this code:

//bitwasp/bitcoin library
require_once(__DIR__.'\..\../vendor/autoload.php');
//use BitWasp\Bitcoin\Bitcoin;
use BitWasp\Bitcoin\Key\Deterministic\HierarchicalKeyFactory;
use BitWasp\Bitcoin\Key\Deterministic\HierarchicalKeySequence;
use BitWasp\Bitcoin\Key\Deterministic\MultisigHD;
use BitWasp\Bitcoin\Network\NetworkFactory;
use BitWasp\Bitcoin\Address\PayToPubKeyHashAddress;

//$xpub = 'xpub661MyMwAqRbcGYcu6n1FmV1TbE8EwnSKecRZLvKAMyj4qLf15qXsoNryiKNvCkRq3z5kBCeZG8115jj28eVqmeKBJZPqjAfwRD3TGx1w5hY';
//$xpub = 'xpub6CUGRUonZSQ4TWtTMmzXdrXDtypWKiKrhko4egpiMZbpiaQL2jkwSB1icqYh2cfDfVxdx4df189oLKnC5fSwqPfgyP3hooxujYzAu3fDVmz';
//$path = '0/0'; // 1st receiving address
// $path = '0/2'; // 3rd receiving address
// $path = '1/0'; // 1st change address
// $path = '1/1'; // 2nd change address
public static function NewReceivingAddress($xpub, $index, $change = false){
    $key = HierarchicalKeyFactory::fromExtended($xpub, NetworkFactory::bitcoin());
    $path = ($change ? '1' : '0').'/'.$index;
    $child_key = $key->derivePath($path);
    return new Result('data',(new PayToPubKeyHashAddress($child_key->getPublicKey()->getPubKeyHash()))->getAddress());
}


texts: Bitcoin core How do I get the transaction fee while using sendtoaddress

texts:
I have a bitcoin core running on testnet, so for suppose I have a wallet balance of 1BTC and I have to send it to an addressx, so how can I know the amount of transaction fee so that I can subtract it from the sending amount.

bitcoin-cli sendtoaddress x 1

This will return an error stating that

error code: -4
error message:
Error: This transaction requires a transaction fee of at least 0.00000488

How can I know it beforehand the fee required for a transaction?


texts: What is so special about chacha20 stream cipher along with poly1305 for message authentication codes?

texts:
I am currently trying to dissect the low level cryptography protocols of the lightning network and I realize that in many places chacha20 is being used. I tried reading about it in the Wikipedia Article there it says:

  This gives Salsa20 and ChaCha the unusual advantage that the user can efficiently seek to any position in the key stream in constant time. Salsa20 offers speeds of around 4–14 cycles per byte in software on modern x86 processors, and reasonable hardware performance. It is not patented, and Bernstein has written several public domain implementations optimized for common architectures.

While I see the later parts about not being patented and optimzed for many architectures is nice I don't get the first sentence of the Quote. What does it mean that one can efficiently seek to any position in the key stream in constant time?


texts: If i have 42 tera hashes of mining power, how long will it take me to mine a block solo, and if i join a mining pool, how much bitcoin will I get? I am intrested in buying 4 Bitmain Antminer T9+.


texts:
I've linked my Copay wallet to my Coinbase account. I wasn't aware of the 15 day hold from my bank account on the funds I purchased.

Has anyone had that happen before? If so, did it take the full 15 days or did it clear sooner than that?

Also, my Coinbase account shows that my Copay account is connected to it when I'm logged in on a computer but not the app. And the Copay app doesn't show my Coinbase account is connected to it. I've completed the authorization process and I still don't see my Coinbase on my Copay app.


texts: Can you send a Bitcoin transaction to a Bitcoin address that does not exist?

texts:
Say I arbitrarily pick an address "abcdefg" (for example's sake), which does not exist in the network; no one "owns" the address.

What happens when I attempt to make a transaction to this address?

Is the transaction rejected by the network?

If not is this transaction stored in the blockchain?


texts: Is OP_RETURN combined with a hash, appropriate for proof of existence of an asset?

texts:
I want to store a hash (of a tweet) in a way that is :

Censorship proof
Public
Unchangeable
Persistent
Non centralized
Less expensive as possible, obviously free if possible

Technology offered by the blockchain seems to fit my needs.

Since I don't want to run my own blockchain because I didn't find a way to do it for free (or does it makes sense to run my own blockchain on my own server ?).
After reading on the subject, I came up using an existing coin (Bitcoin ?) and as you may guess to the OP_RETURN field in a transaction.
But storing my hash in that field is really appropriate ?

Can't I use other coins for that, or create my own coin ?

Since I will store lots (3k/day) of tweets, will it not be expensive to do so ?


texts: Is It Possible to Prove Ownership of Public Key Hash without Public Key?

texts:
I am building a system where I would like the user to specify a public key hash of a wallet that they have control over in the event of tips, refunds, and/or otherwise needing to send value back to them.

From there, I would like to further provide a feature that lets the user verify that they own this hashed address.

If I understand correctly, they can prove this by signing a message that I send them, and then they could send the signature back to me along with the public key.

However, I also understand that exposing your public key is considered less than ideal.

So, I am curious if there is some solution somewhere that will allow me to verify ownership based on the hashed address alone, without the use of a public key.

I suppose that since this verification process is transient and will not be permanently stored in a public blockchain (or anywhere else), it is not as potentially harmful of a scenario (or rather, more "trustworthy" for the user).  However, I am wanting to be as mindful to their privacy and security as possible and provide them with the opportunity to verify their ownership to this hashed address in the least invasive way available.

Is it enough to simply state somewhere in the user interface that this verification process will not store the public key in any way?  This is all assuming a HTTPS connection, but of course the risk is that since bad actors will know that public keys are being transmitted, it opens up one more potential vector of possible attack.

Also, I am very much interested in other approaches that are preferred/known here, as well as any examples of other sites and/or services that have tackled this problem in an elegant way.


texts:
Can anyone tell me why many prefer to use application when compared to web based wallets.

What are the drawbacks of using a web based wallet and how to overcome that?


texts: Could Bitcoin dust spam be effectively combatted by actually including it in the block-chain?

texts:
After reading this question I got interested in these mysterious spammers who sent satoshis randomly. For what I read, here's been plenty of discussion about this, mainly at Bitcoin talk (discussions here, here and here - in Spanish also here,
here and here) but also somewhere else on the network (as in here).

I got sad when I saw I hadn't received such micro-payments, doubly sad when I read most of such transfers won't ever be included since most miner pools actively avoid collecting such "dust" - so spammer gets his message out for free, even though it may only last for a short while.

And I wondered - why not do include such dust, so that spammers are harmed economically and stop doing it? Plus, plenty of people would get tiny bits of money.

What would be the cons? Plus, if I've understood how Bitcoin operates correctly, spammers would end up paying much more in transaction fees than the amounts they actually send - which makes it doubly mysterious to me why not include them.


texts: Sending a transaction from a Trezor One with outdated firmware and lost recovery seed

texts:
I have a Trezor One with firmware 1.4.2 and I have lost the recovery seed. I'd like to send a transaction from the device to another address that I control. However, because of its outdated firmware, only older versions of wallet software can interface with the device. I've found that Electrum 3.0.6 is the latest version of that wallet that can work with this firmware.
The firmware update process on certain versions will wipe the device, and if the device gets disconnected during the process it will be wiped. So I'd like to avoid the firmware updates until I'm sure that the coins are in a wallet I can control.
Would it be possible to create an unsigned transaction on a newer wallet without the private key, then somehow signing it manually with the device before sending it to the network using the newer wallet?


texts: Is it possible to edit Bitcoin Core to broadcast non-standard transactions?

texts:
Is it possible to edit Bitcoin Core to remove the IsStandard function and broadcast non-standard transactions?

Also is there a version like this available already?


texts:
I have some BTC on my Mycelium (Android) wallet and I was wondering if it's possible to now access (hopefully) my Bitcoin Gold. It seems I can't get the normal private keys off of Mycelium, but I have my 12 word seed at hand.

Are there any wallets compatible with Mycelium's 12 word seed that will allow my to access the Bitcoin Gold?


texts:
Assume we have a transaction in hex (tx_hex) and we want to find a nonce such that
SHA-256(SHA-256(nonce|| tx_hex)) = new_transaction_id   ('||' denotes concatenation)
first bits consist of 32 zeros. I understand that this nonce can be found only by brute force.
However, I cannot figure out how you check this condition in practice. new_transaction_id is in hex, so is that equivalent to checking that its first 8 digits are 0?
And if so to find the nonce, I just have to try every possible number (let's say up to 32 bits) for the first 8 digits of new_transaction_id to be 0?
That is my code BTW
def mine(self, tx_hex):
    for i in range(1,4294967295):
        nonce = hex(i)[2:]
        new_tx = self.add_nonce(nonce, tx_hex)
        sha = self.get_tx_id(new_tx)
        print(sha[:2])
        if sha[:8] == '00000000':
            print('Nonce:', i)
            break


texts: Is there a way to determine the optimal size of a batched transaction to save on fees?

texts:
I've been looking at other questions about fees and batching, but it seems no one asked if there is some way to determine the optimal size of a transaction to save on fees (assuming all inputs are spending from segwit native UTXOs for simplicity).
To expand a bit on what I have in mind: I need to pay various amounts to different people (let's consider their number can be anywhere between 1 and infinite), and I guess that by making one "big" transaction paying them all at once instead of 1 transaction for each of them I can save on fees. But is it the more people I can add up in the same transaction the better, or would I save less at some point if my transaction keeps getting bigger? Is there some model to calculate the "optimal" size for my batched transaction, or maybe it doesn't make sense?
Here's my best guess for now: adding more people means really adding outputs, which makes the transaction grow linearily (assuming all ouputs are pretty standard and roughly of the same size), so assuming the fees are split between each receivers the more people you can onboard on the same transaction the cheaper it gets for everyone.
But at some point the sum of the amounts of the ouputs will grow bigger than the one input I added at first and I'll need to add another input. If I have relatively big ouputs to spend this is probably ok, but if I only have small outputs and/or I'm adding relatively big amounts in the outputs at some point adding one more output could need to add one or maybe more inputs, making the growth in size transaction not worthing the save in fees, so I'd rather just stop it and send the batch at this point.
[EDIT] I came across this article that seems to confirm what I was thinking, and that all things being equal it will always save fees to add a new output.


texts: What's the magic key version bytes for BIP49

texts:
I'm implementing BIP49-compatible key derivation for bitcoin-s, but I'm having a hard time finding the magic version bytes to use for the extended keys.

I've been looking at BIP49, but can't find anything there.

Also, is there multiple schemes for deriving P2WPKH-nested-in-P2SH? I've been looking at the Samourai fork of BitcoinJ, Trezor's implementation and the test vectors in BIP49, and I can't get the vectors to pass by using the magic version bytes from Trezor/Samourai.

Maybe I'm confused by which magic bytes from Samourai corresponds to mainnet/testnet P2WPKH-nested-in-P2SH, so any clarification is appreciated here. From my understanding, the mainnet version bytes are 0x049D7CB2 (pub) and 0x049D7878 (priv) and testnet are 0x044a5262 (pub) and 0x044a4e28 (priv).

As a final thing, any pointers to test vectors for BIP49 and BIP84 is appreciated. Currently I've come across the BIPs themselves, as well as SLIP132.


texts: Is there any reasonable way to short-sell Bitcoin

texts: It is not an official currency (yet?) but definitely has a market, and as such, I might be intrested in short-selling some. Are there any reliable, way to bet against it?


texts: What does the FBI think about Bitcoin, in brief?

texts:
Also related: The context of FBI involvement with Bitcoin

The FBI document regarding Bitcoin that was leaked in May 2012 is very long. Is there a brief summary of the most important points somewhere?


texts: Example accepted getwork function input and output?

texts:
I'm looking for example getwork input and output of a successful block hash to verify a getwork client I've implemented.

I'd also accept suggestions on better ways to verify this. I've looked at TestNet but this seems to be a slow process.


texts:
I am running bitcoin testnet daemon for development, but lately I have trouble with starting the daemon. Blockchain is downloaded and it seems that everything runs fine till

  init message: Verifying blocks... Verifying last 288 blocks at level 3

then it seems stuck or takes hours before doing anything. Interesting is that restarting the daemon helped me couple times and daemon started in several minutes as usual. In this time i cant obviously use RPC commands.
I dont have trouble starting mainnet daemon. Anybody has any idea what might cause and how to fix this overly long verification?


texts:
I want to sell 1 LTC via BTC-e.

How does selling LTC for USD takes place at BTC-e? Most probably I'll firstly deposit 1 LTC in the BTC-e wallet and then go to LTC/USD and then enter 1 LTC under the 'Sell LTC' section and click on 'Sell LTC.' What happens after that?

I want to know because I don't want to waste any bit of my hard earned Litecoins!


texts: How to find new values from json file in btc-e api

texts:
Hello i cannot find solution on this issue:

On address https://btc-e.com/api/2/btc_usd/depth is json list from btc-e api.
I'm searching for solution parse only new values from json list and store to the database.
There isn't any identifier, but only values.
I'm using MySQL + PHP.
Is there any solution to solve this?

Thank you.


texts: Is multisig address belong to the same wallet created by?

texts:
I created 2-of-3 multisig address using bitcoinqt by three public keys from my wallet . when I tried to validate this address after creation it shows :

"isvalid" : true
"ismine" : false

should it be is mine as it is created by 3 of my addresses ? can you explain me why it does not belong to the wallet ?


texts: What is the maximum amount of users bitcoin is ideally suited for?

texts: In terms of user scalability, how many total users is the current bitcoin system best suited for? Example: The current bitcoin mining limit is set at 21 million, therefore the bitcoin ceiling does not allow for 7 billion+ users (Earth's growing population). So, what is the maximum amount of users bitcoin is ideally suited for?


texts:
Someone could help me to get my transaction confirmed?
https://blockchain.info/tx/b4d0654d76c4a324da92643270b174c0439b59c42fe5f1d6d570b768f9febf89

Regards,


texts: What are the ways to create an offline Ripple wallet?

texts:
Do I have to download/compile my own version of the client? Is there a difference between the Ripple and Bitcoin wallet address creation methods, or can I use, say brainwallet, also for Ripple?

Note: even if it is not correct, I use terms wallet and address interchangeably. I assume that wallet is just a (possibly encrypted) container of addresses and corresponding public/private keys.


texts: Why does merely having Windows Media Player open double my GPU hashrate?

texts:
I'm using poclbm to mine under Windows... processor is an AMD A6-3400M with integrated Radeon HD 6250G GPU. When Windows Media Player is closed, I get a rate of 16 megahashes/second, but when it is open (even if stopped or paused) poclbm reports a rate of around 33 megahashes/second.

I'm wondering if this has something to do with Windows Media Player increasing the system timer resolution, but that doesn't seem like it would affect performance.

Ideally I would like to achieve maximum GPU performance without having Media Player constantly open.


texts: How are Bitcoin generated in Video Games?

texts:
There are a lot of video games out there which reward the player in Bitcoins or other cryptocurrencies for winning the game or achieving a specific objective. But from where does those crypto come from?

Do the players act as bitcoin miners while playing the game or is there any other mechanism which generates the bitcoin for the game? How does this work? Is the game itself decentralized or they embed the bitcoin blockchain in it?


texts: Becoming Bitcoin wallet provider from scratch

texts:
I want to launch a bitcoin wallet service website for creating new wallets.

And i want to provide a tool for user for importing their old wallets using public and private key.

I know i can use some API's like blockchain.info api and some others

But they just allow to create wallets in their system , and you can not import other wallets using their api in your account.

How can i be a bitcoin wallet service provider from scratch?

i want to let my clients create new account with new wallet address + import and exporting wallets using public and private key + send & recieve money with other wallets + etc

Please +1 question if you don't know too


texts: How do "trustless third-party watchers" work in Lightning Network?

texts:
The main point with LN is the need to monitor the blockchain. The reason for this is to detect if the counterparty misbehaves by publishing an old channel state to the blockchain. For a node running on a server, that is not a big problem since it is always online, but mobile nodes might go offline for days, so how do we deal with this issue?

The need to monitor the blockchain actually only exists if the channel is used in both directions: if you are only paying, any outdated commitment transaction will be more in your favor than the current one, so there is really nothing to do!

But in case of two-way payment channels, this seems to be resolved by "trustless third-party watchers". Since I can't find much literature on the internet about them, I was wondering, how do they work and how exactly are they trustless? For that matter, how do you actually trust that anybody is going to publish on your behalf, and why? Are there incentive mechanisms in place for this to be completely trustless?


texts: Could mining calculations be used to crack private key?

texts: Could mining calculations be used to crack private key, in addition to mining for checking against few million accounts with positive balances? If that possible, at the current mining rate (30TH/s) network can check 1.8 x 10^16 hashes every 10 mins (per block). May be few (<10) of these could be a lucky guess for the corresponding private key, in a year.


texts: Stopping Hash field in GetBlocks Message

texts: Reading Bitcoin Developer Guide, I couldn't fully answer following question:  What is the exact purpose of the Stopping Hash field inside a GetBlocks Message?


texts:
Has there been any demographic analysis of multisignature operations?

If so, who's using them?  Is it true that multisignature operations are limited mostly to exchanges?


texts: What is the correct use of the term "validating"?

texts:
First, in the Bitcoin context what does validating mean?

Second, is it incorrect to say something like

  " the average time it takes to validate a block by the network is 10 minutes."

The way, I understand it,  validating is a split second procedure. Or am I confusing things. What is incorrect?


texts:
Earlier this month I requested 2 payouts from BTCGuild for .25 each.

Neither one ever showed up in my wallet, and I just figured I messed up somehow and lost it.  But today I started sniffing around after requesting another payout (which I have received) and found this:

With the "Request Payment" button, is this still something I can retrieve?
And if so, how do I do it?
Thanks in advance for any and all info, good or bad.  Either way it will be a lesson learned.


texts: What is the max allowed depth for bip32 derivation paths?

texts:
Generally I see that bip32 derivation paths are something like m/1/2/3/4, etc

How deep is allowed? Is there a limit on how deep the tree can go?


texts: How could be useful the softforks field that provides the RPC command getblockchaininfo?

texts:
When I execute the command getblockchaininfo I see useful information but I don't understand how to be useful the information that is displayed through field softforks, the example below:

bitcoin-cli getblockchaininfo

  "chain": "main",
  "blocks": 623195,
  "headers": 623195,
  "bestblockhash": "00000000000000000010596cbf2767824bbb4828b331f2533938f1650ba96202",
  "difficulty": 13912524048945.91,
  "mediantime": 1585317240,
  "verificationprogress": 0.9999826836456495,
  "initialblockdownload": false,
  "chainwork": "00000000000000000000000000000000000000000df5647c802d85a8d1fea0b0",
  "size_on_disk": 305751602545,
  "pruned": false,
  "**softforks**": {
    "bip34": {
      "type": "buried",
      "active": true,
      "height": 227931
    },
    "bip66": {
      "type": "buried",
      "active": true,
      "height": 363725
    },
    "bip65": {
      "type": "buried",
      "active": true,
      "height": 388381
    },
    "csv": {
      "type": "buried",
      "active": true,
      "height": 419328
    },
    "segwit": {
      "type": "buried",
      "active": true,
      "height": 481824
    }
  },
  "warnings": ""
}


texts: What are some of the Bitcoin inaccuracies in the CBS Show "The Good Wife"?

texts:
The CBS Show "The Good Wife" had a series of shows speaking about the Bitcoin and its creation. Although the show is entertaining, it is prudent for those of you who know the truth to record it for historical purposes, not letting the TV drama perpetuate inaccuracies.

In case you haven't seen it, you can look here: http://www.cbs.com/shows/the_good_wife/video/2186658794/the-good-wife-bitcoin-for-dummies

For example:  Is there a Bitcoin manifesto written by Mr. Nakamoto?  Is it possible to embed a character string in the block chain?  Was Bitcoin incorporated?  Was there a lawyer involved who paid people to write code?  Has anyone accused Mr. Nakamoto of being a lawyer? (sorry Sir, I know this is a low blow).  Is Decode-a-thon the name of the conference where all the cryptologists go?


texts: Is there a lightningd equivalent to bitcoind's -walletnotify or -blocknotify?

texts: I'm looking at the docs, and I see they have lightning-notifications, but it looks like you can't configure where they go, and you can't trigger a shell script with them. Does this mean I have to have all notifications sent to a shell script and filter them, or is there a method/configuration I'm overlooking?


texts:
Based upon any standard you think relevant, how quickly are current blocks being verified for rule-following such as correct balance tallies, true transactions, correct rewards & fees?

Is this an onerous process?  Would a database quicken this process?

Do you have any suggestions for improving block verification speed?


texts: Looking for whitepapers on pool-resistence mining

texts: I have seen several cryptocurrencies list the feature of decentralization of mining through ASIC-resistance and pool-resistance. However, I have not yet found any whitepapers which explain how the pool-resistance feature is implemented and what are the proofs that such feature actually accomplishes its stated purpose. I want to learn more about ASIC-resistance and pool-resistance by reading some indepth white papers.


texts: After several weeks of not updating my QT wallet I get the message "Warning: Displayed transactions may not be correct! You may need to upgrade, or other nodes may need to upgrade."  I tried uninstalling bitcoin QT and installing the latest version but that didn't do anything.  I don't know much about bitcoin wallets so a detailed explanation of how to fix this would be great! thanks


texts: Advice on upgrading firmware on Ledger Nano

texts:
I have the discontinued Ledger Nano hardware wallet.

Ledger have released new firmware for this for SegWit and to allow splitting BCH.

To perform the update, you have to wipe your keys and re-create them from your 24 word recovery backup. If for whatever reason this doesn't work, your Bitcoins are gone!

This seems a bit extreme/risky to me, because I haven't used my 24 word recovery backup before (what if I got 1 letter wrong in one of the words?).

Just wondering what way I should approach this? Would it be safer to transfer my coins to Coinbase temporarily, update the stick, and then transfer them back? I know I'd be hit for 2 sets of fees, but at least I'd feel a bit safer.


texts:
I bought a 200H/s mining contract at genesis mining. I allocated 100% of my hash power to Monero. It's been days and I have yet to see any return on my investment yet. The graph is just flat and it looks like it's doing nothing.

I signed up last weds,and it's saturday now. Is it too soon to see any activity on this contract? Or do I just not have enough hash power for it to have any effect?


texts:
Well after getting a new graphics card (7770) I can mine bitcoins at around 120 - 180 Mhash/s Depending if I run it at full power or not.

Now I thought I would try and mine myself an address using it but the miner just seems to not work.

Using Vanitygen (Linked below) oclvanitygen I set it off mining with reports of it mining at around 4MKeys/s but nothing was showing up after 5 mins worth of time(I tried a simple prefix of 1r).

I then tried using just vanitygen64 and in seconds it found an address.

Does anyone know why?

https://bitcointalk.org/index.php?topic=25804.0


texts: Whats the technical/database entity of a crypto-currency / Bitcoin?

texts:
I know that Bitcoin accounts are public private keys combination.

Is it the same with the currency? Is one Bitcoin a combination of public pvt key? Or is it a token?


texts: Supposedly 'Satoshi' was found in Australia… is there any way to verify this?

texts: So far I can't tell what's true about all this.  It also seems like it'd be easy for someone to claim to be the pseudonymous creator of Bitcoin.  I've only seen information about this from main stream sources.  Does anyone know anything beyond the current main-stream narrative?


texts: Are Bech32 addresses safe for mainnet usage?

texts:
According to github bitcoin/bips, BIP-173 is still a draft. And i saw today that Electrum wallet start using it.

Is this means that the specs for BIP-173 won't change in the future ? or the final version won't introduce breaking changes to the draft version ?

I just learned about Bech32 addresses this week and this gets me a little confused


texts: Finding the timing of blocks, afterwards?

texts:
I understand that the timestamps on blocks are not fully accurate. Given only that information, it's efectively impossible to do retrospective analyses of timing of blocks. (For example, this; http://scienceblogs.com/builtonfacts/2014/01/11/is-bitcoin-currently-experiencing-a-selfish-miner-attack/)

Is there a way to get data on when blocks actually were mined, or (at least) when some API provider received the blocks?


texts: Accepting Bitcoin payments without the full blockchain or third party APIs?

texts:
I want to make a basic program/script that utilizes Bitcoin payments, but I don't have the storage space to sync with the entire blockchain, and I don't want to be dependent on a third-party API like those offered by blockchain.info or block.io.

Basically, I need a wallet with these three properies:

Lightweight (i.e. doesn't require the full blockchain)
Has a CLI to generate and return a receiving address on command
Has a CLI to get the total wallet balance

I'm vaguely familiar with thin clients such as Electrum, MultiBit, and MultiBit HD, and I know Electrum even has a CLI, but there doesn't seem to be anything in their documentation about generating new addresses:

https://docs.electrum.org/en/latest/cmdline.html

I've read that Electrum wallets work with a queue of addresses and generate new ones automatically after they have been used, so even if I could just get a list of addresses associated with the wallet I could get something like the functionality I want. But again, the CLI seems really limited.

All in all, I'm frustrated. Surely there is a way to do what I am trying to do, and if there isn't an obvious solution, why not? It seems counterintuitive that I should have to use centralized services and APIs for basic wallet functionality just because I can't afford to rent a server with 90+GB of space to store the blockchain.


texts: There's talk of increasing the blocksize - if this can be achieved - does this mean that the 21m btc limit can also be changed?

texts:
My understanding of the blocksize debate is that it would require 51% consensus to change the algorithm and accept the new blocksize.

If the algorithm can be changed like this - would the exact same mechanism allow miners to also change the limit of bitcoin?

Or is there something fundamental that prevents this?


texts: What is the link between address and use of the UTXO?

texts:
I state that I'm still a beginner. I need some clarification. I am using the Testnet. This is the information regarding the address I used to receive funds from a Faucet

 bitcoin-cli validateaddress 2N7MaihNErbNH8XTkuZWtJYPzMQAWMPVKHd
{
  "isvalid": true,
  "address": "2N7MaihNErbNH8XTkuZWtJYPzMQAWMPVKHd",
  "scriptPubKey": "a9149ac58ff47e27214b158b38da04bc8cbf72def14387",
  "isscript": true,
  "iswitness": false
}
bitcoin-cli decodescript a9149ac58ff47e27214b158b38da04bc8cbf72def14387
{
  "asm": "OP_HASH160 9ac58ff47e27214b158b38da04bc8cbf72def143 OP_EQUAL",
  "reqSigs": 1,
  "type": "scripthash",
  "addresses": [
    "2N7MaihNErbNH8XTkuZWtJYPzMQAWMPVKHd"
  ]
}

  What do data mean? I interpret that my address will receive UTXO
  blocked by P2SH type scripts, correct? "iswitness": false means that
  this address cannot use UTXO segWit?

On this address I received the following output as input:

{
      "value": 0.01944571,
      "n": 1,
      "scriptPubKey": {
        "asm": "OP_HASH160 9ac58ff47e27214b158b38da04bc8cbf72def143 OP_EQUAL",
        "hex": "a9149ac58ff47e27214b158b38da04bc8cbf72def14387",
        "reqSigs": 1,
        "type": "scripthash",
        "addresses": [
          "2N7MaihNErbNH8XTkuZWtJYPzMQAWMPVKHd"
        ]
      }

The blocked UTXO is as follows:

"txid": "a61389ff9af670770182198a984a4c1785625c60795bd57645ecc78765b23679",
    "vout": 1,
    "address": "2N7MaihNErbNH8XTkuZWtJYPzMQAWMPVKHd",
    "label": "",
    "redeemScript": "0014778daf651b21684b572644b47d551fce0ff71c74",
    "scriptPubKey": "a9149ac58ff47e27214b158b38da04bc8cbf72def14387",
    "amount": 0.01944571,
    "confirmations": 116,
    "spendable": true,
    "solvable": true,
    "desc": "sh(wpkh([7de694b7/0'/0'/7']032c27921f2d15e7eca768c0e8a8b1aeb863328c74d6c194d41dde2888d4b0e75b))#6z7uwusp",

"Sh (wpkh ())" describes a P2SH-P2WPKH output and the public key with which it is associated.

  The descriptor is telling us that the hash (sh) script incorporates
  wpkh (Witness - Public - Key - Hash) output. In simple words the
  RedeemScript should match the HASH of this public key, correct?

When I unlock and use this UTXO my input will generate a separate txinwitness field.

"scriptSig": {
        "asm": "0014778daf651b21684b572644b47d551fce0ff71c74",
        "hex": "160014778daf651b21684b572644b47d551fce0ff71c74"
      },
      "txinwitness": [
        "3044022034a07f088dd88396cd378912a4ed6a156701b075f0facbbae810677048c390e602205df07e13bf4d56feece791a1b5e4d94bec9c93aae14bb87a1b4c6c54ae9bf2f701",
        "032c27921f2d15e7eca768c0e8a8b1aeb863328c74d6c194d41dde2888d4b0e75b"
      ],
      "sequence": 4294967295

I can't understand the link between my address information ("iswitness": false) and the ways in which I received / spent the UTXO.


texts: Can the Bitcoin script make a Google search?

texts:
This very interesting CCN Money article states

  a script uses a data input such as a regular Google search to monitor
  real-world events that would automatically trigger disbursements or
  other actions

This part of the article suggests that the Bitcoin script could monitor external events, such as the result of a Google search, to trigger transfers. Can the Bitcoin script really do that?


texts: Can I spend a coin sent to myself before it confirms?

texts:
If I spend the entire balance in my wallet to another address in my own wallet, do I need to wait until it gets one confirmation in order to spend it, or does the client know it is my own funds and that it can be spent?

This can be done via RPC, but this question is specifically referring to using the bitcoin-qt client for this.


texts: How to get compressed public key with ECKey

texts:
Here some java code. What i need to change to get compressed public address in getPublicAddress?

import com.google.bitcoin.core.Address;
import com.google.bitcoin.core.ECKey;
import com.google.bitcoin.params.MainNetParams;
import org.spongycastle.crypto.digests.RIPEMD160Digest;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class DigestUtil {

    public static byte[] RIPEMD160(byte[] input) {
        RIPEMD160Digest d = new RIPEMD160Digest();

        d.update(input, 0, input.length);

        byte[] o = new byte[d.getDigestSize()];

        d.doFinal(o, 0);

        return o;
    }

    public static byte[] SHA256(byte[] input) {
        byte[] hash = null;

        try {
            MessageDigest md = MessageDigest.getInstance("SHA-256");
            md.update(input);
            hash = md.digest();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }

        return hash;
    }

    public static ECKey createAddress(byte[] secret) {
        byte[] hash = SHA256(secret);

        ECKey key = new ECKey(hash, null);

        return key;
    }

    public static String getPublicAddress(String input) {
        ECKey address = createAddress(input.getBytes());

        byte[] hash160 = RIPEMD160(SHA256(address.getPubKey()));

        Address addr = new Address(MainNetParams.get(), hash160);

        return addr.toString();
    }

}


texts: Can a bad actor omit an unspent address from a pruned chain?

texts:
This isn't a problem today, because if I want to run a pruned node then I still have to download the whole chain, but it sure would be nice if I could just download a pruned chain instead and validate it.

The attack I'm thinking of would be that I download a pruned chain, but the person I got it from omitted an unspent address from a thousand blocks back. I'd have no way of knowing.

This means that the full chain will always have to be downloaded and pruned manually. Right?

edit: I think I figured it out. All the unspent addresses on a pruned chain should add up to all the bitcoin in circulation, which is known based on how many blocks there are. So you could tell right away if someone evil omitted an unspent address.. Turns out that doesn't help


texts:
Its been months since Ive used my electrum wallet.

When I try and send coin I get an invalid password message.

Then when I go to my seed, I type in that same password and it takes me to the seed generator and says my seed is 0 length.

I see there was someone else with this same issue, he was just two characters off. If thats the case, I kind of know my password. What kind of brute force programs could I use to crack my password?

Thanks


texts: What if all the 8 peers of the node are malicious?

texts:
I looked at the question on how transactions are broadcast to the rest of the network in the blockchain network.
In this stack exchange post, the author @morsecoder in the accepted answer mentions that :

  Think of it like how gossip would spread. There are a bunch of people (nodes), and when one of them knows something, they tell it to the few (8 or so) people they are near (connected with), and then those people tell a few more people the message that was told to them, and then... Eventually everyone knows about the original information (transaction).

But what if all the eight nodes to whom a given node send the transaction are malicious/faulty? And all of them change the message in the original transaction. Wouldn't it allow for wrong transaction to get merged in the blockchain network?

Also, once any given node sends the transaction it received to its peers, how does the network know that majority of peers have received the correct transaction and it's ready to get merged in the main chain. I'm not talking about the bitcoin network here. So, I'm not worried about the PoW for now. I just want to know that when a node sends the transaction it received to its peers, the peers send it to their peers, how does the network keep the count of which transaction has been accepted by how many nodes?


texts: What can I do when the blockchain synchronization is stuck at a specific block?

texts:
I hadn't started/used my Bitcoin client for ages. Now, whenever I start the client, it is downloading block 135407 and does not progress past it.

What can I do?


texts: Why are hashes base16 (hex) encoded rather than base58 encoded?

texts: BTC sha256 hashes are hex encoded (as sha256 spits out bytes not a string), why is this? Surely using base58 would be more efficient as would use less space (would output a shorter string)


texts:
i created an altcoin with a premine for the first block. After generating the first block the transaction worked well. But on my wallet it says the that my new balance is "immature". What does that mean and how can i get the "immature balance" confirmed?

https://camo.githubusercontent.com/8403ee1020c3c56d8ee9f4049065d8db717e1870/687474703a2f2f6934362e74696e797069632e636f6d2f33306d37706b6f2e706e67

Kind regards


texts:
The following commentator writes:

  More than two-thirds of all available bitcoin have already been mined, with the majority going to early miners.

My question is: Is it true that two thirds of available bitcoins have already been mined?


texts: Has a spend from a hybrid public key ever made it to the blockchain?

texts: If so, could you please give the TXID of a transaction that spends from a hybrid public key?


texts: Expand lightning channel capacity or open new channel?

texts:
when I got started with my lightning node last week, I made a channel with only 20.000 sats outbound liquidity to test things out. There is no inbound liquidity in this channel.
Now I would like to have a bigger channel with the node on the other end.
I had a look at loop in to increase the capacity to maybe 1.000.000 sats, but the fee would be about 30.000 sats.
Since the channel has no inbound balance I can't rebalance it, right? Is there any cheaper way to top up the channel capacity or do I just open a new channel to the same node?


texts: How long does it take to propagate a new broadcasted message in the Bitmessage?

texts:
When a message has been signed off, it is propagated to the entire network. I would like to know how long does it take "on average"?

There are two types of messages, private messages and broadcast messages.
Private messages are encrypted with receiver's public key.
Broadcast messages are encrypted with sender's public key.
Having said that, there are few reasons for message propagation delay in the network, following are my assumptions.

In the private key's case: once the message is signed off and broadcasted, every node tries to decrypt the content with his own public key, but fails.
Do nodes forwards the message only after trying to decrypt or promptly after receiving it? Because this definitely causes message propagation delay.
Is it the same for the broadcasted messages, i.e. do nodes forward the message only after failing to decrypt it or promptly after receiving it?
Does the message size matter for decryption and propagation?
Network latency delay is regardless of the message size.
The diameter of the network is out of the question as well.

Does anyone keeping track of Bitmessage statistics similar to the Bitcoin's?
I tried to access http://bitmessage.adammelton.com/ but fail to do so, does it work for you?

P.S. Sorry this question might look a little bit irrelevant in the bitcoin's stackexchange, however we consider that Bitmessage is a Bitcoin without a blockchain and the most of techniques were inherited from the Bitcoin. In addition I believe that many developers follow both Bitcoin and Bitmessage. Therefore dear all, please do not remove this question :) Many thanks.


texts: I'm currently doing a research on bitcoin and I would like to know if there is anyway to replicate double spending in the testnet or regtest? If isn't possible is there any other type of "attacks" that can be replicated?


texts: What does "Activating Best Chain" mean? My Bitcoin Core doesn't freeze, it just takes a while. I'm curious as to what it's doing.


texts: Listening to all transactions of the Bitcoin network

texts:
I searched with all terms I could think of, but could not find anything in direction that helps me.

In the context of a research project, I am trying to listen to all transactions that are broadcasted over the Bitcoin network. So we are especially interested in transactions, that will not occur in the blockchain later (e.g. got "lost", took very  long to get accepted, double spent, etc.).

I know of bitcoind, but the list of transactions is rather pull-oriented, whereby I'd like to have something like a callback, that informs me of a new transaction.

Can anybody recommend any software/libs/projects here?

PS: all I intend to do is read-only, so there does not have to be any wallet-support etc. I just like to get a deeper view into how the Bitcoin network actually works.


texts: Duplex micropayment channels: criticisms of Lightning and implementation

texts:
A paper from 2015 by Decker and Wattenhofer proposes an interesting design for a payment channel network, which differs from the Lightning network. The authors claim in the Related work section that Lightning:

"requires exchanging keying material for each update in the channels, which results in either massive storage or computational requirements", and
"cannot be decomposed into smaller units that can be analyzed in isolation, making the security analysis difficult and resulting in complex implementations".

I have two questions:

To what extent are those criticisms of Lightning valid as of November 2017?
Is there an implementation of Duplex micropayment channels or at least plans to create one?


texts: Will the amount of "usable" Bitcoins eventually drop to zero?

texts:
Let's assume that there is a non-zero probability that people lose their bitcoins, e.g. by forgetting their password. The amount of bitcoins these people possess will become "unusable" but still remain in the blockchain and contribute to the maximum quantity of 21.000.000 bitcoins.

Over time the amount of "usable" bitcoins would shrink more and more as people keep losing bitcoins. Will the amount of "usable" bitcoins eventually approach zero? What will happen then? Is there a mechanism to somehow recover lost bitcoins? At the moment I don't see such mechanism.


texts: What is it that frees Bisq from all these KYC/AML laws and regulations?

texts:
I feel as if I should probably not ask about this, and instead just quietly go on using it in my little corner, not bringing any attention to its existence, but I still must ask:
What is it that enables Bisq (the decentralized exchange software/network) from not having to follow KYC/AML laws/regulations?
The obvious answer may be "it's decentralized", but let's be real: their website, forum and Github repo are all very much centralized, and this is the only way that I and 99% of its users would be able to get any updates, and probably for the already installed software to be able to fetch updates as well. Even decentralized applications always have some sort of "hardcoded bootstrap list of nodes", whether by hostname or IP address. Basically, decentralized anything is kind of an illusion in this Internet.
So, if it gets too big and thus poses a real threat, can't "they" just shut it down extremely easily by just taking away the domains/Github accounts, or just going after the public individuals who are known to run/develop the software?
Isn't it only because so few people use/know about it that they "get away" with this?


texts: I sent $50 worth of bitcoin to my cousins blockchain bitcoin address, it said sent and the bitcoin amount deducted from my wallet.  However, the bitcoin did not reflect in my cousin's wallet.  I checked the Transaction ID and it was there showing the transaction and amount sent. Till date my cousin did not receive the bitcoin.  What should I do to get back my bitcoin.


texts: Maximum number of outbound full relay connections

texts:
What is the maximum number of outbound full relay connections a bitcoin core full node can make?
I was assuming it's 8 but then realized we can add another 8 connections using addnode while reviewing this PR: https://github.com/bitcoin/bitcoin/pull/21710
So is it 16 or there is something else that I am missing which can be used to add more outbound full relay connections?
Also do we have any option to decrease the number of MAX_OUTBOUND_FULL_RELAY_CONNECTIONS below 8?


texts:
I have an old AntMiner S1 sitting in my closest, which uses the AntMiner BM1380 mining chip.

I have the data sheet for the chip, found here.

https://bitmaintech.com/files/download/BM1380_Datasheet_v1.0.pdf

there is also this repo, https://github.com/AntMiner/AntGen1, which includes reference designs of the miner, as well as firmware.

However, it is just the firmware images, not the firmware itself.

If I were to want to use a single chip(totally pointless, but I mean in some other configuration then the S1 blades) to make a small miner, how would I go about sending instructions and data to it?

Does anyone have any reference firmware source, or point me towards a document that makes sense of the required inputs?

I see on the data sheet oscillator input, oscillator output, etc. but am not sure what the required input is.

===
I am adding to the question: does anyone have an example on how to test the chip to see if it is good ? Connecting an Arduino or something like that ?


texts:
I'm running my own bitcoin cash node. However, I'm getting stuck on the block where the network hard forked for the May 15th 32mb blocksize update. I believe the version of bitcoin abc I have installed is out of date, hence why it is stuck at block 530361. Here is the version with getinfo:

{
  "version": 160200,
  "protocolversion": 70015,
}

Is my node out of date? How can I upgrade my bitcoin abc node?

I tried:

sudo apt-get update
sudo apt-get upgrade

but nothing changes in the version or protocol version with getinfo. What should I do?


texts: Double spend a tx output already spent but unconfirmed because of low fee

texts:
In the protocol rules for validating transactions it says:

Rule 9:

  For each input, if the referenced output exists in any other tx in the
  pool, reject this transaction.[5]

I assume that when a node receives a transaction it has to validate it applying those rules before adding it to the memory pool and resending it. Also miners will only add transactions to blocks if they are validated, that is, they are in the memory pool. Please correct me if I'm wrong.

Let's say I broadcast a valid transaction with such a low fee that no miner is willing to add it to a block, but it is valid, nodes who received it validated it and miners also validated it but it is stuck in the limbo, it is not in any block so the recipient cannot reference any output in this transaction.

Is there any way of re-spending the inputs referenced in this transaction? I think I have to wait until the transaction is removed from the memory pool of the miners but I'm not sure. If this is true, how long does it take?


texts: Are for-profit companies possible in Ethereum?

texts:
I am getting my head around DAO in Ethereum. In a magazine I read:

  In principle you could programme a taxi company that bought cars and paid drivers to run the cars to make a profit in order to buy more cars. [...] The point is that the management, what would normally be the brains of a corporation, the control structures of a corporation, can now exist autonomously in the cloud, so to speak.

So, if I understand correctly, someone with some level of capital can set up a private, for-profit company in the DAO, use that capital to buy taxis, hire drivers, and, if the business is good, make profits? The benefit of this being that contracts are run automatically, fully transparent? If so, how is this related to descentralisation? What if, for instance, Uber is set up in Ethereum, but still owned by a few people? Does it matter? Perhaps more deeply, are DAOs fully compatible with the standard firms in capitalism (for-profit PLC)?


texts: Mining block are not accepted if BIP related values changed to 0 or 1

texts:
I am creating own alt from LiteCoin source. So I have changed hashGenesisBlock , hashMerkleRoot , nonce , timestamp etc.Things are working fine if i don't make BIP34Height , BIP65Height , BIP66Height & BIP34Hash value to 1 .While doing mining using cpuminer generated hash/blocks are not accepting and that's why blocks are not getting generated/added.

If I change that BIP( BIP34Height , BIP65Height & BIP66Height and BIP34Hash) values(not default which is litecoin values), that generated hash/block should be accepted from cpu miner or any other third party mining binary. I've tried by setting value to 0 & 1 both but same result things are not working as expected.. Here is log URL generated from mining : https://gist.github.com/adneerav/591e61657292e6c6561a26b69dc78870

If I don't change that BIP values things are working fine.Generated blocks are accepted to add.Please check log which is generated from mining process. https://gist.github.com/adneerav/0b30889d3950662201734776b926903a#file-old_script_mining-log-L84

For testing and initial setup i am doing things on LAN.All things are working fine if i don't change BIP values only(changing only genesis , merke minimum chain etc)

I know for this BIP related conceptual should be clear but I've not found any example & proper documentation so I came here to make things clear if anyone can provide more details/document/blogs and help me to solve this things.

Can anyone please help me in this issue ?

Please let me know if this community is not for AltCoin/Crypto Currency questions/answer I mean only for Bitcoin related not for other crypto.

Note :
Before I come to this I've already ask same thing : https://github.com/litecoin-project/litecoin/issues/538

Thanks


texts: Old wallet.dat from 2016 with some btc not confirmed or in mempool

texts: So I backed up a my bitcoin core wallet on an external drive back in 2016 and installed a new OS. I didn't really check on the wallet until recently and am having a bit of trouble getting the coins back. I downloaded the entire blockchain to the most recent Bitcoin core and the value has remained 0 throughout the entire process. Both of my receiving addresses reflect a 0 balance, when there should be about 1.5 BTC or so in the wallet. I have no idea what's going on but I will reward anyone who provides actionable information with 0.03 BTC


texts: When was the first GPU miner made available publicly?

texts: The GPU miners are widely used nowadays, but that wasn't always the case. When was the first GPU mining software made available publicly?


texts: How can I mine dogecoins on debian? I have tried to compile cudaminer but I can't find out how to install nvcc.


texts:
Does a Node connect to all the peers in the network? Or just a few?

If its just a few, how many?
If its just a few, what about if all of those nodes in the list are malicious?


texts: Question on Asymmetric Revocable Commitments

texts:
I'm trying to understand asymmetric revocable commitments from Andreas' book. In particular, I'm looking at page 295 (2nd edition).

  Irene can confidently sign this transaction, since if transmitted it
  will immediately pay her what she is owed. Hitesh holds the
  transaction, but knows that if he transmits it in a unilateral channel
  closing, he will have to wait 1000 blocks to get paid. When the
  channel is advanced to the next state, Hitesh has to revoke this
  commitment transaction before Irene agrees to sign the next commitment
  transaction. To do that, all he has to do is send the revocation key
  to Irene. Once Irene has the revocation key for this commitment, she
  can sign the next commitment with confidence. She knows that if Hitesh
  tries to cheat by publishing the prior commitment, she can use the
  revocation key to redeem Hitesh’s delayed output. If Hitesh cheats,
  Irene gets BOTH outputs.

Output 0 <5 bitcoin>:
    <Irene's Public Key> CHECKSIG
Output 1 <5 bitcoin>:
IF
    # Revocation penalty output
    <Revocation Public Key>
ELSE
    <1000 blocks>
    CHECKSEQUENCEVERIFY
    DROP
    <Hitesh's Public Key>
ENDIF
CHECKSIG

The code example shows that there are two ways of redeeming Hitesh' 5 Bitcoin. Either by posting the "Revocation Public Key" or by waiting for a 1,000 blocks.

What I don't understand is the following. If Hitesh tries to cheat by publishing the prior commitment, why can't he also use his own revocation key (which he knows, since he created it) to redeem the output?

What prevents him from doing this?


texts: How many OP_RETURN transactions in the Blockchain would be too many?

texts:
I realize this question may not have an answer and therefore might not be suitable for SE, but I'm very curious about OP_RETURN transactions.

OP_RETURN transactions appear to be the accepted mechanism for inserting metadata into the Blockchain. Considering the innumerable uses for metadata (contracts, colored coins, proof of ownership...), I foresee more and more non-monetary transactions filling up the Blockchain.

Will that be bad?


texts:
I am considering buying a Lamassu Bitcoin ATM machine.

The small machine is apparently "grab resistant". Does anyone know how the grab resistant mechanism works? Are there hooks on the back?


texts: unconfirmed transactions made 1 month ago


texts: Using confidential transactions with plain-text ouputs

texts:
I was reading about Confidential Transactions (CT) and understand the basic idea behind it. But what if CT must be bootstrapped on an existing Blockchain such as in Bitcoin, where the amounts are for now visible in the outputs?

Is it possible to create a CT transaction, where the inputs reference UTXOs that are not confidential (just as in Bitcoin now), but creating new outputs that are hiding the value using CT's scheme?

What would the network have to do to check that the sum of commitments in the outputs are the same as the sum of clear-text amounts from the inputs?

//Edit: I found some help from the mailing list describing how CT can be implemented as a Soft Fork to Bitcoin: https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2016-January/012194.html

But I am still not sure how the network can make sure that the confidential transaction outputs from "blinding transactions" sum up to the amount that is being stored into the GCTXO.

Similarly when "unblinding", how can the network be sure that the sum of commitments from the confidential inputs is the same as the amount that is being spent from the GCTXO?

//edit2:
The only way I can think of is that the blinding tx also contains a proof using the sum of commitments in the outputs. That sum of commitments corresponds to a value equal to the amounts from the inputs (minus the tx-fee).

More precisely, a CT commitment looks like xG+aH, with G and H being generating points, x a secret key and a being the amount locked with the output. For a proof we sum all commitments from the outputs: C=xG+aH + yG+bH + ... + zG+cH = (x+y+...+z)G + (a+b+...+c)H. A proof can then be provided by subtracting (a+b+...+c)H from C and signing it with the corresponding secret key: C-(a+b+...+c)H=(x+y+...+z)G, where (a+b+...+c) is exactly the amount from the inputs (minus tx fee), and a signature is provided from the public key (x+y+...+z)G, where (x+y+...+z) is the private key.

But from reading the specification I cannot see where such a proof/signature would be provided with the blinding transaction?


texts: Recover corrupted wallet due to system crashed

texts:
My server was crashed suddenly and didn't shut down bitcoin core probably, so now my wallet was corrupted due to it didn't be released. I try to moved the corrupted wallet to a new server but it can't be load:

Wallet file verification failed: wallet.dat corrupt, salvage failed

I have also tried to use pywallet to rescue, but getting this error:

ERROR:root:Couldn't open wallet.dat/main. Try quitting Bitcoin and running this again.

I suspect that my wallet.dat was totally corrupt so pywallet couldn't found main . Any help on this please ? Possible to get back my privatekey from wallet.dat please ? Thanks alot.

Information:

bitcoin version: v0.18
os: centos7


texts: Exchange Transaction versus Blockchain Verification

texts: I am wondering about a question related to this post. According to bitcoinity, the number of bitcoin-trades at major exchanges per minute is roughly 400. However, as also pointed out by @eponymous in this answer, this number exceeds the trades which are verified on the bitcoin blockchain by far. However, how should I trust exchanges who do not provide real transactions in the sense that bitcoins are moved to my wallet? Is there a documentation on which exchanges provide this service and what exactly happens if I trade, say, USD versus BTC on a exchange which is not settling the trade on the blockchain?


texts: Choosing between blocks with chain same work- why pick the first received?

texts:
What if one block contains many more transactions than the other? Wouldn't it be better to pick the block with more transactions?
Also, why is a tie ultimately broken randomly, rather than a deterministic way that helps the network?


texts: How to install correctly this PiWallet Script in Ubuntu?

texts:
Good evening everyone.
  I'm trying to set up the piWallet wallet (https://github.com/johnathanmartin/piWallet) on Linux.

 I was able to successfully install the "Bitcoind Server" (which works very well when I type in a Terminal the commands "bitcoind -daemon" and then "bitcoin-cli getinfo", I get the Info of Blocks, Balance, etc. ..), PHP5 (then the Script is based on PHP5), PHPMyAdmin, Apache2 and MySQL on Linux Ubuntu 14.04.
But the concern I encounter is that the file "jsonRPCClient.php" fails to connect the client and displays the following error:

Warning: fopen(http://...@127.0.0.1:8332/): failed to open stream: HTTP request failed! HTTP/1.0 401 Unauthorized in /var/www/html/piwallet/jsonRPCClient.php on line 133

Fatal error: Uncaught exception 'Exception' with message 'Unable to connect to http://greg:pass123@127.0.0.1:8332' in /var/www/html/piwallet/jsonRPCClient.php:141 Stack trace: #0 /var/www/html/piwallet/classes/Client.php(17): jsonRPCClient->__call('getbalance', Array) #1 /var/www/html/piwallet/classes/Client.php(17): jsonRPCClient->getbalance('zelles(chegadmi...', 6) #2 /var/www/html/piwallet/index.php(22): Client->getBalance('chegadmin') #3 {main} thrown in /var/www/html/piwallet/jsonRPCClient.php on line 141

I do everything but Zero; no solution; I even searched the internet but no satisfactory answer. The bug to check if PiWallet really connects to the Daemon Server (Bitcoind), I run "greg:pass123@127.0.0.1:8332" in a Browser, and I get the following error saying that we did not Need authentication to connect to 127.0.0.1:8332.

Help me really because I need it.


texts: Bitcoin creating wallet without seeing private key

texts: I would like to create a Bitcoin paper wallet for a friend. However, I know that I should not have the private key as well. Is it possible to create a wallet but where I only have the public key and my friend gets the private key via. email or something like that? Or am I forced to get the private key as well when I create the wallet. I know it sounds stupid but I hope someone can help me.


texts:
I've configured the -keypool=n parameter to create a lot of keys at once.
During the generation, the hdd has a lot of IO, why?


texts: Possibility of hardware wallets being 'unsupported' in the future?

texts:
I was reading online about getting a hardware wallet/vs a paper wallet, and some comments online were mentioning that "Tech changes so quickly that in 16 years the hardware wallet might be completely unsupported. Perhaps the usb connection it uses will no longer be available at all. Maybe the company that made that wallet goes under. Sound too risky to me". I  found this really interesting, as I had never thought about the technical limitations. At the same time, it seems a bit crazy that those things would happen. Even if the company goes under, you still have your wallet and keys. Even if it isnt the same type of USB, getting an older computer with a USB with it is definitely possible.

I thought a hardware wallet was one of the more secure ways to store crypto, are these fears legitimate?


texts: Lnd - how to open a double-funded channel

texts: I know about lncli openchannel, however this means I will open a (bidirectional) channel with my peer, but initially just my side will have some balance. Let's say I agree with a collegue running another lightning node that we both want to have some initial balance. I'd expect to use something like lncli halfopenchannel on both sides and after we both do it the funding transaction and everything aftewards will get created. Same as TCP SYN this is prone to DoS and there needs to be some timeout. Of course the workaround is that he gives me some funds and I then push some of them directly to his side, but that's not really the most optimal approach. Any other possibility? Does any other lightning implementation address this?


texts: Understanding blockchain 'under the hood' how a block is created

texts:
Bitcoin newbie here: I'm trying to understand the concept of the blockchain but what I don't get is what's going on behind the scenes?

So let's say that there are only 10 miners in the universe and Alice sends 15 BTC to Bob, what happens now?

I understand that a verification needs to happen (to ensure that Alice has 15 BTC to transfer)

Assume miner_1 gets this 'request' and verifies the request as valid. Does he build a block?
How a block is created? Is it created for every request?
How all nodes on the network are being updated that there
s a request/new block?
When SHA256(SHA256(transaction?) occurs? On verification or when adding a block? Is there a good example that shows how this works?
How the miner who managed to find the hash get's a reward?


texts:
Does anyone know how the Bitcoin wallet developers earn money?

Do they live on only donations? Is it possible to survive on only donations?

Why would they develop wallets if they don't make any profit from it? :)


texts:
So, I'm setting up an altcoin for educational purposes and I've essentially forked Litecoin.

It's got a 10% premine on it but this wasn't showing up in my wallet so I deleted the $HOME/.mycoin/ directories on my nodes and my %appdata%/mycoin folder on my wallet host in an attempt to restart the blockchain.

However, the blocks that I have attempted to delete are still reappearing as soon as I start my daemon up again.

Any idea what directories/files I need to delete to completely restart the blockchain. This ought to be fairly trivial as I have complete control of the two nodes and the only machine that's connected to it.

Thanks


texts: How to get the historical data from bitfinex.com with out a limit?

texts:
I am drawing a chart using the data pulled from bitfinex.com via a simple API query. As the result, i will need to render a chart which is going to show the historical data of BTCUSD for the past two years. Docs are available right here: https://bitfinex.readme.io/v2/reference#rest-public-candles Everything works fine except the limit of the retrieved data.

This is my request: https://api.bitfinex.com/v2/candles/trade:1h:tBTCUSD/hist?start=1514764800000&sort=1

The result can be seen over here or you can copy the request to the browser: https://docs.google.com/document/d/1sG11Ro0X21_UFgUtdqrlitcCchoSh30NzGCgAe6M0u0/edit?usp=sharing

The problem is that I receive candles for only 5 days no matter what dates or parameters I use. I can get more candles if i add the limit parameter to the string. But still, I can not get more than 1100-1000 candles. I even get the 500 error from the server:

Server error: GET https://api.bitfinex.com/v2/candles/trade:1h:tBTCUSD/hist?limit=1100&start=1512086400000&end=1516233600000&sort=1 resulted in a 500 Internal Server Error response:\n ["error",10020,"limit: invalid"]. What should be the valid limit? There is no such information in the docs.

How can I get the desired amount of data for the two years period of time? I do not want to break my query down into smaller pieces and go step by step. It will look ugly.


texts: Bitcoin core syncing at 60% since December 13 and barely moving

texts: I am using a macOS Sierra version 10.12.6. my wallet has been syncing since December 13, 2017 and is still at 60% and hardly advancing. Is this normal? Is there anything I can do to speed it up?


texts: Fetch Balance of wallet without Core wallets of all coin?

texts: I'm creating an exchange like service, I need some for showing all transaction to user like deposit and withdrawal but I'm not using core wallets of any coin, using paper wallets for wallet creation and I want to show balance of user and transaction. So, is there any API available for so that I can fetch such details of user? Please give such API for Altcoins also or provide me name of any wallet through which my task can be completed.


texts: How can I reverse a Bitcoin transaction mistakenly sent to the wrong address?

texts:
I bought a bitcoin cash at a place called Bithumb in Korea and mistakenly copied the bitcoin address and sent it to the wrong. Obviously my fault is, but the fact that I can't get the cancellation done and lose all that money is very upsetting now.

Bitcoin, return my money right away. The money will not be sent anywhere, but it does not make sense that no refund is available.

2019. 5. 22. 13:20:14 BCH 20.121968
BitSumTXID:
7553dfd8ce04b2f78889224434f6602070c0ccdf81fb38a9e18307809d10d553

Id: 010  7122  1223

33zQhR8VGnHrXZuq4qz89VMqiWdCnPE51R


texts: Which API provides the logo for a cryptocurrency?

texts: I've been searching for an API that returns the logo/image for a cryptocurrency. API's like CoinCap.io and Bittrex don't return this information in the response. Is there any public API which provides the logo for a specific cryptocurrency?


texts:
People often talk about building a protocol “on top of” the bitcoin blockchain. Those same people often call this building a layer 2 protocol.

To be clear, “on top of” is clearly metaphorical language here (this is a visuospatial metaphor for what is a technical abstraction). Can someone explain what is actually happening when someone says that? Feel free to use the example of a well known application.


texts: Is there any address monitoring application with support for multiple cryptocurrencies?

texts:
This would be beneficial for all long-term investors who have many different cryptocurrencies in their portfolio and don't usually perform any transactions. Simply just to check whether your money are still there. No need to login into all your wallets, entering passwords etc. With support for many different cryptocurrencies.

I have just decided to develop such an application for my own use (it is open source, you can check it here - Cryptocheck ), but maybe there is already a good solution for this.


texts: How to generate a payment request [BIP70] with specified fees

texts:
I am working on an bitcoin payment system that generates invoices, because the invoice is time sensitive we like to control the fees our users pay as much as possible.

Is it possible to create a BIP70 payment request that specifies the fee the payee is expected to pay (either per output to be summed up, or in total for the transaction)? We can do our own validation, this question is just about the creation of the payment request (if the bip70 spec allows for the specifying of fees).


texts:
I have been reading about the security of thin clients and I came across the section that discusses the proposal of Unused Output Tree in the Block chain.

  Unused Output Tree in the Block chain (UOT)
  There have been several proposals (the first appears to be this one by gmaxwell, who called it an "open transaction tree", although the term "open" is now taken to mean "not yet mined into the block chain" rather than "unspent") to form a tree of unused transaction outputs at each block in the chain, hash it as a Merkle tree, and encode the root hash in the block chain (probably as part of the coinbase input). This will be called an Unused Output Tree (UOT). The first detailed proposal so far appears to be Alberto Torres' proposal; etotheipi's ultimate block chain compression is a variant of this.

  If such UOT hashes were included in the block chain, a client which shipped with a checkpoint block that had a UOT would only need to download blocks after the checkpoint. Moreover, once the client had downloaded those blocks and confirmed their UOTs, it could discard all but the most recent block containing a UOT.

I understand this part, and how the merkle tree is going to be constructed, but the next part that talks about associated risks is what confuses me:

  Hostile miners may insert blocks into the chain which have what claims to be a UOT, but which is actually invalid. It is unlikely that such blocks could be kept out of the chain because, again, this would require adding a new block validity criterion, and miners implementing this new criterion would risk "mining on the wrong side" of a fork, which could cost them a lot of money. Therefore, any UOT strategy would need to cope with the fact that not every block containing a UOT entry can be trusted.

So my questions are:

I assume that an invalid UOT means a tree that contains outputs that are either double spend, or doesn't even exist in the chain. Why wouldn't the bitcoin network be able to reject those? Also are full nodes also vulnerable to this attack? I think that Full nodes can always check the outputs in the UOT against the previous to make sure that all outputs are either included in the prev UOT or generated by transactions in the current block.
I understand that implementing this would require some modifications to the current validity criteria, but whhy would nodes up-taking these changes risk "mining on the wrong side"?


texts: (Script) Is it possible to create a transaction that is spendable to only one address?

texts:
I'm reading up on Script, which is pretty advanced stuff for a web developer like myself. I'm wondering, is it possible to send a transaction that can only be spent to a particular address?

Example, "Alice sends 1 BTC to Bob. Bob cannot do anything with that BTC except send it back to Alice."

Is that possible and how would it be accomplished?


texts: How to report the tax if I trade BTC to LTC?

texts:
Assume I traded 100 times between BTC and LTC and I earned $100 IF I sell all coins at market price.

However, I don't want to sell my coins yet. How I can report to the US tax?


texts: Most important spec to look for on a GPU for scrypt mining (e.g. Litecoin)

texts:
By taking a look at all the current AMD cards comparison:

http://en.wikipedia.org/w/index.php?title=Comparison_of_AMD_graphics_processing_units

I was wondering if GFLOPS would be the best way to compare the raw power those cards would have for Litecoin mining.
In that case is single or double precision more important for the current mining software?

Also I'm aware that power consumption is another key factor.

Edit:

No answers so far...
A friend of mine who has been mining for a while thinks the number of shaders is the most important one. Still in the comparison chart above there are more specs that could be important I guess:

Pixel pipelines
Vertex shaders
Texture mapping units
Render output units

Still I think that they should all be reflected into the Processing Power GFLOPs, either single or double precision.


texts: How to actually handle the xPub gap limit when receiving Bitcoin deposits?

texts:
I've read the other questions involving this, including How to solve Blockchain 20 address gap-limit problem? and Blockchain gap limit which don't actually remedy the issue in a practical sense, only further explain why it exists.
I understand why the gap exists, how it works, and how Blockchain.info handles it. (Both with callbacks, checkgap API requests, returning an error when the gap reaches over 20, etc)
My question is, what can I, as a developer, do to prevent exhausting this gap? Is this even a valid method for handling a larger website's Bitcoin deposits from users? Do I just have to hope that 20 users don't generate an address for fun, sending operations into a standstill?


texts: Can I generate payment adresses while offline?

texts:
So I'm using the original bitcoin client.
What if on a computer without internet (A) I generate a bitcoin address and
then use this address to receive a payment (by using an other computer with internet (B))

Once I transfer my wallet.dat to computer B and let it sync, will I still get the payment ?

I'm asking because I'm doing stuff from work and the bitcoin-qt can't synchronize from over there.

Do I need to be online in order to generate a ready to use payment address?


texts: How does changing transaction data in a block change the hash of previous block?

texts:
I am reading this article, within which it mentions that

"Imagine this for a second, a hacker attacks block 3 and tries to change the data. Because of the properties of hash functions, a slight change in data will change the hash drastically. This means that any slight changes made in block 3, will change the hash which is stored in block 2, now that in turn will change the data and the hash of block 2 which will result in changes in block 1 and so on and so forth."

And I do not understand if a hacker attacks block 3 and try to edit the transaction data within it, how would this affect the hash stored in block 2? And hash of what is stored in block 2 ?

Can someone kindly clarify for me please ? I am just getting confused.


texts: Why is two hours the maximum acceptable offset for Bitcoin blocks?

texts:
As far as I understand, Bitcoin transactions include a timestamp, but the only requirement is that they don't differ for more than two hours.

But why two hours? For computers that are constantly synced via NTP, two hours seem like a very big difference. I would expect that a difference of 10 minutes should be enough.

Or, if this is about time zones and summer time, shouldn't they be using UTC time?


texts:
I cant find this info: How can I ban through CLI a peer connected to my full node?

I like how can I do it in the 0.12.0 GUI just with right-click and choosing for how much time I want to ban the peer.

tia


texts: Is there any reason to invest on GPU based system these days? (March 2013)

texts:
I wonder whether I should spend around 1000$ - 1500$ for buying a GPU based system that will mine at 2GH/s. Is it still worth it? What will happen when all those ASIC machines will arrive? will i still be mining at a decent rate?

Thanks.


texts:
When we plot the attacker's computational power against the probability of double spending with a number of blocks equal to zero, we always get a chance of 100%.

This plot is based on the original white paper that models the probability of success as a Poisson distribution.

Is this correct?

Shouldn't the probability of success then be related to the computational power the attacker possesses?


texts: Why does Blockchain (the company) open source their code but not license it?

texts:
I'm very curious as to why Blockchain (the company) doesn't license their open source software. Also, does this mean we (the public) can just use their software and license it using Apache's 2.0 license?

David


texts:
Some wallets (such as inputs.io) claim to provide off-chain transactions. Note: I have not used that wallet yet.

Say if I have a Bitcoin address A in such a wallet provider and send 1 Bitcoin to address B from the same wallet provider, what will show on the public blockchain?

Will there be 1 Bitcoin in B on the public blockchain?
If yes to 1, will that Bitcoin show as coming from A?


texts: I want to begin experimenting with bitcoin. I notice the estimated upload traffic for the real bitcoin network is around 200 GB per month. That's too much for an experiment. How much traffic per month could I expect for a node on the test network?


texts: How to detect that full node is in sync (using jsonrpc)?

texts: I have full bitcoin node available through jsonrpc interface. How my app can detect if this node  is in sync with the network?


texts:
http://www.zerohedge.com/news/2013-10-08/bitcoin-1-0-fbi

How did the FBI seize 26000 BTC? I thought that all wallets are supposed to be safe. Can you give the technical details?


texts: How do you find historic VWAP at a given time in a specific exchange?

texts:
Suppose I want to find the VWAP of BTC-USD in a specific exchange (e.g. Bitstamp) at a specific point in time (e.g. 1/1/2013 00:00:00).

What's an easy way to do this?


texts: How to restore from backup of Android Bitcoin Wallet

texts:
Bitcoin Wallet for Android allows you to back up your wallet.  It asks for a password when doing so.

After much faffing, I finally managed to.. dum, dum, dum! .. copy the file to the SD card, and then I removed the SD card and mounted on a Linux system.

According to this question, the way to decrypt it is

$ openssl enc -d -aes-256-cbc -a -in bitcoin-wallet-backup-2016-09-30

but I get:

enter aes-256-cbc decryption password:
error reading input file

when doing so.  This is an extremely poor error message from openssl.  I have confirmed that the file is readable using other utilities.


texts: Forking PIVX - ERROR: CheckBlockHeader() : proof of work failed

texts:
I have forked PIVX and generated new genesis block hash, merkle root and nonce, and changed the rewards parameters.

It compiles fine and the daemon starts, I have even got 2 nodes connected, but attempting to mine the first block with setgenerate true -1 does not work. getmininginfo says mining = true but the hashratepersec is 0.

My debug.log shows pages and pages of this:

2018-02-01 13:16:55 CreateNewBlock() : TestBlockValidity failed
2018-02-01 13:16:55 CreateNewBlock(): total size 1000
2018-02-01 13:16:55 ERROR: CheckProofOfWork() : hash doesn't match nBits
2018-02-01 13:16:55 ERROR: CheckBlockHeader() : proof of work failed
2018-02-01 13:16:55 ERROR: CheckBlock() : CheckBlockHeader failed
2018-02-01 13:16:55 CreateNewBlock() : TestBlockValidity failed
2018-02-01 13:16:55 CreateNewBlock(): total size 1000
2018-02-01 13:16:55 ERROR: CheckProofOfWork() : hash doesn't match nBits
2018-02-01 13:16:55 ERROR: CheckBlockHeader() : proof of work failed
2018-02-01 13:16:55 ERROR: CheckBlock() : CheckBlockHeader failed
2018-02-01 13:16:55 CreateNewBlock() : TestBlockValidity failed
2018-02-01 13:16:55 CreateNewBlock(): total size 1000
2018-02-01 13:16:55 ERROR: CheckProofOfWork() : hash doesn't match nBits
2018-02-01 13:16:55 ERROR: CheckBlockHeader() : proof of work failed
2018-02-01 13:16:55 ERROR: CheckBlock() : CheckBlockHeader failed
2018-02-01 13:16:55 CreateNewBlock() : TestBlockValidity failed
2018-02-01 13:16:55 CreateNewBlock(): total size 1000
2018-02-01 13:16:55 ERROR: CheckProofOfWork() : hash doesn't match nBits
2018-02-01 13:16:55 ERROR: CheckBlockHeader() : proof of work failed

I think this maybe a small error somewhere but not exactly sure where. Maybe someone would know from experience?

If you are commenting to say "not another coin clone" please save your energy for something more productive.

Thanks!


texts: Does anyone have an experience in using BTC Robot? Can it make some money or is it just a scam?


texts: How to send user input data(Bitcoin address) from iPhone to server and then send Bitcoin back to user's Bitcoin address?

texts:
Background I just got started yesterday learning Python and I'm currently building my first iPhone game.

What I'm trying to do is create a Bitcoin Pot Jar inside an iPhone app like Sarutobi:https://itunes.apple.com/us/app/id932194840?mt=8

You can test out the game to see how it works. All the user does is paste their bitcoin address in an input field, somehow this data goes somewhere and then the user receives randomly small tip during gameplay. How do I create something like this? What code is used to make this work?


texts: What is the signature digest for Segwit outputs

texts:
(Assume there's no OP_CODESEPERATOR)

For standard P2PKH, the signature digest is generated this way:

NewTransaction

settle the TxOuts well
set all TxIn scripts to empty
insert the Previous Locking Script into the TxIn you are signing
append hash type code to the end of the transaction
SHA256 twice this transaction
Be a digest.

For standard P2SH, the signature digest is generated this way:

NewTransaction

settle the TxOuts well
set all TxIn scripts to empty
insert the Previous Unlocking Script's Redeem Script into the TxIn you are signing
append hash type code to the end of the transaction
SHA256 twice this transaction
Be a digest.

I learned those above from here. As for those above, I have written programs and successfully signed and submitted Bitcoin transactions to the blockchain.

But when it comes to Segwit, I don't know what the digest should be. For P2WPKH output, I tried to use the same method to get the digest as P2PKH, but it failed. Blockchain told me my signature was wrong.


texts: Can two crypto currencies have the same name?

texts:
I noted today that coingen.io makes it easy to make crypto currencies.
I was wondering if it makes sense to register currencies named after countries, gods and companies to hoard them. AFAIK there is nothing that ensures uniqueness of the names of the crypto currencies, right ? there is nothing in the block-chain that critically depends on the name of the currency.


texts: How do I get my BTC back into my exchange without losing my BCC?

texts: I put my BTC in a paper wallet before the fork. Now, I'm desperately looking for a way to get my BTC off my paper wallet and back into circulation without losing my BCC. I don't really want to send my BTC to a newly developed BCC-dedicated wallet (because it's a large amount and that makes me nervous), but to my understanding sending my coins back to Gemini will make my lose my BCC.


texts: How does lending / leasing in NXT work? What are some use case scenarios?

texts:
Since you can lend / lease you nxt to another account.

What are the pros/cons of this nxt lending feature?

What are some use case scenarios?


texts: Can I process my own transactions from my wallet on my miner? I would like to process my own transactions because then I could have my transactions go faster and not have to pay extra because it would be processed locally? I know this might sound dumb but I would still like to know.


texts:
I am starting with the execution of internet marketing activities for one Bitcoin gambling site that I owe, and I am trying to figure what best describes owners of bitcoin.

Are there any demographics information available? What sites / habbits dothe bitcoin user have, where does he browse sites online, is he using Bitcoin for gambling purposes etc etc

If someone can help with some insights or useful information I thank you in advance.


texts: How to implement cold storage payments using bitcoind

texts: I wonder what APIs of bitcoind I can use to sign a transaction without actually publishing it. I read that createrawtransaction (in conjunction with signrawtransaction) is a bit risky and for sure poorly documented. Are there any alternatives?


texts: Aren't blocks generated too slowly to catch up to transactions?

texts:
I read somewhere that it takes 10 minutes to mine a block.

What happens when the number of transactions exceeds the block size. Do we all have to wait 10 minutes until another block comes in?


texts: Changes for bitcoin.conf file and details on the testnet network bitcoin-core

texts:
I have installed bitcoin core testnet and it is now synchronized with the network after 24 hours.
My question is about bitcoin.conf file.
I will tell you the procedure I used to install:
I created the start testnet.bat file with this command :
start "" bitcoin-qt.exe -regnet -datadir=./data_regnet/ -prune=550

Now There is this bitcoin.conf file in "data_testnet" folder. But the thing is it is empty.
And as I am new to this so want to know should I make any changes to bitcoin.conf file or leave it as it is.
And another question is right now I haven't closed the wallet in fear of losing the synchronization that it took so long, So the next time when I want to access the wallet I can directly start my start testnet.bat file??
Operating System: Windows 10 (x64-bit)
Bitcoin-core version: 0.16.3
Thank you:)


texts: Litecoin transaction sent to Bitcoin address that starts with (3)

texts: I have an issue where I have paid and received litecoin into my Bitcoin addres that starts with (3) I am now trying to get my coins and sell them or move to a litecoin address! Can anyone advise on what to do?


texts: How can I sign a message with a multi signature address?

texts: I want to use message signing to prove control of a multi signature Bitcoin address. Is it possible? In theory it must be. In practice, are there any Bitcoin wallets that allow this? Specifically, how can I do this with Armory Lockboxes?


texts: How can Bitcoin protect itself from a "dumb majority soft fork"?

texts:
Let's say a majority of miners change to using software that prohibits timelocks. This would be a softfork, so the blockchain would still look valid to nodes using the previous software, however nodes that mine blocks with a timehash would be orphaned from the network by the mining majority and outpace any chain containing timelocks. No chain that contains timelocks could grow, and existing nodes would treat the chain with new rules as the one true chain.

How would the users/miners that want to keep the use of timelocks be able to recover in this situation?


texts: Is split possible in bitcoins (like in stocks)?

texts:
I see that bitcoin is reaching 1000USD. If bitcoin becomes widely accepted currency, then we'll have to deal with decimal numbers like 0.00023 for onions etc. This can be cumbersome and might become a blocker for bitcoin adoption.

To overcome this problem, some people already started using mBTC (milli bitcoin) as units. But this is confusing. The better solution would be to split the bitcoins (like we do in stocks). With this approach, when BTC reaches 1000USD, we can split 1BTC into 1000BTC and it would be easy to manage the currency.

So my question is, does the bitcoin algorithm supports splitting of bitcoin?


texts: Why is only the block header SHA256-hashed and not the whole block?

texts:
I read in many places that mining involves finding nonce such that SHA256(SHA256 (blockheader_including_nonce)) meets a specific criteria (0 bits...).

Why is this hashing done only on the < 100 bytes of the block header? If it's only done on header, doesn't this mean we could modify a transaction in the block and keep the same block header and hash?

How is this not a weakness?


texts:
Im trying to get the estimation of how much the fees will be when a final amount is decided on. I would say im getting familiar with bitcoinj but not completely with java so im still learning how to code and exploring how to get information.

this is my present code. I put everything inside a method.

public static String SendFund(String amount, String receiver){
        String text;
        Coin value = Coin.parseCoin(amount);
        LegacyAddress to = LegacyAddress.fromBase58(MainPage.params, receiver);
        try {
            System.out.println(gbal()+" - "+gaddress());
            Wallet.SendResult result = kit.wallet().sendCoins(kit.peerGroup(), to, value);
            text = ""+amount+" BTC sent to address

"+receiver+".";
            System.out.println("Check transaction : https://testnet.blockchain.info/tx/"+result.tx.getHashAsString());
        }catch(InsufficientMoneyException e){
            text = "Insufficient Funds.";
        }
        return text;
    }

Currently it doesnt deal with fees. But when i view a transaction such as this ==> https://testnet.blockchain.info/tx/194b2a7505a537307abe9443b048bc7ddce6ca0d833d5758c3be3c03a9c7b838 you can clearly see the fee.

Also when i purposely tried to send coins when i know the wallet doesnt have enough it doesnt tell me that it failed

0.8625106 - n2uEm2QXqe2PCSsbHTdAJN9aDm2mDjz6iZ
May 02, 2018 5:08:58 PM org.bitcoinj.wallet.Wallet completeTx
INFO: Completing send tx with 1 outputs totalling 1.00 BTC and a fee of 0.001 BTC/kB

What am i doing wrong for failing to check? do i have to actually perform an if statement just to check? And also how can i calculate reliably on what the final amount would be?


texts:
I am running OS X Yosemite. I cloned the bitcoin repo and checkout-ed the v0.9.3 tag to get the most recent stable version.

Then I followed the steps described here to compile the code.

It compiled for a long time, and then ended with the following error:

clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[4]: *** [test_bitcoin] Error 1
make[3]: *** [all] Error 2
make[2]: *** [all-recursive] Error 1
make[1]: *** [all] Error 2
make: *** [all-recursive] Error 1

Has anyone seen this error before? Why was it caused? What can I do to fix it?


texts: Why does coinbase make 2 transfers instead of one

texts:
I'm new to bitcoin in general and coinbase.com in particular. Can somebody explain what happens when I order a payment (in bitcoins) from their web interface?

Say that my acount owns 1 BTC. I create an address AAA to pay 0.1 BTC for my loaf of bread to my baker's address BBB. I order the transfer from coinbase.com web interface, and looking at blockchain.info, I see the following (amounts rounded):

// webUI says I own 1.0 BTC

AAA  pays 0.1032   --> X = 0.1     BTC to BBB (my baker)  // what I wanted
                   --> Y = 0.0002  BTC as network fees    // fine with that
                   --> Z = 0.003   BTC to CCC             // what is that ?

// after payment, webUI says I own 0.8998 (= 1.0 - X - Y)
// The mysterious Z = 0.003 BTC have *not* been removed.

But what is that 0.003 BTC transfer to an address I don't know CCC? Apparently I own this address, or at least coinbase.com does on my behalf. Is it a standard way of processing I'm not aware of? Is it a safety feature managed by coinbase to authenticate the transaction?

Obviously there are a lot of informations on this reddit, but it's too technical for me.


texts: Bitcoin TX decode failed while sending to a the network(regtest)

texts:
I have created a signature manually (referring the signature output formats in bitcoin-cli). But i tried to send the same to the network I am getting

error code: -22

error message:

TX decode failed

Below is the signed tx

signed tx:

020000000138c059adfe41e80fb46e14d23949304343abc560a6fbcef4b2e3110f8241816d00000000002c2b0768616e756d616ea8201ca35897540ec7ae7294a8cacd11caf2c09f95f026c925c6ce4e4c29b20e3c4187ffffffff0280507401000000001976a9146a3ffadddae4ccb4223a8c7215d4b481daf6967788ac00d012130000000017a914def347cf3b01bf03a30d7ee9f62d86ed5109b5478700000000

Spliting the same signed tx:

02 00 00 00  // version

01   // number of inputs (var_uint)

38 c0 59 ad fe 41 e8 0f b4 6e 14 d2 39 49 30 43 43 ab c5 60 a6 fb ce f4 b2 e3

11 0f 82 41 81 6d  // input transaction hash

00 00 00 00 00 //  input index

2c // size of script (var_uint)

2b // data needs to be pushed  the below 43 bytes will be pushed

07 // push 7 bytes to stack

68 61 6e 75 6d 61 6e // data needs to be pushed

a8 // OP_HASH256

20 // push 32 bytes

1c a3 58 97 54 0e c7 ae 72 94 a8 ca cd 11 ca f2 c0 9f 95 f0 26 c9 25 c6 ce 4e

4c 29 b2 0e 3c 41

87 // OP_EQUAL

ff ff ff ff // sequence

02  // no of vouts

80 50 74 01 00 00 00 00 // amount

19 // size of script (var_uint)

76 //OP_DUP

a9 // OP_HAH160

14  // 20 bytes needs to be pushed

6a 3f fa dd da e4 cc b4 22 3a 8c 72 15 d4 b4 81 da f6 96 77

88 // OP_EQUALVERIFY

ac //OP_CHECKSIG

00 d0 12 13 00 00 00 00 // amount

17 // size of script (var_uint)

a9 //  OP_HASH160

14 // 20 bytes needs to be pushed

de f3 47 cf 3b 01 bf 03 a3 0d 7e e9 f6 2d 86 ed 51 09 b5 47

87 // OP_EQUAL

00000000 // lock time

Can anyone please help me to find what is that I am missing ?


texts: What is the minimum transaction fee used for?

texts:
I have the bitcoin-qt client running on Ubuntu 12.10 and I see a transaction fee box in the preferences, but I am unsure of what it actually means - the wiki is overly complex, and I am unable to find another help website about this.

Can anyone give a easy to understand explenation of a minimum transaction fee. Do I have to pay it, or the sender? Etc.


texts:
CentOS6 x64, build last cgminer with openCL support

[ay@pandora6 log]$ sudo lshw | grep -i geforce
             product: G73 [GeForce 7600 GS]

[ay@pandora6 log]$ uname -a
Linux pandora6 2.6.32-358.2.1.el6.x86_64 #1 SMP Wed Mar 13 00:26:49 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

[ay@pandora6 log]$ cat /etc/redhat-release
CentOS release 6.4 (Final)

[ay@pandora6 /]$ nvidia-settings -v
nvidia-settings:  version 304.108  (buildmeister@swio-display-x64-rhel04-06)  Wed Jul 31 20:47:31 PDT 2013

Why cgminer does not use GPU ?

[ay@pandora6 /]$ /usr/local/bin/cgminer -n
 [2013-10-11 14:58:09] CL Platform 0 vendor: Advanced Micro Devices, Inc.
 [2013-10-11 14:58:09] CL Platform 0 name: AMD Accelerated Parallel Processing
 [2013-10-11 14:58:09] CL Platform 0 version: OpenCL 1.1 AMD-APP-SDK-v2.5 (684.213)
 [2013-10-11 14:58:09] Error -1: Getting Device IDs (num)
 [2013-10-11 14:58:09] clDevicesNum returned error, no GPUs usable
 [2013-10-11 14:58:09] 0 GPU devices max detected