texts: Is it possible to cancel an unconfirmed transaction?

texts: If you submit a transaction to the network but it hasn't yet be confirmed by a block, is it possible to cancel this transaction?


texts: Estimate of Net % of transaction fees in bitcoin transactions

texts:
one of the major pain points that bitcoin is trying to solve is the 2% transaction fee. However bitcoin is not necessarily free, even if it gets mass acceptance (say the entire USD is replaced by bitcoins). There will be additional transaction costs such as 1. generation of bitcoins 2. storage of bitcoins 3. apps that enable people to transact in bitcoins 4. credit history monitoring services etc. Some of these will be paid directly while exchange of value for currency (such as through transcation fees in bitcoin based credit cards), some of them may be indirect (such as an app which allows you to store/monitor bitcoins, but then uses ads to support itself. The ads inturn increase the price of the commodities that are being bought or sold. So you are paying for the bitcoin indirectly).

I am curious to know whether any study has been done to calculate the net % that will be lost in transcation fees (paid directly or indirectly by the purchaser of the goods) as compared to that of credit cards (~2%)?


texts:
I am currently in the process of creating a fairly simple bitcoin miner for CPU and GPU (for demonstration purposes not for money earning).

However I am having a little troubling understanding how the GPU miners generally work. Now I do want a fairly simple version of this, but I hope to be able to get one that performs decently (hopefully within 10-30% of normal miners, and definitely faster than CPU version).

In general I would think the strategy you have for executing on the GPU is something like the below. I hope someone could help me out on whether I am doing something completely wrong and give me some pointers towards how you usually do it.

Transfer the binary version of the data to hash to the kernel (I noticed a lot of input arguments to the OpenCL kernels on some of the versions I have seen, I assume this is some sort of optimizations of data transfer)
Now, calculate the double sha256 hash of the data (Is it generally advisable to have a loop checking multiple nonces or just one per kernel?)
Return a result. What is the best way of doing this? Do I check inside the kernel if it is lower than the desired target, do I just return any value and return to the host device to check for validity or how is this generally done? If checking multiple nonces I assume you should keep track of what was the best result during the run.

I do have a general and very basic GPU implementation but it is currently slower than the CPU implementation I have. I do more or less as above where each kernel check several nonces and return the "best" one (i.e. most trailing zeros of the hash (using getwork protocol) ).


texts: Watch a BitCoin account for incoming payments

texts:
I want to watch a set of BitCoin addresses and be notified (preferably by email) when they receive a payment.

I prefer me not to write my own software for this and not to install it on my own server, but programming suggestions are welcome.


texts: Prompt user for payment amount using bitcoin bip 70?

texts:
When specifying the details for the payment object I have noticed that if I leave amount blank I am not prompted to enter an amount by the bitcoin-qt 0.9 client.

xpd = x.PaymentDetails()
xpd.time = int(time())
xpd.outputs.add(amount = 10000000, script = serialized_script)
xpd.memo = 'this is xpd memo'
xpdstring = xpd.SerializeToString()
xpr = x.PaymentRequest()
xpr.serialized_payment_details = xpd.SerializeToString()
xprstring = xpd.SerializeToString()

If I do not specify an amount then it is set to zero by default and I am presented with the error that the bitcoin amount is too small and is considered 'dust'.

Please can someone help me understand how to prompt the user for a deposit amount if the amount field is blank?

Thanks.

Additionally I should note that I am using the testnet.


texts: Instant confirmations with pre-published, locked, transactions

texts:
(Clarification: This is not an attempt to solve the problem of a vendor taking the money and running without handing over the merchandise.  Problems like that can't be solved without some third party.  The purpose here is for A to give bitcoin to B, where B can be instantly certain that he has access to the bitcoin.)

I have an idea that depends on the Script system in Bitcoin, but maybe I'm asking too much.  It would allow for instant confirmations between parties who arrange a negotiation a few hours in advance.  I don't know very much about Script though.  Is the following scheme possible?  Would extensions to the Script be required?

Person A and Person B are going to meet in a few hours for a business deal.  If all goes well, they hope to shake hands and A will want to instantly send some BTC to B.

In advance, A publishes a transaction that sends the money to B.  By the time the meeting occurs it will have received enough confirmations.  But this won't be a normal transaction.  It should include some further conditions:

First, the transaction should include a hash, such that the transaction won't complete unless a document is produced which has that hash.

When they shake hands, A can instantly show that document to B and B can verify that the document produces the correct hash.  B can then be confident that the transaction will be processed fully later when he produces the document.

There is no double-spending problem here.  The output of the special transaction has already been locked to send to B, it cannot be sent anywhere else.

We need a way to rollback this if A and B do not reach agreement.  Can Script allow a transaction to be cancelled if its outputs are not used a specified timeframe?  I guess not.  (Partially cancelled, the transaction fee should remain valid.)

Another approach to this rollback is for the special transaction to also include a special output which sends all the money back to another of A's address.  But this should have some sort of time lock on it, such that it isn't allowed to happen until a suitable delay, 24 hours, has occured.  Is it possible for the outputs to be double the total inputs in a case like this, where maybe we can prove that only one output can be claimed?  (I envisage having non-overlapping timelocks on both transactions in order.)


texts: How are Lightning network, duplex channels, and micropayment channels related?

texts:
I'm new to Bitcoin and just became familiar with Micropayment channels. But how exactly do they relate to:

Lightning network
Duplex Micropayment Channels
?

I am reading about these but can't find a "big picture" view. Most big-picture posts are over-simplistic or promoting either of these I found.

Also, micropayment channels, as implemented by bitcoinJ, are used in practice I believe. What about Lightning and Duplex?

(Successful efforts to implement Lightning exist (e.g., blockchain.info, Lightning). Has there been any effort to implement Duplex?)

thank you


texts: Why are the mining rewards set to reduce in such dramatic steps?

texts:
The mining rewards are scheduled to drop from 50btc to 25btc. The next drop again will be from 25 to 12.5btc. In each of the steps into a new "era" the mining reward is reduced by 50%.

This seems like a very dramatic pay cut at each juncture, Is there a reason why the amount isn't being decreased more gradually by smaller and more frequent amounts?


texts:
Maybe my question is stupid, but

imagine that I'm trying to spend inputs from p2sh.

For example, p2sh scriptPubKey looks like:

OP_SHA256 4bf5122f344554c53bde2ebb8cd2b7e3d1600ad631c385a5d7cce23c7785459a OP_EQUAL

I know, that the SHA256(0x01) = 4bf5122f...85459a (hacker do not know that, until I broadcast tx)

So I broadcast transaction with the folowing scriptsig:

OP_1 (0x51)

Why hacker can't take this unconfirmed transaction, extract scriptsig, and replace outputs to his own outputs ?

Also, what to do, if RBF (replace-by-fee) flag is set?

Of course, I'm not talking about transactions with OP_CHECKSIG


texts: How do I generate a paper wallet for Bitcoin Cash

texts: I can't find any tools to generate Bitcoin cash paper wallet - any ideas?


texts: When joining the bitcoin network, why aren't we connected to the most geographically closest nodes?

texts: Is this a safety/security reason or is it just convenience?


texts: Can I mine with BFGMiner on an ATI Radeon

texts:
I have managed to connect to the pool via the command line but when I went to manage devices it says I have none. I tried to use auto and all commands to add the GPU and seemingly it will not pick it up.

Is it even possible to use a amd m880g?

Any advice appriciated

EDIT
I have also found the same is true with cgminer. Is it impossible to use this card?


texts: Sending transaction with Python + raw protocol

texts:
Two days ago I've found a few articles, about using raw bitcoin protocol, and now I'm still trying to send a transaction.

My code is based on this class, and
if I understand all of this bitcoin magic right, I need to sign my raw input transaction with the private key for address 1LwPhYQi4BRBuuyWSGVeb6kPrTqpSVmoYz and add my public key right after it - and it will be a valid unlocking script?

Here's a part of my code, which I have completely copied from the previous link:

tx_in_count = struct.pack("<B", 1)
tx_in = {}                                                                                tx_in["outpoint_hash"] = flip_byte_order(previous_output_hash).decode("hex")
tx_in["outpoint_index"] = struct.pack("<L", 1)
tx_in["script"] = ("76a914%s88ac" % private_key).decode("hex")
tx_in["script_bytes"] = struct.pack("<B", (len(tx_in["script"])))
tx_in["sequence"] = "ffffffff".decode("hex")

I'm not sure about tx_in["script"] line, because there is nothing about signing transaction or public keys, so probably it's the reason for my failures.

Thanks for any answers :)


texts: Is Proof-Of-Work simply a decentralized clock?

texts:
I have not seen anyone explain Proof-Of-Work this way, so I thought
I'd share it here, I'd be curious to know if I'm completely off.

It seems to me that PoW is simply a distributed decentralized source of
ticks, a clock, to which data can be "tied"?

The challenge of Proof-Of-Work is a singleton problem (for lack of a
better term), i.e. there is only one instance of it in the universe. This means that it is known to every participant, and anyone working on it is affecting the outcome.

Most importantly even if one is participating in complete secrecy until a solution is found, it still affects the outcome.

An analogy might be looking for the largest known prime. You
don't need to tell anyone you decided to find one, you only announce
when and if you actually find one. Your participation makes finding a
solution a possibility, whereas if no one ever looks for the largest
prime, it will never be found.

The difficulty algorithm adjusts in such a way that a solution is
found on average every 10 minutes. It's a distributed decentralized
clock which ticks on average once every 10 minutes. The miners make it
possible through their participation, and curiously, miners do not
need to tell anyone they are participating, they only need to
communicate with others if and when a solution is found.

The clock has an interesting property - you can tie data to its ticks,
simply by making the data the input to the SHA. A solved block is
nothing more than simply an event that happened exactly at the tick of
this clock.

And essentially this is all that Proof-Of-Work does for
the blockchain: it provides ticks of a clock, to which events can be
tied. Everything else is an "add-on" to this "feature", e.g. using the Merkle tree we can cryptographically record the ordering of the ticks. But without the "PoW clock" none of it would be possible.

Edit: these ticks do come at irregular intervals, so one wouldn't set their watch to it. But that doesn't matter for as long as it is approximately 10 minutes, which it is.

Edit: here is a much more detailed explanation: https://grisha.org/blog/2018/01/23/explaining-proof-of-work/


texts: Why is it so that if some bitcoin is spent by any user, the rest of his account's amount should also be spent and paid him back?

texts:
I guess this is called Circular spending.

Why is it required in the bitcoin protocol?


texts:
Bitcoin secures its network by forcing miners to solve a cryptographic puzzle who's difficulty increases based on the total hashing power of the network. If someone were to develop an algorithm that enables them to solve this puzzle say 1,000 times more efficiently (faster) than anyone else on the network they would be able to mine most (or a good portion) of new Bitcoin for pennies on the dollar. Assuming the person only uses his knowledge to mine Bitcoin at a much greater speed/efficiency compared to other miners (and does not hack anything or attempt to double spend etc) would the network be able to detect that something like this is happening?
I suppose not, because the hashing power of the network is not something that is known explicitly. It is something that is implicitly calculated based on the assumption that there is no possible way for a single individual to solve the cryptographic puzzle more efficiently than anyone else.
Is my assessment accurate?
Thanks


texts: Is it possible to run electrum without QT on Ubuntu?

texts:
I want to run an electrum server and don't need the GUI. When I install it, I get:

ubuntu@comp:~$ electrum                                                                                qt.qpa.screen: QXcbConnection: Could not connect to display
Could not connect to any X display.

Which is because I don't have an X display, obviously. How can I install with pure command line?


texts: Are there any signatures where the recid (v) is equal to 29,30 (or 33,34 compressed)?

texts:
Peter Wuille recently explained how ECDSA pubkey recovery is done, in response to my question.

So it's basically that for a given base64 signature, the value v in v,r,s provides the specific coordinates, hence the recid (recovery ID).

Example from BitcoinCore test vectors:

> sig =
> "H8PgOb/liZzt3QQHJn9kLBqH7E/i+SC6JTwYGtdNdOjnXzFqXnHMZqP7oZ1wb1QiQ3H/kF8xC9Yx7pK9ddlx8TA"
> addr = "1K5Z1nxN4mjUgCLpSXMRkeZxuAMpbn2CQB" wif =
> "KwfJTiKdcjNMjBu4ksgGd21EZXz6JomoZNbirP3nfd3K9ZMXMEUi"
>
> v,r,s = vrs = (31,
> 88597177789312009809148107221292570613390338668815747761545214128303675599079L,
> 43057030252916568867525408201971649068117337291455262356277580652864892694832L)

The value of v is 27 + recid for uncompressed keys and 31 + recid for compressed keys.

Ive run a Python loop using pybitcointools which signs a message using a random key, and I've yet to ever see v=29 or v=30. Why is this? Is it by design, or is it just a very low probability event?


texts: Miners, did Catalyst version 11.9 fix CPU usage issue for you?

texts: Miners, did the new Catalyst version 11.9 fix 100% CPU usage issue for you? what's the best version of Catalyst to use for mining?


texts:
I made a payment to somebody and now he is not replying me regarding the product I made the payment for and think its a fraud.
So I want to block the transaction.
All I have is the QR code of the person to whom the payment was made.
I also have the QR code detail
Bitcoin:1PNPnadF26twbAxTZTVeEaQKjbYeXDmeNJ


texts: On Cryptowatch (or equivalent): see percentage change to custom reference point

texts: Given that I bought a certain amount of BTC at a given point in time. Is there a way on cryptowat.ch or an equivalent platform, to mark the price and point of time at which I bought the BTCs and get information about how the current price is to the reference price in percent (preferably live)?


texts:
After placing a market order, I got its order_id & checked its status via this end point /v1/order/status and I got the following:

Array
(
[id] => 18141116927
[cid] => 43611135723
[cid_date] => 2018-10-17
[gid] =>
[symbol] => iotusd
[exchange] => bitfinex
[price] => 0.51251
[avg_execution_price] => 0.51234
[side] => sell
[type] => market
[timestamp] => 1539778090.0
[is_live] =>
[is_cancelled] =>
[is_hidden] =>
[oco_order] =>
[was_forced] =>
[original_amount] => 20.0
[remaining_amount] => 0.0
[executed_amount] => 20.0
[src] => api
)

In this array, I don't see exchange fees for this order. Also the above order is closing a margin position and I was expecting to see fees associated to margin like borrowing costs etc.

How do I get these information via API?

Thanks


texts: How are taproot scripts represented in general?

texts:
I'm pretty familiar with the opcode style of writing down scripts. I can understand the stack-based language nature of bitcoin script where you can write down different script spend paths via ifs like this:
OP_IF
   <3, publicKey1, publicKey2, publicKey3, 2, ...> OP_CHECKMULTISIGVERIFY
OP_ELSE
   <7 days> OP_CHECKSEQUENCEVERIFY
   <3, publicKey1, publicKey2, publicKey3, 1, ...> OP_CHECKMULTISIGVERIFY
OP_ENDIF

which can then be executed with a scriptSig like "ignored" key1Sig 1 or "ignored" key2Sig 0.
However, I don't know a good way to write down spend paths for taproot. Eg, if I want to say have a key spend-path using a threshold signature, and I want 3 script spend-paths, one of which has two nested script spend-paths, what's a good way to represent that. Or rather, how has that been represented in the past? And how does a transaction spending an output select which taproot script spend-path it wants to use? In the current script, one of the if branches is selected with either 1 or 0 pushed onto the stack via the scriptSig. In Taproot, how is the spend path selected?


texts: How can I brute force decrypt my blockchain wallet?

texts:
I have a Blockchain wallet but am unable to decrypt my wallet and login.  I created the wallet on OSX and am trying to login on a PC but it's not working.

What are my options to brute force this account, when I know most of the characters involved?

I'm a programmer, and can write the code, so knowing what URLs and data files I need to work with would be a help.


texts: How to remove a transaction from the memory pool

texts:
Using Bitcoind and Json-RPC, how to remove an unconfirmed transaction from the memory pool?

The scenario being removing the unconfirmed transaction because it's not getting confirmed, and it's preventing me from sending new transactions spending the same inputs because Bitcoind considers it a double spend.


texts:
I hope that no such question already has appeared here. I've searched for a solution but cannot find one.

My problem is as follows:
I want to use multisig with Armory on Linux. I've created new wallet, new address and changed Armory to Expert mode, since that is the mode for using Multisig/Lockboxes etc. In order to that I need need my address' public key. So I've checked it - these are two numbers - coordinates of an elliptic curve (I'm a newbie here as you can see :3). I wonder - how can I obtain my address' pubkey in a starting with 02, 03 or 04, as a one string. I've tried ECDSA calc built it Armory, but it's not that. I suppose I need to express it in HEX or sth. I need it to obtain my multisig pubkey.

Please, help
Thanks a lot


texts: Does the software to conduct a 51% attack exist?

texts: I know that it would cost hundreds of millions of dollars to do a 51% attack on Bitcoin, but if somebody did that, bought the hardware, etc could Bitcoin Core or any other software be easily configured to do what they want (e.g, ignore blocks containing a certain transaction in order to try to get rid of it), or would such an attacker need to write their own software?


texts: What are the economics of confirming a block of transactions?

texts:
From what I understand, CREATING a block to confirm or verify transactions is hard work, and is rewarded with 25 bitcoins, or something like $12,325 (depending on the daily exchange rate). But how do the economics change afterward?

Is it a case of "high fixed costs (to create the block), low variable costs (to follow the path of a particular set of bitcoins)? Suppose you take a single bitcoin and carve it up for numerous smaller transactions? Is this economically feasible because the forward-going costs are low after you've absorbed your fixed costs creating the block? Or is this kind of transaction where confirming it is likely to cost more than the transaction is worth?

Edit: In searching the literature on the site, what is described in the paragraph 2 appears to be the case. This link, explains how a person earns 25 bitcoins creating a block. What does a person do to earn the .03334571 bitcoins (about $16) as a commission in this link?


texts:
Hi am looking at creating a currency using NXT creation generator and have been looking for parts in the code to modify and test, this is more of a learning experience for myself.

Is there a way to change certain paramiters

Blocksize to increase it?
Block timing can this be increased either along side blocksize or separately?
Datacloud can this size be increased to upload larger files and also can it be changed so these are permenatly uploaded or put up and only removed when required by the person that uploaded them ?
Fees such as uploads, currency creation, asset creation can these be modified increase or decreased there base and max ?

I will probly have more questions, but I am looking were to find to modify these
appreciate the help!!


texts: Is it possible to simulate a mining pool with localhost in windows?

texts:
All I want to do is run the miner in CPU (without mining any real coins, no online pool, and no wallet) without connecting to any online miner. I tried using XMRig miner to do a localhost run but setting up the localhost to mimic a miner was not an option.

How can the localhost mimic the mining pool to miner so that the miner runs in the system?


texts: How do we check the time when a transaction hits x confirmations?

texts:
Consider the transaction 948a427.. which has 3341 confirmations as of now:

We can see that the time the relay is received at 8:36:30 and it has one confirmation at 08:50:04 (after 14 minutes).

How do we find out the exact time when it has 3 confirmations?


texts: I have a 100 character text message and I want to encrypt this message with my bitcoin "PUBLIC KEY" and decrypt it with my private key in Javascript

texts:
Are there any javascript libraries that can encrypt a 100 character text message using your bitcoin public key, but only be able to decrypt it with your bitcoin private key?

I'm looking to create a web form that can encrypt the form values using only your bitcoin public key. And on the other end when received it can be decrypted with the private key.


texts: Does miner's reward get added to blockchain

texts:
Whenever someone makes a transaction it gets verified by the miners & after that it becomes the part of the ledger. So as a reward miners get a small amount of bitcoin. Now my doubt is the reward that a miner is getting for successful validation, it should also be added to ledger and needs to be verified by someone say 'new miner'. The new miner's reward should also be verified by someone else. And this process of verifying rewards will continue forever.

Is my understanding right or am I missing something?


texts:
( I have almost no background of coding, so please explain this in relatively easy words :) )

I want to know what are pubkey script, signature, full public key and the roles of these.

Specifically, I want to understand this diagram:

Here is how I understand this diagram;

Say, A wants to send 1btc to B.

Then, A gets something called Pubkey script from the most recent block in a block chain (Let’s call it PubkeyScript 1). Again, A uses something which is also called Pubkey script using the public key of B. (Let’s call it PubkeyScript 2) After that, A types a message “A sends 1btc to B”. Now, using A’s private key, convert the PubkeyScript1 to something called signature. Now, a chunk of signature and A’s public key and PubkeyScipt2 and the message “A sends 1btc to B” is called a transaction.

Am I understanding it correctly?


texts:
How can i get the current balance of massive addresses?
I'm getting address balances now on blockchain.info but I need to check about 1000 of addresses in one minute.

The issue is that they blocking my requests every once in a while.

I do tried to look for open XML RPC API but I didn't find one.

How can i make this happen and check many addresses as possible?

P.S
I know that I can have my node but for only checking addresses its seems to me way to overkill + holding 200gb server only for node will costs.

thanks.


texts: Create master public key after HMAC-SHA512


texts: Can the transaction log history size scale?

texts:
Four Reasons You Shouldn't Buy Bitcoins, Forbes.com:

  Scaling. The Bitcoin protocol requires that every node in the network
  download a copy of every Bitcoin transaction that has ever occurred.
  As Bitcoin has grown more popular, running the “full” Bitcoin client
  has become more and more resource-intensive. The last time I started
  up my Bitcoin client, it took several hours to download all the
  transactions that had occurred in the few weeks since the last time I
  ran it.

  To prevent things from becoming completely unwieldy, the Bitcoin
  protocol limits the size of each “block,” the basic unit of Bitcoin’s
  shared transaction register, to one megabyte. Since one block is
  created every 10 minutes, on average, this places a hard limit on the
  number of transactions the network can process each hour. Right now,
  the network is operating well below the limit. But it’s not that far
  below the limit. If the Bitcoin economy continues to grow rapidly,
  we’re likely to hit it in the next few years.

  Reaching the limit wouldn’t be catastrophic; the Bitcoin protocol has
  an elegant system of transaction fees to process the most urgent
  transactions first. But it does place some limits on Bitcoin’s
  long-term future. For example, it’s hard to imagine Bitcoin ever
  becoming a replacement for conventional credit cards. There are far
  too many credit card transactions for the Bitcoin network to
  accomodate.

Currently, every Bitcoin client knows the entire network history. This sums up to a few GB, which a modern computer can easily hold.

The number of transactions, however, is growing quickly. I roughly estimate than in a matter of a year or two, the total size on disk will exceed the abilities of a normal desktop computer.

How will the network function when the transaction history log grows beyond the powers of a normal desktop?


texts:
I want to know whether there exists any software that can let people create their own private personal Bitcoin, and mine their own Bitcoin.

Or any other software that can let people issue their own digital currency.


texts:
Hi how can I look up my bitcoin-core address. I have generated multiple addresses to received bitcoins but when I look them up in a bitcoin explorer they do not show the balance I see in bitcoin core.
Thanks guys.


texts:
According to this page: https://en.bitcoin.it/wiki/Poolservers bitcoind's rollntime support is 'Supported, but not advertised'.  I am taking that to mean that it doesn't provide the X-Roll-NTime header that would advertise this support, but you can increment the ntime value to get extra nonce space and still submit found blocks after doing this.

Is this correct?  If so, what would be the max amount that a mining client can increment the ntime value?


texts: I'm looking for a good place to buy and sell litecoins in Canada. Does anyone have a good list for reference? I know of Vault of Satoshi and a newer service Harborly, but that's about it.


texts: Whats the use of QR-codes during wallet to wallet transfer?

texts: I want to know hen the QR-code scanning actually takes place. For instance, if I send my wallet address to someone, how does the person verify that the sender is me, and what do I need to do as soon as I receive the bitcoins in my wallet? Is there any point where I need to scan the QR-code?


texts:
I'm developing a bitcoin wallet app using BitcoinJ framework. While deploying the app using Tomcat 8, I get the following stack of errors,

12-Jun-2017 14:18:12.511 INFO [PeerGroup Thread] com.subgraph.orchid.TorClient.start Starting Orchid (version: 1.0.0)

12-Jun-2017 14:18:12.514 INFO [Thread-12] com.subgraph.orchid.directory.DirectoryImpl.loadFromStore
Loading cached network information from disk

12-Jun-2017 14:18:12.516 INFO [Thread-12] com.subgraph.orchid.directory.DirectoryImpl.loadFromStore Loading certificates

12-Jun-2017 14:18:12.518 INFO [CircuitManager worker-0] com.subgraph.orchid.circuits.CircuitCreationTask.checkCircuitsForCreation
Cannot build circuits because we don't have enough directory information

12-Jun-2017 14:18:12.601 INFO [Thread-12] com.subgraph.orchid.directory.DirectoryImpl.loadFromStore Loading consensus

12-Jun-2017 14:18:12.917 WARNING [Thread-12] com.subgraph.orchid.directory.consensus.ConsensusDocumentImpl.verifySingleAuthority
Consensus signed by unrecognized directory authority: 0232af901c31a04ee9848595af9bb7620d4c5b2e

12-Jun-2017 14:18:12.943 INFO [Thread-12] com.subgraph.orchid.directory.DirectoryImpl.loadFromStore Loading
microdescriptor cache

12-Jun-2017 14:18:13.160 INFO [Thread-12] com.subgraph.orchid.directory.DirectoryImpl.loadFromStore loading state file

12-Jun-2017 14:18:15.662 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying
web application directory [/Applications/Tomcat-8.5.15/webapps/manager]

The last 2 lines of the stack,

org.bitcoinj.core.PeerGroup: 06/12/2017 14:53:36 - Tor ready
org.bitcoinj.core.PeerGroup: 06/12/2017 14:53:36 - Localhost peer not detected.

I believe Tomcat deployment is fine and one of the errors is crucial informing -com.subgraph.orchid.circuits.CircuitCreationTask.checkCircuitsForCreation Cannot build circuits because we don't have enough directory information

I use maven as the build tool and get the RELEASE version of the BitcoinJ as dependency in the project.

<dependency>
    <groupId>org.bitcoinj</groupId>
    <artifactId>bitcoinj-core</artifactId>
    <version>RELEASE</version>
</dependency>

I recently loaded RAM in the system and upgraded to the OS Sierra. I had the surprise, I couldn't use maven from the terminal afterwards and set that up manually. Current Maven information,

$ mvn -version

Apache Maven 3.5.0 (ff8f5e7444045639af65f6095c62210b5713f426; 2017-04-04T01:39:06+06:00)
Maven home: /Users/Chaklader/apache-maven-3.5.0
Java version: 1.8.0_131, vendor: Oracle Corporation
Java home: /Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home/jre
Default locale: en_US, platform encoding: UTF-8
OS name: "mac os x", version: "10.12.4", arch: "x86_64", family: "mac"

How to approach to the problem properly ?


texts: Does running an alternative full node implementation benefit the Bitcoin network?

texts:
I've seen discussions suggesting that
a monoculture of full nodes
is a risk to the security of Bitcoin.

The accepted answer
to the question
"What benefit does a non-mining client provide to the network?"
gives an explanation with regard to full nodes in general.
I'm interested in alternative full node implementations in particular,
ignoring any wallet or wallet API capabilities.

Let's assume that
one or more alternative full node implementations
can run the protocol reliably and accurately.
What are the short-term and long-term benefits of running such nodes
compared to running the Satoshi client?

Edit: See also "What's the status of alternative full node implementations?"


texts: Missing bit coins two years later after purchased

texts: I bought 100 euro worth of coins in Dec 2018 via Coinmama and provided the wallet address to which I am convinced they were sent there because it shows on the order confirmation. It was a one off transaction and I went off due to other life pressing issues. I knew at the back of my mind that I bought a few coins. When I heard about the new BTC value I decided to log back. I had misplaced my passed word but I played around until I managed to get it right. But surprise there were no coins. I wrote to Coinmama who assured me that they completed the order and sent the coins to the address I gave them. I then gave them my wallet address and they confirmed that the coins were not there and I should check with BC. Now I am at a loss. I dont remember selling those coins. What could have happened? How do I trace what happened to the coins. I wrote to Blockchain and they have not responded.


texts: Is the merkle root random? (Crytographically secure?)

texts:
If I look at a block

000000000000000004f0cc322f551e39676f781186441614da3281bbc7d373e0

I can see the value of the merkel root: 9fe31d0d9d06d9da341a3ee757c57bb29af522796d5d9efa5efded8cda1684a4

Which is supposedly the hash of the hash of all transactions.

Is this value randomly? Could it be manipulated, through people spoofing transactions, or is it cryptographically improbable to know in advance?

I know that the block isn't cryptographically secure for the reason mentioned below, but I was wondering if the merkle tree itself was, thanks!


texts: Can a raspberry pi zero run bitcoin core 0.16.1 and sync up without downloading the entire blockchain?

texts: I'm looking to run a bitcoin core 0.16.1 node on a raspberry pi zero, but I don't have a 200gb+ microsd. Would I even be able to sync up with the blockchain without downloading the entire thing? Is there a lite version mode of bitcoin core 0.16.1 just for raspberry pi zero? I want to just use it to sweep private keys and make transactions.


texts: Problem to link to libsecp256k1 on ARM architecture

texts:
Trying to compile with g++ -o addr 69_addr2.cpp $(pkg-config --cflags --libs libbitcoin) is getting me this error:

/usr/bin/ld: /home/pi/libbitcoininstall/lib/libsecp256k1.a(libsecp256k1_la-secp256k1.o): in function `secp256k1_num_mod_inverse':
/home/pi/GitBen/LibbitcoinBen/build-libbitcoin/secp256k1/src/num_gmp_impl.h:128: undefined reference to `__gmpn_gcdext'
/usr/bin/ld: /home/pi/libbitcoininstall/lib/libsecp256k1.a(libsecp256k1_la-secp256k1.o): in function `__gmpn_sub':
/usr/include/arm-linux-gnueabihf/gmp.h:2190: undefined reference to `__gmpn_sub_n'
/usr/bin/ld: /home/pi/libbitcoininstall/lib/libsecp256k1.a(libsecp256k1_la-secp256k1.o): in function `secp256k1_num_set_bin':
/home/pi/GitBen/LibbitcoinBen/build-libbitcoin/secp256k1/src/num_gmp_impl.h:49: undefined reference to `__gmpn_set_str'
/usr/bin/ld: /home/pi/GitBen/LibbitcoinBen/build-libbitcoin/secp256k1/src/num_gmp_impl.h:49: undefined reference to `__gmpn_set_str'
/usr/bin/ld: /home/pi/libbitcoininstall/lib/libsecp256k1.a(libsecp256k1_la-secp256k1.o): in function `secp256k1_num_get_bin':
/home/pi/GitBen/LibbitcoinBen/build-libbitcoin/secp256k1/src/num_gmp_impl.h:34: undefined reference to `__gmpn_get_str'
/usr/bin/ld: /home/pi/libbitcoininstall/lib/libsecp256k1.a(libsecp256k1_la-secp256k1.o): in function `secp256k1_num_set_bin':
/home/pi/GitBen/LibbitcoinBen/build-libbitcoin/secp256k1/src/num_gmp_impl.h:49: undefined reference to `__gmpn_set_str'
/usr/bin/ld: /home/pi/GitBen/LibbitcoinBen/build-libbitcoin/secp256k1/src/num_gmp_impl.h:49: undefined reference to `__gmpn_set_str'
/usr/bin/ld: /home/pi/libbitcoininstall/lib/libsecp256k1.a(libsecp256k1_la-secp256k1.o): in function `secp256k1_num_get_bin':
/home/pi/GitBen/LibbitcoinBen/build-libbitcoin/secp256k1/src/num_gmp_impl.h:34: undefined reference to `__gmpn_get_str'
collect2: error: ld returned 1 exit status

Why is there a reference to the build-libbitcoin directory?

I installed libbitcoin in /home/pi/libbitcoininstall and the other directory is just the git where the automatic install script placed all the files.

So, this process should be finished. Why do I even get a print with that directory?

The installation went without error.

I am doing this on a Raspberry (should it matter?)

The small program I try to compile is from a textbook:

#include <bitcoin/bitcoin.hpp>

int main()
{
  bc::ec_secret secret;
  bool success = bc::decode_base16(secret,"038109007313a5807b2eccc082c8c3fbb988a973cacf1a7df9ce725c31v14776");
  assert(success);

  bc::ec_point public_key = bc::secret_to_public_key(secret);
  std::cout << "Public key: " << bc::encode_hex(public_key) << std::endl;

  const bc::short_hash hash = bc::bitcoin_short_hash(public_key);

  bc::data_chunk unencoded_address;
  unencoded_address.reserve(25);
  unencoded_address.push_back(0);
  bc::extend_data(unencoded_address, hash);
  bc::append_checksum(unencoded_address);
  assert(unencoded_address.size() == 25);
  const std::string address = bc::encode_base58(unencoded_address);

  std::cout << "Address: " << address << std::endl;
  return 0;
}


texts: bitcoind and figuring out if it's still downloading blocks

texts:
I've asked around, and it seems that to figure out that bitcoind is still downloading blocks is to run ./bitcoind getinfo and see if the "block count" is increasing.

Is there an easier way to do this, or is there a better way? How do those clients figure out that there's "30 blocks left" to download etc?


texts: Bitstamp streamline API: how to get all contents of the ordebooks?

texts:
I've been trying to work with Bitstamp streamline API, which uses Pusher.

So I managed to connect to some channels, specifically to 'orderbook' and it even returned me 6 items. However it looks like some kind of limit. Does anybody know how do I get the full contents of the orderbook (that is, all orders) throught this streamline API? (I know you can do it via regular REST api, but due to some limitation, I really have to use Websockets and Pusher in this case).


texts:
Proof of work in spam

I understand very well how proof of work is used to prevent email spam for example. Reasoning is since computing the right hash (e.g. with predefined number of zeros for example) for a single email is expensive, it will not be desirable for people sending spam to million recipients to compute that hash for each email. Now this reasoning makes perfect sense.

Proof of work in bitcoin

However, I don't know how the proof of work system is used in bitcoin, more precisely:

which problem does it try to solve
and more importantly how does it solve this

Can someone explain it (in layman terms)?


texts: How does the bitcoin network disallow people generating a key pair already generated?

texts:
Is it possible to generate a key pair that has already been generated? Wouldn't it collide with an existing value?

I assume it is mathematically very unlikely, but odds higher than 0 are still possible.


texts: Do you need to change 'rpcuser' and 'rpcpassword' for each bitcoind node you run?

texts: When running several bitcoind nodes on different machines, can I simply keep the same bitcoin.conf file everywhere, or do I need to ensure that a different rpcuser is set up for each?


texts: How do I restore a Ripple wallet backup?

texts:
In the Ripple client (as of 0.2.48-2) there is a way to backup a wallet to a text file. How can we use this file to restore a wallet (for example, to a new browser)?

I am aware how to regain access to my wallet having the secret key, yet, I would also like to reimport the contacts that were stored in my wallet.


texts: bitcoinlib 'There was a problem sending the request to the wallet'

texts:
I've configured the bitcoin.conf and web.config file in visual studio to match, and I keep getting the above exception, also getting this when I run it...

'No connection could be made because the target machine actively refused it'

Only thing I currently have commented out which may be the culprit is;

'add key="Bitcoin_WalletPassword" value=""'

as I'm not sure where to set the corresponding value in bitcoin-qt.

Thanks


texts: Accept Credit Card Online to Bitcoin Address Backend

texts:
I'm looking to start an online business, and I want to accept Credit Cards.
I want the funds transferred to my Bitcoin Address natively.

I've done some Duck-Duck-Go-Foo (Search Engine) but even the Big Boys, such as Mt. Gox, BitPay, etc. all refer to accepting BitCoin directly.

How do I accept Credit Cards and have it natively transferred to my BitCoin Address?

Thanks!


texts:
I have heard increased talk of an idea known as "segwit" or segregated witness.

Quite simply, what is "segwit", why are people discussing it now and what are its main implications?


texts: How does one calculate the profitability of GPU mining?

texts:
As GPU mining made CPU mining non-profitable, at some point in time more specialized mining hardwares (FPGA and ASIC) would make GPU mining non-profitable.

When is GPU mining considered not-profitable?

Considering $1000 rig, $0.2 per kWh and one year break-even period,
at which difficulty does GPU mining become non-profitable?

Or, what is the formula to find out "max non-profitable Mhash" for given parameters like, rig cost, power consumption, investment break-even period, difficulty, exchange rate, etc. (please ignore redundant parameters, and include more parameters if required.)

Or, whats the current "max non-profitable Mhash"?

Or, what is the required current energy efficiency (Mhash/J = millions hashes per joule) for mining to be profitable?

(energy efficiency; 1 joule of energy is 1 watt during 1 second: 1 J = 1 W*s)

For given parameters, Max. Non-profitable Hash Rate, is breakeven point for hash rate after which mining becomes profitable.


texts: Running into ELIFECYCLE error while trying to install filebazaar

texts:
Trying to install filebazaar on Ubuntu 18.04 and getting an error on the canvas module... anyone familiar with this issue? I've been all over node-canvas's github issues (such as this one where I left a comment), but none of the solutions are working for me so far.

Here's the command I'm running:

$ sudo npm install -g filebazaar

And here's the error output:

$ sudo npm install -g canvas@1.6.13

> canvas@1.6.13 install /usr/local/lib/node_modules/canvas
> node-gyp rebuild

gyp ERR! configure error
gyp ERR! stack Error: EACCES: permission denied, mkdir '/usr/local/lib/node_modules/canvas/build'
gyp ERR! System Linux 4.15.0-55-generic
gyp ERR! command "/usr/local/bin/node" "/usr/local/lib/node_modules/npm/node_modules/node-gyp/bin/node-gyp.js" "rebuild"
gyp ERR! cwd /usr/local/lib/node_modules/canvas
gyp ERR! node -v v12.5.0
gyp ERR! node-gyp -v v3.8.0
gyp ERR! not ok
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! canvas@1.6.13 install: `node-gyp rebuild`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the canvas@1.6.13 install script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/chris/.npm/_logs/2019-09-17T20_39_13_514Z-debug.log

Any assistance is appreciated :)


texts:
Possible Duplicate:
  Is it possible to brute force bitcoin address creation in order to steal money?

I've tried brainwallet.org and now I wonder, what happens if someone starts to generate a lot of private keys and add them to his wallet (or MtGox account)? That person will eventually get somebody else's private key and be able to use his/her Bitcoins. Am I missing something?


texts: Error While making windows.exe using gitian build?

texts:
Actually I'm making a logos windows exe (logosd and logos-qt) following the release process, which is mention on below path on any coin you can find that path, I'm working logos LGS Coin that's why I'm mentioning.

logos/contrib/gitian-descriptor/README

# Build Win32 dependencies: These three command successfully completed and generated a zip file

./bin/gbuild --commit logos=HEAD ../logos/contrib/gitian-descriptors/boost-win32.yml
./bin/gbuild --commit logos=HEAD ../logos/contrib/gitian-descriptors/deps-win32.yml
./bin/gbuild --commit logos=HEAD ../logos/contrib/gitian-descriptors/qt-win32.yml

But when I run below mention command it will give me error

# Build Win32 release:

./bin/gbuild --commit logos=HEAD ../logos/contrib/gitian-descriptors/gitian-win32.yml

Error

/home/ubuntu/build/logos/src/leveldb/libleveldb.a: could not read symbols: Archive has no index; run ranlib to add one
collect2: ld returned 1 exit status
make[1]: *** [release/logos-qt.exe] Error 1
make[1]: Leaving directory `/home/ubuntu/build/logos'
make: *** [release] Error 2

I've search on internet found that execute these command ranlib libleveldb.a  and it will compile, but still I'm getting same error again and again.
So please let me know how to resolve that issue.

My System is ubuntu 14.04 64bit architecture.


texts: I'am writing an application which receives information about new tx and blocks via ZeroMQ. There is a chance that I will receive notifs about blocks which will later on become stale blocks. Is there a way to verify whether the block has become stale?


texts: What is the mechanism to ensure execution of contract parameters specified in a contract reference transaction?

texts:
If it is allowed to specify contract parameters within the contract reference transaction, it should be possible to adapt the HelloWorld example contract to send a message to an account specified in the reference transaction.

For example, when I send a trigger transaction from account A to the contract runner account B, the contract responses with a message to Account C (where account C is specified in the reference transaction).

What if there is another reference transaction that specifies an account D? How can I be sure that the response will be sent to account C? Is there a parameter for the trigger transaction to reference a specific contract reference transaction?


texts: Bitcoin full database is not equal on each node

texts:
Is it true that a full bitcoin database is not equal on each node?

I mean database (files) in blocks dir, which create official bitcoin client locally.

What is that bitcoin database?


texts: Pycoin: How to sign SegWit transaction via Pycoin?

texts:
My target is to make transaction with unspent transaction outputs(UTXOS).
The information of UTXOs is as follow.

[
  {
    "pt_idx": 0,
    "subaccount": 37,
    "ga_asset_id": 1,
    "value": "92343",
    "block_height": 1288714,
    "txhash": "9e2d2d56632b609e9b5d0a1990cf0ffbd9865cec558b68ed106df352fd89cfb1",
    "pointer": 1083,
    "script_type": 14
  },
  {
    "pt_idx": 1,
    "subaccount": 37,
    "ga_asset_id": 1,
    "value": "9961066",
    "block_height": 1288718,
    "txhash": "b0e37f463aba4e3abb078eb77c472b29621cfdd17ed83ae41122b0b95df5e518",
    "pointer": 1096,
    "script_type": 14
  },
  {
    "pt_idx": 1,
    "subaccount": 37,
    "ga_asset_id": 1,
    "value": "315595",
    "block_height": 1288721,
    "txhash": "b062efcab010d436ca2f6bed0dc61b90d8cbced756e1ed7cc7593cac30d87326",
    "pointer": 1099,
    "script_type": 14
  },
  {
    "pt_idx": 1,
    "subaccount": 37,
    "ga_asset_id": 1,
    "value": "1872759",
    "block_height": 1288716,
    "txhash": "f88cfdb328f9d298b0ff8a641198d3e63ea7efaf6f98f5692ba3f88a03a73c2b",
    "pointer": 1088,
    "script_type": 14   }
]

From these I made transaction using pycoin library.
By the way, it is difficult to sign a SegWit transaction.
If anyone knows about this, please tell me.


texts:
From what I can gather coloured coins add some additional data to a UTXO, I'm trying to understand what mechanism us used to store the extra data and how the data is maintained in tact if the UTXO is sent to another party.
So let's say I have a 1 Satoshi UTXO, I can (somehow) write that it represents my car, registration number 123 ABC.
Now I transfer that 1 Satoshi to you as proof of transfer of ownership of what is now your car.  Does the data get destroyed at that time?
I assume for divisible items like bottles of wine, if I had 12 Satoshi in 1 UTXO, I could not send 1 Satoshi to you to transfer just 1 bottle?

An example from an explorer would be great, thanks.


texts: How do people actually try double-spends?

texts:
I've occasionally seen people online claiming they were victims of a double-spend because they handed over something of value in exchange for a bitcoin payment with no confirmations.

Although I understand this is theoretically possible, how would someone try this practically?  All available bitcoin clients would not allow you to make a transaction that spends an output that has already been spent, and the client would know about the first transaction very soon after it was broadcast.

Are there specialized double-spend-friendly bitcoin clients out there?

EDIT:  Please note: I am not asking for theory of any kind (especially not theory on how the blockchain / proof-of-work / waiting for confirmations solves the dobule-spend problem).  I am asking purely practically ... how does someone pull off a double-spend attempt?


texts: Different balance for same private key using bcoin and copay

texts:
I´ve got a copay wallet for test purpose. In there I have used a wallet for quite a while. Now I´ve started to play around with bcoin and wanted to import the wallet from copay to bcoin. therefore I´ve imported the tpriv into bcoin with /wallet/importedDemoWallet:

{
    "witness":false,
    "passphrase":"sample",
    "watchOnly": false,
    "accountKey":"tprvxxxxxxxxxxxxx[...]"
}

Here I´ve got the problem that in bcoin it only shows me a balance around 1.4 tBTC while in the copay wallet it shows 2.4 tBTC. even after a rescan the result does not change. can someone tell me whats wrong here? shouldn´t be the balance in both case the same?

UPDATE:

result from get server info:

    "result": {
        "version": "2.0.0-dev",
        "protocolversion": 70015,
        "walletversion": 0,
        "balance": 0,
        "blocks": 1722115,
        "timeoffset": 0,
        "connections": 12,
        "proxy": "",
        "difficulty": 1,
        "testnet": true,
        "keypoololdest": 0,
        "keypoolsize": 0,
        "unlocked_until": 0,
        "paytxfee": 0.0002,
        "relayfee": 0.00001,
        "errors": ""
    },
    "error": null,
    "id": null
}


texts: P2SH address as a product of public keys

texts:
Assuming the multisig 2 of 3, if I do have extended public keys (xpub) for all 3 cosigners (with proper derivations), can I somewhat get the result address (P2SH)? How to calculate the "script" out of these public keys?
Would be cool to have scheme for doing so or a code/pseudocode in python if possible.


texts: I have an android phone as I can not afford an iPhone, but my friend has an iPhone. I am using Bitcoin Wallet from Andreas Schildbach and it's really easy. Is there something like that for the iPhone as we can't seem to find it?


texts: My altcoin bitcoinj fork is failing when trying to compile an Android wallet

texts:
I've been sent a bitcoinj fork which is meant to work for the android wallet I'm building. Unfortunately it seems to be causing a failure when tests are run during the wallet compile.

I get the following error message when I try to compile the wallet:

Running com.machadocrypto.kobocoin_android_wallet.util.BluetoothTest
Tests run: 3, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.052 sec - in com.machadocrypto.kobocoin_android_wallet.util.BluetoothTest
Running com.machadocrypto.kobocoin_android_wallet.util.GenericUtilsTest
Tests run: 3, Failures: 3, Errors: 0, Skipped: 0, Time elapsed: 0.039 sec <<< FAILURE! - in com.machadocrypto.kobocoin_android_wallet.util.GenericUtilsTest

formatMKOBOValue(com.machadocrypto.kobocoin_android_wallet.util.GenericUtilsTest)  Time elapsed: 0.032 sec  <<< FAILURE!
org.junit.ComparisonFailure: expected:<[200]0000000000.00> but was:<[35]0000000000.00>
at org.junit.Assert.assertEquals(Assert.java:115)
at org.junit.Assert.assertEquals(Assert.java:144)
at com.machadocrypto.kobocoin_android_wallet.util.GenericUtilsTest.formatMKOBOValue(GenericUtilsTest.java:75)

formatUKOBOValue(com.machadocrypto.kobocoin_android_wallet.util.GenericUtilsTest)  Time elapsed: 0.003 sec  <<< FAILURE!
org.junit.ComparisonFailure: expected:<[200]0000000000000> but was:<[35]0000000000000>
at org.junit.Assert.assertEquals(Assert.java:115)
at org.junit.Assert.assertEquals(Assert.java:144)
at com.machadocrypto.kobocoin_android_wallet.util.GenericUtilsTest.formatUKOBOValue(GenericUtilsTest.java:97)

formatValue(com.machadocrypto.kobocoin_android_wallet.util.GenericUtilsTest)  Time elapsed: 0.003 sec  <<< FAILURE!
org.junit.ComparisonFailure: expected:<[200]0000000.00> but was:<[35]0000000.00>
at org.junit.Assert.assertEquals(Assert.java:115)
at org.junit.Assert.assertEquals(Assert.java:144)
at com.machadocrypto.kobocoin_android_wallet.util.GenericUtilsTest.formatValue(GenericUtilsTest.java:53)

Running com.machadocrypto.kobocoin_android_wallet.util.Base43Test
Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0 sec - in com.machadocrypto.kobocoin_android_wallet.util.Base43Test
Running com.machadocrypto.kobocoin_android_wallet.util.CryptoTest
Tests run: 5, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 5.254 sec - in com.machadocrypto.kobocoin_android_wallet.util.CryptoTest

Failed tests:
GenericUtilsTest.formatMKOBOValue:75 expected:<[200]0000000000.00> but was:<[35]0000000000.00>
GenericUtilsTest.formatUKOBOValue:97 expected:<[200]0000000000000> but was:<[35]0000000000000>
GenericUtilsTest.formatValue:53 expected:<[200]0000000.00> but was:<[35]0000000.00>

Tests run: 13, Failures: 3, Errors: 0, Skipped: 0

The error is coming from the kobocoinj. I've posted the error message on github

https://github.com/machado-rev/kobocoinj/issues/1

Can anyone give ANY tip on how to move forward from this? I'm just looking for the name of a file to edit that will cause ANY of the numbers in the failure message above to change. Once I'm in the right ball park at least I have something to work with. Right now I'm 99% done but dead in the water.

Any tips or pointers appreciated.


texts: Bitcoin mining algorithm - target - Java

texts:
Default share difficulty is 1 (big-endian target for difficulty 1 is 0x00000000ffff0000000000000000000000000000000000000000000000000000)

How to calculate this?
How it look like on Java code?
What algorithm of calculate this value?


texts: How do I broadcast an "alert" message to the network

texts: I am curious about how to broadcast an alert. I  know that this is possible because the system to send alerts has been shut down and this probably won't work, but I am curious about how I can broadcast an "alert" using bitcoin-cli.


texts: What does "PROOF OF WORK RESULT: false (booooo)" mean when mining?

texts:
I'm mining (Litecoin miner, shouldn't matter) with minerd, and got this in the output:

[2011-10-13 07:12:02] thread 1: 5524 hashes, 0.96 khash/sec
[2011-10-13 07:12:02] thread 0: 5415 hashes, 0.95 khash/sec
[2011-10-13 07:12:04] thread 0: 1588 hashes, 0.94 khash/sec
[2011-10-13 07:12:04] PROOF OF WORK RESULT: false (booooo)
[2011-10-13 07:12:04] thread 6: 5319 hashes, 0.95 khash/sec
[2011-10-13 07:12:04] thread 5: 6026 hashes, 0.96 khash/sec

What does the "Proof of work result: false" mean? Is it a stale block, meaning a block I just solved, but someone else beat me to it and published it first?


texts: Using blockcypher BitcoinJs at clientside is secure or not?

texts:
I am trying to create new transaction using bitcoinjs at client side.
Is it a secure way to create a transaction from Client side, which includes curl call.

Scenario, if I start from creating the new address using the library it includes curl call which can be easily accessible from the browsers dev tool which leads to direct access to my private keys.

So, is it safe to handle the transaction at client side or not?


texts:
I am trying to get real fee per trasnaction.

So I have an account whit balance 0.06940000 and have a second account with balance 0.00000000.

To get current fee I have run the command

bitcoin-cli getmempoolinfo

and got the mempoolminfee = 0.00001000.
I thought that when I send the 0.06939000 in my account rest balance will 0.00000000. but I got 0.00004860. Actually the fee was  0.0000514.

general question is WhY ?

Please tell me to understand how is fees working!


texts: Can hashtype in BTC scriptSig contained value other than 0x01, 0x02, 0x03, 0x80, 0x81, 0x82, 0x83?

texts:
As per hashtype value in https://en.bitcoin.it/wiki/OP_CHECKSIG or https://developer.bitcoin.org/devguide/transactions.html#signature-hash-types, hashtype could either be 0x01, 0x02, 0x03, 0x80, 0x81, 0x82, 0x83.

However, looking at bitcoin testing data in https://github.com/bitcoin/bitcoin/blob/452bb90c718da18a79bfad50ff9b7d1c8f1b4aa3/src/test/data/sighash.json, the hashtype could be in many other value such 1190874345 or -886562767 or other numerical value

Thanks for in advance!


texts: Can you create a bitcoin transaction where you specify the miner?

texts: I want to be able to specify which bitcoin miner receives the fee. Is that even possible?


texts: Why is it bad to download the full chain from a third party with Bitcoin Core?

texts:
I know Bitcoin Core downloads and processes the full chain much quicker now than it used to but what exactly is so bad about downloading a compressed blocks, chainstate and database folder from a third party?
In the event of any malicious changes to the chainstate, wouldn't Bitcoin Core at its startup reject the new blocks anyway?


texts: Partially sign a transaction with coinb.in

texts:
I'm trying to generate a 2-of-2 multisig address:

pubkey1 and privkey1 on coinb.in
pubkey2 and privkey2 a bitcoin core client
I use createmultisig 2 '''["<pubkey1>", "<pubkey2>']''' on the core to generate the 2-of-2 multisig address.

.

{
  "address": "38RmRDRp4YedPXdh9Vu82akPRtXwvsPeRp",
  "redeemScript": "5221020150ce6954f0cdcc2c5d57cf249f25eab0eed23e39549c4f06bcb42a37f308ce2102224aca2849ddad9c663c0bcfdac5ce3ca06f784ac8eca83404a4ea4ac61dbe7d52ae"
}

I transferred 0.00001BTC to that address in txid 20615db3dcda53ab1e780bb9f2c417c5ad2acfbd475d168b205caba3db401f1a  and my goal is to spend this amount from the multisig address:

I created a raw transaction on the bitcoincore:

.

createrawtransaction '''[{ "txid": "20615db3dcda53ab1e780bb9f2c417c5ad2acfbd475d168b205caba3db401f1a", "vout": 1 }]''' '''{ "1BT8tmV9Exfrx7FUjNvLQaUBgpZJaHyXMT": 0.00000900  }'''

I attempt to sign this transaction on coinb.in with privkey2:

I attempt to sign the second transaction on the core:

.

signrawtransaction "01000000011a1f40dba3ab5c208b165d47bdcf2aadc517c4f2b90b781eab53dadcb35d6120010000006b483045022100d4367946074622b6e22a936adbded609fba5d2501c603b630d3e2edadcb5bcc402203ac6693fbf2ac7ac4d4234ef19be348b6511a0fcdf5991cb26ac2b695876534c0121020150ce6954f0cdcc2c5d57cf249f25eab0eed23e39549c4f06bcb42a37f308ceffffffff0184030000000000001976a91472a2a94468e42593656cc9803c7a48c1863fc3e588ac00000000"
'''[
     {
       "txid": "20615db3dcda53ab1e780bb9f2c417c5ad2acfbd475d168b205caba3db401f1a",
       "vout": 1,
       "scriptPubKey": "a91449e688475c78033674b8a645f4339fe41366251587",
       "redeemScript": "5221020150ce6954f0cdcc2c5d57cf249f25eab0eed23e39549c4f06bcb42a37f308ce2102224aca2849ddad9c663c0bcfdac5ce3ca06f784ac8eca83404a4ea4ac61dbe7d52ae"}
]'''
'''["privkey2"]'''

Output

{
  "hex": "01000000011a1f40dba3ab5c208b165d47bdcf2aadc517c4f2b90b781eab53dadcb35d6120010000009200473044022015ededd076573807b25a4e7facef5ad132683d54ffde8d28c1dbcab4be8e852e02204a063aec61cf6e1eee4825b9f19566a06f87db02913b283f9281a133127002030100475221020150ce6954f0cdcc2c5d57cf249f25eab0eed23e39549c4f06bcb42a37f308ce2102224aca2849ddad9c663c0bcfdac5ce3ca06f784ac8eca83404a4ea4ac61dbe7d52aeffffffff0184030000000000001976a91472a2a94468e42593656cc9803c7a48c1863fc3e588ac00000000",
  "complete": false,
  "errors": [
    {
      "txid": "20615db3dcda53ab1e780bb9f2c417c5ad2acfbd475d168b205caba3db401f1a",
      "vout": 1,
      "scriptSig": "00473044022015ededd076573807b25a4e7facef5ad132683d54ffde8d28c1dbcab4be8e852e02204a063aec61cf6e1eee4825b9f19566a06f87db02913b283f9281a133127002030100475221020150ce6954f0cdcc2c5d57cf249f25eab0eed23e39549c4f06bcb42a37f308ce2102224aca2849ddad9c663c0bcfdac5ce3ca06f784ac8eca83404a4ea4ac61dbe7d52ae",
      "sequence": 4294967295,
      "error": "Script evaluated without error but finished with a false/empty top stack element"
    }
  ]
}

What am I doing wrong? Unfortunately I can't specify the pubkeyscript or redeemscrit to coinb.in, so could this be the reason why the signatures are not validating?

Note: I can sign the transaction successfully on bitcoin core when I specify both private keys in the command.


texts: Can one GPU mine on Mac OS X using cgminer?

texts:
I succesfully installed cgminer on my mac but every time I try to run it I get the message

[2013-09-16 15:03:49] clDevicesNum returned error, no GPUs usable

why is this? Is it that you cannot mine with the GPU on a mac, or am I just doing something wrong?

Specs:

Macbook Pro (2011)
Mac OS X Lion 10.7.5
Intel HD Graphics 3000 384 MB


texts: what's the principle of sending money and receiving money? who do the work to put money into account？

texts:
If i want to send money, Who gives the payment address. You know, it is said there are no center.
Another question is that if someone send money to me, who help me  put the money into my account?


texts: Maximum number of block erupters raspberry pi can handle?

texts:
I'm trying to figure out where the bottle neck in terms of bandwidth would be.

Assume:

no other processes running on raspberry pi (700MHz processor, no
overclocking)
no limit on internet up/down rates no limit on power of
external USB hub (5V, 12A power supply)

What is the maximum data rate that the usb bus can handle?
What is the maximum data rate a block erupter could ever need (I don't know how to convert Hashes/s to Bytes/s on the USB bus)

Are there tools I can use to grab these numbers (e.g. some utility like netcat?)

Can I put a 10-port usb hub in each of the two raspberry pi usb ports?


texts: How to resynchronize all blocks using `bitcoin-cli`?

texts:
Sometimes, I need to resynchronize all blocks using bitcoin core, but I want to do that through bitcoin-cli. I found a command called -rescan that may resolve my question on this site, but as I searched the api list of bitcoin on the official site for
-rescan, I couldn't find it out, therefore, I want to make it sure.


texts:
I have seen various Proof of Identity Proposal that all required some degree of trust (to verify the person in physical possession of a Passport is also the owner of it for example).

Have their been any proposals that are completely trustless? Is so what methods have been suggested to cryptographically tie real life identities to identities on a Bitcoin sidechain in a trustless manner?

For example could we use multi sig to require a sufficient percentage of randomly selected scientists to verify that a DNA sample, video recording with face and Passport, certified birth certificate and PGP message received from a specific person matches the person trying to verify their identity on the blockchain?


texts: Where is the code that specifies when a block is released?

texts:
I'm not sure how this exactly works. So roughly every 10 mins a block is released to the network. How is this done?

Does my bitcoin client signal this? Would that mean in theory if there was just one user, one client, you would just mine alone?


texts: Create a wallet from the HD recovery phrase

texts:
Is there a way to create a wallet from a Hierarchical Deterministic recovery phrase in Bitcoin Core 0.21.0?
I'm using the x64 Windows cli version, in case that matters.


texts: where is located the implementation of getaddressutxos method of litecoin rpc

texts:
Hi I have started to play with litecoin node making queries via rpc using litecoin-cli. There are some methods that caught my attention and have something related to "addressindex" these are:
getaddressbalance
getaddressdeltas
getaddressmempool
getaddresstxids
getaddressutxos

I have looked for them in github litecoin-project but I haven't found where is the implementation. Probably I haven't searched in the right place or missed something in the way are called so. Would you help me to find where is the code that implement those methods? Also have you an idea why those methods are not present in Bitcoin? from my perspective are very useful. Thanks in advance

-- UPDATE --

According to this link the methods are already present in Bitcoin. Anyone has an idea at which version they were added? and of course the location


texts: I just sent my Bitcoins to a Bitcoin Cash wallet. Did I lose my coins?

texts: I just sent my Bitcoins to a Bitcoin Cash wallet by mistake. Did I lose my coins or will they be converted to Bitcoin Cash coins after August the first?


texts:
It is said that Drivechain works by sending a transaction output to a miner/hashrate-controlled escrow. I know it works by allowing miners to vote over a large number of blocks on transactions, that want to spend from these outputs. Only after a transaction has acquired a number of votes can it be published.

However, how is that supposed to work practically in Script? Is there a new proposed opcode like OP_CHECKTRANSACTIONHASENOUGHVOTESVERIFY or something like that?


texts:
Quote from Meni Rosenfeld's post explaining PPLNS:

  Choose a parameter X, which represents multiples of D to include in the window when difficulty is static. X=2 is a good choice. When a
  share is submitted, assign to it a score of 1/D, where D is the
  difficulty at the time the share is submitted.
  When a block is found, pay (sB)/X for the last share (the one before the winning share), where s is the share's score and B is the
  block reward. Continue backwards, paying each share based on its
  score, until you reach a share which brings the total score of the
  shares counted above X. Pay that share the amount (sB)/(tX) * min
  (r,t), where r is the score required to bring the total to exactly X
  and t is the score of the winning share. Don't pay any older shares.
  If the pool has just started, and a block is found before there are shares totaling a score of X, there will be leftover rewards and
  it should be decided what to do with them. It doesn't matter much, but
  I recommend that the operator keeps them (in a macroscopic view, if
  the pool ever changes, this is compensation for the funds needed to
  cash participants out). Other options include donating to charity, or
  distributing among the miners.

So far so good. One thing I'm struggling to understand is where the difficulty of a share itself fits into the picture. How do I scale the reward by share difficulty without screwing up the algorithm?

Update:

What I also would like to know is how to handle cases where the network difficulty recorded with a share is different from the current network difficulty.


texts: Does Bitcoin security rely on the assumption of nearly continuous transactions?

texts: So for an attacker not to overcome good nodes, I believe we rely on the fact that blocks are always being produced, making the attacker essentially outpaced. But in the extreme and ridiculously unlikely case that no Bitcoin transactions occur within a certain sufficiently large time window, could an attacker gain control of the chain and do damage? If not, why?


texts:
I just set up a personal wallet, and the QR code on my phone, looks different from the QR code that blockchain.info shows. When I scan, the code on blockchain.info, I get the same address. I thought the QR codes were Unique.

what is going on?
This is a new wallet, and I used the copay app, to create it.

Im not sure how to get the QR code off my phone, this is why I went to blockchain.info, so I could get an address I can print. The image from blockchain.info


texts: Problems accessing BTCE api after certificate change?

texts:
I used to have a bot that interacted with the btce api through java/netbeans, and then after the MtGox fiasco I shut it down for a while. Now I am trying to start it back up, but while bitstamp and cbx are working fine, my btce exchange interface is broken. I am getting a "PKIK path building failed, unable to find valid certification path". Given that btce changed their certificate recently, it seems that this certificate change must be related to the problem.

I have done some research and evidently this means that I need to add the new btce certificate to my trust store in java. After some further research, I understand that this involves adding a cetificate file to my cacerts keystore in myc:/program files/java/jre8/lib/security directory. I have tried doing it manually through firefox to a cer file,  and putting it inside program files (x86)/java/jre8/bin and installing it through the command line using the following commands inside the same /java/jre8/bin directory:

$set KEYTOOL_PASS = 'changeit'
$keytool -import trustcacerts -keystore ../lib/security/cacerts -storepass %KEYTOOL_PASS% -noprompt -alias 'BTCE' -file btce.cer

But this did not work either. I talked to a friend who told me that perhaps I not only need to add the btce certificate, but also the godaddy G2 certificates on which it depends. So I exported those from firefox and added them to my keystore as well. But still I am getting the same "PKIK path building failed" error when I try to run my program in netbeans.

I cannot figure out what to do from here. My friend who is a server-side programmer is out of ideas, and I have tried every linux command I can find by googling this issue. And BTC-E.com says that they do not offer programming support, and said, I quote, "there is nothing we can do to help". so I am now turning to bc stack exchange. I would appreciate your help!

Best,

Paul


texts:
Is the below scenario is how transaction are carried out in lightning network? Is this a proper understanding?

Alice & Bob where they transfer 1 BTC each other.
1. Both Alice & Bob transfer 1 BTC into a shared multisig address.
2. A ‘balance sheet’ is created where 1 BTC is paid by Alice -> Bob and 1 BTC is paid by Bob -> Alice.
3. In the above transaction, Alice signs the transaction and gives to Bob and vice-versa.
4. Either Alice or Bob can sign their counterparts payout transaction and broadcast it to the blockchain.
5. Alice will update the ‘Balance sheet’ as 0.5 BTC to Alice and 1.5 to Bob and send the payout transaction to Bob to sign.
6. To ensure neither Alice  or Bob revert to the old transaction, each will create an ‘anti-cheat’ transaction.
7. If Alice and Bob wants to close the channel, they can consensually close the channel and broadcast the transaction to the blockchain.


texts: to create the block chain, the Bitcoin network runs hashing algorithms for each block, is it mathematically possible to predict the hash value of say, the 100th block from the last block currently in the chain?


texts:
The 12th of February 2017 numerai gave 1M NMR to 12K users.
NMR is based on ERC-20 (ethereum protocol). I was one of the lucky receivers. A few months later, crypto exchanges started trading with NMR and I sold my share.

In my country, the authorities started taxing cryptos with retrospective effect.

There is one way I can avoid paying tax: If the crypto was worthless or untradeable at the time I received it.

Question: Was it (theoretically) possible for me to trade the NMR at the time I received them (12th of February 2017)?


texts: Can a single transaction have multiple outputs going to the same address?

texts:
I understand that a transaction can have multiple outputs. But can two outputs  in a transaction refer to the same target address?

Here's how this would like in pseudo style:

[vout] => Array
        (
            [0] => Array
                (
                    [value] => 0.01
                    [scriptPubKey] => Array
                        (
                            [addresses] => Array
                                (
                                    [0] => bitcoinaddress_xyz
                                )

                        )

                )

            [1] => Array
                (
                    [value] => 0.02
                    [scriptPubKey] => Array
                        (
                            [addresses] => Array
                                (
                                    [0] => bitcoinaddress_xyz
                                )

                        )

                )

        )

Here the same address "bitcoinaddress_xyz" appears in both outputs.

I know that it would not make much sense to construct a transaction like this – I just would like to know if it is technically possible.

Thanks.


texts: How does bitaddress.org ensure unique address?

texts: You can use this service offline (as it's done with JS) so how can they possibly ensure a unique address is generated?


texts: Has anyone tried transfering 0.00000001 BTC (the currently minimum amount) successfully?

texts:
I did an experiment of withdrawing 0.00000001 BTC from MtGox. And this transaction still cannot be seen on http://blockexplorer.com/ after about an hour.

Concern solved, thank you everybody!

http://blockexplorer.com/address/1Mm1YSodmgoDEHEQtQaZLjBW8Nemje3kFw


texts: How can one redeem a Casascius Physical Bitcoin?

texts:
These physical coins are supposed to be worth 1 BTC each - they have a hologram and a private key that somehow gives access to a real (digital) Bitcoin.

What is the process of claiming this real (digital) BTC for the physical one?


texts:
I am running full bitcoin node locally. Currently, the size of the blockchain is around 70 GB.
Blockchain size

Further, I stored all the blocks in a text file in json format. It turned out that the size of this text file is around 10 GB. I am wondering what is the rest of the 60 GB used for?


texts: What are the web3py equivalent for communicating with bitcoin in Python?

texts:
I am fairly new to working with Python, I have a requirement where I need to perform some basic bitcoin operations on my local system rather than relying on some external API's, those function mainly include :

1. Wallet Creation

2. Address Creation

3. Transaction signing

For other operations, I am willing to use external API's like blockcypher. I need the above operations to be performed locally so to ensure some security. FOr ethereum I use web3.py which provides me these functions.
Can anyone help me with the same for bitcoin?


texts:
I have 5 Transactions sent by moonlite.in fausit but none ever show any bitcoin and they should. Here is the latest for you to have a look for me.Thank you. Isdaan.
http://ltc.blockr.io/tx/info/f553aa1275908e6e95d89d1454b0f4ba571cf4fdbb9412d7c73917bb51a94bc7


texts:
I am trying to generate my own genesis hash by modifying some hardcoded parameter in main.cpp.

It worked in previous version of Bitcoin, but now it seems that the "Genesis Generator" has been removed.

Where is the "New Genesis Hash Generator" code in newest Bitcoin source code?


texts:
I just can't seem to understand how bitcoin works. Here is what I understand so far.

Alice sends 1 Bitcoin to bob's public address
A new transaction gets created for miners to approve. A transaction will have the following properties

Sender's public address
Receivers public address
Amount
Timestamp

The transaction gets broadcasted to multiple nodes on the bitcoin network
Miners/Nodes listening for incoming transactions receive Alice's transaction and want to make sure that the transaction is legit and there is not double spending.
Miners/Nodes start looking up the ledger (block chain) which holds all the transactions that every happened from the beginning of time to find if all the previous transactions by Alice have been completed and if they are, only then execute the new transaction.
When a miner validates the new transaction it transfers the 1BTC over to Bob's account minus transaction fee.
And Bob is 1BTC richer and he lives happily ever after.

Please correct me if I am wrong and I honestly don't understand whats the story with the 'n' number of zeros being added to the a string to prove a transaction is valid.

Please help. I'm trying to understand this so that I can contribute to Bitcoin's source code.


texts:
How do I get my private key from this? I found an old file on one of my hard drives with a wallet address and something that looks like this (changed for obvious reasons).

What is this and how can I get my private key from it?

LZEuGNcDIJI5mRCATBouTmQgdpaycce0rDH/B//+w7v0hofB6+Apt0bepR8pUUxHEHAXHHAv7+67AHwh80Lx9g==

I tried this https://bitcoin.stackexchange.com/a/43438/105403. When I plug the WIF into bitaddress.org it's not matching my actual bitcoin address so I must be doing something wrong.


texts: Does RevokeSSL Require Self-Signed Certs to Work?

texts:
// ,

I don't want to go to https://bankofamerica.com and see it self-certified.

I don't want to go to https://amazon.com and see it self-certified.

I don't mind going to https://patriotact.wordpress.com and seeing it self-certified, because it doesn't take orders for money, or handle messages.

Now, our government wants everything tagged with the legal ID of the site owner.

How do the above provenance requirements for compliance affect RevokeSSL's effectiveness?

If I use a certificate that is not self-signed, is there a point to using RevokeSSL on the blockchain?

Christopher Allen recently gave a presentation here: http://www.meetup.com/SF-Bitcoin-Devs/events/222712738/

However, I left with a feeling like I did not have a sure y/n on certain core issues.

Am I asking this question correctly? Is this specific enough?

Can we add an SSL tag?


texts: Why is getdescriptorinfo returning an error "Invalid descriptor (code -5)"

texts:
I am using Bitcoin Core bitcoin-cli with getdescriptorinfo like so:

curl --data-binary '{"jsonrpc": "1.0", "id":"curltest", "method": "getdescriptorinfo", "params":["sh(multi(2,[3c60330a/1]03061b79f20d49790c15bdaf15ec8db6d75275f62f04a56eaac31f5c2db48736fc,[d54e4481/1]0396bd8d30f0128dcc67e143cf46efd686bf9e4dc8587facc07f81bb248d1b0209,[1e132a06/1]03c77aa842edc8af76b76f5c29a1133b45b78c8c26a170090184e500232abd15a4))#3qpdv9la"] }' -H 'content-type: text/plain;' http://bitcoin:password@127.0.0.1:18332/

But it returns Invalid descriptor (code -5)

What am I doing wrong?


texts:
I'd like to secure my bitcoin with an offline wallet. A lot of security conscious people seem to use Armory. I am trying to get a better understanding of the differences between these two clients.

I plan on having a cheap netbook, never touched the internet, and using it as an air gapped offline wallet. If I need to make transfers then use a USB to sign transactions for the online wallet.


texts: How do I find my b64secret from GDAX API?

texts:
How did I find the b64secret that is automatically generated by GDAX API? I have a passphrase and API key that I got from GDAX, but I don't know what/where the b64secret is. The documentation says that the secret will be randomly generated and provided to me. I have read the documentation and also the exact same question here, but the answer did not help and only directed me to the documentation. I hit create keys but I never saw the secret.

So for someone that has actually done this before, how do I find/get the b64secret?

I originally asked on SO but it wasn't answered, and I didn't find the same question after a very brief search on here.


texts: How to handle POST data sent from Blockcypher WebHook API

texts:
I've been trying to get this to work for the past 3 days and I've all but given up on it. Basically, I've used requestb.in to monitor if any POST requests are going through; requestb.in always displays a response. However, I can't replicate this on my own website.

I simply can't find a way to read the body of the response that's getting called back to my server.

For reference, I'm using this sample provided by BlockCypher:

 require __DIR__ . '/../bootstrap.php';

$webHook = new \BlockCypher\Api\WebHook();
$webHook->setUrl("http://mysite.com/dev/data/index.php");
$webHook->setEvent('unconfirmed-tx');

/// For Sample Purposes Only.
$request = clone $webHook;

$webHookClient = new \BlockCypher\Client\WebHookClient($apiContexts['BTC.main']);

/// Create WebHook
try {
    $output = $webHookClient->create($webHook);
} catch (Exception $ex) {
    ResultPrinter::printError("Created WebHook", "WebHook", null, $request, $ex);
    exit(1);
}

ResultPrinter::printResult("Created WebHook", "WebHook", $output->getId(), $request, $output);

return $output;

I had tested the callback url using requestb.in:

http://requestb.in/zphhv1zp?inspect

I've been going crazy testing everything I could find online, but nothing really helped me out. What should I be using to retrieve the POST data?

PS: this is the code that I've been testing most recently

<html lang="en">
<head>
</head>
<body>
    <?php
        $url = "http://requestb.in/zphhv1zp";
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        $data = curl_exec($ch);
        curl_close($ch);
        echo $data;

        // $inputJSON = file_get_contents('');
        // $input = json_decode( $inputJSON, TRUE );
        // echo $input['hash'];
    ?>
</body>
</html>


texts: Why use OP_RETURN for long-term timestamping if they are pruneable?

texts:
There are some timestamping services such as proofofxistence.com that use OP_RETURNS transactions to store a document's hash, so in the future a 3rd party can verify the existence of the hash (and the document) at that particular time.

One of the assumptions of using the blockchain for trusted timestamping is that the data will be there for a long period of time. However, the OP_RETURN ouputs are unspendable (then pruneable). It can be theoretically forgotten by everybody without affecting the integrity of the blockchain.

Is it a good idea to use OP_RETURN transactions for long-term timestamping?


texts:
If the order book looks like the following…

A)  Ask: 2 bitcoin at $100

B)  Bid: 2 bitcoin at $100

A trade will be done from A to B.

But what happens in the following situation:

C)  Ask: 1 bitcoin $100

D)  Bid: 2 bitcoin $100

Do bitcoin exchanges partially fill orders?

Does one of the following occur:

Nothing the orders need to be the same quantity.
Does the trade occur for one bitcoin.
If the trade does occur, what happens if the bid is cancelled? Is the trade for 1 bitcoin still valid.

Also, what happens in this situation:

E)  Ask:2 bitcoin $90

F)  Bid: 2 bitcoin $100

Does the Bid pay $100 or $90?

Thank You for your help


texts:
I'm trying to understand the following:

There is a limited amount of mining reward for every currency and a precise amount is rewarded for every block a person wins per time. Since most people mine in pools technically the more miners or rigs there are in the world the less money an individual makes? Is this really how this works and if so how can it stay "profitable"?


texts: What is the expected rate of transactions per second that I should expect from Bitcoin's ZMQ service?

texts:
I'm currently subscribed to the hashtx topic for Bitcoin's ZMQ service. I am noticing that I used to get an average of 3 transactions/second, but lately, I've been getting an average of 0.1 transactions/second. Is this a sign of bad peers to my bitcoind?

When I check on blockchain.info, I see that the number of Bitcoin transactions added to the mempool per second fluctuates between 2 and 11. Should the rate of transactions that I see from the ZMQ topic hashtx be the same as the rate of transactions added to the mempool?


texts: cant send btc, Uneconomical UTXO requested

texts: Im trying to send btc worth of 2$ and i keep getting message "Uneconomical UTXO requested [type: 1 (limit 46629), txOut.val: 38546, required: 83847]" i even tried sending 1$ but its still the same can anyone solve this? "wallet.btc.com" im using


texts: How do miners decode the input transaction?

texts:
When a transaction is broadcasted to the network, the transaction string contains the little-endian of SHA256(SHA256(X)) where X is the transaction string of input transaction.

Now, since SHA is irreversible, miners will not be able to get the full transaction string (X). So, how do miners verify the authencity of the input? How do they know that the mentioned input transaction actually had 'n' outputs? I am looking to understand the alogirthm behind this.


texts: Is there a maximum amount of money a transaction can handle?

texts: Apart from the limited transaction size in MB, which theoretically limits the maximum amount of money a transaction can handle, is there any standardized bound?


texts:
I often come across papers written in the Bitcoin space involving some math that I am not formally versed in.

Could anyone point out general topics in math that I should have a formal grasp on in order to really understand cryptography?


texts: How to recover wallet by importing private key on testnet?

texts:
I want to test the functionality of wallet recovery via private key import on the testnet. Preferably thru an online service.

I only want to test the functionality so that I can verify that it's basically working since I'm working on some Python code that I want to use on the mainnet later.

So for that, I don't want to download the whole blockchain but instead, want to verify that my private key is generated correctly and I can access the funds that way. But I can't find any possibility to do that on testnet...

EDIT: I did not use mainnet for anything yet. I'm exclusively used testnet to create the wallet and get some coins and want to verify on testnet the wallet recovery thru private key


texts: Targetting a specific wallet when sending commands using RPC commands to bitcoind

texts:
I'm very new to Bitcoin development, using its RPC API.

I created a wallet using

{
    "method": "createwallet",
    "params": {
        "wallet_name": "/wallets/walletA"
    }
}

Now I want to get info about this wallet. I try to use the getwalletinfo command.

But it seems you can't specify the wallet name/path when running this command? You have to "load" the wallet first (using loadwallet)?

This is the part I do not understand. Let's say I have created 10 wallets and I try to run a getwalletinfo command in a multithreaded environment... How can I make sure I target the right wallet? Do I really have to send a loadwallet request to specify the wallet I want to work on, before getting info about it?

What will occure if I want to get information about "walletA" so I run loadwallet walletA, but before I can run getwalletinfo to get its info, a loadwallet walletB request is made?


texts:
Is there a reference that can give me information on the programming languages used in Blockchain development?

For example, Bitcoin is C++, Ethereum makes use of C++, Golang and Python, whilst its smart contracts are based usually on Solidity, Serpent and LLL.

What about other (more enterprise based) implementations? Ripple, Hyperledger, Quorum, Multichain, Monax.


texts: Is there a difference between "In" and "Out" peer connections?

texts: On bitcoin-qt, some peers are called "Out" and some are "In". Is there any difference besides who initiated the connection?


texts: Are the blocks in blkxxxxx.dat files ordered by block height?

texts: I'm parsing out de blockxxxxx.dat files for the bitcoin blockchain. Are the blocks ordered by height? So is the order of the data for everybody the same?


texts: Library for generating HD keys/addresses (ideally for python)

texts:
I require a library that I can create (and later import) a HD master key, which I will use to generate hundreds of addresses for both testnet and mainnet!

Ideally, I need a python library (but had trouble of finding a good library for both testnet and mainnet addresses.

An example of how to create testnet addresses would be greatly appreciated (default functionality seems to be for mainnet, e.g. pybitcointools)

Good libraries for other languages are also very welcome!


texts: Is there any party who is archiving all transactions that have been broadcast?

texts:
There is a person claiming that Blockchain.info/wallet sent a transaction but for whatever reason that transaction never got included in a block.

If the transaction is valid today but perhaps just didn't get re-broadcast for whatever reason and has since expired from each node's memory pool, any party  with an archive of transactions could re-broadcast that transaction and it now might get included in a block.

Does anyone maintain an archive of all transactions, for instance, by archiving each OnTransaction event in BitcoinJ?


texts:
When client A opens a connection to client B, it opens its TCP connection to second client's port 8333. Is this connection solely used for A's queries and B's answers to A's query, or can B also query A using the same connection?

For example, A can ask B for list of known peers using this connection, but can B ask A for the same using the connection A established, or does B need to open a new connection to A's port 8333, exchange version messages, and only then send its queries?


texts: bitcoind getrawtransaction returning numbers and letters

texts: I’m not sure how to get this data in a format I can use and consume? I was expecting some kind of JSON structure, hopefully there’s a way to get this info easily?


texts: What's the difference between MtGox streaming API hosts?

texts:
I'm trying to find out what the difference is between websocket.mtgox.com and socketio.mtgox.com for the MtGox streaming API. Looking at the Connecting section it looks like there are several combinations to be used:

websocket.mtgox.com/mtgox
socketio.mtgox.com/mtgox

both with http or https.

As far as I can see, there is no mention that they are different, however, I know from trying out things myself that they do behave differently. I've also seen in forums that other people have similar questions/problems as I have related to this.

Does anyone know what the differences are? Also are these differences expected and documented somewhere?

Further, the code snippet uses https as the protocol. Excuse my ignorance, but shouldn't we use ws or wss instead of http and https? Can someone explain that difference?

Thanks in advance for any information related to my questions!

UPDATE:
Actually, it looks like the URI scheme for websockets should be ws: or wss: and not like in the example http: or https:. Maybe this is a typo in the example or what's the deal for MtGox?

UPDATE:
So testing things in the browser, {ws,wss,http,https}://socketio.mtgox.com/mtgox all work and I don't see any difference. On the other hand, {ws,wss,http,https}://websocket.mtgox.com/mtgox all result in HTTP 400 Bad Request. Looking in the browser console I got the following error:

XMLHttpRequest cannot load http://websocket.mtgox.com/socket.io/1/?t=1367857246057. Origin null is not allowed by Access-Control-Allow-Origin.

Any ideas what might be going on?


texts:
I was using the same random entrophy (d2310508c6c5313795dc80a7408b608ffda7176dbedefac00f8114c5dd89a673) to generate the BIP32 Root ExtendedKey (path: m) in the libbitcoin-explorer and web-based wallet respectively.

But I don't know why i got two different results?

In the libbitcoin-explorer, I typed the command (./bx hd-new d2310508c6c5313795dc80a7408b608ffda7176dbedefac00f8114c5dd89a673) and got:
xprv9s21ZrQH143K4bPcDZFCnACLDrv2ta2XUpPyMU2j98VEpw1XPPTt7oPiQbbXscESmatehXLGGUGLRZ5yYBiN2y2VR1q6pmH69YBuDWkqW1f

In the web based wallet I had:
 xprv9s21ZrQH143K4EQpRE59bbF9QXCW7QxJSW4LF9wWWWJCamtjVqnn5yuQGh9Y3XDAr9NSwyszLGjqXCuVc3gYMgRjy7FrW12MuaBY5jc4jVu


texts: Bitcoin Core v0.21 RPC credentials going bad

texts:
I have tried to upgrade to bitcoin core 0.21 but things are not going good. I need some help.
I'm using Debian Buster.
I was using bitcoin core 0.20.1 before.
The folder locations are as I have in my config file:
dbbatchsize=4294967000
dbcache=12288
par=1 -daemon
server=1
maxtxfee=0.00002000
mintxfee=0.00000002

\# Options only for mainnet
[main]
conf=/media/WdElements/blockchain-backup/bitcoin.conf
datadir=/media/WdElements/blockchain-backup
debug=net
debug=rpc
debuglogfile=/media/WdElements/blockchain-backup/debug.log
addresstype=bech32
changetype=bech32
txindex=1
listen=1

When I start bitcoin daemon I see the following output:
2021-01-24T15:24:36Z ThreadRPCServer incorrect password attempt from [::1]:34362
2021-01-24T15:24:36Z ThreadRPCServer incorrect password attempt from 127.0.0.1:36146
2021-01-24T15:24:41Z ThreadRPCServer incorrect password attempt from 127.0.0.1:36146
2021-01-24T15:24:41Z ThreadRPCServer incorrect password attempt from [::1]:34362
2021-01-24T15:24:45Z ThreadRPCServer incorrect password attempt from [::1]:34362
2021-01-24T15:24:45Z ThreadRPCServer incorrect password attempt from 127.0.0.1:36146
2021-01-24T15:24:49Z ThreadRPCServer incorrect password attempt from 127.0.0.1:36146
2021-01-24T15:24:49Z ThreadRPCServer incorrect password attempt from [::1]:34362
2021-01-24T15:24:53Z ThreadRPCServer incorrect password attempt from [::1]:34362
2021-01-24T15:24:53Z ThreadRPCServer incorrect password attempt from 127.0.0.1:36146
2021-01-24T15:24:58Z ThreadRPCServer incorrect password attempt from 127.0.0.1:36146
2021-01-24T15:24:58Z ThreadRPCServer incorrect password attempt from [::1]:34362
2021-01-24T15:25:02Z ThreadRPCServer incorrect password attempt from [::1]:34362
2021-01-24T15:25:02Z ThreadRPCServer incorrect password attempt from 127.0.0.1:36146

I already tried to generate my RPC credentials from ./share/rpcauth/ python plugin like this:
$ python3 rpcauth.py btc-user
String to be appended to bitcoin.conf:
rpcauth=btc-user:[REPLACEDHASH]
Your password:
[REPLACEDPSSWD]

and paste the first line into bitcoin.conf  like this:
dbbatchsize=4294967000
dbcache=12288
par=1 -daemon
server=1
rpcauth=btc-user:[REPLACEDHASH]
maxtxfee=0.00002000
mintxfee=0.00000002

\# Options only for mainnet
[main]
conf=/media/WdElements/blockchain-backup/bitcoin.conf
datadir=/media/WdElements/blockchain-backup
debug=net
debug=rpc
debuglogfile=/media/WdElements/blockchain-backup/debug.log
addresstype=bech32
changetype=bech32
txindex=1
listen=1

but I still get the same error messages when I start bitcoind as bitcoind:
2021-01-24T15:32:19Z ThreadRPCServer incorrect password attempt from [::1]:35906
2021-01-24T15:32:19Z ThreadRPCServer incorrect password attempt from 127.0.0.1:37690
2021-01-24T15:32:23Z ThreadRPCServer incorrect password attempt from 127.0.0.1:37690
2021-01-24T15:32:23Z ThreadRPCServer incorrect password attempt from [::1]:35906
2021-01-24T15:32:27Z ThreadRPCServer incorrect password attempt from [::1]:35906
2021-01-24T15:32:27Z ThreadRPCServer incorrect password attempt from 127.0.0.1:37690
2021-01-24T15:32:31Z ThreadRPCServer incorrect password attempt from [::1]:35906
2021-01-24T15:32:31Z ThreadRPCServer incorrect password attempt from 127.0.0.1:37690
2021-01-24T15:32:36Z ThreadRPCServer incorrect password attempt from 127.0.0.1:37690
2021-01-24T15:32:36Z ThreadRPCServer incorrect password attempt from [::1]:35906
2021-01-24T15:32:40Z ThreadRPCServer incorrect password attempt from [::1]:35906
2021-01-24T15:32:40Z ThreadRPCServer incorrect password attempt from 127.0.0.1:37690
2021-01-24T15:32:44Z ThreadRPCServer incorrect password attempt from [::1]:35906
2021-01-24T15:32:44Z ThreadRPCServer incorrect password attempt from 127.0.0.1:37690

Anyone can help me figuring out what might I be doing wrong?


texts: How to do precise accounting with bitcoind?

texts:
I'm considering making a service that would be handling user deposits in Bitcoins through a server running bitcoind. Upon purchasing something through the service, I want to withdraw the precise amount of Bitcoins out of the account associated with the user along with a commission proportional to the amount of coins spent. As Bitcoin charges a fee for each Transaction depending on its size, it can vary between Transactions. I don't think there is a way of predicting how much will be charged exactly before the Transaction is executed, so it makes it hard for me to tell the user exactly how much they will be charged, or lower the commission to take into account the fee.

How should I go about doing precise accounting with bitcoind?


texts: If ASIC based machines can run at 14TH/s, why isn't the answer found almost immediately?

texts: As far I understand correctly, the objective is to find a nonce which creates a hash with the specified difficulty. The current difficulty being around 1.4 trillion. If that is so, why doesn't a machine which runs at 14 TH/s calculate the nonce in under a second?


texts: What is the difference between a market and limit property in the MTGox API?

texts:
I'm using the MTGox API to get data about historic trades.

When I run https://mtgox.com/api/1/BTCGBP/public/trades?since={trade_id}, I get the latest 500 trades since that {trade_id}.

Now I have for example these two trades returned:

Trade #1
{
    "date":1342135345,
    "price":"4.77728",
    "amount":"5107.98029213",
    "price_int":"477728",
    "amount_int":"510798029213",
    "tid":"1342135345801755",
    "price_currency":"GBP",
    "item":"BTC",
    "trade_type":"bid",
    "primary":"Y",
    "properties":"market,mixed_currency"
},

Trade #2
{
    "date":1342136454,
    "price":"4.78",
    "amount":"0.02000488",
    "price_int":"478000",
    "amount_int":"2000488",
    "tid":"1342136454726203",
    "price_currency":"GBP",
    "item":"BTC",
    "trade_type":"bid",
    "primary":"N",
    "properties":"limit,mixed_currency"
},

Note the different properties: "market,mixed_currency" & "limit,mixed_currency".

What is the difference between a market and a limit property? What do both mean? (I couldn't find it here https://en.bitcoin.it/wiki/MtGox/API/HTTP/v1)
what does it mean for a trade to be mixed_currency?
Bitcoincharts does seem to include all trades regardless of the limit/market/mixed currency, is this the right approach if you want to have a honest view of all markets?


texts: What happens to a spent Bitcoin that was earned from a chain replaced by a longer chain?

texts: Let's say miner Moe mines a block taht is accepted by the network.  Moe presumably receives some Bitcoins in his wallet for this.  So let's say Moe "spends" that Bitcoin by buying some anti-poking goggles from Curly, even though his newly mined block is at the top of the chain and has no blocks on top of it.  Curly sends the goggles to Moe via FedEx.  Then another miner Larry mines a longer block and that replaces the original one Moe mined.  So now Larry has some Bitcoins.  So does the transaction between Moe and Curly disappear and Curly is left without a pair of goggles and with no Bitcoin?