texts: How exactly do I decode the block file info in leveldb?

texts:
Base on the links
https://github.com/bitcoin/bitcoin/blob/fcbc8bfa6d10cac4f16699d6e6e68fb6eb98acd0/src/main.h#L392 and
What are the keys used in the blockchain levelDB (ie what are the key:value pairs)?
I should simply read in the results as varints. So I wrote some Python code shown below. But I did not get the results I expected.

Below is my code to decode the file information with file number 0.
I parse through my blk00000.dat and found that the first block was the genesis block and the last block was block 177 with blockhash 00000000480c9799dd2b35009ff1833f69690f76c26a9bea7e00cd0042f67db1.

nBlocks looks to be correct with 134 blocks which was how many blocks I found in blk00000.dat.
nHeightFirst looks right with the value being 0, but I nHeightLast is not 177. nSize and nUndoSize dont look right since it doesn't match the file size with I found on the terminal doing

ls -l  ~/.bitcoin/blocks/blk00000.dat

and

ls -l  ~/.bitcoin/blocks/rev00000.dat

Also the nTimeFirst does not match the timestamp of the genesis block.
And nTimeLast does not match the timestamp of block 177, which I found to be the block with the highest timestamp in blk00000.dat.
What am doing wrong?

import plyvel
blockIndexDB = plyvel.DB('/home/chris/.bitcoin/blocks/index')
result = blockIndexDB.get(b'f\x00\x00\x00\x00')

# result value from leveldb
# result = b'\x86\xa8%\xbe\xfe\xf4E\x88\xa5\xa7}\x00\x86\xa8r\x83\xc9\xfd\xd5)\x83\xec\xd3\xa1N'
# hexString = b'86a825befef44588a5a77d0086a87283c9fdd52983ecd3a14e'

nBlocks = int.from_bytes(result[0:1], byteorder='little')
print('nBlocks', nBlocks)
print(nBlocks == 134)

s = int.from_bytes(result[1:2], byteorder='little')
# print('s', s)
nSize = int.from_bytes(result[2:6], byteorder='little')
print('nSize', nSize)
print(nSize == 134216389) # blk00000.dat file size

s = int.from_bytes(result[6:7], byteorder='little')
# print('s', s)
nUndoSize = int.from_bytes(result[7:11], byteorder='little')
print('nUndoSize', nUndoSize)
print(nUndoSize == 19502205) # rev00000.dat file size

nHeightFirst = int.from_bytes(result[11:12], byteorder='little')
print('nHeightFirst', nHeightFirst)
print(nHeightFirst == 0)
nHeightLast = int.from_bytes(result[12:13], byteorder='little')
print('nHeightLast', nHeightLast)
print(nHeightLast == 177)

s = int.from_bytes(result[15:16], byteorder='little')
# print('s', s)
nTimeFirst = int.from_bytes(result[16:20], byteorder='little')
print('nTimeFirst', nTimeFirst)
print(nTimeFirst == 1231006505) # block 0 timestamp

s = int.from_bytes(result[20:21], byteorder='little')
# print('s', s)
nTimeLast = int.from_bytes(result[21:], byteorder='little')
print('nTimeLast', nTimeLast)
# block 177 is the last block in blk00000.dat file
print(nTimeLast == 1231736557) # block 177 timestamp


texts: What settings required to privately run bitcoin core on tails?

texts:
I am running bitcoin-core on TailsOS which seems to work out of the box.  I think TailsOS blocks all unsafe requests but I would like to know what settings I should enable to run it really privately.  So far I start my node via
$ ./bitcoin-qt onlynet=onion

Is anything else required?  In this answer I read about a bunch of other settings but feel that isn't required on tails, correct?


texts: Electrum won't send bitcoin: ascii error

texts:
I was trying to transfer some bitcoins from my electrum wallet to coinbase. However Electrum I get this ascii error whenever I attempt a transfer:

"ascii codec can't decode byte 0xb6 in position 2: ordinal not in range(128)

I have no idea on what's causing this.


texts: Sync too low when using BitCoinJ to create and host own wallet

texts:
I need to use BitcoinJ to create and host wallet on my own website. However, it keeps downloading blocks and the sync seems taking forever. I need to be able to create a wallet within a few seconds.

Could anyone please advice what should i do to optimize the sync time?

ECKey key = new ECKey();
Address addressFromKey = key.toAddress(params);

Wallet wallet = new Wallet(params);
wallet.importKey(key);

File blockFile = new File(“/tmp/bitcoinblocks”);
BlockStore blockStore = new MemoryBlockStore(params);
BlockChain chain = new BlockChain(params,blockStore);
PeerGroup peerGroup = new PeerGroup(params, chain);
peerGroup.addPeerDiscovery(new DnsDiscovery(params));
peerGroup.addWallet(wallet);
peerGroup.start();
peerGroup.downloadedBlockChain();


texts:
According to https://www.file.net/process/bitcoin-qt.exe.html

"The application uses ports to connect to or from a LAN or the Internet. Bitcoin-qt.exe is able to connect to the Internet, record keyboard and mouse inputs and monitor applications. Therefore the technical security rating is 31% dangerous."

It is my understanding that when port 8333 is enabled the node shares its blockchain data with other nodes through the network, however this is not a requirement to run Bitcoin Core and is not enabled by default. Is there any other ports used or possible vulnerabilities when a node is not configured to transmit outbound information through port 8333?

Also curious if anyone can elaborate on these safety concerns particularly relating to "record[ing] keyboard and mouse inputs and monitor[ing] applications"?

Thank you


texts: How can I pull the "Candles" argument from the Huobi websocket data?

texts:
I've a problem with Huobi Websocket, I know my ways in REST API but new to asyncio and websockets, and Huobi only gives resonable amount of history through websocket request so I'm stuck with it. I'm using their [sdk](https://github.com/HuobiRDCenter/huobi_Python. I managed to figure this out:
from huobi.client.market import MarketClient
from huobi.client.market import CandlestickInterval
import pandas as pd
from pandas import DataFrame as df

def callback(candlestick_req: "CandlestickReq"):
    Candles = candlestick_req.data

Market_client = MarketClient()
Market_client.req_candlestick("btcusdt", CandlestickInterval.MIN60, callback, from_ts_second = 1611788400, end_ts_second = 1614812400)

History_dataframe_new["Date"] = [Candles[f].id for f in range(len(Candles))]
History_dataframe_new["Open"] = [Candles[f].open for f in range(len(Candles))]
History_dataframe_new["High"] = [Candles[f].high for f in range(len(Candles))]
History_dataframe_new["Low"] = [Candles[f].low for f in range(len(Candles))]
History_dataframe_new["Close"] = [Candles[f].close for f in range(len(Candles))]
History_dataframe_new["Volume"] = [Candles[f].vol for f in range(len(Candles))]

The problem is, how can I get this Candles argument out of the callback to use below? I'm not calling callback directly, only in the req_candlestick so return won't work. And it's a callback so I propably have to wait for the response somehow. And tips how to do that? Or if what I'm trying here is the correct way?


texts: Is how can I enable my wifi router to accept Bitcoin for adhoc/ anonymous usage?

texts:
I want to find a WiFi solution where I can sell my internet service with anyone who needs to use it... ideally paying in an altcoin or Bitcoin.

Are there any router modifications, or infrastructures that support a wallet service?  (e.g. the user pays at the captive portal) and then has time or bandwith limited access to the internet?

I found this list of router firmware that may support such modding, but not sure which one is best (and most secure) for the job.

Lacking that, perhaps I can leverage RADIUS authentication.


texts: When importing a wallet from private key or seed phrase, how do you guess the correct address format?

texts: I am building a bitcoin wallet. I can derive addresses using the derivation paths. How do I determine the derivation path for the seed when importing it?


texts: What is the standard deviation of block generation times?

texts:
A block is generated every 10 minutes, on average.
What is the standard deviation of this distribution?

It seems to be a measurable property, not a calculable one.

Is there a chart of the standard dev over time somewhere (should be added to blockchain.info)?


texts: I have the phrase words but I donot know which words shall i insert to get my wallet back , what shall I do?

texts:
Trust wallet
I have my 12 phrase but I am not able to get my trust wallet back


texts: How propagation delay depends on the block size?

texts:
According the paper 'Information propagation in the bitcoin network'. by Decker and Wattenhofer.
For sizes larger than 20kB the cost can be said to be constant, whereas for small sizes there is a considerable overhead. Actually, I didn't get how small blocks take more time than messages whose size is greater than 20KB ?
How delay taken by blocks with size greater than 20KB is almost constant? As shown in image below:
.


texts: 18 word mnemonic seed that contains words outside of BIP39 wordlist, struggling to recover BTC

texts:
I recently recovered a document containing information relating to some BTC I purchased in 2015. I only have: a passphrase/password, an 18 word mnemonic phrase(the majority of which are not in the BIP39 wordlist, nor the electrum old/new wordlists, e.g. mccartney, hopkinton), and the address: 1CfadqyBDRPt62S9UvBHDPtqRu2kSvwPPu.
I idiotically forgot to add what wallet I used, so I'm a bit stuck.

Any ideas about what the mnemonic could be for?


texts:
Is it possible to download a recent snapshot of the chainstate database?

I'm running bitcoind (v. 0.11.8) on a machine with ~1mb/s download speed. After my client reached 300000 blocks, the synchronization is going insanely slow. I suspect it's because verification is very slow. The bitcoind processs is using nearly 100% CPU. However, for my purposes I only need a reasonably recent (i.e., up to 30 days old) chainstate database.


texts: What are the core changes to bitcoind that allow one to merge-mine? Are there any new JSON-RPC commands that are enabled, or changes to the existing ones?


texts: Where is the code that sends generated Bitcoins from mining to the wallet?

texts:
I was just looking through the Bitcoin code but since I am relatively new to C++ I was wondering, if anybody could tell me where the code responsible for sending coins generated through mining to the wallet is located.

Thanks.


texts: Where did the idea of blockchain come from? Git was already using it since 2005

texts:
With bitcoin's blockchain, each block's hash is computed with the previous block's hash. That makes all blocks an immutable chain.

This is not the first time people used a hash-chain. As far as I know, Git was already used it since 2005 for the commit-hash computing.

So, what is the earliest use of hash chains? Where did the idea of blockchain come from?


texts:
Is there a formal proof that with N bits to iterate in the nonce of the block, a hash satisfying proof of work will be ever found?

How large that N (number of bits in the nonce) should be to satisfy proof of work in 10 years, 100 years?


texts: What's the consensus on using a non-networked VM as a cold wallet/airgapped computer?

texts:
I'm wondering if connecting a hardware wallet like a Ledger Nano S to the Ledger Live desktop app running on a computer that's connected to the internet not considered a 'fully cold' wallet setup. How about installing/running the Ledger Live app inside a VM that has the networking components disabled? I know that there is a possibility that VMs can be breached or compromised but I'm thinking that the probability of accessing the private seed or spend key would be low to non-existent.

Has anyone have experiences or research data on this subject?


texts: What exactly are colored coins? I've tried understanding, but I don't quite get it yet . . . Do any examples exist?


texts:
There is a known form of address that called P2SH-wrapped SegWit, wrapping SegWit address as Base58 (P2SH) address.
Thinking about such address type, I come up with the question: Is P2SH-wrapped P2PKH possible?
I know that it is completely useless and meaningless, but I want to think about it now.

Step 1: Decide an address to convert

Let's use the address 1CciesT23BNionJeXrbxmjc7ywfiyM4oLW as it is used as a sample here.

Step 2: Convert it into "output script", then hash it using "hash160"

I got OP_DUP OP_HASH160 7f6ab65fa911f558ca2dde3e9d073acb02c0d5c6 OP_EQUALVERIFY OP_CHECKSIG.
Hashed result is c852ac34a1c76b63a279c97502c9ccc4e3cb9e8b.

Step 3: Make P2SH address from hashed script

toBase58Check(c852ac34a1c76b63a279c97502c9ccc4e3cb9e8b, 5) = 3KxE77EHe1ip6WGRifwr9fZ5WBDGsLyWFz
The result 3KxE77EHe1ip6WGRifwr9fZ5WBDGsLyWFz is what I want.

Here is the code to reproduce this address generation.

Question

Is that possible to spend coins sent to 3KxE77EHe1ip6WGRifwr9fZ5WBDGsLyWFz (P2SH-wrapped P2PKH address), like how we spend coins sent to P2PKH addresses?


texts:
So I'm using an antminer s3. I have been on btc guild for about a week. Today they announce they are closing. So I looked around and figured I would join antpool.

The problem is when I changed all my pool config, my antminer won't start. It turns on and the fans spin very slowly.

When I was on btc guild the miner ran right away. I'm not sure what the problem is. My miner stats say this section contains no values yet.

I input everything the way it showed me on antpools website. Any ideas what I'm doing wrong? Is there something else I need to change?


texts:
I'm confused by a statement in https://bitcoin.org/en/developer-guide#hardened-keys

  "For this reason, the chain code part of an extended public key should
  be better secured than standard public keys"

I'm confused because I thought the chain code was an intrinsic and easily deciphered part of an extended public key.  For example the top answer here explains how to derive the chain code from any extended public key:

Key derivation in HD wallets using the extended private key vs hardened derivation

So how exactly is one supposed to obey the advice from bitcoin.org to "secure" this chain code when it's openly exposed in the public key itself?  Does a "hardened" public key not likewise expose its chain code?


texts: Bitcoin Core 0.17 sethdseed then dumpwallet how to recompute extended private masterkey?

texts:
Using bitcoin-cli -datadir=X sethdseed true "WIF_KEY" the current wallet within datadir is updated
Then, using bitcoin-cli -datadir=X dumpwallet my_dump.txt shows a fresh new  # extended private masterkey: tpriv..., which is determiniscally generated from the WIF_KEY

Now, using the # extended private masterkey I could indeed generate the same address than bitcoin core with the m/0'/0'/i' derivated path.

How could I compute the # extended private masterkey without dumping the wallet, using tools like libbitcoin bx ?

Also, the dumping file show a WIF_KEY 2019-03-22T14:43:55Z hdseed=1 # addr=mnMEP6P92XKxKfEM5v2SxzLBMVB2tf7Lsj hdkeypath=s which is exactly the m/44'/1'/0'/0/0 from the WIF_KEY passed in sethdseed cmd, why ?


texts: Mining: GetWork, Get Nonce, ???, Submit Hash?

texts:
I make a getwork request and get back data, hash1, midstate, and target. Mining on a KC705 development FPGA board, and following the readme.md file here:
https://github.com/progranism/Open-Source-FPGA-Bitcoin-Miner/tree/master/projects/KC705_experimental

I do a uart_write of a section of data plus the midstate, and that would return the golden nonces. Doing that does in fact return the 0E33337A as stated along with two others, 9CCDEF20 and ACBBA77F.

Now I start getting confused. Given the response from the getwork request and 3 nonces, what exactly am I submitting back? From what I gather, I am supposed to do a hash using each nonce, check it if it's smaller than the target, and if it is, submit that hash?


texts: Which values are GetValueIn() and GetValueOut() calculate?

texts:
In Transaction.cpp, there is a function CAmount CTransaction::GetValueOut() const.
In Coins.cpp, there is a function CAmount CCoinsViewCache::GetValueIn(const CTransaction& tx) const.
My understand the GetValueIn() is calculater all vin value for a Tx.
But what the GetValueOut() calculate - all vout for a Tx?


texts: Will calling "walletpassphrase" twice in a short amount of time increase the time the wallet stays unlocked?

texts: The Bitcoin API call for walletpassphrase allows one to open the wallet for a set amount of time. If one calls it again while the wallet is still unlocked, we get an error of 'Error: Wallet is already unlocked.'. Does the call extend the amount of time the wallet is unlocked, or not?


texts: Does the bitcoin testnet3 network support Segwit and OP_CSV?

texts:
As far as I know, Segregated Witness and OP_CHECKSEQUENCEVERIFY are the last features needed to be able to fully implement a trustless bi-directional payment channel, from start to finish. (Technically you don't need OP_CHECKSEQUENCEVERIFY, it just makes channels a lot better)

Does testnet3 support those features?

If not, is there another public development chain which has those features?


texts:
There is this very helpful post detailing how to lock and unlock your bitcoin wallet using walletlock and walletpassphrase api calls. Unfortunately the litecoin api does not boast these features.

I was wondering if there is a similar strategy in place for securing a litecoin wallet perhaps using the lockunspent command?


texts: I'm using kryptokit to send my funds. I sent a transaction at about 10pm last night and here it is 10+ hrs later still unconfirmed. Is there a way to cancel it that's easy?


texts: Can I raise a lawsuit against a bitcoin wallet provider?

texts:
I think I'm not only one on this boat. I have bitfix bitcoin wallet, it's installed on my phone as it's phone's app anyway, it's got option to create login and password so obviously it connects to the online server managed by bitfix where user's accounts with funds are kept so you can use it on a different phone if needed.

Short story: it was working well until I've noticed the funds from the wallet gone and found a transaction which I didn't do at all, also the transaction was at the night time and my phone was powered off at the time. the bitfix support said that many accounts have been hacked and coins got stolen from their wallets.

WTF? Bitfix, who manages so many accounts do not have a simple security and encryption? Also they do not hold any responsibility for this at all and will not refund my funds. Stuff them, I didn't have much about $100 was on my wallet but it's not the point as you understand, I'm a bit pissed off with this and suspect the Bitfix's admins were involved in this as they do not want to investigate further and do not want to refund anything, also admins could have access to the private keys info and be able to withdraw funds from the user's wallets as the wallet's info stored online. Any thoughts on this?


texts: getblockchaininfo timeout using API only

texts:
Thanks in advance.
If I call getblockchaininfo through bitcoin-cli it just works. It might take a while but it works all the time.
If I call it from within a Python Script

from bitcoin.rpc import RawProxy
...
# create a connection to local Bitcoin Core node
p = RawProxy()
...
info = p.getblockchaininfo()
...

then 8 out of 10 times it breaks...

~$python .bitcoin/blockheigh.py
Traceback (most recent call last):
  File ".bitcoin/blockheigh.py", line 58, in <module>
    info = p.getblockchaininfo()
  File "/home/user/.local/lib/python2.7/site-packages/bitcoin/rpc.py", line 296, in <lambda>
    f = lambda *args: self._call(name, *args)
  File "/home/user/.local/lib/python2.7/site-packages/bitcoin/rpc.py", line 229, in _call
    response = self._get_response()
  File "/home/user/.local/lib/python2.7/site-packages/bitcoin/rpc.py", line 254, in _get_response
    http_response = self.__conn.getresponse()
  File "/usr/lib/python2.7/httplib.py", line 1136, in getresponse
    response.begin()
  File "/usr/lib/python2.7/httplib.py", line 453, in begin
    version, status, reason = self._read_status()
  File "/usr/lib/python2.7/httplib.py", line 409, in _read_status
    line = self.fp.readline(_MAXLINE + 1)
  File "/usr/lib/python2.7/socket.py", line 480, in readline
    data = self._sock.recv(self._rbufsize)
socket.timeout: timed out

How can I force it to wait for the response?

Thanks


texts:
I have a problem, when i created my new wallet, so i took a photo my seed to my mobile, that then i will write to my notebook. But next day, my mobile shuted down and i must to reset it, what my seed has been deleted.
Is it possible, how to refresh my seed or gain it back?

Do you know to help me?

Thank you so much


texts: Confused about input and output spending limitations and consolidation

texts:
I am sure the answer to this is trivial to someone who already knows the answer, but not to me.
I recently wanted to spend some received bitcoin for the first time and discovered that the associated transaction fee was huge (more than I wanted to spend!), for two reasons:

Fees are presently naturally high due to network congestion.
The address has small amounts of bitcoin from many sources, which apparently is problematic.

I spent some time researching the problem and learned that all money in an address must be spent at once. I read about the analogies to not being able to split a coin. Hence the need for change addresses and such. I learned about "consolidation" and how to consolidate transactions during times of low fees.
Experimentally, I consolidated the 3 inputs of a different address into 1 new address, using a low fee. It took a few weeks for the transaction to confirm, but now has successfully made that money more spendable, because the consolidation reduces future fees. Okay, fair enough.
Now I want to do that to my main bitcoin address which has 22 received inputs. So I will consolidate them all with a (relatively) low fee, into 1 new address, which, when it finally confirms, I will finally be able to spend.
But entirely by accident I discovered something weird in Electrum:

If I right-click an address, there is a secret feature "Spend from" which lets me select the source address. (This is useful, because previously the only way I knew to select the source address was to fudge the spending and fees numbers until they exactly matched the total of a particular address, which tricked the program into using that address.)

On the "Send" tab, Electrum then lists each individual received input to that source address. If I right-click the individual inputs, I can remove them. WHHHAAT?!?!?

This contradicts everything I spent days reading about, which was that I had to spend the entirety of inputs at once.
Is this configuration valid? Or will there be an error when I try to commit the transaction? Or will all the other inputs to the address be permanently lost? I am too scared to try it.
Perhaps, for example, the design purpose of being able to remove specific inputs from a transaction is a way to purge "dust", to prevent an attack whereby somebody could DoS a bitcoin address by sending it many 1-satoshi inputs, causing the address to become practically unspendable without incurring a fortune in fees. But this design would discard the unused inputs forever, or gift them to miners as fees.
If it is valid to spend only part of an address, and I won't lose the rest, then why did I wait 3 weeks for this silly consolidation lark? And why was Electrum moronically trying to force me to spend all of the address at once, phenomenally increasing the fee when I was perfectly happy leaving the rest of the damn money exactly where it was. And why are there so many articles online explaining why you have to spend inputs all at once?
I am terrified I will lose all my bitcoin if I try this, so I would appreciate links to example transactions on the blockchain to satisfy myself that this partial inputs thingie is valid.


texts: Does private key belong to one public key in Bitcoin?

texts: More address belong to one wallet in Copay. I have a 12-word mnemonic to my old Copay wallet, but not the private key. If I would infer the private key of the 12-word could I reach all the public adresses with that private-key and start withdrawal?


texts: How could the protocol or client be altered to mitigate a timejacking attack?

texts:
I've read about the proposed Timejacking attack:

http://culubas.blogspot.com/2011/05/timejacking-bitcoin_802.html

There are a number of solutions proposed, but it seems like there might be a simpler solution to make the selection of peers more random.

As I understand it, the attack relies on an attacker being able to connect to a specific target node.

Wouldn't either of the following two solutions work?

Differentiate between input and output peers. Allow anyone to connect to you to receive information from you but only take information from peers that you connect to. This would make it very difficult for an attacker to have a large number of connections to a specific node because the node is randomly choosing which nodes to receive data from.
Continuously change connected nodes. i.e. every minute or so, disconnect from one connected node and find a new one to connect to. This would create a constant rotation of nodes that would make it much harder for an attacker to keep his/her connections to your node.


texts: Running pybitcointools & python-bitcoinlib concurrently

texts:
This is somewhat Python-based, but I feel it is more a Bitcoin question than a Python question.

The problem is running pybitcointools and python-bitcoinlib concurrently, as both packages use the name bitcoin. This BountySource discussion sums up the issue succinctly:

  It seems that on PyPi the name bitcoin is free but... (the) ... python-bitcoinlib package on installation uses the same name "bitcoin" as the current pybitcointools, and I've had them clash (one overwrote the other)

It's also worth noting that using pip, pip install pybitcointools = version 1.1.15, whereas pip install bitcoin = version 1.1.25 (newer version).

I generally prefer Python 2.7 but whatever solutions may be applicable just to Python 3.x would also be greatly appreciated, as using both libraries concurrently would be great.


texts: Have any security vendors developed any Bitcoin Cross Domain Solutions (CDS) implementions yet?

texts: Such technology (deep packet inspection firewall on steroids), which is typically on the US ITAR Export Control List (having EAL4+ Common Criteria ratings), should be very high on the Christmas List for all Exchanges?  Was interested in knowing the existing list of vendors in this market space. It sounds like this technology is sorely needed to plug the gaping security holes that we hear about in the news...


texts: Is Blockchain safe to store personal information?

texts:
I do my first steps in blockchain development and I have a questions about storing some sensitive data on a chain.
Assuming two companies developed the protocol of document exchange through Blockchain. They don't want to give access to their information to anybody except themselves.
Ok, I think they can choose between two possibilities:
1) Content of docs is encoded cryptographically. The result is recorded on Blockchain directly.
Pro: companies must not maintain their own DB's for storing docs.
Contra: maybe it is expensive to store big data on blockchain; (the main) if verification key of a counterparty is stolen then malefactor get access to all documents since nobody can remove data from blockchain.
2) Counterparties can record on a chain hash result of docs' content only.
Pro: It is more safely.
Contra: In this scenario it is impossible to create completely decentralized db since every must maintain the needed data by oneself to get whole content of docs.

Do best practices exist for storing sensitive information on Blockchain?


texts: How do I import a private key into Bitcoin-Core?

texts: How do I import a private key into Bitcoin-Qt? bitcoind is nowhere to be found, and pywallet says it requires "bsddb" when I run it, which is also nowhere to be found. I generated some vanity addresses and I want to use them.


texts: Is it possible to view unconfirmed transactions with the bitcoin client?

texts:
This site shows you unconfirmed bitcoin transactions:
https://blockchain.info/unconfirmed-transactions

As I understand it, these unconfirmed transactions are received and rebroadcast by every bitcoin client. Given that they are on my computer, how would I go about extracting this information (i.e. a list of all unconfirmed bitcoin transactions) from the bitcoin client?


texts: Are there public LN nodes that have some gRPC LND API endpoints accessible for 3rd parties?

texts:
My lnd node died but I'm doing some research on lightning channels. So I'm rebuilding a new btc/lnd node, but in the meantime: are there open nodes that I can access, especially for SubscribeChannelGraph?

Update:
I found this repo that pretty much had everything I needed. It's a modular implementation of the BOLT specification in NodeJS, meant exactly for uses cases like mine.

https://github.com/altangent/lntools


texts: How cooperative or competitive is the mining process?

texts: As each miner works out which nonces it has tried, does it notify the network so that energy isn't wasted on re-processing the same thing by each node? Or is it totally competitive with everyone for themselves?


texts: Finding legitimate sources of research and info regarding crypto, mining and the blockchain

texts:
I'm relatively new to Bitcoin, crypto and the blockchain and mining etc, however due to having over 15 years experience in IT Ive followed BTC etc since it kicked off in (2009?), and would like to learn more about it from a tech point of view and get involved in this exciting new tech that is, in my opinion kind of like e.g Linux (Ubuntu etc) and open source SW, where knowledge and freedom are more important than profit and all of its problems (eg greed , power, etc) and Linux Desktop open source is amazingly secure reliable OS that is available as an alternative to MS, IOS etc.
I am a firm believer in the internet and IT (even its all its current problems eg scams , hacking, etc) and shortfalls is the great leveler for the "the people" to connect, learn, collaborate etc without government or political and corporate interference or control.
I believe that BTC and its decentralized automatic system of transactions is the way of the future, but with so much -ve press its hard to find good sources of learning/info and how to get involved as a "genuine supporter of the new digital tech"
BTC, crypt etc is fast, very secure, and offers an alternative to corporate, government controlled and owned currency assets.
Your help is appreciated


texts: Is the ordering of blocks in the rev*.dat files same as the blk*.dat files?

texts:
I understand that blk*.dat files save the blocks in the order it gets them from it's peers. Is the rev*.dat files in the same order as the blk*.dat files?

For example, would the 400th magicbyte in the blk00000.dat file be representative of the same block as the 400th magicbyte in the rev00000.dat file?


texts: Can Taproot be used to commit arbitrary data to chain without any additional footprint?

texts:
A common way of committing some data to the chain is through an OP_RETURN with some hash. Doing this marks an output unspendable, but the output still requires some footprint (and cost) on the chain as it contributes to the TX hash.
So I'm wondering if it is possible to embed some data in an OP_RETURN in a script of a TapLeaf which is never intended to be part of a spend. If we assume that the Taproot output is spent using the key path, and it has already confirmed, it should be possible to later reveal the paths and scripts containing the OP_RETURNs, and it could be proven that the TapTweak hash did indeed commit to these hashes via the TapBranch hashes.
A single transaction could commit to a large number of OP_RETURNs which have no on-chain outputs, but whose hashes are indirectly committed to the chain. These could be revealed individually to whatever parties they concern. The paths and scripts would have no presence on the blockchain.
Maybe this doesn't even require the OP_RETURN as you could just use the TapBranch/TapLeaf hash itself as the data you wish to commit.
Would this not significantly reduce the cost of services like colored coins, timestamping services, etc, which commit their data directly onto the chain?


texts: Is Bitcoin mining profitable on a 8 core, 32 GB server with unused capacity?

texts:
I have a server with following specs which is using avg. 20% CPU daily :

Quad Core 3.20Ghz (E3-1230)
32GB RAM
1Gbps unmetered b/w

My questions are :

1). With today's rates does it makes sense to CPU mine Bitcoins, what results should I expect? I used http://www.coinish.com/calc/ but it does not have anything near to my hardware specs. All other answers to similar questions take the old Bitcoin rates into consideration of profitability - with 1BTC=$1200+ the scenario must have changed a lot ?

2). Secondly, can I use multiple servers and computers to work as a farm towards the common goal of mining bitcoins working as a team and will this help achieve the goal of profitability.

The servers are used for hosting websites and I pay a fixed rental. So there is no additional investment or charges involved.


texts:
How do sites like blockchain.info and bitaddress.org generate private keys by simply hashing a string? (the passphrase?)

In this wiki article,
https://en.bitcoin.it/wiki/Technical_background_of_version_1_Bitcoin_addresses
Step "0" starts with an ECDSA key pair already generated.

Does this mean that any 256-bit value can be a valid ECDSA private key? So wherever I am in the world, I can always just SHA256(passphrase) and get my private key?


texts: How Do I Calculate the profit of the value of my bitcoin?

texts:
Lets say I buy $50 of a bitcoin for 3916.74, And then the price goes up to $4200. How Do I calculate how much I have made in profit?
As in What type of formula do I use to see how much more my $50 is worth now that the price is higher than when I bought it?


texts: Why do miners seem to be using consecutive letters for the Coinbase transaction text?

texts:
If you look at coin.dance, it looks like the coinbase transactions text start with consecutive letters. For example, block 478529 starts with "AM" and 478530 starts with "BM" and 478531 starts with "CM" and so on. This continues with DM, EM, ... all the way to ZM despite being mined by lots of different miners.

This looks coordinated in some way. Why is this? Can't the coinbase text be whatever the miner wants?


texts: Can I claim my BCH if my BTC is held with Coinbase?

texts:
I have BTC in an account with Coinbase.

Since Coinbase doesn't support BCH, they don't provide access to it.

In all honesty I don't know much about bitcoin and how to move my BTC from Coinbase to an offline wallet, so when I received the notification they wouldn't support the split, I didn't understand the ramifications.

From the little I understand at this point, I believe this is the situation I find myself in, and I am looking for verification that my points below are correct - hence this question:

Coinbase owns the private key to my wallet with them.
If I now move my BTC to a different wallet, to which I own the private key, only the BTC will be moved.
As such, the BCH (which is technically mine), is held against the private key in my Coinbase wallet, and won't be moved.
Therefore, to all intents and purposes, unless Coinbase is somehow persuaded to release the BCH and/or private keys to their BTC customers, that BCH is lost to me.

Final question:

Is there any way for me to obtain access to my BCH?


texts: How do I know that the majority of bitcoin miners are not XYZ government's facilities?

texts: Even if "Satoshi Nakamoto" is/was actually a real person, how can I be sure that XYZ government (XYZ can be US, or China, or ...) does not have now (or will not have in the future) 51% of the hashing power to mess with the bitcoin network transactions when the right time, in their opinion, comes?


texts: Safely convert paper wallet to encrypted online wallet

texts:
I started investing a not insignificant part of my salary into BTC a few years ago. I created 10 paper wallets (using bitcoinpaperwallet.com) on a dedicated laptop disconnected from the Internet. I then stored them in my office drawer however I no longer feel safe due to potential theft/elements etc. and I don't have access to a safety deposit box.

I want to digitize them and use strong encryption so I can store them on a few different servers that I own for redundancy. I don't need to regularly withdraw BTC from these wallets as they are for investment, I keep a separate small hot wallet on blockchain.info for spending. I'm confused as to how I should;

a) Digitize the paper wallets. I dont want to have to  manually enter the private keys and make a mistake. Is there software I can run on the disconnected laptop that can scan the QR codes for the private keys using the webcam? I know blockchain.info does this but the laptop doesn't have Internet access.
b) Once I have the private keys in a digital format (either in a plain text file or some wallet format) what form of encryption do you recommend. I'm currently planning on using PGP with 8k RSA keys.

Any advice would be most appreciated.


texts: What is the "Untrustworthy" tag on bitcointalk?

texts: I just saw some people that were once labeled "Scammers" are now labeled "Untrustworthy" instead. Does anyone retain scammer tags, or was this a rename? Where was this discussed/announced?


texts: How to make bitcoind connect to more nodes?

texts:
Let's say I have a dedicated server just for my bitcoind and for better reliability and some security reasons I want it to be connected to a much bigger number of nodes than it is willing to do by default (about 40-50).

Providing that I have enough resources, how can I set my bitcoind to keep a specific number of connections to other nodes? Is this possible without recompiling it?

Note: there's a maxconnections option which sets the upper bound, but it doesn't seem bitcoind strives to reach it. Need to kick it off somehow.


texts: Implementation of the Variable length integer in C

texts:
Anyone can give me a idea of how implement in C this concept of Variable length integer which encoded the numer of transactions in a block? based on what is described here, I think is something lime that:

if(value=?)
    uint8_t number_transactions = length;
else if(value=?)
    uint16_t number_transactions = 0xFD+length;
else if(value=?)
    uint32_t number_transactions = 0xFE_length;
else
    uint64_t number_transactions = 0xFF_length;

where number_transactions would be the value concatenated on the block. But how implement this? This code does the same described in the bitcoin wiki?

UPDATE

char* varint(unsigned long size) {
  char* number;
  if(size < 252) {
    number = malloc(1);
    number[0] = (uint8_t)size;
  } else if(size>=253 && size<65535) {
    number = malloc(3);
    number[0] = 0xfd;
    memcpy(&number[1], (uint16_t)&size, sizeof(uint16_t));
  } else if(size>=65536 && size<4294967295) {
    number = malloc(5);
    number[0] = 0xfe;
    memcpy(&number[1], (uint32_t)&size, sizeof(uint32_t));
  } else if(size>=4294967296) {
    number = malloc(9);
    number[0] = 0xff;
    memcpy(&number[1], (uint64_t)&size, sizeof(uint64_t));
  }
  return NULL;
}

message from compiler:

bitcoin_rpc.c: In function ‘varint’:
bitcoin_rpc.c:230:24: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
     memcpy(&number[1], (uint16_t)&size, sizeof(uint16_t));
                        ^
bitcoin_rpc.c:230:24: warning: passing argument 2 of ‘memcpy’ makes pointer from integer without a cast [-Wint-conversion]
In file included from bitcoin_rpc.c:4:0:
/usr/include/string.h:42:14: note: expected ‘const void * restrict’ but argument is of type ‘short unsigned int’
 extern void *memcpy (void *__restrict __dest, const void *__restrict __src,
              ^~~~~~
bitcoin_rpc.c:234:24: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
     memcpy(&number[1], (uint32_t)&size, sizeof(uint32_t));
                        ^
bitcoin_rpc.c:234:24: warning: passing argument 2 of ‘memcpy’ makes pointer from integer without a cast [-Wint-conversion]
In file included from bitcoin_rpc.c:4:0:
/usr/include/string.h:42:14: note: expected ‘const void * restrict’ but argument is of type ‘unsigned int’
 extern void *memcpy (void *__restrict __dest, const void *__restrict __src,
              ^~~~~~
bitcoin_rpc.c:238:24: warning: passing argument 2 of ‘memcpy’ makes pointer from integer without a cast [-Wint-conversion]
     memcpy(&number[1], (uint64_t)&size, sizeof(uint64_t));
                        ^
In file included from bitcoin_rpc.c:4:0:
/usr/include/string.h:42:14: note: expected ‘const void * restrict’ but argument is of type ‘long unsigned int’
 extern void *memcpy (void *__restrict __dest, const void *__restrict __src,


texts: How to know where number of inputs field ends in a transaction if it is not a fixedsize field?

texts:
I know that we parse a transaction in bytes. So there are 2 quesions that I search for the answers of:

1- Can VarInt field -that gives the number of inputs in a transaction- be more than 2 hex digits(2 Hex = 8 bits = 1 byte)? I am asking this to be sure that it is not fixed size. We know that 2^8 = max 256 and I am pretty sure that there can be more than 256 inputs in a tx.

2- If it is not a fixed size field how do we know where number of inputs field ends or prevTx field starts?


texts:
I'm able to create multisig with bitcoin-cli with addmultisigaddress

bitcoin-cli addmultisigaddress 2 '["'$ADDR_MITT_1'","'$ADDR_MITT_2'","'$ADDR_MITT_3'"]'

But How can I add extra OP like CLTV or another OP? Can I use bitcoin-cli to generate redeemscript and address?


texts: Is there any tech that uses a signature as a private key?

texts:
I've been pondering how the Lightning Network will work when one of the parties in a channel tries to cheat.  It seems that publishing a transaction that shouldn't be published (a "bad act") must involve publishing something the victim can use to unwind everything.  I'm trying to identify what it is that the bad act provides to the victim, the "signature as a private key" seemed like a possibility.
Even if the "signature as a private key" idea isn't used in LN, it seems like a useful concept, but I couldn't find anything on the internet discussing it.  I tried a Google search and then came here.


texts: I have sent a Bitcoin amount to someone who wants the transaction ID. What is this? Is it the hash shown on the LHS of the transaction?


texts: What EURO exchanges have web APIs currently?

texts:
I'm wondering what exchanges in that operate in native euro, who most likely support sepa transactions have web apis?

Bitcoin-24.com was great until they had banking problems. now who is left? Is BTCe the only one?


texts: Bitcoin Sellers who Request Photo ID, is this safe?

texts:
I wanted to comment on this but couldn't due to low rep:

What's the safest way to buy bitcoins in the UK?

Looks like quickbitcoin.co.uk is a good place to buy bitcoins, however; I'm not comfortable sending my driving licence or other ID.

Why do companies/sellers of crypto currency want photo ID of customers?  Is it safe?


texts: Is there a javascript library for generating litecoin address from a string?

texts: Is there a bitcoinjs equivalent for litecoin? I want to be able to generate a litecoin address using a long string.


texts: bitcoin-cli importprivkey to the same user or different users

texts: If i call the bitcoin-cli importprivkey multiple times, does it import the private key to the same user or to different users? In the bitcoin-cli importprivkey, it does not specify to which user account is the key importing to.


texts: Does Bitcoin mining benefit at all from having more video memory?

texts: Example: I am mining on a Windows computer with guiminer on an onboard gpu. Will assigning more memory to the IGP improve its performance while mining?


texts: Pending BTC transaction for more than 30 hours

texts:
I have made a transaction 0.0387621 BTC yesterday, its been more than 30 hrs, the transaction is still in pending status.

I have put the right address and BTC value (excluding the token charges).

Kindly let me know any solutions that can resolve it.

Any help would be highly appreciated.


texts: I'd like to setup a Bitcoin DNS seed node for learning purposes. Would I be able to actually aid in the peer discovery process? How would my dns be discovered so that it could be queried?


texts: Is Bitcoin core V.0.9 not updated on PPA ppa:bitcoin/bitcoin?

texts: Version 0.9 of Bitcoin-Qt just came out. When will ppa:bitcoin/bitcoin be updated? In the meanwhile, any steps showing how to upgrade are welcome!


texts: How can i accept Bitcoin donations or payments on my website?

texts: I have seen all these other posts on how to do it, but they are all so complicated, what is the quickest, easiesy way to accept Bitcoin payments or donations on my website? Why is it all so difficult?


texts:
Bitcoin defines you need to sign the previous hash and the destination public key. By doing so, you assume that you transferred the money. That provides non-repudiation of the transaction to a given key pair.

If you used bitcoin to buy "guns", how can the court legally prove that you, a person, are the owner of the key that made the transaction?

Since the key is not certified by a trustable third-party, you can't prove the association between the key and its owner. Am I correct?


texts: What's the purpose of CSHA256::Write and CSHA256::Finalize

texts:
Looking at Bitcoin Core implementation of SHA256, I noticed it was a bit different from OpenSSL's implementation.

In OpenSSL, you would initialize a variable with SHA256_CTX when in Bitcoin Core it's done with either valtype (aka. std::vector<unsigned char>) or uint256. Also, you would go through the steps INIT, Update, Final.

In Bitcoin Core, it's Write and Finalize.

It would be awesome if someone could go through the basic steps and perhaps explain why it's implemented differently. Thank you!


texts:
I am having trouble finding this information so I would like to ask those who use BitPay:

Can you create a BitPay account and spend coins without having a Credit/Debit Card associated with your account?
Tying into the first question can you use Bitpay without tying any personal information to your Bitpay account?

Some stores only accept bitcoin via Bitpay but I don't want to create a Bitpay account if it removes my anonymity.


texts:
Whenever I try running some command like:
bitcoin-cli getinfo
The prompt just hangs and does not return anything, similar to SQL interface if you do not enter semicolon.
Running only "bitcoin-cli" returns the help screen but running any command just hangs and need to press CTRL+C to get back.


texts: Where can one find the listing of the 3-call letters for all of the altcoins?

texts: There's BTC, and everything else.  But how are the call letters registered and is there a comprehensive list of them all?


texts: I have a random and maybe crazy question. Can I sell test coins? Someone recently told me that Advanced Market Terminal is buying them. It is strange to me Since they should hold no value.


texts: Running both bitcoind and bitcoin-qt for use with lightning

texts:
I've been toying around with bitcoin & lightning nodes.
I like having the Bitcoin Core Qt GUI around for things, but also like being able to change specific configuration / startup flags (maybe eventually contributing) with the source + bitcoind.
My proposed solution is to download Qt GUI (current version 0.20.1) and then get the same version from github and share the same bitcoin chain database.
To do this, I want to have the same version. Is this as easy as:
# I downloaded 0.20.1 .dmg file from Bitcoin Core and installed it, thus I need that tag from Github
git clone https://github.com/bitcoin/bitcoin.git
git checkout tags/0.20.1
# ... do build here

Then, depending on what I'm doing I run either 1) Qt, or 2) bitcoind, but never at same time.
Any additional steps I need to do to check the versions are the same? Is there an easier way to achieve this? Maybe it's just safer to build Qt stuff myself...


texts: Digging into debug message: "socket recv flood control disconnect (x bytes) "

texts:
I set the following when I run
bitcoind -debug -server -detachdb -printtodebugger -printtoconsole

Debug.log

socket recv flood control disconnect (5018020 bytes)
disconnecting node 82.41.255.68:8333

Question

What client actions would cause this entry to appear?

What settings (client side or server side) are available to adjust this for higher or lower capacity?

What side effects are there with adjusting this capacity (semaphore lockups, db contention, etc)


texts: Bitcoin contracts. Are there good examples in the blockchain?

texts:
I have been checking the Bitcoin wiki for script and Bitcoin contracts and I have some doubts about advanced contracts.

For instance, I have seen in many places references to password controlled transfers, where only the owner of a keyword could get the BTC in the contract. Do you know of any example in the blockchain? I am curious about anything with script commands beyond the standard use.


texts: Why does Bitcoin make my computer lag/freeze?

texts:
Whenever I run bitcoin, my computer (Dell E4200 running Ubuntu 12.04, with AwesomeWM) lags quite heavily.

It will operate normally for 10-15 seconds, then 'freeze' for 10 to 15 seconds, during which time keyboard and mouse input seems not to register. Some actions are more affected than others. Chrome won't output keystokes in this textarea during such a lag, but I can change tabs freely. All the keystrokes show when the freeze ends.

I am running bitcoin-qt from this repository: https://launchpad.net/~bitcoin/+archive/bitcoin

I installed it with sudo apt-get install bitcoin-qt

Version shown during install:
Unpacking bitcoin-qt (from .../bitcoin-qt_0.6.2-precise0_amd64.deb) ...

I had the same issue when I was running Ubuntu Unity, and the 'original' bitcoin client.

My client is currently synchronizing with the network.

My total CPU usage is between 20-60%, with occasional spikes to 90+%.

Memory usage is steady at ~60%, and swap is ~5%.

Any clues to help me diagnose / solve this issue?

Thank you.


texts: Is it possible to create multisig wallet from command line?

texts:
In a situation where electrum script is included in PATH so that electrum command args... is possible from terminal command line, is it possible to create multisig wallet in this terminal?

I know that electrum create -w path/to/wallet will create wallet in the path path/to/wallet.  I'm wondering if it's possible to create multisig wallet from command line also.


texts:
I see block chain is stored basically four pieces of data that are maintained:

blocks/blk*.dat:

the actual Bitcoin blocks, in network format, dumped in raw on disk. They are only needed for rescanning missing transactions in a wallet, reorganizing to a different part of the chain, and serving the block data to other nodes that are synchronizing.

blocks/index/*:

this is a LevelDB database that contains metadata about all known blocks, and where to find them on disk. Without this, finding a block would be very slow.

chainstate/*:

this is a LevelDB database with a compact representation of all currently unspent transaction outputs and some metadata about the transactions they are from.

blocks/rev*.dat:

these contain "undo" data. You can see blocks as 'patches' to the chain state (they consume some unspent outputs, and produce new ones), and see the undo data as reverse patches. They are necessary for rolling back the chainstate, which is necessary in case of reorganisations.

But I still don't understand how rev*.dat work. Can somebody explain in detail how to use them?


texts:
I am new to bitcoin node, recently I tried to running my node with rpcbind and rpcallowip, with the setting of rpcbind and rpcallowip, I am not able to stop the node with locall cli...
error: server returned HTTP error 403
it returning a 403 forbidden when I execute command.
Any idea how can I stop the node if I am not able to send command from the allowip...


texts: What are Tonal Bitcoins? In what application is this system of notation superior to the decimal notation? Are there any clients or other services supporting the tonal system?


texts: Can anyone without knowledge of encrypted tech use bitcoin?

texts: I am interested in registering online, however I haven't got any knowledge on encrypted language not even on software design or whatever it is called.  Is it possible for a person like me to register and enjoy the benefits from bitcoin that surely will become the currency of our modern generation:)


texts: Why does the "global lottery" prove the validity of the blockchain?

texts:
As far as I understand it currently, when winning the "lottery" (mining) you can add a block, sum of transactions, to the blockchain. This block is in the first instance verified by all network users.

BUT can`t a lottery winner also add a fraudulent block to the chain?

What does this lottery contribute to the validity of the chain?

Or in other words: How are miners approving a bitcoin transaction, besides adding it to the blockchain when they win? Potentially, they could also add a lot of "sh**" to the blockchain.


texts: Why is the value of the input way higher than the output resulting in a second change output?

texts:
Background: I'm experimenting on the LTC testnet client.

My client has a balance of 0.4 LTC and I sent 0.1 LTC to another wallet address.

https://chain.so/tx/LTCTEST/cc7d6e5e488593fded214e3073195fbaca3807a27d18a7f2550b6fc4909c48f6

Why is the value of the input 0.19 instead of 0.1? Why is this type of transaction created?

Why can't a transaction just be created with 0.1 input and 0.1 output without any change returned?

Thanks in advance.


texts: Why is my bitcoind daemon not listening on RPC port at 8332?

texts:
I have read a similar post which had no answer at this location. I am trying to use bitcoin-cli from a host that different from the host that runs bitcoind.  I also would be happy with being able to use curl to issue rpc requests.  I have had much success with getting bitcoind and bitcoin-cli to communicate within the same host, but activating the rpc port for external communication has proven to be beyond difficult if not impossible, and I am seeking your help.

I have started bitcoind with the following configuration file:

server=1
rpcuser=jared
rpcpassword=1234
rpcport=8332
rpcallow=192.168.*.*
gen=0
prune=600

(Note, the password will be changed after the system is working)

I have confirmed that the system is functioning on the local machine using bitcoin-cli to get the following:

{
    "version" : 110200,
    "protocolversion" : 70002,
    "blocks" : 183745,
    "timeoffset" : -1,
    "connections" : 8,
    "proxy" : "",
    "difficulty" : 1583177.84744401,
    "testnet" : false,
    "paytxfee" : 0.00000000,
    "relayfee" : 0.00005000,
    "errors" : ""
}

And from another host on the network, I have used nmap to scan the ports to display:

Starting Nmap 6.47 ( http://nmap.org ) at 2015-12-19 15:20 PST
Nmap scan report for c161.attlocal.net (192.168.1.68)
Host is up (0.0014s latency).
Not shown: 997 closed ports
PORT     STATE SERVICE
22/tcp   open  ssh
80/tcp   open  http
8333/tcp open  unknown

In the question referenced above, the user was able to cause the rpc port to open by removing the rpcallow lines from his configuration file. He commented them out, and the problem fixed itself. I have also tried this and not had any luck.

I also have tried using rpcallow of '192.168.1.*', '192.168.0.0/16', '192.168.1.0/24' and once tried using rpcbind, which appears to be related to an older version of bitcoind as it is no longer listed in the man pages for bitcoin.conf.

My system is running the following OS:

Distributor ID: Ubuntu
Description:    Ubuntu 15.10
Release:    15.10
Codename:   wily

Any and all help is appreciated!  Kind regards, and thank you.


texts: Thin command line-capable client for Linux

texts:
I need to set up linux server for web service that could generate bitcoin addresses and check the balance on them, etc (basically, receive payments in BTC). And I do not want to use third-party online wallets and services.

Original bitcoind client is too large now, you need almost 20 GB just to store blockchain files, and that'd be pretty expensive even for VPS.

Are there any thin command-line linux clients for this purpose? Electrum is GUI-based (it's command-line capable, but to set it up you need GUI anyway), Multibit too.


texts: paytxfee vs maxtxfee which one overrides the other

texts:
In wallet options section it shows these two settings

-paytxfee=<amt>  Fee (in BTC/kB) to add to transactions you send (default: 0.00)
-maxtxfee=<amt>  Maximum total fees to use in a single wallet transaction, setting too low may abort large transactions (default: 0.10)

If I set these two settings in the bitcoin.conf which one will override the other ? or how does in work ?


texts: Do you 'own' Bitcoins purchased via an exchange?

texts:
I have been told by some that bitcoin exchanges do NOT record BTC transactions by a buyer/seller on the blockchain, but rather hold them in their own name and ledger -
eg, if I buy one BTC via an exchange, I do not own a UTXO on the blockchain, but simply have been 'assigned' a BTC that the exchange owns.

This of course, would give rise to counterparty risk, even ignoring fraud risk.

Truth or fiction?


texts: How can a block be considered more difficult to solve/hash than another one?

texts:
In this answer: https://bitcoin.stackexchange.com/a/760/28219

It is said:

  Because of all this work, when a Bitcoin client signs on to the
  network it can trust the block chain that was most difficult to
  produce (since this is evidently the one that was being worked on by
  the most miners).

There is nothing evident there :)

Can someone explain how can a block be more difficult to solve than another one? Does it have to do with the number of transactions it contains?


texts: How do I prevent the standard Bitcoin client from sending some of my Bitcoins to a change address?

texts: I found somebody that imported a paper wallet with 100BTC then used 2BTC BUT the other 98BTC were sent to a change address. Why and how can I prevent this; how can I enter a custom change address?


texts: How to track Segregated Witness adoption rates

texts: How can I find out what the current Segregated witness adoption rate is, so as to see how it is progressing towards the 95% readiness required for it to activate.


texts: How to process refunds and ensure that after a crash you don't resend to someone?

texts:
I want to have a server running that will be processing payments and refunds.  However, I also want to ensure that should my server die, that after a restart I will continue sending out any applicable refunds without sending a refund to someone I have already sent one too. I plan on using a WAL to achieve this, but I need to know what to store in the WAL. Is it possible to know your transaction ID before submitting the transaction?

That way I could just log the ID before submitting, and if I crash, I can just check the blockchain to see if that transaction already exists or not.

This seems like it would be a common problem for payment processors, but looking at the JSON-RPC documentation it appears that you only ever get the transaction ID after submitting the sendfrom/sendtoaddress.


texts: 2 of 3 multisignature transaction vulnerability when one of the private keys is compromised

texts:
I was wondering if and how multisignature wallets protect the owners from getting robbed.

So in 2 of 3 multisignature scheme, if one of the owners' machines has been compromised (i.e. bad actor possesses the private key and can initiate a transaction without the actual owner knowing about it and the 2nd owner signs the transaction who assumes that transaction request was made by the legitimate owner), does multi-signature wallet protect users from this kind of scenario?

Does it even have a way to protect in this case? Is the assumption that wallet owners will be communicating about the transaction request offline?


texts: What are some good resources for understanding Bitcoin?

texts: I've tried to read about what a Bitcoin is, how to mine, etc.  I find them to be confusing in that I don't understand the underlying factors driving Bitcoin.  Everything I've read seems to assume the reader has some knowledge of Bitcoin (even the wiki).  Where should I start?


texts: Is there a website that compares the features of different cryptocoins?

texts:
Is there any website where I can find a comparison of different altcoins by features?

I'm not interested in hashrate, price, difficulty, but rather in implemented features such as:

Used difficulty retargeting algorithm
Anonymous blockchain
Encrypted transaction network


texts: What are the chances that Bitcoin changes its proof-concept one day?

texts:
Is it realistic/possible that the bitcoin core team make a new Bitcoin Improvement Proposal (BIP) on day in which they propose to change Proof of Work (POW) with something else (proof of stake for example)?

And yes, I know that POW was already part of "Satoshi Nakamoto's" paper Bitcoin: A Peer-to-Peer Electronic Cash System.

POW takes already more energy than smaller countries and it's proved that there are cheeper solutions (the existence of many alt-coins proves that).

Do you think, it's realistic? Maybe far in the future? Maybe without a hardfork?


texts:
There have been almost an infinite amount of Bitcoin clones, but I have yet to see a Ripple clone or a Peercoin clone for that matter.  I'd include Nextcoin, but I don't think the full source has been released yet.

Is this correct?  If so, why not?

Ripple seems the most logical to clone because of the superiority of the code, and all one need do is generate a new genesis and checkpoint etc.

Are there a ton of Bitcoin clones because it has the largest market cap, and all want to get a piece, or does all of the undeserved bad rap that comes with Ripple repel clones?  That last logic doesn't hold much water when it comes to Peercoin.  Or is it harder to attract miners for Ripple because of the fee structure?

This makes no sense to me.  Why haven't the other major coins been cloned into oblivion like Bitcon?


texts: What is the reason for the recent drop in Bitcoin classic nodes?

texts: Was it just a VPS based ploy to temporarily fake demand for the protocol?


texts: Is there a Bitcoin Cash explorer that supports Xpub addresses?

texts: As the title says... I've been unable to find a block explorer that supports Xpub for Bitcoin Cash.  Anyone know of any?  In particular and preferably, one that will allow for fetching via GET (so I can import the data into a Google Spreadsheet).


texts: What is the superscript number in Bitcoinica prices?

texts: Since Bitcoinica has been released I've been reading a bit about Forex. But i don't know what the superscript number refers to in the price quotes on the front page. How is this number calculated and what does it indicate? Or are they just simply pips?


texts: How can I get address's balance that doesn't belong to my Bitcoin core wallet?

texts:
I have been looking for a way to see the address's balance that doesn't belong to my own Bitcoin core wallet.
I don't like to use an external API, I have this full node and I really wonder if this is possible.
I saw this Pieter Wuille's answer: How to get an address's balance with the bitcoin client?
But it is an old answer when Bitcoin core even didn't support addresses as watch-only.
What I can understand from his answer is I can't see this information on my Bitcoin core, but right now with Bitcoin core v0.20.1, is that still not possible?


texts: Missed a letter on the bitcoin address when sending

texts: I generated a Bitcoin address from a site and made payment to that address from my PM through an exchange site. The problem is the bitcoin wallet had "h" at the end of it, but I missed it when typing the wallet for payment. The address I intended on sending the payment to has not received the payment due to this error. Have I lost the bitcoin that was sent? I have tried communicating with the exchange site but no luck and the site I was hoping to send payment to has not responded to my emails either.


texts: IP Addresses of inbound connections in bitcoin full node (TOR) looking as a localhost (127.0.0.1)

texts:
I run bitcoin full node (mynode) through TOR and I see that inbound connections appear only as a localhost with varying ports usually in high range (examples 127.0.0.1:35010, 127.0.0.1:58188, 127.0.0.1:38804, 127.0.0.1:56338).
My config setup for TOR in bitcoin node is:
proxy=127.0.0.1:9050
listen=1
bind=127.0.0.1
onlynet=onion
dnsseed=0
dns=0

What are these inbound connections? Are they nodes of other people or some apps running on my mynode? And if they are nodes of others why are they channeled through my home address and how?


texts: bcoin daemon killed over and over again [BCOIN]

texts:
I am setting up a full bitcoin node using BCOIN.

I spinned up a VPS on Google Cloud. Specs: 2 CPUs and 7.5 GB of RAM. 500gb of standard storage. OS: Linux ubuntu.

As I start the daemon, things go well at first. Then, I receive less and less blocks and after 10-15 minutes the daemon gets killed.

I even tried to beef up my VPS with 4 CPU and 15 GB of RAM. I also added a SWAP file. Same resault: deamon dead after 10 minutes.

I checked resource consumpion and it seems that there is plenty of spare RAM and CPU. So the VPS set up is not a problem.

Can anyone help me to solve this problem ? Thanks :-)


texts: How to setup USB Cold Storage for Bitcoin and Monero?

texts: Is it possible to keep many currencies (Bitcoin, Monero...) on one USB drive? If not, how can I setup USB Cold Storage for Bitcoin and Monero?


texts: How do you derive the lambda and beta values for endomorphism on the secp256k1 curve?

texts:
You can see a little background about this on this bitcointalk post by the late Hal Finney.

Beta and lambda are the values on the secp256k1 curve where:

λ^3 (mod N) = 1

β^3 (mod P) = 1

As seen here, in hex, N and P are:

N = FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFE BAAEDCE6 AF48A03B BFD25E8C D0364141

P = FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFE FFFFFC2F

The actual values of lambda and beta are easily verifiable and are:

λ = 5363ad4cc05c30e0a5261c028812645a122e22ea20816678df02967c1b23bd72

β = 7ae96a2b657c07106e64479eac3434e99cf0497512f58995c1396c28719501ee

The question for me is, how do you derive this? Can someone show me step-by-step how you can figure out these values?

Also posted to the Cryptography Stack Exchange


texts: How to estimate mining fee for raw transaction?

texts:
In our application we are generating a trasaction hex using the createrawtransaction call to "handcraft" a transaction. The problem we are facing is that we would like to estimate the mining fee for this transaction. I realize that we could call estimatefee x to estimate the mining fee per byte. But the problem is we are generating the transaction, so we don't know the size of the transaction yet! Chicken or egg?! I realize that we can generate a transaction and then account for the mining fee based on the hex, but this sounds like a hack to me.

So the question is: what's the best way to estimate the optimal mining fee while using createrawtransaction ?


texts: How does one mine a fraction of a bitcoin?

texts:
I'm new to the whole bitcoin stuff.
The stuff I've read about mining so far told me that when a node in blockchain finally finds the correct nonce for a block that can be accepted in blockchain, it then advertises it to others and they verify and put the block to the blockchain (at least this is what i understood from the explainations). I have also read that prize for mining a block is 12.5 BTC. My question here is how do nodes mine a fraction of a bitcoin when mining?(shouldn't it be 12.5 BTC per mined block for each node? is it even possible?)

  Example: this

Answer to this question mentions 0.04 BTC,but how?


texts: Is it possible to have duplicate transactions in "listsinceblock" RPC call ? If yes, why?

texts: Is it possible to have duplicate transactions(same transactions in the response) in "listsinceblock" RPC call ? If yes, why?


texts: Receiving payment on Lightning Network with LNBig as initial funder?

texts:
I was able to open a channel to myself from LNBig and withdrew 100 sats from Reddit's lntipbot. This appeared to be successful!

Output of lncli channelbalance:

{
    "balance": "100",
    "pending_open_balance": "0"
}

However, when I attempt to re-deposit 10 sats back to lntipbot, I get this error:

[lncli] insufficient local balance

I was hoping I could do this without doing an on chain transaction myself, hoping LNBig provided this piece of the puzzle. Am I having a large misunderstanding, should I be able to spend from my channelbalance without doing an actual on chain funding transaction myself?


texts: In getrawtransaction, what is the vout integer in the vin list?


texts: How should I integrate Bitcoin payments in an online service?

texts: I am implementing a website where some users can create surveys and pay the people that complete them with bitcoins. What steps should I follow to implement this payment system? Like, information needed from each party, steps to take to confirm payment, etc.


texts: Why does Bitcoin store all transaction inputs and outputs, instead of just an "account/balance" ledger?

texts: From what I can tell, the Ethereum blockchain just stores accounts and balances - why did the original Bitcoin developers choose the method of storing all transactions for validation instead of just account balances? It seems like that would reduce blockchain size on disk quite a bit...


texts: What are the downsides of Hodl Invoices?

texts: As far as I understand hodl invoices enable some interesting use cases. However, I heard that they can be detrimental to the network. Is that correct and in what way? Additionally, at a talk at the Lightning Conference 2019 it was mentioned that people should avoid relying on them in the future. Why?


texts:
First of all, i would like to say, i really don't want this thread to be some debate about your favorite video card manufacturer. So please just take that elsewhere.

I have heard from a lot of people that ATI & Open CL is much better for mining than NVidia with Cuda.

When i first heard this i was kind of shocked, because pretty much everything i have ever heard in the past was that Nvidia's Cuda was quite powerful at solving mathematical problems, and I even had a couple university professors that swore by Nvida cards over ATI for this very reason.

So what is it, about the Bitcoin and Litecoin algorithms that make it so much easier for ATI cards, or should i say harder for NVidia cards?  I want to understand the technical reason behind the common knowledge.

Thanks.


texts:
I am wondering on how a wallet's balance is computed. Basically, from what I've read I assume that you look back at all transactions involving all the keypairs of a given wallet. Adding up all the transactions' balances (negating a transaction balance when the transaction was outbound) should match the wallet's balance, right?

A) Is there Python code available that computes a given wallet's balance? I am not looking for a complete wallet software, just a minimalistic (academic) Python code example.

B) If using a web service, e.g. https://blockchain.info/q/addressbalance/$addr, how do I derive the address $addr to query from a given wallet? Any Python code?


texts:
This is a picture of my reminato deposit history.
Hello,i received btc on my reminato wallet,the btc did not credit but shows in transaction status lockef


texts: Why doesn't the Bitcoin Wallet mobile app require the whole blockchain?

texts:
I use the Bitcoin-Core on PC, where it starts by downloading the whole blockchain, before one can use the wallet.
Why doesn't it require to download the blockchain in case of the mobile app?


texts: Forking Bitcoin how to prevent a 51% majority attack

texts: Lets say I fork Bitcoin, to lets call it StackCoin. How do I prevent a 51% majority attack when miners are not in abundance? Would I have to setup a lot of miners to create the infrastructure of the network?


texts: Rewriting the entire blockchain: is it possible to spoof block timestamps of a privately mined chain?

texts:
According to fork.lol and Pieter's bitcoin.sipa, it would currently take ~200 days for an attacker with 100% of the current hashpower to rewrite the entire btc blockchain. My question pertains to how an attack like this could actually play out:

Lets assume that 100% of the hashpower is in an attackers hands, and the btc chain has stopped progressing. The attacker points 100% of the hashpower towards mining on the genesis block, so they will generate the first 2016 blocks SUPER fast, and then the difficulty will increase by a factor of 4. This will continue until the difficulty reaches it's current levels, and after ~200 days the attacker's chain will have a higher cumulative difficulty, despite having a much lower block height.

But I don't think that is very interesting, the rest of the network will realize there is a problem well before 200 days have passed, and probably code up a solution of some sort to keep things running smoothly.

So how possible is a more covert attack? Could an attacker with a modest amount of hashpower mine a private chain, and spoof the timestamps to keep the difficulty lower than it should be? Thus allowing the creation of a 'replica' chain with a few txs changed for the attackers benefit?

This could be done while the honest chain is still operating, and the attacker would slowly catch up to the honest chain. The further along the attacker makes it, the more hash power they will need to dedicate to the attack to keep outrunning any honest miners. But if a modest amount of hashpower can privately rewrite a good chunk of the early history, it seems like the current 200 day window might actually be a slight overestimate.

Note: In this scenario, the total time to enact the attack would be longer than 200 days, but some of this time would be spent privately mining with a portion of hash power that 'won't be missed' by the network. So the rest of the network may only be able to notice that an attack is happening inside of the 200-day window.

I do not see this as a real threat, I'm more interested in understanding what is actually possible, particularly in regards to spoofing time stamps on a private chain to keep difficulty targets low.


texts: Can a transaction be conditioned on signing another transaction?

texts:
I was thinking around http://lightning.network/ .

My problem is Alice sending coins to Bob via Eve: A -- tx1 -> E -- tx2 -> B

Is there a way to condition tx1 on Eve signing tx2?


texts: How is the whitepaper decoded from the blockchain (Tx with ~1000x m of n multisig outputs)


texts: I must have written my 24 seed words incorrectly, options?

texts:
I have 24 seed words for a wallet (greenaddress), and also had access to that wallet with a simple passphrase on my machine. I wrote down two backups of the seed words which are identical, yet I must have made a mistake as it isn't working to restore the wallet. This is after my passphrase failed 3 times and was reset which was odd.

Anyway entering it into greenadress tells me nothing except "log in failed". So I downloaded electrum to try and restore there. Entering the words into their text box doesn't allow me to click on "next" with no error warning. There are in fact 24 words so I'm assuming I misspelled one or put one out of order.

What are my options here for most efficiently finding out which it is and regaining access to my funds?


texts: Does the mempool size equal roughly the unconfirmed transactions?

texts:
My bitcoind (v0.13.0) mempool size is currently 12k transactions as can be seen from:

tail -f ~/.bitcoin/debug.log

I find this number very surprising as I naively expected it to keep in line with the number of 'Unmatched transaction' as reported say by blockchain.info which currently shows 3k transactions.

https://blockchain.info/unconfirmed-transactions

What am I missing?


texts: Recovering and transferring Bitcoin to new wallet

texts:
Question from a new bee.
I received a bitcoin in 2013.
That one is on my old computer with a Bitcoin wallet (version 0.8.1-win32).
It is visible and verified
Unfortunately this wallet still has over 4.000 days to sync.
And it takes ages to complete
Besides the fact that the old laptop keeps running out of storage space :-(
On my new computer I now have the wallet Bitcoin Core (version v0.21.0)
How can I move the Bitcoin from my old laptop to my new one?
As I said, I am a bit of a nitwit on this, so please do not make it to technical ;-)
Appreciate your help.


texts:
I'm trying to compile from latest tag the bitcoin repo and in my use case scenario ZeroMQ support would definitely help me.

Reading the documentation I realized this rudimental docker container. The Dockerfile installs the libzmq3-dev dependency and I define these configurations in the bitcoin.conf file.

The result is that inside the container there isn't any bind for the defined mq enpoints and I cannot realize where the error is.

Could someone please help me to enable mq publish mechanism?

Update: Now the bitcoin.conf file used is this running in in debug it logs this debug_log.txt.


texts: What level of mathematical understanding do I need in order to contribute or to understand the crypto behind bitcoin?

texts: My mathematical knowledge is up to CALC II (college level.) Is this enough mathematical maturity in order to understand the crypto in bitcoin or do I need more knowledge? If I do indeed need more knowledge than please point me to good books/resources to learn them. Thanks!


texts: How to create a tx that cannot be replayed?

texts:
I've got a very precise question about (self-)protection vs replay attacks in Bitcoin but to clearly explain myself, I need to explain what I did with Ethereum.

When the Ethereum fork happened (ETH / ETC) I did split my ETH / ETC myself.  At first I failed (my tx got replayed on both chains, but I was in control of all the addresses, including the destination address) and then I did it like this:

I had 2500 ETH pre-fork on a single address, so post post fork I had 2500 ETH and 2500 ETC.
sent 5 ETHs on the ETH chain only
Move 2505 ETHs to an ETH-only wallet
Move 2500 ETC to an ETC-only wallet

My thinking was that the tx to move 2505 ETH on the ETH chain wouldn't be replayable (because on the ETC chain I had only 2500 ETC, not 2505 ETC) and, surely enough, this time it worked.

I know that there were other ways to achieve the same result but that's how I choosed to do it because I really liked the idea of creating a tx that wouldn't be valid on the other chain.

However I'm not familiar enough with Bitcoin and UTXO and what precisely makes a tx nor how it is signed to understand how this would work under Bitcoin.

If there's one (or several) hard fork, can I use the same technique to "split the BTCs" myself?

For example if I have 80 BTC on a hierarchical deterministic wallet (Ledger Nano S in my case), can I send 0.1 BTC there, then move 80.1 BTC and be sure this movement of 80.1 BTC is not going to be replayable on the fork where I still only have 80 BTC?

Would that work?

Note that this question is not: "How do I split my coins in case of a hardfork?" but "Would this particular method of splitting work on Bitcoin too, just liked it worked for me on Ethereum?"


texts: How to withdraw all funds from a Ripple account?

texts: I'm trying to close my account by withdrawing all my XRP into a new account. But the Ripple client insists on keeping a minimum balance of 50 XRP. How can I properly close this account?


texts: Section 7 of the official Bitcoin paper "Reclaiming Disk Space" explains that only block headers are needed to verify transactions. Essentially by making sure that the transaction has been buried behind enough blocks. Why is the block chain so big then? It seems like we could all just store headers and reclaim a lot of disk space. Can I independently verify the integrity of the network with only block headers?


texts: Signmessagewithprivkey result is different than txinwitness

texts:
I'm studying segwit and I'm doing some experiment in regtest.
I create a raw transaction with P2SH address.

My Transaction data without signature is:

0200000001faf19017fe7e20747535ac41009922e4beb76e17a7fd5423bc60e75fbc8381c40000000000ffffffff01606b042a0100000017a914b63007b51b936175644dcf654f77c528e35f01178700000000

that's my message to sign, instead to use signrawtransactionwithkey I try to use signmessagewithprivkey and I expect the signature that I can find in txwitness field (first row).

signmessagewithprivkey return base64 signature then I convert it in hex.
result is:

20db4febb769c43c9072daf30934a345b2327b6107e701f21c7fe052a040180d4129dc3079dc7dad29db37c31fa6401013819e386beb9396e330b3b6e9f7fbcf5b

signrawtransactionwithkey return:

"txinwitness": [
      "3044022077f49ad0371ea5baf0ce60d3d15175c9bb5e37ff7f3bc023b76863b2a91d379e022073010deba5eef8619745cd79d94a73c4a4527391253731104fc734449322d85b01",            "02985586bf43d26229a97092f76086cfe6f9bf09d93bef16a92f65185c8f7f0b17"
      ],

I wonder, why the result of signmessagewithprivkey isn't equal at first raw of txwitness?


texts: How long it would take if I withdraw bitcoin to my bitcoin address through mtgox?

texts:
I want to get bitcoin ,not Dollars.
A friend of mine wants to travel to China next month.The prize of bitcoin in China is higher than America.So he think it is good way to change Dollars into RMB.
So I come up with this question.


texts:
As the mere size of the constantly changing data file tampers with my backup concept, I would like to ask if there is a way to split this file into many smaller pieces. I have no problem with the size as such, but with the amount of changes.

Background is, I do my backups with rsnapshot. This links files which haven't been changed on the target together, while changed files are copied in full.

That's why I would imagine to split the currently about 763 MB big blk0001.dat into two files:

blk0001.dat having maybe 700 MB, and not changing (frequently) in the future.
blk0002.dat holding the rest.

As the 2nd file grows steadily, I would, after it has reached a certain size, put more data from it into blk0001.dat, and eventually stop changing this file at all, starting a 3rd one.

Has someone done this already?


texts:
Please, advise wallet which supports testnet Bitcoin Cash.
I used https://ccoin.cash/#wallet, but they support only https://rest.bitcoin.com/v1.

Thanks for answers in advance!


texts: Can nLockTime TX be used to flood Mempools?

texts:
What would happen, if I would create a large number of large transactions with a very high nLockTime?

Would something stop me from filling not only the miners', but also regular nodes' mempools?

Would miners drop transactions with unreasonably high nLockTime and low transaction fee?

What would BitcoinCore do?


texts: How to determine estimated block or transaction time

texts:
I would like to know if there is any possible way to determine the estimated block time for a special cryptocurrency at the present time so I can estimate the transaction time it takes to send coins from one to another wallet.

Any help in this matter?


texts: Cannot synchronize with Bitcoin in testnet mode

texts:
I downloaded Bitcoin-QT for Windows 7 into:

MYUSERNAME/Downloads/bitcoin-0.8.6-win32/bitcoin-0.8.6-win32

I want to run Bitcoin in testnet mode, so I created bitcoin.conf with only the following content:

testnet=1

I put copies of bitcoin.conf into the following folders:

MYUSERNAME/Downloads/bitcoin-0.8.6-win32/bitcoin-0.8.6-win32
User/MYUSERNAME/AppData/Roaming/Bitcoin

When I double clicked on the Bitcoin-QT icon to execute the following, Bitcoin-QT starts up but it does not appear to be in testnet mode.

MYUSERNAME/Downloads/bitcoin-0.8.6-win32/bitcoin-0.8.6-win32/bitcoin-qt.exe

Can anyone tell me why it does not seem to go into testnet mode?

I went to Start > cmd to get the DOS prompt. I entered the following and it worked:

C:\User\MYUSERNAME\Downloads\bitcoin-0.8.-win32\bitcoin-0.8.6-win32>bitcoin-qt.exe -testnet

Bitcoin-QT launches in testnet mode.  However, it is not synchronizing with the network.  At the bottom, it shows "No block source available...155 weeks behind".

I tried adding the following to bitcoin.conf and restarted bitcoin-qt.exe -testnet but it didn't make any difference.

addnode=1.2.3.4
checklevel=2

After a few hours, it still shows "No block source available...155 weeks behind".  How do I get this to synchronize?


texts: How can I verify someone controls the private key behind a segwit address?

texts:
With a legacy P2PKH address, signmessage and verifymessage can be used to verify that the other party actually controls the bitcoin address in question. However, P2SH, P2WPKH and P2WSH addresses throw an error for signmessage, and we don't know when or if this will be made to work. So, another procedure is necessary if we want to accomplish the same thing with segwit.

As a work-around, I could have the owner of the segwit address send 1 satoshi to a verification address that I create in my wallet just for them. But that's a hassle and it's off-putting to them. And what if they want their satoshi back? =D; that would be a hassle.

Is there a way to accomplish the same proof of ownership without them having to send me coin?

I prefer an answer using the json rpc on my end (But failing that, I also have access to bitwasp, and failing that, I'm open to anything that runs in php), and the easiest (manual) procedure on their end. These are non-technical ordinary users. I might be able to nudge them into using a particular wallet if that wallet has a feature which will allow them to implement the idea in a better work-around.

I didn't tag this with json-rpc because I don't know what technology the answer will come from.


texts: GreenAddress: Noticfication of receiving transaction

texts:
I'm developing python project using greenaddress API. I use pycoin package.
I almost completed, but I can't resolve notification problem.
Using greenaddress API, the notification received is as follow.

{'wallet_id': '139183', 'txhash':    '0fd5cdf75d8a9979b454b36ba8dc36917dfc5b3726622f5291a24f0dcd4ab27f',    'subaccounts': [37], 'value': '-207'}

I want to get raw tx from this information, but I can't.
Can I get raw tx from this information by using pycoin and greenaddress API?
Pls, help me.


texts: In creating a scriptSig, how do I sign the hash of a raw transaction?

texts: I have created a raw transaction, added the hash code, and Double-sha256 this result.  Now I should sign this hash with the private key, which would give me the DER encoded signature, but I'm not clear on what exactly I should be doing.  How do I SIGN this hash with the private key?  What exactly would I be doing?  I am not using any crypto library, except for SHA256, and I have implemented secp256k1 my self, so I guess in relation to that, what should I be doing with the private key and the hash?  I am specifically aimed at step 15.  If I were to guess, this and this are essentially my answer, unless I am mistaken, and if I am, I would like to know why.  Otherwise, the caveat with those answers is the introduction of a random nonce.  Why could I not just have the private key = "k" (since you shouldn't reuse addresses anyway, right?), calculate "s", and concatenate "r" and "s"?  Or is this how it IS done?


texts: I want to exchange my Canadian dollars for Bitcoins. How can this be done? If it helps I have some American cash.


texts: In case of physical wallet theft, quickest way to offload funds in wallet backup?

texts:
Assume one makes a secure online backup of their wallet and then their laptop or device that has it is stolen. For the sake of argument assume that the thief watched the user type their wallet password in somehow, or the owner kept the password in a text file or something... what is the fastest way to transfer the funds from the online backup into a new wallet?

I would imagine this would be something like a easy online service that imports a wallet so that user is not forced to use the slower default of: find computer, download client, wait forever for the blockchain sync, then transfer.


texts: How do I clear a stuck Bitcoin transaction.The other answers did not help my situation

texts:
How do I clear a stuck Bitcoin transaction without being in control of the senders wallet?
I have a #number to go on and my wallet address.
The sender does not know how to help me.


texts: Where to buy non scam bitcoin with ICBC credit card?

texts: I've tried several bitcoin sites which accept credit cards, but they didn't accept my bank's credit card (miicard require bank verification and ICBC is not on the list), so where can I buy bitcoin from a reliable exchange with an ICBC credit card?


texts: Checkout time for consumers in stores accepting bitcoins

texts: If the general practice is use to different bitcoin address for every new transaction, does it mean that merchant in a retail store that accepts bitcoins has to change his QR code for every new customer in the line. Would it not increase the checkout time for consumers significantly


texts: What does a Bitcoin lightning private key look like?

texts: I know bitcoin private keys start with a 5... But how does a lightning bitcoin private key look like? Say I wanted to printed it out as a paper wallet.


texts: Idea on how to keep my altcoin private, make it impossible for others to mine even if they have my altcoin's source code

texts:
I've been doing freelance to create an altcoin and my client wants this new coin to be private which means only authorized users can mine and use the coin. What I've been doing so far is to make a new altcoin, keep it in a private repo, implement mobile wallet apps with authentication gate that requires user to enter his credential info (I have a server to contain this kind of info), etc. Everything seems to work well 'til yesterday when I see a strange IP in the output of getpeerinfo command. So I was wondering how could someone get my code and whether he was able to mine my altcoin.

So my question is: Has anyone of you had experiences in such situation of creating private coin? And do you have any ideas or suggestions on how I can stop someone from mining my altcoin or only allow certain machines from certain IP addresses can connect to my network and mine even if they have my altcoin source code?

Thank you in advance and have a nice day!


texts:
I followed the prices of Bitcoins during this day, but I am actually very cofused as to why Preev reports it always about $70-$100 less than Bitcoinity. News websites say the price soared to $900 today, which fits Bitcoinity's chart, but I also see people on the BitcoinTalk forums saying it is $500 now, which fits Preev's.

I understand Bitcoinity says that "the big number here is the price at which last trade was made". But since I also understand there is no institution that decides an "exchange rate" for Bitcoins, could I assume it as the price of the last trades? Why such a big difference?

EDIT: Now Preev is reporting more, but it is still a big difference compared to Bitcoinity. Just as a reference, when I wrote this question, Preev was reporting about $510, whereas Bitcoinity $600.


texts: Creating Payment system using Blockchain API

texts: I see a whole lot of websites using the blockchain API to create bitcoin wallets (if i am correct), send and receive payments, I know how to ordinarily make a payment system using C#/MSSQL or PHP/MySQL but it seems a whole lot of things are different implementing the blockchain API, hence I wanted to know how can I go about setting up a wallet, like using PHP to implement an online wallet so I can create user accounts, create wallets, send payment from my site (which has a wallet) to another bitcoin wallet on another site, since I think all of them actually use the same blockchain API, any ideas how to go about something like this?


texts: At what prices I will be buying/selling bitcoins?

texts:
Scenario 1:

I bought k bitcoins at unit rate X in the past, with amount A. If I want to sell them now, I look at three unit prices:

Buy Price
Sell Price
Spot Price

Question # 1: At which price I will be selling the k bitcoins that I have?

Scenario 2:

I have A dollars with me and I want to buy bitcoins with it. I am looking at 3 unit prices:

Buy Price
Sell Price
Spot Price

Question # 2: At which of these unit prices I will be buying the bitcoins?

For the sake of understanding, lets say I am using either Coinbase or GDAX

List item

to buy/sell in both above scenarios.

Thanks


texts: How to claim bitcoin cash for Bitcoin Wallet backup created before 1st August2017?

texts:
I use this bitcoin wallet for android for my bitcoins..

I had created backup well before 1st August 2017 from Safety>>Backup My Wallet..
The backup is encrypted with name
bitcoin-wallet-backup-2017-xx-xx

How can I claim Bitcoin Cash for these bitcoins?

I have read about decrypting wallet using openssl but output is random symbols since the wallet is in protobuf format..

Can you explain to me the procedure for claiming bitcoin cash in detailed steps?

I use Ubuntu 14.04 as my OS on laptop if it is needed for decryption process..

Also now If I move these bitcoins to another wallet, say Electruk them Can I use the other simplified process? Or I have to use that baclup Bitcoin Wallet for android?


texts: Do we put all the transactions in the memory pool?

texts: I wonder if orphan transactions are also stored in the memory pool? If yes, how do the Bitcoin client distinguish between the orphan and non-orphan transactions?


texts: How to reduce the amount of transactions with handling wallets?

texts:
i'm working on a Web Application that will allow users to deposit Bitcoin into their own wallet, leading to a service that invests their funds in X(lets say alt-coins).i'm having issues on how to approach this.

So, if i'm not mistaken it will go like this:

Bob deposits BTC to wallet W => W sends to service S => Bob wins money => S sends funds back to W.

Until bob has funds again it takes 2 transactions

If the goal is to minimize fees by reducing the amount of transactions,
Would you create a private key for each of the users? or is there a way to create different public addresses that point to the same private key?
I Thought about initially giving Bob the option to deposit directly to the service S but the whole idea is giving funds to more than one service.

Thanks for any advice.


texts: Why is 550 (MiB) chosen for minimum storage size for prune mode?

texts:
As you know Bitcoind can run in pruned mode, thus not advertising blocks to other nodes. Even though it has some drawbacks, saving you storage space isn't a benefit you can ignore.

My question is about the magic 550(MiB) default/minimum number. Why they've selected that limit? (& Why not less or more?)

I know it implicitly indicates blocks will be kept for the last (about) 3.8 days (91 hours) (one MiB because of one block every 10 minutes). But where that number come from? I know there is also a dust limit equal to 546 Satoshis.[182*3 ~ 550 here! Even though it is unlikely to be related to this case]

Would you please explaining what the logic behind 550 is? Is there any kind of difficulty level relating to 51% attack or any other stuff like that?

Edit:
From 0.12.0, bitcoind supports relaying NEW blocks to other nodes, thus the first assumption up there, isn't an accurate sentence!


texts: How to build Bitcoin binaries for Windows on Ubuntu using cross-compile

texts:
I am trying to build Bitcoin 0.13 for Windows. I've always used this guide for building previous versions. Now seems that developers have changed their mind regarding Windows, and the new way seems cross-compile from Ubuntu. I have followed step by step the new instructions, but I haven't been able to get it built. Seems that instructions are either not correct or not up to date. Here is what I've found so far:

zconf.h file not found, solved manually copying it from /usr/include/x86_64-linux-gnu to projectdir/depends/x86_64-w64-mingw32/include
[unsolved]warning: undefined symbols not allowed in x86_64-w64-mingw32 shared libraries; building static only while compiling secp256k1 lib
[unsolved] I tried to configure and make secp256k1 manually before running the "main" make for solving previous issue, but then I get this error: /usr/bin/x86_64-w64-mingw32-ld: attempted static link of dynamic object secp256k1/.libs/libsecp256k1.so

I stuck here, any help is appreciated. Also, I could also accept to build on Windows (like before) if necessary, as long as it works. Thanks.


texts: How automatically to forward bitcoins from one address to another?

texts:
I have a bitcoin wallet address (the private key is known by other people). I periodically receive payment on this address (and cannot change it/receive to other address).

I need:
When I receive a payment on it, automatically and immediately (at 0 confirmations, like in BlockChain.info wallet) send/forward them to my new wallet address (the private key is known only by me).

Is this possible and how?


texts: How to recover Bitcoin sent to example address on Bitcoin.org info page

texts:
Please,

I am very new and accidentally loaded funds into a sample wallet on the Bitcoin.org information site instead of my personal wallet.

This happened October 11, 2018.

Would you please help me.

Candace


texts:
I am interested in communicating with the Mastercoin network through an API to control various assets. In Bitcoin, I would run the Bitcoin daemon and use the documented API. For Mastercoin, I'm hearing conflicting opinions - either using omniwallet, mastercoin-tools or mastercore.

What is the best approach to take to communicate with the Mastercoin network through an API?


texts: Bitcoin not received from Coinmama to Blockchain Wallet

texts: I made a small purchase from Coinmama and transferred it to my Blockchain wallet. It has been over two hours and it hasn't appeared. I'm relatively new to this, but it has never taken this long. Can anyone clue me in?


texts: What Bitcoin-esque alternatives are there?

texts: I'm seeing lots of bitcoin-esque alternatives mentioned here. What alternatives exist and how do they differ from Bitcoins?