texts: Possible error in the white paper Calculations section?

texts:
Section 11 presents calculations of the probability of double spending, P(z, q), given an attacker relative hash rate q and a block count z.

P(z, q) can only be understood by knowing exactly what z represents. From the Calculations section:

  The recipient waits until the transaction has been added to a block and z blocks have been linked after it. He doesn't know the exact amount of progress the attacker has made, but assuming the honest blocks took the average expected time per block, the attacker's potential progress will be a Poisson distribution with expected value... [my emphasis]

Clearly, the transaction has one confirmation. The transaction "has been added to a block" and zero blocks have been linked after it. In other words, the transaction is hosted by the tip of the active chain.

Nevertheless, the probability of this transaction being double-spent is 100%, regardless of the attacker's hash power. In fact, the probability is 100% even with no active attacker.

This contradiction is reinforced by the equation Satoshi gives:

When z = 0, P = 1.0.

What am I missing?

There is at least one answer to this question that claims that z=0 means that the transaction is unconfirmed. That's inconsistent with the paragraph I quoted.

There appears to be an error somewhere in the Calculations section leading to a contradiction. I'm looking for an answer that either points the error out, or explains what I'm misinterpreting.

EDIT

One response offers the suggestion that Satoshi may have been talking about a Finney attack. In other words, the attacker has already pre-mined a block before attempting the double spend. Assuming the attacker can propagate blocks faster than the network, there would be a 100% chance of success. In this scenario, the attacker and network are tied at z=0, and given faster block propagation, the advantage goes to the attacker.

However, the Calculations section explicitly disallows a Finney attack. In particular, the attacker has mined no blocks prior to the attack:

  The receiver generates a new key pair and gives the public key to the sender shortly before signing. This prevents the sender from preparing a chain of blocks ahead of time by working on it continuously until he is lucky enough to get far enough ahead, then executing the transaction at that moment. Once the transaction is sent, the dishonest sender starts working in secret on a parallel chain containing an alternate version of his transaction.

I believe at least part of the problem is mathematical. Specifically, Satoshi gives the value of λ as:

When z=0, λ=0.

Referring back to Satoshi's original derivation of double-spending probability P(z, q):

λ=0 means that every term is zero, independent of hash rate. In other words, the attacker can never double spend.

This contradicts the "rearranged" form of the equation, which gives a probability of 100% as noted above.

I'm no math specialist, but from what I can tell, the two forms of P(z, q) that Satoshi gives are not equivalent for z=0. In fact, they give the opposite answer:

in one case, the attacker always fails, P(z, q) = 0
in the other case, the attacker succeeds with 100% probability, P(z, q) = 1.

Either way, the attacker's relative hash rate doesn't factor into the analysis when z=0.

I realize that other treatments of this problem have appeared. For now, I'm just interested in fixing the apparent problem with the white paper's analysis for z=0.

Is this possible, and if so, how can I do that?


texts:
I put BTC on the coolwallet card and now I cannot access my BCC. Does anyone know how to access funds with a number seed? It states on the coolwallet website that if you have word seeds you can access BCC but if you have number seeds you're out of luck and you'll have to wait until gods knows when.

I cannot find any information on number seeds so if anyone can give some input on this it would be appreciated, thanks.


texts:
My question is in relation to the operational difference between a merkle root and a plain old message digest.

To calculate a merkle root I need to complete the following steps :

hash each transaction in a block
create a merkle tree from all the hashed transactions
work back up the merkle tree hashing pairs of transactions until I calculate the merkle root

To create a plain old message digest I would do the following :

Take all transactions in a block hash them at the same time to create a message digest

My question is, how is a merkle root more beneficial from an operational standpoint than a plain old message digest?


texts: How do I monitor and track the legal proceedings of Silk Road founder Ross Ulbricht?

texts:
I'm interested in tracking the litigation, timing of hearings and other matters relating to the case against Ross Ulbricht.

What website, or resource would have up-to-date information of upcoming arraignments and other matters pertaining to the case?


texts: Does a blockchain.info My Wallet have a key pool?

texts:
Does a wallet in blockchain.info My Wallet contain a pool of extra keys as in bitcoin-qt?

Should the wallet be backed up after every new address is created, or only after several are created?


texts: How do transactions leave the memory pool?

texts:
How does my bitcoin core client know when to drop a transaction from the memory pool?

Is it as simple as a specific period of time?


texts: Recover electrum wallet with only wallet file?

texts:
I have an electrum wallet file and I thought I created a backup of the seed, but now I cannot find it anywhere.

When I try use it with the current version of electrum, it won't open it.

Is there anyway to recover the coins from the wallet file?


texts: Random Number In R Value , what is it actually, is it the same as Nonce in the blocks

texts:
I wonder about the random number in R value ...
if i am right , the R value is First part of the script signature which is combined of two parts (r,s)
r = Gk  (elliptic curve scalar multiplication) Or does the whole signature is the Gk ??
So r , is a multiplication of random number ( k ) times G (elliptic curve scalar multiplication )
while
r = xcoordinate(R) , is just the first part of the ( r,s )
I read an article the most repeated R values in transactions is
0x00000000000000000000003b78ce563f89a0ed9414f5aa28ad0d96d6795f9c63
while G is the Double of this point means that the random number is (1/2)
so R value Is simply is simply calculated by multiplying any number by G ???
and they do call it nonce , so is it the same nonce shown in blocks ? that is already public ?
or it is another nonce ?


texts: Trying to claim my bitcoin cash but transaction history doesn't match

texts:
Upon discovering the meteoric rise in value for Bitcoin Cash, I decided to actually claim the little Bitcoin Cash that I had from after the August 1st 2017 fork.  I had sold most of my crypto holdings awhile ago but retained about 17 mBTC.  My last valid transaction was a Send of 0.4 BTC to my Coinbase on July 15th which was prefork and left me with the remaining 17 mBTC balance.

I am using Bitcoin Core on a Windows 7 machine with a password protected wallet that is kept in a KeePass database that is protected with a private key I keep on a USB thumb drive. I decided to install Electron Cash and the install asked if I wanted to import private keys from a Bitcoin wallet.  I decided to do this and got the private keys from the Debug Console in Bitcoin Core for all of my receiving addresses.

I can see the correct amount of transactions in the History tab in Electron Cash after importing my private keys, however the amounts are wrong and the dates seem slightly off.  What is most concerning is that the final transaction shows my balance being sent out but the transaction id on Blockchair doesn't seem to match up with what I am seeing in my wallet.  Electron Cash wallet shows my balance as 0 which is incorrect.

BTW, I verified the ElectronCash 3.0 executable against the sig and checksum and my download is legit.

I am incredibly confused and wondering if I did something wrong on the import or if my money was pilfered.  Could this be a bug in ElectronCash 3.0?  Should I try a different wallet?


texts: Trezor Firmware update just hangs indefinitely

texts: Trezor out of the box - first firmware update with the wallet not even set up and just hangs on "Installing...Please Wait". Read through all of the troubleshooting section on Trezor's website but no help at all. Can someone help me?


texts:
Are ripple validation nodes appointed by central authority? If not, what prevents 51% attack through validator nodes? Why ripple.txt file contains validation nodes list? Who maintains this list? What is incentive for users to run validator nodes?

Thanx!


texts: Bitcoin transaction as been unconfirmed for 9 days

texts:
Please what can I do? I received a transfer of 0.559btc and it has remained unconfirmed for 9 days, I can't even find it again on the blockchain.info but it was there for almost 4 days. I can see the transaction here on tradeblock. I have alerted the company that made the transfer to me but their customer service is horrible. Please any help? Can I still get this deposit?

Also why did it disappear from blockchain.info?


texts: Why does vanitygen ban certain letters on testnet?

texts:
I'm guessing that vanitygen is more strict or has different rules than production's  Base58 rules.

Why are some of thse names marked not possible?

C:\vanitygen>oclvanitygen -k -o gpukeystestout.txt -i -f gpukeystest.txt  -T
Prefix 'mdemo1' not possible
Prefix 'mcoin' not possible
Prefix 'mBITname' not possible
Prefix 'mBITclear' not possible
Prefix 'mBITnic' not possible
Prefix 'mbotarmy' not possible
Prefix 'mdmzlist' not possible
Prefix 'maker7' not possible
Prefix 'makerofthings7' not possible
Prefix 'meventvwr' not possible
Prefix 'mdmzadmin' not possible
Next match difficulty: 5908459 (15 prefixes)


texts: Is this a usable systemd startup script for bitcoind?

texts:
The script here in the official github repo

https://github.com/bitcoin/bitcoin/blob/0.13/contrib/init/bitcoind.service

looks like a systemd startupscript to me. However, it's from 2014.

Can I put this into my /etc/systemd/system directory as a bitcoind.service startscript and enable it? Or do I have to configure something extra?

This what the source code of the script looks like in Sept 2017:

[Unit]
Description=Bitcoin's distributed currency daemon
After=network.target

[Service]
User=bitcoin
Group=bitcoin

Type=forking
PIDFile=/var/lib/bitcoind/bitcoind.pid
ExecStart=/usr/bin/bitcoind -daemon -pid=/var/lib/bitcoind/bitcoind.pid \
-conf=/etc/bitcoin/bitcoin.conf -datadir=/var/lib/bitcoind -disablewallet

Restart=always
PrivateTmp=true
TimeoutStopSec=60s
TimeoutStartSec=2s
StartLimitInterval=120s
StartLimitBurst=5

[Install]
WantedBy=multi-user.target

The script mentions a config-file -conf=/etc/bitcoin/bitcoin.conf - but I'm on Ubuntu/Debian, and the bitcoind package does not create a /etc/bitcoin/bitcoin.conf file.

What should I put it in there? Or should I leave it empty?

(I've already read this related question: Newbie question, bitcoind installation doubte )

Ahh there is already a pull request from June 2017 discussing various topics:

https://github.com/bitcoin/bitcoin/pull/10529/files

They propose, for instance, to rename /etc/bitcoin to /etc/bitcoind, for consistency reasons.


texts: On a practical level, how exactly is the amount of a Bitcoin transaction fee determined?

texts:
Yes, I know that you can actually set the transaction fee to anything you want, but I'm of course talking about a transaction which will actually be "processed" in a reasonable timeframe, "reasonable" being "what the average person would accept".
I've been working for a long time now on a service which exclusively supports Bitcoin for payments. I'm afraid that somebody who is supposed to pay me the Bitcoin amount of $5 USD will feel appalled at the very notion of paying another $5 in Bitcoin just to send my service that actual $5.
I've done numerous Bitcoin transactions, but it has varied wildly in the amount. I can't really figure out how Bitcoin Core is deciding on the amount. (I've never changed it in.)
I'm aware of these "side-chains", but I don't understand how I'm supposed to actually use them in practice. Introducing a bunch of requirements and extra complexity seems even worse than having people "bite the bullet" with large fees (compared to the amount sent).
You might say that I should be having them "deposit" Bitcoin and then hold it on my side, but due to the way that this service is constructed technically, as well as the expected usage pattern, such an "account" cannot be made; they have to get an "invoice" for each time they purchase something, with a unique Bitcoin receive address to which they send the amount. Again, the problem is that I fear that the transaction fees will put people off.
In general, how should I handle this?


texts: Bitfinex - Market order that uses all available

texts:
When calling the New Order Rest API (V1) to do a Buy order I get an error saying that I have insufficient funds. This is due to the fact that the price has changed off the original calculation.  When doing a Sell one can set the use_all_available which will "post an order that will use all of your available balance." See: https://docs.bitfinex.com/v1/reference#rest-auth-new-order

I'm looking for equivalent functionality which will: Take all the balance you have in a given Symbol (i.e. LTC) and buy as much as you can with it.

Does anyone know if there is something like this or if there's a work around?
My current work around is to recalculate amount again.

Thanks :)


texts: Can quantum computing improve Bitcoin mining?

texts: Would a D-Wave 2 with 512 qbits be faster than the fastest ASIC when mining bitcoins?


texts: Is there any testnet faucet site that sends out to bech32?

texts: I am writing a wallet for the far future and I am planning to completely drop the support for receiving to P2PKH addresses. I don't want to add P2SH over P2WPKH either.


texts: Decrypting BitcoinJ/MultiBit key (scrypt/aes-256) from protobuf with NodeJS

texts:
I'm trying to decrypt an encrypted private key from an encrypted Multibit Classic .wallet file but the resulting public key / wif doesn't match the original.

Here is my code:

'use strict'
var fs = require('fs')
var crypto = require('crypto')
var scrypt = require('scrypt')
var protobuf = require('protobufjs')
var bitcore = require('bitcore-lib')
var network = bitcore.Networks.livenet

function parseWallet (wallet, cb) {
  protobuf.load('bitcoin.proto', function (err, root) {
  if (err) cb(err, null)

  var buffer = fs.readFileSync(wallet)
  var walletMessage = root.lookup('wallet.Wallet')
  var message = walletMessage.decode(buffer)
  console.log('protobuf:', JSON.stringify(message, 0, 1))

  message.key.forEach(function (k) {
    var res = {}
    var address = new bitcore.PublicKey(k.publicKey.toString('hex'))

    res.encryptionType = message.encryptionType
    res.pubkey = address.toAddress(network).toString()
    res.iv = k.encryptedPrivateKey.initialisationVector
    res.salt = message.encryptionParameters.salt
    res.encryptedPrivateKey = k.encryptedPrivateKey.encryptedPrivateKey

    cb(null, res)
    })
    // var message = walletMessage.decode(buffer)
  })
}

parseWallet('dev.wallet', function (err, res) {
  if (err) throw err

  console.log('parsed:', res)
  var passphrase = new Buffer('dev123456')
  var scryptParams = {N: 16384, r: 8, p: 1}
  var derivedKeySize = 32
  var derivedKey = scrypt.hashSync(passphrase, scryptParams, derivedKeySize, res.salt)
  var decipher = crypto.createDecipheriv('aes-256-cbc', derivedKey, res.iv)
  var decryptedPrivateKey = decipher.update(res.encryptedPrivateKey)

  var privateKey = new bitcore.PrivateKey(decryptedPrivateKey.toString('hex'))
  var publicKey = privateKey.toPublicKey()
  var address = publicKey.toAddress()

  var output = {}
  output.decryptedPrivateKey = decryptedPrivateKey.toString('hex')
  output.pubKey = address.toString()
  console.log('output:', JSON.stringify(output, 0, 0))
})

The public key / private key doesn't match after the decryption. I suspect that I'm missing something about encoding and I would appreciate any help.

protobuf: {
 "networkIdentifier": "org.bitcoin.production",
 "lastSeenBlockHash": "AAAAAAAAAAAzUIO4ArpXPqbCZNnaltVmjJsWob3cLb4=",
 "key": [
  {
   "encryptedPrivateKey": {
    "initialisationVector": "CiKlKV+J1LhmMZWtiPHJKA==",
    "encryptedPrivateKey": "0C7HTASrcjsvPHxZE5OLr2MS4oFdfEC4BID81WH+prFhUunkQNb8itg4vimaBln5"
   },
   "publicKey": "AqrhHqufQRw63h4EDHK7ylZlWktTZxANdPpGun6JKwsO",
   "creationTimestamp": "1486547219000"
  }
 ],
 "encryptionType": "ENCRYPTED_SCRYPT_AES",
 "encryptionParameters": {
  "salt": "J7kt6NuBTIo="
 },
 "majorVersion": 2,
 "extension": [
  {
   "id": "org.multibit.walletProtect.2",
   "data": "AA==",
   "mandatory": true
  }
 ]
}

parsed: { encryptionType: 2,
  pubkey: '1MWq1EiwYh79GHu9PLnVBuPQu66Fs2ph6Z',
  iv: <Buffer 0a 22 a5 29 5f 89 d4 b8 66 31 95 ad 88 f1 c9 28>,
  salt: <Buffer 27 b9 2d e8 db 81 4c 8a>,
  encryptedPrivateKey: <Buffer d0 2e c7 4c 04 ab 72 3b 2f 3c 7c 59 13 93 8b af 63 12 e2 81 5d 7c 40 b8 04 80 fc d5 61 fe a6 b1 61 52 e9 e4 40 d6 fc 8a d8 38 be 29 9a 06 59 f9> }

output: {"decryptedPrivateKey":"ae0ee2bacc68e3f67dce176a99663ced485885a45f685208794c5356c7795a25","pubKey":"1By9rGSNZDMXCv8iSaZF5BpiMnpZKx5k4e"}


texts: Balance zero after recovering wallet from seed-phrase

texts:
I recently got help my some experts on how i can recover my wallet using my private key, so i went ahead and downloaded brd wallet and block chain, then proceeded to recover wallet in the first and recover funds in the latter, but both brought up my account with zero funds in it.

I am a bit confused and worried now as i just made that payment i dont know how i can go about it, and secondly if i get the Qr code of my old wallet and i scan it into blockchain addresses and it comes up as non- spendable, and i am being told to scan my private key if i have it in written how can i go about unlocking that...

Original question: I forgot which software I created my wallet with. How can I recover from a 12 word seed phrase?,


texts: Why does it take so long to initially sync with my bitcoin wallet?

texts:
I have downloaded the bitcoin software and I am starting it up for the first time.

However, it begins to download the entire transaction history, which takes a huge amount of time (for some reason). I thought it was my connection in the beginning, but even when I arrived home with a relatively good connection (I can download 1.5MBps without disconnections, and a good latency), it still takes very very long (It's been up for 2 whole nights, and it's not even past 50%. Either the size of it is over 500 GB (which isn't likely), or something is wrong.

Did anyone else experience the problem? Is it even a problem? (or is their server not that good?).


texts:
i'm solo mining but it just doesnt feel right that i don't get any accepts while solo mining.

is this right? (see picture below; the top pool with the blacked out adress)

settings:

bfgminer options: -S all -c /opt/minepeon/etc/miner.conf --no-longpoll --coinbase-addr 1NCWZT4hbfPw5LMpPsPauXYdVB9LYKrZM7 --icarus-options 115200:1:1 --icarus-timing 3.0=100


texts:
Example for 'pay-to-pubkey-hash' is quoted in Wiki bitcoin script.
I have a doubt that 14 is for bytes to push. But the data to push is 20 bytes.
Please anyone could explain to me?

Script:

76 --> OP_DUP
A9 --> OP_HASH160
14 --> Bytes to push

89 AB CD EF AB BA AB BA AB BA AB BA AB BA AB BA AB BA AB BA --> Data to push

88 --> OP_EQUALVERIFY
AC --> OP_CHECKSIG


texts: How to check a bitcoin account from a dead person

texts:
My father in law died 4 months ago.
On the tablet of my mother in law we noticed he had invested in bitcoins.
How can we check this still exist/that this is real?
Does he have a customernumber or how can I check this?

thank you in advance

Best Regards


texts: Can malicious payer deanonymize payee in Zcash?

texts:
Looking at both the Zcash original paper and the updated Zcash protocol specification, it seems that after Alice paid Bob, she can reveal to the world that she did so.

Alice can do so by revealing the randomness of the new coin commitments she generated, one of which contains Bob's PK and the amount. For example, in the image below, Alice reveals the elements highlighted in red (i.e., Alice's randomness) and purple (i.e., Bob's PK and the value), while the elements in yellow are already public.

The same attack works in the updated Zcash proposal (see Section 4.4 on page 19 in v2018-beta2.0, plus image below).

I just want to confirm that (1) I am not missing anything and this is possible and (2) it's potentially problematic. For example, if Alice paid Bob for some illicit goods or services, she can later reveal that she did so.

Thoughts would be welcome!


texts:
I keep getting this error message after running 'make' or 'make check':
Making check in src
  CXXLD    bitcoind
Undefined symbols for architecture x86_64:
  "__ZN2Db6verifyEPKcS1_PSoj", referenced from:
      __ZN16BerkeleyDatabase6VerifyER13bilingual_str in libbitcoin_wallet.a(libbitcoin_wallet_a-bdb.o)
  "__ZN5boost10filesystem4path5imbueERKSt6locale", referenced from:
      __Z16SetupEnvironmentv in libbitcoin_util.a(libbitcoin_util_a-system.o)
ld: symbol(s) not found for architecture x86_64
collect2: error: ld returned 1 exit status
make[2]: *** [bitcoind] Error 1
make[1]: *** [check-recursive] Error 1
make: *** [check-recursive] Error 1

Any ideas on how to fix it?


texts: How do exchanges set their transaction fees?

texts:
I was reading on the Bitcoin wiki (https://en.bitcoin.it/wiki/Transaction_fees
) that a user can set his own fees when conducting a bitcoin transaction.  Like many, I have a Coinbase account, but I don't see anywhere in there where I can set the transaction fee.  Is this something the exchanges come up with?  How do they figure out what transaction fee to propose so that the transaction will be accepted by miners?


texts: Does the entire blockchain have to be recomputed to validate a transaction?

texts:
Are transactions validated by recomputing the entire blockchain? If not, how else can it be confirmed that a bitcoin I'm attempting to transact is one that I actually had come into acquisition of previously and still have?

If yes on the other hand, how long does that recomputation typically take in practice, and does that pose a scalability risk in the potential for Bitcoin usage (and hence the length of the blockchain) to outpace Moore's law?


texts: Is the transactions in one block effect the hash of the next block? How?

texts:
What I understand about blockchain is that:
Blocks are secured by the hash.
Transactions are secured by the markle-tree.

What i'm asking is, does the contents -transactions- of one block effect the hash of the next block? if so, how it happens?

If not, doesn't this mean that we can manipulate the transactions inside a block? because if we do so, the next block will have no idea what happens the previous block.

For example, lets say that we mined 10 blocks.

Then, we hacked block number 5 and changed the transactions.

How is this going to effect blocks number 6, 7,....?

I understand that if the majority of the nodes have the same values then the blockchain will be safe.

But what about a small blockchain owned by one node. In theory, does this mean that the block contents can be manipulated very easily?

Thank you


texts: In Proof-of-Stake, can the same miner mine a block multiple times in a row?

texts:
In Proof-of-Work, there are no rules on who will mine the next block - the selection is random and proportional to miners' computing power.

How is the next miner selected in various Proof-of-Stake block creation algorithms? Can the same miner / address / person be chosen to create multiple blocks in a row, or are there some mechanisms preventing this from happening?


texts:
As i was going through my twitter timeline, I saw some post this on his timeline with an emoticon of a two eyes

The old Darth Maul wick $link

I quickly understand it must be a candle or a candle chart or chart pattern.
I don't really understand what he means, and have tried to surf the web for answers but nothing good is coming from there.
My question is what does the "The old Darth Maul wick" means


texts: Understanding private keys, public keys, adresses and transactions

texts:
I need some claryfication about the things, here it goes:
1. For what I've read, for generate a bitcoin address is following this flow:(General speaking) Private Key (SK) -> Public Key (PK) -> Address (A). Some say that SK -> PK == A. Which one is correct?
2. Now, in a transaction when X to Y of "n" bitcoins happens this: X signs (digitally) the transaction "t" with its SK and this the part that I don't get it. How "Y" does to open and verify that the transaction was send from X? or besides that X signs the transaction he encrypts? the transaction again with the PK/A of Y for Y can open it? There's something that I missing?

Note that my native language it's not english and it's hard for me to understand this complex topic.

Thanks in advance


texts:
I heard stories of people on the Web making money with Bitcoins. I heard the term "mining", with bitcoin mining, but I don't really know how it works.

Can someone explain to me the process and what equipement I need to do this?

i just want to make a few hundred bicks/months, steady, and I know that some people deal with Bitcoins and similar virtual currencies.


texts:
I am a gamer who simply uses his rig to mine when idle. A year ago I was getting 0.5 Ghs using a Radeon HD7970 3072MB 384bit OC Boost, then due to a technical issue I stopped mining for a few months and eventually replaced the Radeon with GeForce GTX770 4096MB 256bit OC...

On which I am currently getting a consistent 126Mhs.

What follows may be a dumb question, but did anything change (eg some network property), that would explain a much lower hashrate on a better card? Or is there something wrong with my setup?

I'm using: BTCGuild and BitMinter, GUIMiner, Win7


texts: I cannot see the expected OP_CODE in transactions

texts:
According to different answers on this site the format of the standard TX claim script should be [OP_PUSH DER(R+S)+HashType OP_PUSH PubKey]

The OP_PUSH code is 4C, 4D or 4E depending on push length.

However in this transaction I cannot see the expected code. I could not even find the definition of the one there:
https://blockchain.info/rawtx/db320e85d8bef3895052d9bf002aeb185fa12eeef8445e3e45f31b9a0c90f9f6?format=hex

01 00 00 00 is txin index, 8C is the scriptin length and then comes 49.
Instead of 49 I would expect 4C.

Is it because you can leave out the OP_CODEs or what am I missing?


texts:
Is there a list of problematic blocks? I mean blocks in official blockchain that may cause carelessly written bitcoin client to stuck after receiving them? Can you provide a link for further reading about different type of such blocks and ways to cope with them?

Note: The most similar question I found is Is there a listing of strange or unusual scripts found in transactions?


texts: Is there a visualisation tool for discarded block chains in Bitcoin?

texts:
A lot of papers about cryptocurrencies explain the concept of the "longest chain", which goes along with these kind of figures:

I was wondering if there exist any kind of visualisation tool for these kind of discarded block chains within Bitcoin itself? There are a lot of visualisations available for transactions, but I'm interested in the amount of block chains that did not make it into the final blockchain (blocks that were discarded because they were no longer the longest chain).


texts: How to handle return address Output field using bitcoin bip 70?

texts:
More specifically, how do I derive the return address from the Output field in a protocol buffer Payment object?

I can convert the serialized byte string from the 'script' field of the Output into a 25 character scriptPubKey but I'm stuck as to where to go from here?

Any help greatly appreciated :)


texts:
I am having a tough time in understanding how Bitcoin payment verification works:

How is Merkle tree related to Bitcoin blocks?
Had Merkle tree not been there, what would have been the problem?


texts: Is there an alternative to salvagewallet that keeps account info?

texts:
I am using the accounts feature of bitcoind , if a wallet gets corrupted and bitcoind is started with -salvagewallet then the account information is lost.

So, is there any built in feature that will rebuilt also my accounts ?


texts: Public mining pool account w private access

texts:
I have several systems available that i would like to use to mine to a pool account. The problem is that other people have access to these machines and i dont want them to get my password from the config file, log into my account on the pool server and be able to change the destination of the found coins to their wallet.

What is the best solution for this?

The two that i can think of are if there is a pool that does not require a password to contribute the hashes, or setting up my own pool server that does that but this sounds more complicated.


texts: What was the last life sign of Satoshi Nakamoto?

texts:
I heard that the name may be a pseudonym and that very little is known about the initiator of bitcoin. Also it seems that he has stopped working on the main client.

When was his last verifiable life sign? Did he ever mention or announce his retirement?


texts: I need details explaination about " BLOCKCHAIN BITCOIN ADDER BOT"

texts:
I saw this file titled "
BLOCKCHAIN BITCOIN ADDER" on facebook and i tried to follow the process by importing the wallet that was given. On doing that I received a lots of bitcoin that i never dream i can earn. At the end of the file the private key was given without the password. Payment was asked in order to give the password. As per me i don't have upto 2dollar worth of bitcoin not to talk of the 20 dollar that was asking.

I want to know if this method of earning of bitcoin is possible. More than 3BTC is sucked in blockchain wallet. Another curiosity is that payment is keeping on entering the wallet. There is no day i won't received a payment to the wallet.

Is this possible, real and genuine  ? Is it possible to get the password? If not, how can I remove those balances from my account?

Thank


texts: Can you really trust a non-open-source desktop wallet?

texts:
I am a newbie in the crypto markets, but as a software engineer, it seems to me that a huge security vulnerability could be choosing a wrong wallet.
If you are using a hot wallet, and can't see the app code, doesn't that mean it is theoretically possible for the devs to steal your crypto, even if you can see your private key?
Shouldn't everyone be using exclusively open-sourced wallets for this reason?


texts: How does blockchain.info determine when a payment is received?

texts:
Can anyone help me understand how their payment API works at a bitcoind rpc level?  As far as I can tell, there is no way to see what the balance of an address is, only the number of bitcoins that address has received along with the confirmations for it.

If I were to replicate the blockchain API, i would have to:

create an address and associated it to an account (destination address)
check the balance of all accounts
get a list of all addresses in that account
check all the addresses looking for the lowest confirmations

if value < balance loop back to ensure to check other addresses

locate callback and call that
move btcs from account to destination address
repeat

Is it really that convoluted or am I missing something much simpler?  I currently run a website that processes BTC payments but i'd like to move away from relying on blockchain.info.


texts:
"Your Open Orders" in MtGox lists all of our orders. However, some orders are not open. I sometimes see them as pending.

The HTTPv1 API states that there are 6 possible statuses:

pending
executing
post-pending
open
stop
invalid

What do these statuses mean?


texts: How Segwit makes transactions smaller? What about the witness?

texts:
I have seen similar questions without a clear answer. So, how does Segregated Witness make transactions smaller? I understand it removes data from the transaction hash and solves malleability ... But it adds a field called "witness", so, how does this save space?

Also (this is related and helps understand the question), how is block size calculated? Does it include the witness?


texts: Does adding more miners create more bitcoin?

texts:
I was on another forum and the claim was made that the miners using new technology GPUs are flooding in and because of this there will be more bitcoin produced.  My understanding of block rewards is it's like a horserace between miners (or group of miners) to solve the blocks and the 1st to solve gets all of the reward.
Who is correct?


texts:
I tried doing it using bitcoin-qt but it wouldn't let me. Is this to avoid blockchain spam?

What clients would allow me to send that amount?

Will I have to pay fee if I send such a small amount?


texts: Must I have an account with every gateway I use as an issuer?

texts:
In the Ripple Client, in order to convert to BTC, I need to select a Base Currency (it currently says BTC ???.)

I searched for a Base Currency Issuer address and found how to grant trust to BitStamp, which lists what is supposedly BitStamp's address.  I realize, however, that I cannot trust this address because it comes from http://www.nofiatcoin.com/ instead of https://www.bitstamp.net/.

I assume BitStamp requires signing up for an account before showing an address.

Is having an account just BitStamp's policy? Say I had a secure way of getting BitStamp's address without signing up for an account and I added this address as a BTC issuer. Couldn't I just buy/sell BitStamp-IOU's over the Ripple Network, even without an account at BitStamp? If so, why would BitStamp only divulge its issuer address if the user has an account?


texts: Amount of block locator hashes in "getblocks" message

texts: How many block locator hashes are sent in a getblocks message? And how distant are these locator hashes from one another?


texts:
I'm using an alt coin.

The wallet would not sync so I deleted the blkindex.dat file to restart the download. I restarted the wallet client and it downloaded all the blocks, but all my coins are gone. Using a block explorer and it says the address does not exist on the network. On the transactions, all the transaction statuses show as unconfirmed.

Is it possible to get my coins back? What caused this to happen?


texts: how do I mark coins spent in invalid blocks as unspent?

texts: I was just testing bitcoin (v17) in regtest mode with the local, built-in wallet. If I send money to an address (I don't own), generate 1, and then invalidate that block, the local wallet does not mark the coin spent in the invalid block as unspent. It keeps it in the spent state. Rolling back further, generating more blocks on a different chain, and rescaning the transactions doesn't seem to mark that money as unspent again. How do I respend my coin when it was spent in an invalid chain? From the local wallet CLI, is there a way to mark things as unspent?


texts: Why is the block reward slightly higher than what it should be?

texts:
https://blockchain.info/block-index/143685

The block reward here is 50.04 BTC instead of 50. Why is this so? I notice many blocks have this slight excess.


texts: Dragonmint T1, cannot find on network anymore (AngryIP Scanner) + NO SDCARD SLOT

texts: I was using Braiins OS for a while, but couldn't get the voltages to settle down no matter what I did, so I went to Braiins OS website and noticed they would no longer be supporting the DM-T1, so I decided to revert via ssh, and upon reboot it never came back online. I've tried hard resets. I've been given instructions by BraiinsOS via email on how to restore it via ssh because it's the NO SDCARD version, and cannot find it anymore. Even with Angry IP scanning for dead hosts, I can find my L3plusplus that's unpowered, but cannot find any, let alone any with port 22 open. I've even tried rigging my arduino with an mp3 player shield, which has an sdcard slot, to try to reflash it. I did manage to hook into it with a USB to TTL adapter I used before to unbrick my Linksys router, but being able to make use of it is outside my scope. I did get the hash control board to light up with that method, showing a valid connection, but I have no idea what if any options that presents. I should probably just give up and buy a new board, or newer machine, but always enjoy fixing things as opposed to giving up. Any help would be appreciated. It's been down since before the halving, so I've lost more than it's worth worrying about at this point.


texts: Why is wallet.dat BerkeleyDB instead of LevelDB?

texts:
Why wasn't wallet.dat migrated to LevelDB?

Is it because

BerkeleyDB is better at [something]
Backwards compatibility


texts: What has a lower long term cost per hash: LTC, BTC or other alt coin?

texts:
I'm trying to understand the cost per hash operation with Litecoin vs Bitcoin over time.  The theory is that the network that has the best prospects for long-term security (via hashing) will set a standard that may influence its own price.

Specifically I'd like to compare

Capital outlays (reasonable mining hardware ASIC vs GPU)
OPEX (Electrical, etc)

Suppose I were to compare BTC/Litecoin mining to ore mining.  Once the ore is extracted and purified, no more cost is needed other than to secure the facility where the gold is stored.

Its clear the mining process is technology dependent (ASIC vs GPU).  What isn't clear to me is once the technology matures, what approach has a greater chance for long term efficiency for maintaining and securing the network.

I suspect that the scrypt -vs- sha256 implementations will have different power requirements, and I'd like to understand which one is "greener" for the environment in the long haul.

Any information relating to

Cost of current mining rigs to power efficiency
Cost of future mining rigs and projected efficiency

Would be very interesting.


texts:
I have several wallets on blockchain.info

My problem is that when I log in to my wallet the id of one of the wallets appears automatically and I can't type the data in of the other wallets.

How can I operate several wallets from the same browser (not simultaneously though)?

Can anyone help?


texts: could trezor be used to store passwords like 1 pass?

texts:
I'm wondering if trezor be used to store password(s) like you do with 1pass?
If not, is it something you'd contemplate in developing?

Thank you


texts: Bitcoin-core restored HD wallet reusing payment address?

texts: As I was testing my new bitcoin core HD wallet through the bitcoin-qt interface (v0.13.0), when using Receive > Request payment I realized that I was presented with the a payment address which had already been used (despite the checkbox Reuse an existing address not being checked). Looking more closely into this, it seems that this happens if you restore your HD wallet from a backup file (specifically delete your wallet.dat file and replace it by the wallet.dat which you had saved just after creating your new wallet and encrypting it). So it seems if you need to restore an HD wallet from an old backup file, it will be reusing prior addresses (unless you are being careful and click on Request payment several times until you obtain a brand new address). Is this a known feature of bitcoin-qt? I am guessing this is not a desirable behavior, but is it avoidable? I am not sure HD wallets can be implemented without it, as we no longer simply randomly generate.


texts: Broblem for wallet blockchain privet key

texts:
When I want to convert btc from my wallet blockchain, they ask me to enter my private-key. When I enter it, I am asked to enter the password for the private-key. I do not know the password for private-key.

Is there a solution?


texts:
I am intrigued by this Bitcoin Script Language, I want to learn how to program Bitcoin with it.
Any idea where I can, find some documentation to read/practice  with ?


texts: Can I use Bitcoin mining as a data furnace to heat my home?

texts:
One of the waste products from Bitcoin mining is the heat that is given off by the GPUs. On cold days could this excess heat be used to warm a home, essentially creating a data furnace? When it gets warmer then the rig can be optionally shut down.

As I understand it, the income generated from mining bitcoins at least pays for the electricity so long as you have a rig that is capable of meeting the difficulty. This would therefore imply that so long as you have already got a suitable rig lying around the house (e.g. for gaming) then running it up during the day would be useful. If the house also had solar panels then that would also benefit the earning potential.

Are there any calculations available to support/refute this?


texts: How do I find out the reward value of a generated block

texts: Using the bitcoin client's JSON API (or any other altcoin client) how do I find out the reward given for finding that block?


texts:
I have tried reaching out for assistance in other Bitcoin forums, to no avail as apparently I have bought miner hardware that is not supported by the people who are responsible for CGMiner software.  While I respect that, I am struggling with support on my kit and I would really appreciate some assistance if possible.

I have a WhatsMiner M3 that runs CGMiner 4.9.2.  When it arrived, I switched it on and it had 3 mining pools already configured from the factory.  It looked like CGMiner was running and it was mining.  The device became very hot, 83 degrees I think it was and then the screaming fans seemed to slow down to a crawl.  Within a few minutes the device had cooled down significantly and the fans sped back up to full speed.  I changed the pool settings from factory to the pool information using my chosen pool and worker name for the device.  I then restarted CGMiner but it would not restart.  I then rebooted the box too but that made no difference.  The device does not get hot at all currently.

At that point I only had 1 pool setup, so I added in 3 just to be sure and tried restarting CGMiner but it still didn't work.  The power supply is fine, and the device itself seems fine and I get get into the web interface as well as connect to the device via SSH.  The only visual feedback I have is from the device overview page which gives me the following error:

EventCode: E011
EventCause: Slot-0 Zero HS 4500 Seconds
EventAction: Zero HS Warning
EventCount: 6
LastTime: Thu Dec 7 12:59:42 2017
EventSource: system-monitor

Please see these images, they describe what I am seeing:

1) The device overview where it shows that CGMiner is waiting to start:  https://drive.google.com/open?id=1c6N1YvdUHrC6pYo0L3aaPgZhwes3AP4i

2) The pool settings:  https://drive.google.com/open?id=1m0uYPcc_o-T_I2ZQ8G3M6qDk_wUVgX-2

3) The device status I get when I try start CGMiner vis SSH:  https://drive.google.com/open?id=1OHxwqlqoFGfer6qyv8VuRkrimXWtI7O6

4) The event code error as described above:  https://drive.google.com/open?id=1aYE0-RhxfB-W-eGx2AW0XKh64cvIBReQ

My concern is that the initial run where it got up to 83 degrees has broken the miner, because it doesn't get hot at all currently.  Also, because CGMiner will not start, the device shows no system status information, I cannot see temperature info, I can't see if the hashboards are okay, I can't tell at all where the proble lies.  Please could I ask someone to assist me with figuring out what it wrong with this device?  I have looked at the logs but I cannot make sense of the logs as I do not know what I am looking for.

Thank you for any assistance.


texts: When I use the "send_many()" function in the blockchain.info api, have I to pay the fee only once or for each?

texts:
The blockchain.info api looks like this:

The link is: https://github.com/blockchain/api-v1-client-python/blob/master/docs/wallet.md

But when I give a fee like this:

add={'address1':amount1,'address2':amount2}
fee=5000
pay = wallet.send_many(recipients=add,fee=fee)

Will it then be 10000 (two times 5000) or will it be 5000?

Thanks for the answers.


texts:
I am trying to create a transaction on the bitcoin testnet, using bitcore:

Error Message :

  SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data

Here is my code:

var transaction = new bitcore.Transaction()
.from({"address":"msxGdsTJJYu7YrmkV4sbHNK8Z21pHFZ2gX","txid":"0c0d9ad92f07e774a76194823a92bf2521aa57381ad4782becf20fdf385e1922","vout":0,"scriptPubKey":"76a914886b382436985b195d1dfcdb00c722c1f2fcd0ea88ac","amount":0.01})
.to('mjsVogqLetdUjT9raJY6WgYmy3tifJ3DJz', 20000)
.sign('0497427ad1b6177fe950758f10151ba38a6b38d44577ba45fb06423143bb55a2')
.change('mhCpGNNHQmu4P9pUZcCmgXkxbYxys5pKBw')

<Transaction: 010000000122195e38df0ff2ec2b78d41a3857aa2125bf923a829461a774e7072fd99a0d0c0000000000ffffffff02204e0000000000001976a9142fc320597ba67a66167721bc9c36d987e03c225b88ac10cd0e00000000001976a91412820fdb8340e5198b3c31de5688faa7927b0d7188ac00000000>

transaction.serialize()
010000000122195e38df0ff2ec2b78d41a3857aa2125bf923a829461a774e7072fd99a0d0c0000000000ffffffff02204e0000000000001976a9142fc320597ba67a66167721bc9c36d987e03c225b88ac10cd0e00000000001976a91412820fdb8340e5198b3c31de5688faa7927b0d7188ac00000000

>> var Insight = require('bitcore-explorers')
[object Object]
>> var client = new Insight.Insight()
[object Object]
>> client.broadcast(transaction, function(err, txId) { console.log('Id:', txId, err);})
undefined
Id: undefined SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data

When I try to broadcast this transaction using BlockCypher, the error message is :

  Error validating transaction: Rejected script for input 0 referencing 0c0d9ad92f07e774a76194823a92bf2521aa57381ad4782becf20fdf385e1922 at 0.

Any help is highly appreciated!


texts: How do I open up the transaction dialog popup in Ardor Ignis via the URL parameters when the wallet gui loads in the browser?

texts: I'm able to get to open up the wallet gui via the browser and go straight to the asset page, but how do I open up a transaction popup?


texts: Comparison between Bitcoin and other currencies

texts: I am doing a research about comparison between Bitcoin, Litecoin and Ripple (I am thinking about change it to Dogecoin). One of the comparison criteria is privacy. I need some information about that, for example about encryption algorithms that are used in each currency, any help please?


texts: Does an exchange of only virtual currencies fall under FinCEN regulations?

texts: If a business only exchanges between say bitcoin, litecoin and namecoin. No fiat currencies. Does it still fall under finCEN's regulations?


texts:
I would like to print qr-code with transaction that contains my home address to print it for my dog's necklace. If dog will get lost everyone can scan it and get the address.
How can I prepare the transaction?


texts: What were the main technological reasons that Bitcoin Cash did not want to adopt SegWit?

texts: What are the key risks/drawbacks to SegWit and why did the Bitcoin Cash community conduct a risky hard fork to avoid it?


texts: Where can I find a graph of the current size of mining pools?

texts: Where can I find a graph of the estimated size of each mining pool relative to the overall hashrate of the entire bitcoin network?


texts: What is a Finney attack? Extra points for explaining its purpose, the prerequisites for it to be possible, how the attack can be performed and the origin of the name "Finney attack".


texts:
I am very new to bitcoin mining and am unsure if I set up GUIMiner correctly. I have a new MacBook Pro with a discrete graphics card (ATI Radeon R9 M370X) and am getting about 129 Mhash/s according to GUIMiner. However, it says "Shares: 0 accepted" in the bottom left side of the window. How long does it take for shares to accumulate? Did I set something up wrong? It has been running for about 3.5 hours.

Thanks!


texts: Why has Intersango stopped accepting UK bank transfers?

texts:
http://www.reddit.com/r/Bitcoin/comments/ztjcf/intersango_no_longer_accepting_uk_bank_transfers/

  I hadn't been on the site in a while, but last night I sent £30 to
  Intersango, only to find out today that they no longer accept
  transfers. Have opened a ticket with them but am a bit worried that my
  money will be lost in the ether!

Was the a formal announcement? Do they expect bank transfers to resume?

What's the deal?


texts: How to create a Bech32 address from a public key?

texts: What are the steps to create a Bech32 address from an ECDSA public key? Bitcoin wiki has a nice step-by-step guide to create an address from a public key but what about Bech32 addresses? I've read BIP173 but I don't understand what to give as an input.


texts:
The Bitcoin TestNet is a network identical to Bitcoin in every respect except that the bitcoins on it are worthless because no one accepts them in payment or values them for anything other than testing purposes.  In essence, TestNet btc are valuable because they are worthless, allowing for useful experimentation when developing.

I read somewhere that one way the TestNet can be prevented from acquiring significant value and mining power is by being reset from time to time so that TestNet btc remain easy to mine and acquire for testing purposes.  This made me curious--has this ever happened before?


texts: How can I enable RPC access debug log on my bitcoind. My application calls some commands to the bitcoind via RPC. I want to see all of RPC accesses with their parameters like command name and caller IP address as well if possible.


texts:
I was debugging my little project and I've found this pair of txs without fees (they caused an alarm):

[txId=e8f6f08430ab6b1f3e645f499cf90c69acf2eb8a8d9766abb9d76314f29209dd, fees=0, weight=879600], [txId=cf7ba67c57d72dc735c200f5bf81789f6464adf65816b7640562d38a8c706a05, fees=0, weight=16052]}

both in block 618858.

first one is very heavy (almost a quarter of a block).

just curiosity. Do I have to suppose that it's probably the miner the one who has auto-sent this tx?


texts: Difference between bitcoin and testnet, really

texts:
Other than what is listed in the wiki, what is the difference between the two networks?

Could you sell test Bitcoins for money if you could find someone willing to buy?

What would happen if you tried to send test Bitcoins to a 'real' account and vice versa?


texts: How does Bitcoin Core sort memory pool transactions by fee?

texts:
I'm trying to understand the algorithm Bitcoin Core uses to sort memory pool transactions by fee.

Gavin's fee rework proposal states:

  Next, sort all remaining memory pool transactions by fee-paid-per-kilobyte, and include as many as will fit until the block is maximum block size bytes big, not including "free" transactions (transactions with fee-per-kb of less than the default spam threshold of 0.0001 BTC/kilobyte).

This makes sense, because a miner should want to load a block with transactions carrying the most "fee density", or fee per byte.

However, reviewing the CreateNewBlock function in miner.cpp, it's not clear how Bitcoin Core accounts for transaction length when prioritizing memory pool items:

// Prioritise by fee once past the priority size or we run out of high-priority
// transactions:
if (!fSortedByFee &&
    ((nBlockSize + nTxSize >= nBlockPrioritySize) || !AllowFree(dPriority)))
{
    fSortedByFee = true;
    comparer = TxPriorityCompare(fSortedByFee);
    std::make_heap(vecPriority.begin(), vecPriority.end(), comparer);
}

TXPriorityCompare seems to just look at absolute fee:

public:
    TxPriorityCompare(bool _byFee) : byFee(_byFee) { }

    bool operator()(const TxPriority& a, const TxPriority& b)
    {
        if (byFee)
        {
            if (a.get<1>() == b.get<1>())
                return a.get<0>() < b.get<0>();
            return a.get<1>() < b.get<1>();
        }
        else
        {
            if (a.get<0>() == b.get<0>())
                return a.get<1>() < b.get<1>();
            return a.get<0>() < b.get<0>();
        }
    }
};

In other words, this looks like a sort on absolute transaction fee, not fee density. What am I missing?


texts:
I have checked the bitcoin marketcap charts on coinmarketcap.com. Looking at the charts I see time on the horizontal line and k, M and G on the vertical line.

What does G stand for?


texts: Is it possible to get bitcoin-cli without having to build all bitcoin source?

texts: I'd like to use the bitcoin client to examine some of the inner workings of bitcoin-qt (non-invasively, using gets and lists mostly). Is it possible to do this alongside the standard executable? I don't really want to download and build everything from source.


texts: transaction has received 0 confirmations past 24 hour

texts:
I have the following transactions that stays unconfirmed for the past 24 hour:
https://www.blockchain.com/btc/tx/4f52b345789e3fbdefd07842c7df993a3609047ee1fa51c1b3c53b863fc7dbfa
is there anything that i can do ?


texts: If you had the resources of a Nation-State, could you invalidate Bitcoin chain?

texts:
Scenario:
The financial 1% feel threatened by bitcoin. The United States Federal Reserve convinces the senate that bitcoins utility for terrorism and untraceable payments and will cause tremendous fincanial upheaval. In secret, DARPA sets out in a Manhattan Project scale endeavor to preserve the American dollar, and of course by extension, the American way.

Filled with patriotic zeal to "defeat the terrorists", with money flowing less like rivers and more like major oceanic currents, could someone with the resources of the Federal Government of the United States of America undermine the bitcoin blockchain to destroy the bitcoin market, and if they could, how best would they go about it?


texts: Is it normal to be asked for an advance fee on a withdrawal?

texts:
I was approached out of the blue being told that I was supposed to receive a sudden windfall, someone opened an automatic trading account in my name, or offered to invest in a lucrative mining contract. A while later, I'm being told that there are now "thousands of dollars" waiting to be claimed by me.
However, when I try to withdraw the money, the operator asks me for an "advance fee" or an "unlocking fee" so that they can pay me out my money.
That sounds fishy, what is going on? What should I do?

This is a canonical question for a frequently occurring line of questions. Please help by building out the answers on this topic and using this canonical question as a duplicate target for new instances of these questions. Related meta discussion: What's the best Q&A to promote to the canonical answer for “advance fee scam” questions?
Related:

Someone else created a wallet for me to use. Is this a scam?
How do I recover from a cryptocurrency scam?


texts:
I was thinking about which bitcoin block has the lowest numbered hash. What I mean by a hash as a number is that. For example, the number "1" has a lower hash than "2" in SHA256. Their values are 6b86b273ff34fce19d6b804eff5a3f5747ada4eaa22f1d49c01e52ddb7875b4b and d4735e3a265e16eee03f59718b9b5d03019c07d8b6c51f90da3a666eec13ab35. Which bitcoin block, as of me asking, has the lowest number?
To be clear, I mean by "lowest number" as the smallest hexadecimal hash. An example of a number would be block #651520 which is numbered 0000000000000000000d1f8cf49fe57d034214693cd7f7678abec20427355c82. Interestingly, the lower the number, the more work tends to be required to generate it.
I kind of like this question because the Bitcoin network is basically an extremely large SHA256 brute force machine. This hash would likely be from after the all time high in 2017 in price.


texts: I have a PSBT (in Base64 format) which I need to sign using GoLang, but I can't figure out which steps I need to do that. I found this but I'm not really confident with Bitcoin and Python, so I didn't fully understood the Signer Algorithm. What should I do?


texts: What happens when a gateway on the Ripple network defaults or simply vanishes? Do people that got their money from it lose that money, do other gateways honour the IOUs issued by that gateway still, or does something else happen?


texts: How do I run Separate Mining Devices With BFGMINER?

texts:
I have 2 devices plug into my computer.
The 1st device is the USB block erupter.
The 2nd device is the BFL machine.

When I run the BFGminer, I only want one device to mine at one pool and the other device to mine at another pool?

How do I do that using BFGminer?


texts:
Some people recommended that I leave my Bitcoin client open because it helps the network.

Apart from the security implications, why should I do this? I thought that miners were the ones responsible for validating transactions and including them in the blockchain. What role does the Bitcoin client play in the network?


texts: Spending bitcoins - what happens to the change left in your address?

texts:
How do I manage my wallet and addresses when spending bitcoins?

For example, let's say I have address abcdefgh, and I have 10 Euros there. I read that when I buy something worth say 4 euros in bitcoins, I must then spend the rest on another unused address, zyxcvbnm, as the first address becomes unsafe or the change is lost in mining fees or something. It this true? Are all spends a double spend? For example, once for the item you want and once to your savings address?


texts:
I'm learning about BC mining from a developmental level and I'm reading about how a pool delegates shares based on work, but it doesn't explain why the miner who finally finds the correct hash can't steal it from the pool - "turn it in" so to speak (I haven't learned how turning it in works yet, I should mention)

What prevents a pool miner from stealing the block if they find the solution?


texts: Using CLTV can I freeze some funds from a wallet, and make them available, in a single transaction?

texts:
For my scenarios, I want freeze some funds from my wallet for some given time/block and then make that amount spendable in a single transaction.

As I understand so far, I can do it using 2 transactions with CheckLockTimeVerify (CLTV) op_code as follows:

Create a transaction with an output that has the CLTV op_code to freeze some funds from the input(s).
Then create another transaction which uses the above output as the input. The output of this transaction will transfer the funds back to my wallet. The nLockTime of this transaction will be set to the expire time of the previous transaction.

But is there a way to do the same as above in a single transaction? As in create a transaction whose output has CLTV op_code but is a pubkeyhash back to my wallet. This way the frozen coins become spendable without having to create another transaction?


texts: Is it possible to use BitGo's wallet with other software (Electrum or else), what is the used derivation path?

texts:
BitGo wallets are based on a 2-of-3 multi-signature, the end user have access to:
- Public key (xpub) of the 3rd signer (as the main wallet xpub)
- Native Segwit (Bech32), bc1... addresses to receive BTC assets
- Private key/seed (BIP39) of the 1st signer (and public key xpub as well)
- Private key/seed (BIP39) of the 2nd signer (and public key xpub as well)

Seeds can be converted to private key here, BitGo provide it's own recovery-tool (it's debug infos can be used to get the xpub keys of the first and second signer).
Public xpub keys can be converted to Zpub (p2wsh) here or with Electrum with the command ./electrum.AppImage convert_xkey 'xpub...' 'p2wsh' --offline (Electrum and xpub-converter uses those specs and derivations paths).
While it is possible to import the BitGo wallet into Electrum without error, Electrum never generate the same receiving address as BitGo, Following this and this bitcointalk's forum threads:
1. What is the derivation path used by BitGo Bitcoin wallet?
2. Is it possible to use BitGo wallet in any other software like Electrum or else?
Other related QA: 1, 2, 3, (note that I am using Bitgo's wallet through Bitwala)


texts: How can you distinguish the source of Bitcoins?

texts:
As reported on Tech Dirt here the address of where the bitcoins seized from SilkRoad are being stored has been identified here.

This has resulted in many people making micro payments to the wallet and attaching their own messages, I assume for the fun of it.

Can the original funds the FBI paid to their wallet still be distinguished from the total fund now in the wallet after the additional transactions from 3rd parties? I assume they kept a tally of how much they transferred in but for the purposes of evidence I imagine they would need to know the actual coins and not just an amount.


texts: What is protecting the mempool from being DDOSd?

texts:
The mempool currently seems to contain almost 60K unconfirmed transactions, and the number seems to be growing.
According to this question, it seems that unconfirmed transactions are eventually purged.

Other answers indicate that it is impractical to hamper the transactions of others to go through by trying to fill blocks with your own transactions. That question does however not mention problems that the nodes would face in having to deal with a too large number of transactions being passed around (without considering them being included in the block at all).

Would it be possible for a malicious user to send a lot of transactions (say from the same valid address) to the network, aiming to increase the size of the node mempools, and thus cause problems?
Has something like this happened?

Or does the purging happen fast enough, and are the unspent transactions small enough, for a growing mempool not to be a problem for the network nodes?
Are there any other common features implemented that protect against a bloating of the mempool?


texts: What's the point of trading BTC if you're limited in the things you can buy

texts: If you're trying to make a profit by trading BTC... fine, I get it. What other reasons are there to trade BTC?


texts:
Good day. Can you help me out regarding my question.

The company (legal entity) at the moment want to confirm the fact, tha certain BTC core wallet actually belongs to her. Though, i would like to clarify: can we refer to our Private key as to prove of ownership on wallet and on it's funds?


texts:
Is there a bitcoin robot that can automatically trade bitcoin for USD?

I see that bitcoin rates fluctuate every day and has different rates at different exchanges, and it could be easily traded like other currencies.

So, is there a bitcoin robot, similar like forex robots?


texts: Why is a GPU a better tool for bitcoin mining than a CPU and is an FPGA better than both?

texts:
I was looking into the best tools for bitcoin mining and found out that GPUs are a better tool for bitcoin mining than CPU's. What is the reason for this?

furthermore, I found dedicated chips that can only be used for bitcoin mining. How come that these relative small chips are far superior to the best intel/amd/Nvidia chips?


texts: I'm reading paper of Greg Maxwell's Confidential Transactions, I understand the example about Pederson commitment and Range Proof, which assume the amount is interger (example of proof amount range in [0, 32) ). What I can't figure out is  how commitment and Range Proof work when the amounts are expressed using "decimal floating point where the digits are multipiled by a base 10 exponent"(just as the paper mentioned). It's means the amounts is floating point number,like 2.3728BTC ? How can a floating number multiple a point in EC? I thinks there are something important I missed out. Could anybody explain or give a example here to make it clear?


texts: Is there a way to not pay the transaction fees when using the standard Bitcoin client?

texts:
I tried sending one satoshi (0.00000001 BTC) to one of my friend and the client always showed a dialog prompting me to pay 0.0005 BTC in fee, with the only options being OK (pay the fee) or cancel (cancel the transaction). The transaction was using one input and possiby two output (with how the clients jungle with the addresses).

I checked the option and the fee was at 0.00000000 BTC, but the client would not let me placed the transaction.


texts: What should I do if my friend runs a Bitcoin business but doesn't understand how it works?

texts:
My friend doesn't listen to his head of engineering and doesn't fully understand how decentralized consensus based systems like Bitcoin really work. He seems to think a new untested/buggy implementation with conflicting consensus rules can be made to work with the existing implementations that follow existing consensus rules.

What advice can I give to him?


texts: How do decentralized exchanges prevent front running?

texts: With the coming rise of decentralized exchanges for bitcoin and altcoins. How do these exchanges prevent front running of trades? Since all the transactions are transparent, what stops someone from monitoring the blockchain to detect a big order coming in and then immediately execute a similar trade before it?


texts:
I downloaded the original software of Bitcoin at bitcoin.org.
I just created a receive-address. How do I know it will work? How can I test it?


texts: Bitcoinj wallet can't receive coins in Testnet3

texts:
I have a problem with bitcoinj.

I have created a wallet and than trying to send coins to it in Testnet3 using this faucet:
https://coinfaucet.eu/en/btc-testnet/

Coins sended, transaction confirmed, but when I trying to get balance - it's always zero (available = available spendable = extimated = estimated spandable = 0).

Here is how I creating a Wallet:

NetworkParameters params = TestNet3Params.get();
Wallet wallet = new Wallet(params);
BlockChain chain = new BlockChain(params, wallet, new MemoryBlockStore(params));
PeerGroup peerGroup = new PeerGroup(params, chain);
peerGroup.addWallet(wallet);
peerGroup.startAsync();
File file = new File("testwallet");
wallet.saveToFile(file);

Address:

wallet.currentReceiveAddress().toString()

Balance:

wallet.getBalance()
wallet.getBalance(Wallet.BalanceType.AVAILABLE_SPENDABLE)
wallet.getBalance(Wallet.BalanceType.AVAILABLE)
wallet.getBalance(Wallet.BalanceType.ESTIMATED_SPENDABLE)
wallet.getBalance(Wallet.BalanceType.ESTIMATED)

And it's always zero.

What I'm doing wrong? Why I can't receive coins?


texts: Need explanation - limit buy order (Cryptopia)

texts:
If there are sell orders like this:

selling 200 XXX - 100 satoshis per coin
selling 200 XXX - 101 satoshis per coin
selling 200 XXX - 102 satoshis per coin
selling 200 XXX - 103 satoshis per coin
selling 200 XXX - 104 satoshis per coin
selling 200 XXX - 105 satoshis per coin
...

If I put buy order like this: "Buying 600 XXX for price 105 satoshis per coin - total 63000 satoshis" (and let's assume that I have 1 BTC)  - what will happen? Will I spent 63000 satoshis and get more than 600 XXX coins or I will buy exactly 600 XXX for less than 63000 satoshis and what will happen with remaining satoshis for that trade? To rephrase, will my order be filled after spent 63000 satoshis or after buying 600 XXX and what will happen with remaining satoshis for that trade?


texts: How do we know which co-signer signature is in raw hex in multisig?


texts: Signature on Bitcoin. What am I doing wrong?

texts:
I refer to this site How to redeem a basic Tx?

(signing stage) Now we double-SHA256 hash this entire structure, which
yields the hash
9302bda273a887cb40c13e02a50b4071a31fd3aae3ae04021b0b843dd61ad18e

We then create a public/private key pair out of the provided private key.
We sign the hash from step 14 with the private key, which yields the
following DER-encoded signature (this signature will be different in
your case):
30460221009e0339f72c793a89e664a8a932df073962a3f84eda0bd9e02084a6a9567f75aa022100bd9cbaca2e5ec195751efdfac164b76250b1e21302e51ca86dd7ebd7020cdc06
To this signature we append the one-byte hash code type: 01. The
public key is:
0450863ad64a87ae8a2fe83c1af1a8403cb53f53e486d8511dad8a04887e5b23522cd470243453a299fa9e77237716103abc11a1df38855ed6f2ee187e9c582ba6

I try to verify whether the message is correct
The message is 9302bda273a887cb40c13e02a50b4071a31fd3aae3ae04021b0b843dd61ad18e,
The public key is mfcSEPR8EkJrpX91YkTJ9iscdAzppJrG9j, and The signature is 30460221009e0339f72c793a89e664a8a932df073962a3f84eda0bd9e02084a6a9567f75aa022100bd9cbaca2e5ec195751efdfac164b76250b1e21302e51ca86dd7ebd7020cdc06
However, when I verify it on http://www.coinig.com/, signature is wrong. Why is it so? Thank you


texts: Connect mined blocks with various addresses

texts:
From code:

 // Create coinbase tx
 CTransaction txNew;
 txNew.vin.resize(1);
 txNew.vin[0].prevout.SetNull();
 txNew.vout.resize(1);
 CPubKey pubkey;
 if (!reservekey.GetReservedKey(pubkey))
     return NULL;
 txNew.vout[0].scriptPubKey << pubkey << OP_CHECKSIG;

 // Add our coinbase tx as first transaction
 pblock->vtx.push_back(txNew);
 pblocktemplate->vTxFees.push_back(-1); // updated at end
 pblocktemplate->vTxSigOps.push_back(-1); // updated at end

How I can connect mined blocks with various addresses in base58? Not only with miner address.

I want send part of mined value to one address (developer fund), different of miner address.

add vtx[1]?
Only check it in connectblock and createnewblock functions?


texts: Nbitcoin's BitcoinPubKeyAddress not recognizing native segwit addresses

texts:
I'm trying to build a transaction using Nbitcoin. When I run this line there is an error parsing the address. It runs fine with segwit addresses starting with a 1, but not native segwit.
Using System;
Using System.Text;
Using NBitcoin;

static void Main(string[] args) {

    var wallet = new BitcoinPubKeyAddress("bc1q....", Network.Main); //throws error
}

Error: System.FormatException: 'Invalid base58 data'
Is there a way to use native segwit with Nbitcoin? Thanks


texts:
I'm using bitcoind. Now I would like to access the transactions list of a particular account using the bitcoin-cli.

I am using the listtransactions accountname command to get the transactions of a particular account.

Example:

listtransactions karthiktest

Result:

[
  {
    "account": "karthiktest",
    "address": "mnXEfvmLFWz7Exn9oGaEeTN8Ayu7Le5CCz",
    "category": "receive",
    "amount": 0.30000000,
    "label": "karthiktest",
    "vout": 1,
    "confirmations": 18,
    "blockhash": "000000009d17b7b32567f9730b50f2b7e8623ae6c9d20f84d4c414914e214283",
    "blockindex": 86,
    "blocktime": 1507963431,
    "txid": "c94307bef9ece4afe41384e2cd453f183aa7a438899723906e8967e624bc7d6f",
    "walletconflicts": [
    ],
    "time": 1507962288,
    "timereceived": 1507962288,
    "bip125-replaceable": "no",
    "comment": "hello karthik",
    "to": "from arun"
  },
  {
    "account": "karthiktest",
    "address": "miDMgiqduYevZMsRxX4qrY9BD5eXYFmEzg",
    "category": "send",
    "amount": -0.10000000,
    "label": "mahesh123",
    "vout": 0,
    "fee": -0.00000765,
    "confirmations": 17,
    "blockhash": "0000000079c79a5d21af138c80544b307d4ac764b4ed343b84752114c77fc893",
    "blockindex": 76,
    "blocktime": 1507964632,
    "txid": "516c64595c8b7be12419199dd81ae5edd3f4281aa3e52f88c7e3561b901bf881",
    "walletconflicts": [
    ],
    "time": 1507964172,
    "timereceived": 1507964172,
    "bip125-replaceable": "no",
    "comment": "hello mahesh",
    "to": "from karthik",
    "abandoned": false
  }
]

Here in the JSON, it is showing two transactions 1 receive and 1 send.

Now, My requirement is: for receive transaction, I need to get the sender address and for send transaction, I need to get the receiver address(this can be done using the account field).  But I'm confused to get it with receive transaction.

Can anyone help me on this?


texts:
How do I make sure bitcoind's RPC call sendtoaddress adds miner fees to transactions?

Tried adding to our bitcoin.conf file:
mintxfee=0.0001

But some of the transactions still won't get any miner fee attached, causing payments to take hours or days to get confirmed.


texts: Can this double-spend attack happen in Bitcoin?

texts:
I am trying to learn more about Bitcoin.

I was looking at this video to understand how a "double-spend attack" is kept from taking place on the Blockchain (in Bitcoin).

https://youtu.be/Lx9zgZCMqXE?t=12m13s

In this case, Alice might send money to Bob to purchase an item.

Alice may use the same input to send money to Joe for another item at the same time.

It then becomes a race as to which one will get approved and which one will get rejected (the one sent to Bob or Joe).

It is my understanding that a "double-spend attack" could not take place because all of the nodes will be working at the same time.

I have heard of transactions not being processed for days because of a low miners fee.

In such a situation, would not this allow ample time for a "double-spend attack" to take place?

TIA


texts: Generating bitcoin wallets for my customers

texts:
I run an application written in PHP and need to add the option to buy services with bitcoins.
So, for each user i need to generate a unique, unused bitcoin address.

I could generate X number wallets with Electrum and assing 1 address to each user, but then i will have to check manually if someone send a payment, match the address with the user, wait for confirmations, import data, update the balance, every day.
This take too much time and it's tricky.

What's the best and easier approach to achieve this? from where i start?
Using external api and services is not a choice, using a single shared wallet can be okay but how i associate user/transaction?


texts: How to Get Unspent Transaction Outputs from Node

texts:
There is one API called listunspent, however it doesn't return any outputs, and some threads say that it may be because the address is not imported into the node's wallet.

Then how to retrieve the unspent outputs for any address?


texts: How many Bitcoin addresses are/have been carrying a balance?

texts:
Bitcoin addresses can be generated at will, and the theoretical limit to their number is high.  Addresses are constantly being generated to receive funds or balance transactions, but they are also being emptied.

How many addresses are carrying a balance at the moment, and how has this number developed historically? Would this number be a good proxy for the Bitcoin adoption rate?

I'd also be interested in the number of addresses that have been part of transactions during the last x days (i.e. active addresses).

The blockchain contains all necessary data to derive the numbers, so maybe there's even a site that lists/graphs them?


texts: How to deterministically generate large number of bitcoin addresses and monitor them

texts:
I want to generate a large number of bitcoin addresses to provide visitors for each transaction and I want to monitor payments to those addresses.

How do I deterministically generate those large number of addresses and monitor payments to them.


texts: Does Bitcoin have legal status as a corporation? If so, what kind, and in what jurisdiction(s) is it registered?


texts: resilience to sybil attack - public vs private

texts: it appears that although not totally water-proof to Sybil attacks, Bitcoin network seems quite resilient to these kind of attack Preventing Sybil attacks. Is it true to assert that permissioned or private blockchain are less exposed since there is a certain level control of the participant allowed to enter the network ?


texts: What bitcoin core options can be changed without a restart?

texts:
I often experiment with new bitcoin core options (like zmq, debug and fee options) and I would like to avoid restarting my node for them to take effect.
If I am not mistaken, changing the RPC password, for example, can be done without restarting the node but most options require a restart.
What are the options that require (and don't require) a restart to take effect?


texts: Hypothetically, if you formatted over a hard drive and erased your wallet but had your private key and address written down- how would you once again regain access to your wallet?


texts: How to store arbitrary data in the bitcoin blockchain and how can I differentiate between a transaction an those data?

texts:
According to this post, I can store arbitrary data in the blockchain (as the news about "child pornography in the blockchain" tell).
Now I want to store "Hello World" in the blockchain.

Is there a newer website/service that supports me putting data into the blockchain?
And what's the difference between a transaction in the blockchain and such a "message"?
Is the structure different? Why could those researchers even find out that it's inappropriate content instead of a default transaction?


texts: Why do most trading platforms require ID Verification?

texts:
The vast majority of the Bitcoin trading platforms both in the US and the UK require some sort of ID verification in order to make Deposits/Withdrawals.

Is this because of these two countries current legislation? does this obey to some sort of policy?

Thanks.


texts: Can you generate bitcoin addresses without storing a private key?

texts:
Suppose you have a possibly compromised system, which you do not trust enough to stores your private keys on.

Is there some process where you can generate unique bitcoin addresses within the system, that does not contain a private key?

To clarify:

You have a web server that clients use to make orders. You want to create a unique bitcoin address per purchase. In addition, you don't want the server to contain your bitcoin private keys - an attacker gaining access to the server shouldn't be able to touch your bitcoins.


texts: When is the halvening? What are the dates of past halvenings?

texts:
When a miner finds a new block, they receive a block reward that is comprised of the transaction fees from that block, plus a set amount of newly minted BTC. When the network started, this block reward was 50 BTC, but that amount is cut in half every 210,000 blocks, slowly approaching zero. This reduction is commonly referred to as a 'halvening'.

210,000 blocks is equivalent to about 4 years, but what were the actual calendar dates of the previous block reward halvenings? What are the expected dates of future halvenings? How accurately can they be predicted?


texts: Can anyone explain me why I can not buy coins at the advertised price

texts:
Right now I see on mtgox the lowest price as 105$ and the last price 165$ but when I want to buy by the price of 105$ I can not do so, the only option is 165$.

Is there something I understand wrongly?


texts: What are stale shares and what can I do to avoid them?

texts:
When I mine at a pool, only a part of my shares are accepted. There is a small percentage which is marked as stale.

As far as I know I only get paid for accepted shares, so what are these stale shares and how can I avoid them?


texts: What will happen when bitcoin's popularity multiplies and the number of transactions explodes?

texts: As I understand, every transaction in the bitcoin network is stored into one huge "chain". What happens when bitcoin gets more popular and there will be millions of transactions per minute? Doesn't the blockchain grow "too big"?


texts: Why does Mt gox BTC price discounted with other exchanges?

texts: When ever the BTC prices are crashing, MT Gox prices are discounted. What is the logic behind it?


texts: Difference between wallet,accounts and addresses

texts: I know this question has been asked several times, But it never made any sense reading each of them. Can Anyone really explain deeply by using technical language so that I could really understand pros and cons and everything ? Thank you.


texts: Why don't the timestamps in the block chain always increase?


texts: Why connected node count have dropped since august 1st?

texts:
before 1st august i used to connect to 55+ nodes on my bitcoin-core, even if i kept the bitcoin-core running for 12 hours.

but after 1st of august, the connected nodes count is not going above 15-23

why is that ?

what changed on august 1st ?

i  got that number when i do

bitcoin-cli getinfo


texts: What does the Payment Hub learn about its users in TumbleBit?

texts: When a user participates in transactions on a TumbleBit payment hub, what does the payment hub learn about the user's transactions?


texts:
How long does it take for a ripple bridge transaction to clear?

Bitstamp BTC on ripple -> bitcoin address


texts: How is the previous transaction hash calculated?

texts:
Can anyone provide a clear example on how to calculate a previous transaction hash?

Say I want to create a new transaction, I get that the hash is calculated by doubling sha256 a message m, but I'm having a hard time understanding the structure of m.


texts: Does any pool accept higher-fee transactions of a double spend, instead of the earlier one?

texts: Some pools use a modified bitcoind that uses different rules for choosing the transactions to include in a block. Are there any pools that knowing one transaction to be included in a block would discard it if another transaction on the same inputs would arrive with a higher fee? That is to say, when faced with a double spend attack between a transaction that arrived earlier and a transaction that pays them more, the pool would choose the latter?


texts: Can Bitcoin Diamond be claimed on Segwit addresses?

texts:
I currently have my Bitcoin (BTC) on a Trezor hardware wallet with Segwit (Not in a "Legacy account").

Can I claim Bitcoin Diamond (BCD) with this or not?

In general: Should I move my BTC to a Legacy account to be more compatible with future forks?


texts: How to enable website users to transact with each other using bitcoins?

texts:
I have a website which enables users to trade information for a price.
The price is calculated based on an algorithm within the website.
The website charges a percentage per transaction for the service.

I would like to know how to go about enabling the users to perform the transaction using bitcoins as an alternative to credit card transactions.

The website is coded in Ruby on Rails, I am currently investigating bitcoind, and the bitcoin-ruby library but I'm feeling a little overwhelmed with new technology.

Could someone please explain how I might go this? I'm looking for an overview of the process.

For example: The website connects to a bitcoind server, and creates a unique wallet per user, then to provide transactions the users will need to transfer coins from somewhere to their personal website wallet. When the user wishes to purchase information from another user, the website then connects to the bitcoind and creates a transaction between the two wallets, and creates a second transaction to cover the website commision.

I've made up this example from my basic understanding of the system - but what security issues are involved in this. Will this approach work, or is there a better way?


texts: How can I use a hardware wallet with a pool

texts:
This might be a totally dumb question but I am trying to understand bitcoin mining, I hope I am bearable.

I am trying to figure out if I can use a hardware wallet with a mining pool. I have an account on slushpool.com but I don't yet have a mining device yet.

In my current understanding (which might be totally useless), I have to install a software (that works with slushpool) on a computer and configure it, connect the mining device to the computer and have some kind of a wallet for payout. The pool with give me a payout every time I reach a threshhold.

How can I use a hardware wallet with this setup? Is there something different that I need to know? My goal is to come up with a setup with as little dependency on external entities that need a "cut" from what I make.

I would appreciate any help on this.

Thanks,
Paras


texts: Are all strategies to mine PPCoin Proof of Stake blocks equivalent?

texts:
Alice, Bob and Charlie each own 100 PPCoin, and would like to generate more using Proof of Stake.

Alice keeps her ppcoind running all the time
Bob stores them offline for a year, and then runs ppcoind for a week
Charlie uses some other arbitrary "strategy", where I define a strategy by a sequence of ON/OFF schedules, that can possibly depend on whether he finds coins in previous schedules. (Technically it's a decision tree).

Would all the above, on average, achieve equal expected amount of PPCoins in their wallets? Is there a dominant strategy? What about a combination of maximum expected value and security (running your client 24/7 might yield the max amount of PPCoins, but it's also the most volunerable one (wallet must be decrypted for coin generation)).


texts: Does segwit solve malleability of the witness part?

texts:
I understand that after segwit the transaction ID can't be malleated,
but can't the witness part be malleated, just like the scriptSig can in a non-segwit transaction?


texts: Let's say I have a wallet backup burned on a CD. In that moment I have 10 coins. And I start to make transactions. Then my hard-drive crashes and in the moment of crash I have 20 coins. When I restore my wallet.dat from CD what I see in Bitcoin wallet? I need to make a backup after each transaction?


texts: Why does "pre-allocating..." still happen during -reindex?

texts:
I thought -reindex read blocks from disk to rebuild the index, without downloading the chain from the network. If that's so, why is bitcoind allocating memory in the files on disk? Like this:

Pre-allocating up to position 0x3000000 in blk00205.dat


texts: Is there a limit for bitcoin withdrawal at Mt.Gox?

texts:
Their page states (https://support.mtgox.com/entries/20490576-Withdrawals-and-Deposits):

  All methods below are subject to a withdrawal limit of 1000 USD per 24hr period and 10000 USD per 30 Day period

They include bitcoin in the list below this statement too. Does that mean they will allow me to withdraw only number of bitcoins that currently has a value of 1000 USD?


texts: Is it possible to mine with both (2) GPUs in headless mode?

texts:
I've got a Mac Pro with two different GPUs in it—one is a new 5850 and the other is some old (stock) Radeon.

I'm wondering if it is possible to mine with both cards simultaneously if the OS is configured to be headless (i.e., neither card is used to display a GUI)?


texts: Did Satoshi know since its publication all the applications that the blockchain would enable?


texts:
I'm trying to write Python code which utilises the (Insight) Blockexplorer.com API , particularly the POST functions. I'm testing using the iOS REST app, Restler (see screenshot).

The call I'm trying to make is fine when I use GET (https://testnet.blockexplorer.com/api/addrs/2NF2baYuJAkCKo5onjUKEPdARQkZ6SYyKd5,2NAre8sX2povnjy4aeiHKeEh97Qhn97tB1f/txs), however for POST, I'm having problems. I use "addrs" = "2NF2baYuJAkCKo5onjUKEPdARQkZ6SYyKd5,2NAre8sX2povnjy4aeiHKeEh97Qhn97tB1f" as my params (and have tried using dumped JSON, ie"{ "2NF2baYuJAkCKo5onjUKEPdARQkZ6SYyKd5,2NAre8sX2povnjy4aeiHKeEh97Qhn97tB1f" }", but I'm always getting the following error message:

  Invalid addrs param:Cannot call method 'split' of undefined. Code:1

It's clearly a parameters issue, so what gives? (FWIW I'm not versed in JavaScript)

Relevant screenshot of Restler (L) and API documentation (R):


texts: How to derive public child keys from public parent keys with bip39-libs.js?

texts:
I red this doc: https://howieliux.github.io/assets/others/Mastering_bitcoin/Mastering_Bitcoin.html
and found:

As mentioned previously, a very useful characteristic of HD wallets is the ability to derive public child keys from public parent keys, without having the private keys. This gives us two ways to derive a child public key: either from the child private key, or directly from the parent public key.

An extended public key can be used, therefore, to derive all of the public keys (and only the public keys) in that branch of the HD wallet structure.

Which method of bip39-lib.js I need to call to derive address from public parent keys? I haven't found any reference in the doc.
https://github.com/bitcoinjs/bip39


texts: How can Blackcoin get 1st confirmation in 10 seconds?

texts:
According to it's official page, Blackcoin used scrypt as its Proof-of-Work during the phase of initial coins' creation. But now it's purely Proof-of-Stake, and they claim to have a speed of just 10 seconds for first confirmation (and only needing 10 confirmations to get an almost guaranteed transaction).

How does their pure PoS model serve to verify transactions, without the risk of double spends?
How can they create blocks as often as 10 seconds without having massive amounts of orphans?


texts: As an experiment, I will have website visitors mine litecoins. Yes, I know this won't work very well, but I simply want to try it. If I want the visitors to be part of a pool, how should I create user accounts for them? Is it ok if I have them all mine under the same worker name, or do I have to create individual workers?


texts: For over 4 hours it says payment has not been transmitted yet

texts: Been getting message for over 4 hours that says "This payment has not been transmitted yet. Wallet version 7.47. What do I do?


texts: online tool to play around with ECDSA public keys, message signature verification?

texts:
I realize that this question may be borderline bannable because it's asking for suggestions on tools, but it will really help newbies. This online tool allowed me to play around with hashes and to really understand them at a deeper level: http://www.fileformat.info/tool/hash.htm

I can't find a similar tool (that works) for ECDSA cryptography where I can play around with public and private keys, and do digital signatures on messages, and test signature verification.

I've found these 2 sites that claim to do this but didn't work for me:

http://dbis.rwth-aachen.de/~renzel/mobsos/lib/js/jsrsasign/sample-ecdsa.html
http://extranet.cryptomathic.com/ecc/index

Thoughts? Suggestions?

UPDATE: Great suggestions below. Some tools I found:

for hashing:
http://www.fileformat.info/tool/hash.htm

generating public private key pairs and decrypting ciphers:
https://8gwifi.org/rsafunctions.jsp

Generating EC public private key pairs and signing Verifying the Message
https://8gwifi.org/ecsignverify.jsp

generating public private key pairs and testing signing:
https://kjur.github.io/jsrsasign/sample/sample-ecdsa.html


texts: Why do huge wallets often have repeated tiny (< $1) transactions?

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Looking around at some so-called 'whales' on the BTC richlist (as well as other currencies) I see it is quite common a huge wallet is regularly making miniscule transactions as low as a few cents.
Just the one I had open:
https://bitinfocharts.com/bitcoin/address/3LYJfcfHPXYJreMsASk2jkn69LWEYKzexb

In this case the 0.00000547 value comes up many times. What does it signify when wallets have these sort of micro-transactions?


texts: Can two different nonces and different blocks produce the same hash?

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Say, I want to erase the record of a transaction by changing a block. Can I go back to that block and find a new block and nonce combination that makes the same hash?

Is it a case that finding such a new combination is computationally hard or is it actually impossible?


texts: How transaction fees are calculated when buying from exchange and transferring to wallet?

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If I buy bitcoin from a exchange and later want to transfer to my wallet for storing purpose (e.g. Jaxx or other), how the transaction fee will be calculated? I thought I can buy some amount of BTC and transfer the equal amount of BTC to wallet. How this works?

Thanks


texts:
I have been trying to make a comparison between PoW, PoS and Proof of Burn. While I understood the other two, I want to know how exactly Proof of Burn helps in attaining the consensus.

One burns coins by sending it to an address where it cannot be spent, is what I understood.

But why would one "burn" the coins? Isn't it a loss for the person burning or getting rid of some coins?
How is the consensus achieved for the next block in the chain?
How is it beneficial in comparison to PoW and PoS?

My apologies, I have read a lot about Proof Of Burn but I am still not able to comprehend.


texts:
I am running latest bitcoind and p2pool releases (default port settings) on Fedora 21 with ports open for 3332-3333, 8332-8333, and 9332-9333.  Everything appears to be well when connecting to the BC net, but when one of my miners (Antminer S5) connects to http://myhostname/IP port 3333 p2pool will not respond.  When I try to connect with port http://myhostname/IP port 9333, I get a twisted error complaining about authentication, but when I try to connect to port myhostname/IP (stratum+tcp??) port 9333 it looks like the miner is trying to connect and get work, but after several seconds p2pool reports a "handshake timeout" for the miner IP address.

This is the error I get:

2015-02-25 18:05:35.107254 Got peer connection from: IPv4Address(TCP, '192.168.0.21', 45024)
2015-02-25 18:05:45.108525 Handshake timed out, disconnecting from 192.168.0.21:45024
2015-02-25 18:05:45.109817 Peer connection lost: ('192.168.0.21', 45024) [Failure instance: Traceback (failure with no frames): <class  twisted.internet.error.ConnectionAborted'>: Connection was aborted locally, using.
2015-02-25 18:05:45.110143

What am I doing wrong?


texts: Is it possible to find additional key pairs resulting in the same address that I already control?

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I'm not really well versed in the necessary terminology to get the answer I need from searching.
As I understand, there are 2^160 possible addresses, and 2^256 possible private keys, so each address corresponds to roughly 2^(256-160)=2^96 private keys.
Let's say I generate a key pair and the corresponding address, how would one go about finding other key pairs that correspond to the same address if you already have at least 1 set of keys that generated that address? Is it possible?
Apologies if this has been answered already, I couldn't find the answer I am looking for.


texts: Finally synchronized the blockchain, yet not sure if I'm mining for coins. Where do I find out if I am or do I need something else?


texts:
When will we be able to start mining Segwit2x?
I am currently mining with Slush's Pool. Will the entire pool switch or should I switch to a different pool?
Is there anything I should do on my side?


texts: Like Banks, are there better service providers from Bitcoins banks? Can I Find a rating?

texts: I would like to purchase Bitcoins, I am looking and honestly do not know what I am looking at.  Is there a place to see how these Bitcoin places are rated? Services they provide?


texts: What can an attacker who controls majority or all of the full nodes do?

texts:
What happens when a strong attacker has control of majority or all of the full nodes?

What damage can he do and would they be reversible?


texts: Are the mining incentives of bitcoin compatible with the existence of a competing Proof-of-Work chain?

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Scenario A: A chain split occurs due to a bug or contentious rule change (i.e. the miner incentives aren't changed in any way).

Both coins initially start out with the same difficulty (and won't change for another 2016 blocks, in the worst case), but their market price will vary.

A rational economic miner will only mine the chain with the highest reward, which is the chain with the higher market price. Users of the lower value chain can offer high fees to compensate, but this is costly.

Scenario B: A hard fork chain split occurs where one chain has decreased difficulty and/or higher block rewards (not touching the 21 million limit, but pushing the release schedule forward).

Unless the new chain has a really low market value, miners are highly incentivized to mine it. It will be hard for the old chain to compete.

The question for both scenarios: How will the scenario play out? Can both chains coexist or will the less popular chain die from a negative reinforcement loop (lower value -> less blocks mined -> even lower value) and be forced to do a PoW hard fork?

And if both chains can't coexist, does that mean that any chain that tries to out-compete bitcoin for the same PoW is a threat to the network?


texts:
Is there a way to recover the BCH ?

Use his Ledger purse
I've sent BCH
To address BTC Segwit
This link is treated
https://explorer.bitcoin.com/bch/address/36CU6nDniJca1UVhvNhjsDdZpUsyYw5vSx

I want to get it back BCH


texts: What Does "Activation" Actually Mean In Bitcoin?

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During the multiple issues with Bitcoin this year with soft and hard forks, and Segwit, I have read as much as I can about how all these changes are "deployed", eg BIP9, BIP91, BIP148, BIP's 141-146.

However I am still not clear about some of the terminology, such as "locking in", "signalling", "activation", "deployment".

I understand Segwit was implemented in v0.13.1 (and above) of Bitcoin Core which was released on 27/10/2016.

So all the Segwit changes have been in the Bitcoin Core software since that date ?

So when "activation" of Segwit occurred - did that mean a flag within the Bitcoin client, say "ACTIVATION_FLAG", became true and then the Segwit functionality thus started to run - because it is contained inside an "if" block :-

if (ACTIVATION_FLAG) {
    do Segwit stuff
}

However Segwit is a complex upgrade to Bitcoin so there must be many places where changes are made to Bitcoin for Segwit - so how many such "if" blocks are there ?

Can someone give me some links to where these "if" blocks are located in the Bitcoin source code?


texts: Can i use one pair public and private key for all transactions?

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Can I use one pair public and private key for all transactions, digital signatures and wallet addresses?
In the other hand, I have a private key and want to sign all transactions and have a public key for broadcast. Can I do?

Is this way secure?


texts: bitcoin-qt "backup wallet" vs copying wallet.dat

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I am new to bitcoin, I wander what are the differences, and pros/cons (if any) between the file generated by bitcoin-qt when clicking on "backup wallet" vs copying the file "wallet.dat"? I see these files are indeed different with "cmp" so I am assuming that there are differences between these files. Can one of these files recover all of the information in the other?
EDIT: after a few backups I noticed that if I close the wallet, and then wait a few minutes. A backup at this moment equals the wallet.dat file.


texts: What happens if there are no transactions in a block?  Suppose there is a 10 minute time frame  in the middle of the night, maybe on a holiday, and there are no transactions made.  Do the miners get paid 50 bitcoins for processing a zero?