texts: Taproot, potential quantum bug, and general clarification

texts:
Here seeking information. I have 2 questions marked with parens
Would like some clarification pertaining to the Mark Friedenbach article:

Why I'm Against Taproot

The point of contention with Mark seems to be with the space savings for the N-N Musig2 everyone signs/happy path, being embedded into the the root of the MAST/Taproot, thus exposing a pubkey in an output that sits on the blockchain.
(1) please correct if I'm wrong about the way I'm describing this.
I did see Pieter's presentation at Bitdevs from a while back reference, "plain pubkey security model in mind" for taproot. But, it wasn't apparent that this would hypothetically make it quantum vulnerable,.. as Mark's article says, "a naked secp256k1 pubkey on chain at the time the output is created which has absolute spend authority for the underlying bitcoins".
(2) Would love for someone to rebut or verify this claim.


texts: Why is my "spendable_msat" much lower than "msatoshi_to_us"?

texts:
Today I was attempting to send a Lightning Network payment via c-lightning, version v0.7.1-64-gbb30104, using a channel I established in 2018. Strangely, my payment kept failing even if the destination was routable. Finally, I noticed the reason was a relatively large disparity between  spendable_msat and msatoshi_to_us.

"msatoshi_to_us" : 49947931,
"to_us_msat" : "49947930msat",
"msatoshi_to_us_min" : 49947930,
"min_to_us_msat" : "49947930msat",
"msatoshi_to_us_max" : 50000000,
"max_to_us_msat" : "50000000msat",
"msatoshi_total" : 50000000,
"total_msat" : "50000000msat",
"dust_limit_satoshis" : 546,
"dust_limit_msat" : "546000msat",
"max_htlc_value_in_flight_msat" : 18446744073709551615,
"max_total_htlc_in_msat" : "18446744073709551615msat",
"their_channel_reserve_satoshis" : 546,
"their_reserve_msat" : "546000msat",
"our_channel_reserve_satoshis" : 546,
"our_reserve_msat" : "546000msat",
"spendable_msatoshi" : 35617930,
"spendable_msat" : "35617930msat",
"htlc_minimum_msat" : 0,
"minimum_htlc_in_msat" : "0msat",
"their_to_self_delay" : 144,
"our_to_self_delay" : 144,
"max_accepted_htlcs" : 483,
"status" : [
  "CHANNELD_NORMAL:Reconnected, and reestablished.",
  "CHANNELD_NORMAL:Funding transaction locked. Channel announced."
],

As you see, my "spendable_msatoshi" is much lower than "msatoshi_to_us", a difference of 14373070 msatoshis. Even considering "their_reserve_msat" and "our_reserve_msat", it can only explain an amount of 1092000 msatoshis, or ~7% of the unspendable fund, where does the rest go?

Why does this even occur? And what should I do to fix it?

I tried reading the source code of c-lightning, and clearly HTLC and transaction fee is also deduced from "spendable_msat", however, those values are invisible in lightning-cli listpeers and I still cannot determine the reason.

/* Compute how much we can send via this channel. */
if (!amount_msat_sub_sat(&spendable,
             channel->our_msat,
             channel->channel_info.their_config.channel_reserve))
    spendable = AMOUNT_MSAT(0);

/* Take away any currently-offered HTLCs. */
subtract_offered_htlcs(channel, &spendable);

/* If we're funder, subtract txfees we'll need to spend this */
if (channel->funder == LOCAL) {
    if (!amount_msat_sub_sat(&spendable, spendable,
                 commit_txfee(channel, spendable)))
        spendable = AMOUNT_MSAT(0);
}

/* We can't offer an HTLC less than the other side will accept. */
if (amount_msat_less(spendable,
             channel->channel_info.their_config.htlc_minimum))
    spendable = AMOUNT_MSAT(0);

/* We can't offer an HTLC over the max payment threshold either. */
if (amount_msat_greater(spendable, get_chainparams(ld)->max_payment))
    spendable = get_chainparams(ld)->max_payment;

json_add_amount_msat_compat(response, spendable,
                "spendable_msatoshi", "spendable_msat");
json_add_amount_msat_compat(response,
                channel->our_config.htlc_minimum,
                "htlc_minimum_msat",
                "minimum_htlc_in_msat");


texts: Is it safe to invest $100 Million in Bitcon

texts: I have currently $300 Million+ in bank account. Do you think is it safe to get returns by investing in Bitcoin considering it has hit Billions in Market Capitalization.


texts: My local client not showing correct output for listunspent

texts:
I tried using the listunspent command as follows:

bitcoin-cli listunspent 10 9999999 "[\"32jdC23ABv86M2ptiqMzFzCaufBtE2NCdN\"]"

and it shows a blank output ([]), however, when I look up the same address on Blockchaininfo.com it shows the correct outputs. What could be the problem?

The only issue I can think of is that my node is still catching up, but it is 95% done, so the data should be there.


texts: Please help me to solve unconfirmed transaction

texts:
I tried to send a bitcoin transfer and it is still unconfirmed and I have my block chain account set to "use recommended fee" by default. Can anyone help me get this confirmed or teach me how to get it confirm (or how to raised the tx fee to get it be confirmed faster? Many thanks for your kind support.

Here is the link:
https://blockchain.info/tx/c6816a387cb0ca8e33bb7b200372ce05919f6003034faaeecb1f72436827b32b


texts: electrum wallet console - how to get help on a command

texts:
I'm trying to use the electrum wallet console to get help on a command.
I can do help() or any other command
but i cannot do help <some command>
cannot find documentation about the wallet console

Of course i can do from my terminal electrum help <some command>


texts: How can I make my old wallet.dat work in a newer client?

texts: Im having trouble with my wallet.dat file in the old bitcoin qt client the blockchain won't update because the computer is old and outdated so I'm unable to send the bitcoins that I have in the wallet to another address, so I downloaded bitcoin core onto my other computer and copied the wallet.dat file and replaced it and then in command prompt I rescanned and still nothing, could really use some help if anyone has any idea


texts: How can I calculate the possible number of correctly formatted version one minikeys?

texts:
I'm doing a small research project collecting information on minikeys. In that research process I've come across a couple of questions that I have been unable to answer in relation to the assumed keyspace of the version one minikey. The said mini key, was used primarily by Casascius Series 1 coins, and consisted of the following parameters

Generated using Base58 encoding scheme
Consists of a total of 22 Characters, of which 21 are random, with the 1st character being a capital S prefix

Has the following requirements to be considered well formatted:

If the minikey appended by a ? at the end of the string hashed using SHA256 results in the first byte being 00, the string is a well formatted minikey

Key Question: Is there any way to calculate the potential number of keys within the massive 58^21 keyspace that would be considered properly formatted?

My current suspicion is that it's not possible to do so because the validation involves hashing and the entire input of the entire minikey input would be needed to generate a proper hash (meaning potentially in order to calculate the possible number of valid keys, every potential key, of a impossibly large keyspace would need to be generated, which is currently impossible). However I am asking this question with the hope that this suspicion is incorrect and that it is somehow possible to calculate the possible number of valid well formatted keys.

For reading on this subject I would recommend checking out:

https://en.bitcoin.it/wiki/Mini_private_key_format

Be warned, the python script needs minor modifications to run on Python2.7

Bold is for key questions
Italics if for important thoughts

Note: This post intentionally does not cover the more secure Casascius Series 2 Keys, however it is likely assuming that there exists an answer for Series 1 keys that the process can be used on Series 2 as well.


texts: BOLT #7: Can receiving node requirements in channel_update message give rise to malicious attacks?

texts:
Following requirements have been placed on the receiving nodes related to the channel_update message in BOLT #7.

  if timestamp is NOT greater than that of the last-received channel_update for this short_channel_id AND for node_id:

  SHOULD ignore the message.

  otherwise:

  if the timestamp is equal to the last-received channel_update AND the fields (other than signature) differ:

  MAY blacklist this node_id.
  MAY forget all channels associated with it.

According to my understanding the receiving node will first check the signature of related the dsha256 of the entire message before verifying the timestamp and not check the remainder of the message if the signature is invalid. So if other fields apart from signature are changed, then the signature will not be valid (as the message has changed) and the node will not process the message further.

Now here's the thing I'm wrestling with: If the node still plans to check the message (as shown in the quoted text above) even though the signature is invalid and then go forward to blacklist the node, it can give rise to DoS attacks. A malicious nodes will just take a channel_update message that it received in the past from a node, change some fields like htlc_minimum_msat and rebroadcast to other nodes. Those receiving nodes will then simply blacklist the node_id without any wrongdoing from its part as (1) the timestamp is equal to the one it received in the past, (2) signature is same AND (3) other fields have changed.

So I feel that this check is simply not needed and if the software goes on to process this message despite checking the signature then it can give rise to attacks from malicious parties. Where am I incorrect in my thought process?


texts: is it okay to disconnect Antminer like S7 >

texts:
I have a kind of unstable internet connection
sometimes it gets disconnected for over an hour
the question here is , does that hour of mining without internet count ?

thanks


texts:
Here is what I've understood of bitcoin:

Everybody has a public and private key.
If A sends bitcoins to B:

B is generating an address and sends it to A
This addresses are generated for each transaction.
A needs to sign something with his private key and B's address

Am I wrong?

If not, I want to understand how this address is computed.

I have read it is a kind of public key computed from private key. That's it? So we can have many public keys which match to a common private key?
I have also read the address is derived from the public key.


texts: Withrdawing bitcoin from web-based exchange wallet to local wallet. My wallet passphrase is requested- is this necessary?

texts:
I understand (maybe incorrectly) this is the seed passphrase/ the 12 words generated when wallet is created. Is this normal to provide this information to the web-based wallet when sending it, to receive it in a local wallet?

When withdrawing the funds from the "cloud" wallet to my local wallet.. wouldn't providing my seed/passphrase be a security flaw as a wallet can be recovered from it? Or am I interpreting this as the wrong passphrase...? I am using Electrum as my local wallet.


texts: Pushing a large signed transaction (testnet) using Python

texts:
I have been trying to send a signed transaction using pybitcointools (Python) using the blockr_pushtx function, however it consistently returns Exception: {"status":"fail","data":"Could not push your transaction!","code":500,"message":"Did you sign your transaction?"}. The signature isn't the issue. It is likely to be an issue with the size of the transaction.

How does one go about pushing a sizable raw transaction (Testnet, in this case, but both mainnet/testnet answers appreciated) without needing to use Bitcoin Core?


texts: Will the proof-of-work system end when all bitcoins have been mined?

texts:
This article from ArsTechnica is claiming that Bitcoin is not such an environmental disaster, and one of the reasons they mention is that mining will come to an end.

Ok, fair enough, there is an end in mining because the number of bitcoins is fixed but, is there an end to the computation algorithms taking place when generating blocks? My guess was that proof-of-work would still be needed at that time, therefore we would still need ASICs, GPUs or whatnot?


texts: Is there any wallet that that sets fee based on input amounts (not tx size)?

texts:
Generally the fee is based on tx size in the wallets I am aware of. Is there any wallet that allows setting fee based on a fixed fraction of total input value (say, 1/1000th of the inputs value)?

Please include wallets used by developers also (Bitcoinj, bitcoinjs, etc).


texts: Bitcoin halving conflict? Is this a rumor

texts: Is there a conflict as to when the halving will occur and Bitcoin miner rewards become 12.5? Is is set in stone to happen this July or is it after a certain amount of blocks?


texts: How to make a transaction start from a given address?

texts:
Usually, a Bitcoin wallet includes multiple addresses, and each address has a balance of 0 or more Bitcoins. When a payment is sent out, outgoing Bitcoins are taken from one or more addresses, depending on their balance.

Is it possible to choose the transaction source address (assuming that specific address has enough balance, of course)?

I can think of two ways to manually enforce it:

Use (or create) a new wallet with a single address, send Bitcoins from your main wallet to that address, then send the payment from the new wallet.
Move all the Bitcoins in your wallet to a single address in the same wallet; then each new payment will have to be origined from that address.

Is there any simpler way to obtain this?

If this feature is not included in the reference client, does any other wallet include it?


texts: Why is mining an important part of a digital coin?

texts:
I have been playing with the blockchain lately and studying how Bitcoin works. I was wondering though, what is the functional reason for the mining process? I understand that you get a reward for mining, but you could implement that reward also in another way, or do away with it completely.

I first thought it would be to make the blockchain more tamperproof, because the mining will make it extra hard to change a block somewhere up the chain. But, using the signatures and the distributedness this is nigh impossible anyway.

So, why mine?


texts: I sent bitcoin from electrum but never received it , has been confirmed but I can’t tell what’s happened to the btc. Can anyone help me out?

texts: Should be a picture included if information !


texts: How do I use CHECKLOCKTIMEVERIFY to prevent a transaction being spent before 100 blocks?

texts:
I'm creating a Bitcoin based lottery application. An entry into the lottery is a transaction spending 1BTC.

If someone guesses some arbitrary value correctly, they can claim the entry and send this 1 Btc to an address they control.

I wish to have functionality as follows: if no one guesses the correct number after 100 blocks, then I can claim it as the operator of the lottery.

Can I do this via:
Entry transaction
  IF
     CHECKLOCKTIMEVERIFY
    payable to a correct guess
  ELSE
    Payable to my operator public key
  END

Then when I try to spend this entry transaction, I set the nLockTime to the current block.

Throughout I set all the sequence numbers to 0xFFF... So that the transactions are mined.


texts: When installing libbitcoin there are checks of the code, why is this?

texts:
When installing libbitcoin from here with $ ./install.sh --prefix=/home/me/myprefix --build-boost --disable-shared after most of the compilation is done there seem to be checks of the sourcecode with warnings like thise one:

In file included from ./include/bitcoin/bitcoin/machine/operation.hpp:159:0,
                 from ./include/bitcoin/bitcoin/chain/script.hpp:31,
                 from ./include/bitcoin/bitcoin/chain/output.hpp:28,
                 from ./include/bitcoin/bitcoin/chain/output_point.hpp:25,
                 from ./include/bitcoin/bitcoin/chain/input.hpp:27,
                 from ./include/bitcoin/bitcoin/chain/transaction.hpp:30,
                 from ./include/bitcoin/bitcoin/chain/block.hpp:31,
                 from ./include/bitcoin/bitcoin.hpp:24,
                 from test/chain/transaction.cpp:20:
./include/bitcoin/bitcoin/impl/machine/operation.ipp:136:15: warning: ‘size_t libbitcoin::machine::variable_uint_size(uint64_t)’ defined but not used [-Wunused-function]
 static size_t variable_uint_size(uint64_t value)
               ^~~~~~~~~~~~~~~~~~

On my Raspberry Pi 2B this goes on for several hours now. Can someone explain why such a huge amount of tests would be usefull?


texts:
I've got a notebook with these specifics:

CPU: AMD Phenom X3 II N830 3.14GHz (3-Core)
GPU: ATI Radeon HD 5650 1GB

Mining 1 LTC is faster than mining 1 BTC? How I estimate the times for BTC and LTC?
Overall, I get more money with LTC mining or with BTC mining?


texts:
When I'm trying to send a "VERSION" message with my custom bitcoin client, I get:

Warning: Local node 127.0.0.1:56425 misbehaving (delta: 1)!

What does it mean? How do I know what exactly is wrong with my message?


texts: wemineltc.com Unpaid Shares went back to zero on miner restart

texts:
I just joined wemineltc it's my first day EVER mining for Litecoin or any other coin for that matter.

So far the side pannel on the wemineltc.com for me says:

Your Current Hashrate
43 KH/s It takes 20 minutes for your hashrate to be calculated up to full speed and is only approximate, go by your work utility in cgminer.

Paid Shares All submitted shares from previous rounds which are already accounted and paid for.
Your Valid: 0
Invalid: 0

Unpaid Shares Submitted shares between the last 20 confirms block until now.
Your Valid: 9
Pool Valid: 5614664

Round Shares Submitted shares since last found block (ie. round shares)
Pool Valid: Updating...

Round Estimate
1.68E-5 LTC

Account Balance
0.00017 LTC

I am using the cgminer and every now and then it says

Stratum pool1 0 detected new block

and when that happens the side panel increments the number of unpaid shares (Your Valid) it says I have

so I waited until it got to 19 unpaid then in cgminer I pressed [S]ettings & [C]gminer restart when that happened my balance stayed at 0.00017 but my valid unpaid shares now said 0.

now after a while it's back up to 9, but where did those shares go? Should I have claimed them somehow? Is it automatic  but delayed?


texts:
Im just reading a book on the basics of blockchain and I encountered a confusion regarding the 51% attack. If I'm right, it says that an attacker holding 51% or more of the network's computing power can rewrite the blockchain to his own favor.

What confuses me is the following: Blocks in the mainchain can only be added sequentially, hence the growth speed of the blockchain is at most the speed of the fastest miner in the network. So if a attacker is faster than the fastest miner of the rest of the network can start at some lower block (maybe even the genesis block) and add his own blocks on a new branch one after the other. Since he is faster than the official main-chain, his branch will eventually be longer than the latter and consequently become the new main-chain.

So the attacker does not need 51% of the whole computing power, only more than any other node, which is usually much less than 51%. What is wrong here?


texts: With the rise and fall in value of bitcoins, how do I store them once I've accummulated enough

texts: With the rise and fall in value of bitcoins, how do I accumulate the value so that I don't continue to lose them?


texts:
It is known, that UTXOs stored in chainstate database.

But how to get them in simple txt view? Not ballances, but each UTXO.


texts: Why is sharding not possible with a distributed blockchain?

texts:
Hi guys I've been reading a lot about the problem of scalability in crytocurrencies and how to run a full bitcoin node is not a possibility on a mobile device for example, as a result we become relient on centralised 'power nodes',

My question is: what is it about the datastructure which makes sharding the full blockchain across many lite devices not possible?

For example node 1 stores blocks 0-100, node 2 blocks 101-200, etc. A node wishing to verify some transaction can then just keep pinging nodes until they connect with a node which is storing the data they're interested in.

Apologies if this is a noob question, still got a lot of learning to do!


texts:
I have to to use bitcoin api using nodejs. but I cannot understand from where I have to start.Search some node module like bitcoin-core and bitcoin.

Can anyone describe the step how can I set up bitcoin in our system and use using nodejs.
Also refer some link where use of bitcoin api request and response parameter are describe in nodejs.

I have to use bitcoin json-rpc api's with node.js but dont know from where i can start?


texts: Suppose I wanted to print my bitcoins to paper for safekeeping.  It would be impossible for a hacker to get at my computer.  To do so I need to know where to find the private keys.  Is there only one private key and many public keys?   Does it make sense to carry a printed bitcoin in my pocket and type it in someplace else?  Your thoughts on this matter, please.


texts: Slow synchronisation bitcoin-qt - bread wallet

texts:
I have used bitcoin-qt for a while, but I have read now there is bread wallet for iOS more secure than any OS X wallet, is this true ?

I didn't update it for a while and now it is like 60+weeks behind and it will take a year or so to get it up to date... I made bitcoin transfer to someone on last thursday (4 days ago), it still does not show up, I can see in my log it as payment but with 0/6 confirmations (so I quess I need to update my wallet before transaction going out?)

I installed bread wallet to my iPhone, however I don't know how I can move my bitcoin qt data to it ? Breadwallet asks for recovery code OR new wallet, how I can synch wallets ?


texts: Why does a bigger block size infer miner centralisation?

texts: I've read that one of the detriments to increasing bitcoins block size is that it will create a more centralised mining community. How is this so?


texts: Help verifying bitcoind "full node" installation on Debian box

texts:
I've tried my best to follow the installation instructions for a headless Debian server found on github.com/bitcoin and bitcoin.org/en/full-node. However, I can not figure out if everything installed correctly. I don't know the right sanity checks.

To install bitcoind I used wget to download the 0.11.2 tar/zip file from bitcoin.org. I installed all the dependencies through apt-get listed on github. I used wget to download Berkeley DB4.8 and used "make install" to presumably install db4.8. Finally, I used "sudo install" to add the bitcoind binary to "/usr/local/bin".

I can run bitcoind and interact with it using bitcoin-cli. However, how can I determine if the installation is truly a success? How can I verify that bitcoind is using Berkeley DB4.8? I have a suspicion something is off, because I could not find the bitcoin root. This instruction from github baffles me:

cd $BITCOIN_ROOT
./autogen.sh
./configure LDFLAGS="-L${BDB_PREFIX}/lib/" CPPFLAGS="-I${BDB_PREFIX}/include/" # (other args...)

I cannot use autogen.sh, because I cannot find it. Where is the $BITCOIN_ROOT? Where is the configure file? I cannot find this either. I am afraid to use the wallet and lose BTC.


texts: Is there a proof of work system which takes significantly more memory to generate than it does to verify?

texts:
Litecoin resists GPU speedup by using an scrypt-based hashing function that takes some amount of memory to generate and verify. The problem with this is that the r parameter needs to be set high enough that it is difficult to use a GPU, but low enough that low-memory clients (i.e. smartphones) can still efficiently verify blocks.

Is there a proof of work which takes significantly more memory to generate proof of work for a block than it does to verify that a block contains sufficient proof-of-work?

I've heard of two possible approaches: time-memory tradeoff with scrypt and a graph-theory hashing algorithm that takes lots of memory to find solutions.


texts: Which crypto-currency has the most even distribution of wealth?

texts:
Bitcoin, Ripple, PPCoin, Freicoin and most other cryptocurrencies have a significant portion of the currency in the hands of early adopters or a central group charged with 'distributing' the currency. Does anyone know which has been the most successful at distributing the coins evenly?

Thanks


texts: I would like to have Bitcoin Core running as a full node. I thought it is like plus 100 GB. But on the web site it says it is no more than 20 GB. When I run Bitcoin-Qt is it enough to run full node or do I add any parameters before I start the program ?


texts:
I know that for a mining reward, a (special?) transaction is included in the the block (in the merkle tree I believe?)

But how is a transaction fee payed out exactly?

Is this also a special transaction?

I would imagine the sender of the transaction has to then also include an extra transaction to pay out the fee?


texts:
Block 370,434 (00100000000000000000000000000111) and (0x20000007)

Yes: BIP9 says set top 3 bits to 001.
No: BIP101 explicitly says set first, second, third and 30th bits to 1.
No: No mention of BIP9 anywhere in BIP101.
No: BIP9 was published after this block.

Block 398,364 (00110000000000000000000000000000) and (0x30000000)

Yes: This is definitely compatible with BIP9, but not explicitly BIP9. It is mentioned in BIP109.


texts: Why aren't Bitcoin transactions processed and verified by normal Bitcoin clients?

texts:
My understanding is that the blockchain is exclusively built by miners. My question is, why isn't that verification done by every Bitcoin client - kinda like p2p file sharing programs allowed people to use the network (download) and support the network (upload)?

Update:

What is the difference between "verifying" the transaction, and the "proof of work"? My understanding of verifying transactions is that all inputs to and outputs from an address are added up, ensuring along the way that there is enough that has in-come before-hand to allow each output. If each node in the network does this, all nodes will agree and blockchain spoofers would be drowned out by the masses. Is this not sufficient proof?


texts: Unconfirmed outbound transaction with change messing wallet balance

texts:
I noticed a strange behavior with my wallet. I sent a few coins and that generated a change (let's call this change amount X). This transaction is still unconfirmed. Immediately after starting the wallet, the balance shows Y (which includes this unconfirmed change amount X), and after a few minutes the balance shows Z (which equals Y-X, i.e. it does not include the unconfirmed change amount X). If I restart the wallet I get the same behavior (balance is Y then it goes down to Z).

I find it really weird that the balance suddenly goes down! Is this a bug? If not then can you explain why this could be happening?

I'm using Bitcoin Core 0.14.1 and to get the balance I'm using the command "bitcoin-cli getbalance".

Thanks in advance.


texts: Building a small block explorer for fun, stuck with node

texts:
Im trying to build a small btc block explorer for fun.
The problem where i am stuck is that im trying to setup a node.
I got a Ubuntu VPS running and i have bitcoind installed, but what now?
Can someone help me with this? I have read that you need to run the node in txindex mode or something.

Thanks in advance!


texts: Transactions show up on blockchain but not in multibit?

texts: 1JPEobzLgKo5EKEfDVN8aJ61Pdryse6ccf This address shows transactions I was not aware of for unknown reasons, and does not show up in multibit(version 0.5.16). Which one is accurate, and how can I sync them?


texts: Is there a way to create a tx completely offline? Maybe with a script or cli commands?

texts:
I mean generating the transaction itself offline, assuming I know in advance how much bitcoin a UTXO has. In other words, without querying the network for the UTXO balance.
Then I also need to sign that tx, also offline.
And finally I can pass the signed tx to someone via bluetooth, and then he can drive to an Internet connection, and broadcast the tx.
I'm pretty sure there isn't a wallet that does this, so this needs to be some special script or a sequence of cli commands


texts: I have recently finished installing the Bitcoin client. One site i was using to help guide me is called http://www.weusecoins.com/en/. On the mining guide section of that site it says, If you're mining on your own you need to start by setting up your Bitcoin client and set it up for JSON-RPC. I was trying to figure out what it is and how to set it up if i need it but i could not figure it out. My questions then are what is JSON-RPC and do i need it ? Is it set up by default in the original Bitcoin client ?


texts: Would a service for automated repurchasing of Bitcoins encourage spending?

texts: We launched Reload, an online service that binds your bitcoin wallet to your bitcoin exchange account (16 supported so far): whenever you spend bitcoins from your wallet, Reload will use your exchange account to immediately repurchase the same amount of bitcoins. Reload also enables automated reporting and bookkeeping. Do you think such services might encourage Bitcoin spending? Are you repurchasing Bitcoins automatically with some other service already? Do you find this kind of service useful?


texts: How do i loop through all the related address in a given wallet address

texts:
I am using bitcoin block chain API, it is possible to get amount sent in a transaction id and the addresses it was sent to. My problem is getting the RELATED ADDRESSES to the address that sent the payment.. The only fact is that I want to be able to validate who sent the money and who it was sent to.. eg. my site involve users sending bitcoin to other users and submitting transaction ID. Each user register and input their wallet address. if User A sends to USer B and submits transaction ID, I want to be able to find out if the transaction is coming from the Sender User and is going to the Receiver Address. Validating for the receiver address is simple with my lines of code:

$requesturl='https://blockchain.info/tx-index/'.$comment.'? format=json';
$ch=curl_init($requesturl);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$cexecute=curl_exec($ch);
curl_close($ch);
$result = json_decode($cexecute,true);
for($i=0; $i<count($result['out']); $i++) {
$result['out'][$i]["addr"];
}

I can get the receiver addresses from the loop above and validate, and if want to get the sending addresses it is also possible with:

for($i=0; $i<count($result['inputs']); $i++) {
// the addr is in the input
}

Now my problem is if the wallet Address the User A submitted on our website is not in the sending address list, how do I know his address is there in the list.?


texts: How to 'buy the dip' without constantly incurring network fees?

texts:
I'm a newby to the crypto world and one thing that I have seen a lot of is people saying to 'buy the dip!'.
Fair enough, I like that idea. However, I have limited funds, and so thought that the best way to go about this is to wait until Bitcoin is up, sell a bit, wait until the next dip and then buy some more...
The problem is that I do not want to keep all my coins on an exchange like Binance (there are a lot of horror stories floating around there), so I want to move everything to e.g. Exodus. That's fine, but then I will need to constantly transfer between Exodus and an Exchange when I want to sell or buy. This will undoubtedly incur high network fees.
What is the best way to go about this, without spending huge amounts on network fees? Can I convert some of my coins to a stable coin (if so, which one?) when selling and then convert back to my coin of choice when buying?


texts: Dogecoin daemon (dogecoind) returning "Method not found" error

texts:
I am trying to play with dogecoin deamon useing node-dogecoin library.

Unfortunately most calls I try return "Method not found" error

for example :

 dogecoin
.auth('MyUserName', 'mypassword')
.getNewAddress()

The only method I've managed to run successfully so far is :

.getmininginfo();

which makes me feel that deamon is working.

what could be the problem?

thanks.

Edit : debug.log file.

2015-02-16 05:47:57 GetNextWorkRequired() : RETARGET; target: 60, actual: 150, modulated: 71, before: 1b3b3a63, after: 1b461628
2015-02-16 05:47:57 UpdateTip: new best=7db9ae84010185d708f5f1236dd5102b5b4c904bb1099c388485721d2e5b449e  height=194311  log2_work=59.309095  tx=9406440  date=2014-04-24 07:24:42 progress=0.292254
2015-02-16 05:47:57 ProcessBlock: ACCEPTED
2015-02-16 05:47:57 ProcessBlock: ORPHAN BLOCK 152, prev=793c3f50e6725b056963fae977131f16b15b0d1b7e1c9c550fe8cec9a092f126
2015-02-16 05:47:57 ProcessBlock: ORPHAN BLOCK 153, prev=d54393112610200c1d47fb7ced2f9eb8d33f241fec209dfb2cc4502b462b5cb3
2015-02-16 05:47:58 ProcessBlock: ORPHAN BLOCK 154, prev=3a2c422d3996c80bceef7e0a6901178ddf84d00c97d08990be63b4028e99abf7
2015-02-16 05:47:58 ProcessBlock: ORPHAN BLOCK 155, prev=2dbaee58af92c0c92ea500bf88992c02ddddfb5ca7e3c2a1416b27c4f1b9cb9d
2015-02-16 05:47:58 ProcessBlock: ORPHAN BLOCK 156, prev=9058c7d4c4439c074ffb58213a169ed524c142877230cb1823a637c468aec544
2015-02-16 05:47:58 ProcessBlock: ORPHAN BLOCK 157, prev=012a8d8caa54c4115d05433390c060af3ed9d35f4761487bdf94a47aada02335
2015-02-16 05:47:58 ProcessBlock: ORPHAN BLOCK 158, prev=0840f526c0828e6fe1dc9513dfd34acbf3bae8e8bbef719807d7f50180bf3c80
2015-02-16 05:47:58 ProcessBlock: ORPHAN BLOCK 159, prev=4b2ae3b0e5d79b8eb01146128ce98f608d42c450dca75aebe47d8ea072e144ff
2015-02-16 05:47:59 GetNextWorkRequired() : RETARGET; target: 60, actual: 29, modulated: 57, before: 1b461628, after: 1b42950c
2015-02-16 05:47:59 UpdateTip: new best=67981a7bdbbf610ce6bc35ac7065aadbb02c66bbfdb811a133692bc44731aec4  height=194312  log2_work=59.309103  tx=9406445  date=2014-04-24 07:24:56 progress=0.292254
2015-02-16 05:47:59 ProcessBlock: ACCEPTED
2015-02-16 05:47:59 ProcessBlock: ORPHAN BLOCK 160, prev=3872f8f2114d76d82fce03f96a9183f2e623627f0395b0166ecacd4bd604bc47
2015-02-16 05:47:59 ProcessBlock: ORPHAN BLOCK 161, prev=92f508ebcd8f8c5495d14cfbde46a82a6fd40ba00278b8f6d9547df1fb478e99

w.


texts: Can a 0 confirmation Bitcoin Core change output be spent?

texts:
I have a Bitcoin Core wallet which has a utxo which I spent from, in a transaction where around 1% was sent to an external wallet address, with the ~99% change output remaining in the wallet, sent to a new internal change address selected by core.
The fee used turned out to be too low and I am still waiting for the transaction to be confirmed, and now when I attempt to spend using the balance that is displayed in the wallet (with getbalance endpoint), I am told there is "Insufficient funds.".
But when I list the wallet utxos with listunspent, "spendable" has value true for the change output mentioned above - this is what I expected since my understanding is the core wallet by default will use CFPF to still spend an unconfirmed change output (please correct me if this is wrong).
My question is:
Why does the output listed by listunspent indicate that the output is 'spendable', when if I try to spend the output, it fails with an 'Insufficient funds' error?
Is there another reason for the wallet complaining that there is insufficient funds? Probably relevant is that it was an opt-in RBF tx, and I have already tried bumping the fee (still too low and not confirmed) but now would prefer to use CPFP as I have another transaction that I would like to make from the same unconfirmed change output.


texts: Is their any way to identify whether the miner is using renewable or non renewable energy for mining?

texts: Is their any way to identify whether the miner is using renewable or non renewable energy for mining ? in decentralized way?


texts: What if an intruder modify scriptSig to get the same hashMerkleRoot of a block?

texts:
What if an intruder try to modify the coinbase transaction of a block buried in the blockchain, writing as output some other address. The arbitrary content of the scriptSig field could be modified as much as necessary so that the hashMerkleRoot hash match with the one in the original block. What prevents this thing happen?

Thanks.


texts: UAHF implementing sighash, specifically, how are scriptCodes serialized?

texts:
I have managed to get correct sighashes for situations in which there are no OP_CODESEPARATOR ops in the code.  However, I cannot figure out, based on the UAHF documentation nor on the C++ code in the Bitcoin-ABC repository, how I am supposed to serialize the scriptCodes with the codeseparator OP.  Here is my serialization function (from the Picocoin C library):

void uahf_ser_scriptCode(cstring *s, const cstring *scriptCode){

    if(scriptCode == NULL){
        cstr_append_c(s, 0);
        return;
    }
    struct const_buffer it = { scriptCode->str, scriptCode->len };

    struct const_buffer itBegin = it;
    struct bscript_op op;
    unsigned int nCodeSeparators = 0;
    struct bscript_parser bp;

    bsp_start(&bp, &it);
    while (bsp_getop(&op, &bp)) {
        if (op.op == OP_CODESEPARATOR){
            nCodeSeparators++;
            fprintf(stderr,"code separator\n");
        }

    }

    if(nCodeSeparators == 0){
        ser_varlen(s, scriptCode->len);
        ser_bytes(s, scriptCode->str, scriptCode->len);
        return;
    }

    //ser_varlen(s, scriptCode->len - nCodeSeparators);
    it = itBegin;
    bsp_start(&bp, &it);
    int count = 0;
    cstring *x = cstr_new_sz(1024*10);
    while (bsp_getop(&op, &bp) && count < nCodeSeparators) {
        if (op.op == OP_CODESEPARATOR) {
            count++;
            //ser_bytes(s, itBegin.p, it.p - itBegin.p - 1);
            /*if(count == nCodeSeparators){
                ser_bytes(x, itBegin.p, it.p - itBegin.p - 1);
            }*/
            itBegin  = it;
        }
    }

    if (itBegin.p != scriptCode->str + scriptCode->len)
        ser_bytes(x, itBegin.p, it.p - itBegin.p);

    ser_varlen(s,  x->len);
    cstr_append_buf(s,x->str,x->len);
    cstr_free(x, true);

}


texts: How to generate bitcoin target from difficulty?

texts:
Reading the slushpool's manual for the Stratum protocol I found that :

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

Anyone knows how to generate this 64characters long big-endian representation of the number 1 ? I would appreciate any code in Java.

Thank you


texts:
Reading the question and the answer What happens if two miners mine the next block at the same time?, I completely agree with the answer, but there are still 3 very interesting open question:

How does one know which of the two blocks is accepted by 51%?
What prevents two blocks to be accepted by 50/50?
At which point is it obvious that a block is orphaned?


texts: Do testnet networks require the same main network fee?

texts:
As in the title, I'm wondering if testnet networks always require the same fee.

I know the coins aren't worth any thing, so it doesn't matter if I have to pay the fee or not, but I'm just curious.


texts: How difficult is it to invent a new cryptocurrency? (In regards to time, money, technical knowledge, etc.)

texts:
Although I initially believed there were only a couple cryptocurrencies available on the market, after some research, I've discovered that there are well over a thousand different cryptocurrencies!...even if a large percentage of these have extremely small market capitalizations. So my question is: What does it take to "create" a new cryptocurrency? More specifically, what degree of time, money, technical knowledge (and any other pertinent resources) is required?

*I apologize but I should have also mentioned: Since I have limited technical experience, I would appreciate a non-technical "theoretical" answer.


texts: On chain cost of Segwit version 1 versus version 0

texts: How do total blockchain cost for Segwit version 0 compare to version 1 which is being proposed? I'm specifically interested in a single user transactions – both paying to public key (or pk hash) and script (mostly asking about scripts without branching as I understand there are savings in more complex scripts with more branches). By total blockchain cost, I mean the number of bytes, vbytes and weight in both the outputs as well as the inputs that are spending these outputs. In other words, I'm asking if there will be any savings in version 1 scripts compared to the transactions that can be done on version 0.


texts: How does Bitcoin figure out what time it is?

texts:
Bitcoin needs to know the current time in order to validate blocks. How does it decide that?

Note that I'm talking about the Satoshi client specifically.


texts: Creating a multi-sig wallet with bitcoind

texts:
Our server has bitcoind on it and is running on the test network.

I want to make the wallet multi-signature so no one in our company can withdraw any bitcoin from our server without at least 3 signatures.

Can you do this with bitcoind? I tried to follow: How can I create a multi signature 2-of-3 transaction? and How users collectively sign a transaction in a multisig scenario?
.. but could still send the bitcoin from our server with:

bitcoin-cli sendtoaddress "address_here" 0.01


texts: What is NTime rolling/nonce range? And what miners support it?

texts:
From Slush's pool's homepage:

  Pool now supports Long polling and NTime rolling. Older miners have many problems with those new features, which can negatively affect your rewards. Please update your miners to latest version!

What does NTime rolling and nonce range mean for me as a miner?
And what miners support it? (+versions)


texts:
What is PSBT? What does it stand for?
bitcoin-qt has menu items "Load PSBT from file…" and "Load PSBT from clipboard…"; the dialog box says the file format is "Partially Signed Transaction".


texts: How will Mt.Gox select matching orders if asking for a price that is higher than available prices

texts:
E.g. if we have this order stock:

SELL 0.5 BTC @ PRICE $72 $/BTC (1)
SELL 3 BTC @ PRICE $75 $/BTC (2)
SELL 0.5 BTC @ PRICE $76 $/BTC (3)

And trying to buy 3.5 bitcoins for a price at $76.5 (higher than available prices). How will Mt.Gox select matching orders? Will it select the cheapest possible lines (1)&(2)? Is this equal to a market order?


texts:
How to get X value from Y?

ECDSA x,y coordinate validity verification doesn't seem to work

X = 0x79be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798

Python code,

p = 0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffefffffc2f
x = 0x79be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798
ysquared = ((x*x*x+7) % p)
print "ysquared= %s " % hex(ysquared)
y = pow(ysquared, (p+1)/4, p)
print "y1 = %s " % hex(y)
print "y2 = %s " % hex(y * -1 % p)

Output
Y1 = 0x483ada7726a3c4655da4fbfc0e1108a8fd17b448a68554199c47d08ffb10d4b8
Y2 = 0xb7c52588d95c3b9aa25b0403f1eef75702e84bb7597aabe663b82f6f04ef2777

print hex((x**3 + 7 - y1**2) % p)  // output 0

print hex((x**3 + 7 - y2**2) % p) // output 0

above python code to get Two possible y values from x

like the same how to get possible x values from y?,

Is it any formula or script available

My question is how to get x value from y

if y value

Y = 0x483ada7726a3c4655da4fbfc0e1108a8fd17b448a68554199c47d08ffb10d4b8

above y value how to get x value


texts: I want to have a Bitcoind node running in Azure. Obviously there are storage requirements from storing the blockchain, so is Bitcoind a candidate for a worker role? Or would I be better off sticking to a VM?


texts: Bitcoin extortion threat for address 14poC1Jg97vuvsyoKSZYz7h276LoAZcrtn?

texts:
I have received an email saying my computer was hacked a long time ago with a threat of realeasing personal details unless I pay a ransom to a bit coin address: 14poC1Jg97vuvsyoKSZYz7h276LoAZcrtn

Is there any way to check if the this is a hoax?


texts: How do I compile bitcoin-qt 0.13 for Windows 10 and use gdb (or similar) to debug it?

texts:
Currently I'm working on a fork from 0.13, so apologies if this is documented in later version.

I'm cross-compiling bitocin-qt for Windows 10 (following the instructions in the build-windows document), although technically I would consider running an X11 version instead. My preference is to compile the Windows native version and be able to use gdb in the same way that I can do under Linux.

Is this possible?


texts: Understanding how initializing the Ledger Bitcoin hardware wallet works

texts:
One can find the Ledger Bitcoin source code here:
https://github.com/LedgerHQ/app-bitcoin
I am trying to understand how a Ledger app account is initialized or restored.
Can someone point me to another 'official' project, which is communicating with this Ledger firmware?
Wallets typically have user functionality to initialize or restore a wallet. I am interested in how this is mapped or delegated to the hardware device.
I am interested in the parts where APDU commands are sent to the device to initialize or restore the device.
Sorry if this question is vague, or contains factual errors.


texts: Will Lightning be implemented on Bitcoin network?

texts: Lightning cannot currently operate with pruned nodes. I presume without limitation the same applies to SPV nodes. Will Lightning be implemented on the Bitcoin network?


texts: 2-factor authentication key formats for Kraken and Bitstamp

texts:
Does anyone know how to format the string that you type into the Google Authenticator app in order to generate 2FA codes for Kraken? For context, the following URL is highly relevant:—

https://github.com/google/google-authenticator/wiki/Key-Uri-Format

I accidentally deleted everything from my 'phone, so I had to re-install the Google Authenticator app. Unfortunately, my backup file just contains the secret component of each key, and I don't know the format for the rest of the string. For Poloniex, it's enough just to enter the secret while setting up the app, but other exchanges reject this minimalism. Presumably, they want something in the style of

otpauth://totp/BobsExchange:alice@example.com?secret=ABCDEFGHIJKLMN12&issuer=BobsExchange

…where I know that I'm Alice, that Bob owns the exchange and that my secret is ABCDEFGHIJKLMN12. What I don't know is the exact format.

Bonus marks if anyone can answer this question for Bitstamp as well as Kraken. Official support is likely to be overwhelmed during the present cryptocurrency boom.

EDIT: If you've got 2FA set up on your Android 'phone, it means that you have an sqlite database file on it somewhere, with the answer to my question. This page suggests that it's at /data/data/com.google.android.apps.authenticator2/databases/.


texts: How to securly move bitcoins from a wallet.dat file to a paper wallet?

texts:
I have an old wallet.dat file with a few Bitcoins. It is stored in an isolated computer that is not connected to the internet.

I would like to get rid of the wallet.dat file, and move all the Bitcoins in it to a few separate paper wallets (created using bitaddress.org).

The naive approach would be installing Bitcoin-QT, and make the transaction. Unfortunately, this is insecure - hackers could potentially steal my Bitcoins while I am online.

The secure way should probably be something like:

Import the private key from wallet.dat using some command-line tool, on the offline computer.
Sign a transaction on the offline computer.
Copy the signed transaction (sans any private key!) to an online computer using a flash drive.
Publish the transaction from the online computer.

I've inspected a few tools, including Electrum and Armory, but I seek for your advice regarding the simplicity and safety of these tools.

Any advice how to sign a transaction offline and publish it offline, to salvage the bitcoins from my wallet.dat file?


texts: Lightning Network: what about tx fragmentation?

texts:
I really have no idea how to aks it right. Let me give an example:
We have a some peoples A,B,C,D.... And A makes transaction to B, then A need to pay to C, then send some coins to D, etc... After closing channel A must pay fee like in onchain transaction. So there is no reason to use lightning when A need to pay some coins to different recepients?
I hear lightning can do decentralized exchange. Can someone give an example how it will work with less fees (or zero fee if it possible)?

Another example: if A trade BTC with B,C,D,E.... And A got +0.01BTC for each trade, then B need to pay 0.01 BTC, C pay 0.01BTC..... There is a lot onchain inputs, so a lot of fees (after channel close)

Sorry for my English


texts:
I found a web site where you can win bitcoins, freebitco.in. How do they work? Do they use JavaScript to mine for bitcoins on your client?

And when do you get the mBTC you win there?


texts: Pending transaction towards a not syn wallet

texts: Hi guys need a bit of help I send my ember coins from cryptopia to old ember wallet address which is not syn my transaction is coming in pending since 2 days..how do I cancel my transaction so the coins r back to available.


texts: Can Copay iOS wallet sync with the Copay oSX wallet? Hoping to use the same wallet across both devices.


texts: How to set up a private chain/local testnet : reverse engineering the blockchain code

texts:
Long story short, I want to set up a private chain/a testnet blockchain that can run locally just to fiddle and play with it just to learn how it works. So I have a general understanding of how things work and thought that to really learn I would need to reverse engineer and play with it as much as I can.

So, how would I go about that?
What I am looking for is ideally a step by step clear, beginner friendly explanation because I am aiming at blockchains written in javascript (lisk, nimiq) or, in python(bismuth)

Let me first tell you what I thought of or, what I think concerning ways to do that. I imagine I would have to:

Decide which existing blockchain would resemble the most with what I have in mind regarding the consensus algorithm
Download it from GitHub
Establish a dev environment
Run different tests and let my brain do its magic

Now with regards to those steps, I have few questions:

Am I missing something like an intermediary step let’s say?
Regarding step 1 where should I look, what parts of a blockchain will be the deciding factors for me choosing one over the other say considering that I want to introduce a new consensus algorithm?
Regarding step 2, how would I download a blockchain but ignore the transaction history (this will be a new altcoin starting with genesis block) or is that more like something I change within the code not sure?
Regarding step 3, this is where I would appreciate a step by step response since I have no idea what to download and what steps to take to get from: "I have the code" stage to "I can play with it and test different things" stage.
Regarding step 4: except deleting part of the code, changing variables value, switch order or lines what else could help me to understand better how the code works?

Thank you


texts:
I'm living in Turkey and I bought some bitcoins from here.
If, for example, I have a neighbour in America and he bought bitcoin from a different platform, can I transfer my bitcoins to him? And can he transfer it to me?


texts: 2nd 'air-gapped' computer / cold wallet setup for travel

texts:
I travel quite a bit and don't want to lug around a 2nd 'air-gapped' computer. I know that connecting a hardware wallet like a Ledger Nano S to the Ledger Live desktop app running on a computer that's connected to the internet not considered a 'fully cold' wallet setup.

I asked if a non-networked VM would do but it sounds like there's no extra security with that.

So, what would be a good solution for a 2nd 'air-gapped' computer for travelers? Perhaps Tails installed on a USB stick or 'OS on a stick' products that are out on the market, such as the Intel Compute Stick:

https://www.amazon.com/Intel-Compute-Computer-Processor-BOXSTK1AW32SC/dp/B01AZC4NHS

https://www.amazon.com/Intel-Corp-BOXSTCK1A8LFC-Compute-STCK1A8LFC/dp/B00W7KAABK

I'm looking for a solution where I can use my laptop's screen and keyboard.


texts:
Possible Duplicate:
  How can I compute mining profitability?

Do bitcoin miners like the one depicted in the video below with 24 server clusters actually profit from bitcoins at the current prices? Are the bit coin exchange rates high enough to cover their costs of electricity and hardware? And is there enough liquidity in the market to actually unload them?

Or are all these miners hoarding them in hopes the idea will take off in the future?

Bitcoin Mining Rig - 24 Machine Setup - 48Gh


texts: 24 Word Mnemonic Seed Phrase for Ledger Nano S usable on Trezor?

texts: Can I use my 24 word mnemonic backup seed phrase that created on my Ledger Nano S on other devices that use a 24 word seed phrase? An example would be the Trezor hardware wallet.


texts:
I'm working on a multisignature cold storage wallet that adds several features to the Glacier Protocol wallet, namely PSBT support through bitcoin-cli's RPC interface. The wallet intentionally uses a very restricted portion of the PSBT standard in order to make the code as short and easily auditable as possible. I define a function validate_psbt() that aims to exhaustively check whether or not a PSBT is safe for a user to inspect and sign:

A user inputs the M & N policy, 1 xprv and N xpubs at the start of the signing process
The only valid wallet addresses are wsh(sortedmulti(M, [xfp_1]xpub_1/change/idx, [xfp_2]xpub_2/change/idx, ... , [fp_n]xpub_n/change/idx)) where change in {0, 1} (i.e. derivation paths for each xpub must be the same). Only using segwit addresses should prevent signing inputs that overspend fees for example.
The wallet only allows users to sign transactions that spend their own inputs.
To be considered change, sufficient metadata must be provided for output at idx, which the wallet uses to calculate an address cross-checked against the address in the PSBT's tx.vout[idx] field.

Are there any missing validations that need to be performed in this process to ensure that a maliciously created PSBT doesn't pass the safety check, letting a user unknowingly sign away / lock up her bitcoins?


texts: Bitcoin core wallet transactions and synchronisation

texts:
I have Bitcoin Core wallet.

I wanted to know if each transaction I need sync the wallet?

(I have a new business that accept bitcoin and I must to save each transaction)


texts: Does the Share Difficulty given to each miner matter?

texts:
I am running two 7970's and am adding a 3rd here in a few days (Mainly a Gaming Rig)but mining when I am not gaming.  I was wondering though does the minimum share difficulty that BTCguild sends to my miners make a difference?  Currently it is just the default of 1 but can go all the way up to 256 share difficulty. What is going to yield the best results for my hardware?

I am still quite new so any other advise is appreciated!


texts: Trezor; How is it true cold storage if their is a recovery seed?

texts:
I don't understand how a Trezor is considered cold storage if you can lose it, and then recover your keys through their recovery seed and another Trezor.

Where are the keys coming from?

Where are they being stored?


texts: bitcoind not booting, tons of output in debug.log file

texts:
running $ bitcoind -server just hangs, when I look at my debug.log file it's going really crazy:

2016-03-19 01:26:51 UpdateTip: new best=00000000000005f9ff6fe1e9e19f6f64dd9c1167077b7de4b93146df2e6f1004  height=192099  log2_work=68.48247  tx=5576861  date=2012-08-03 09:07:41 progress=0.022371  cache=46.6MiB(128445tx)

The docs show me that running bitcoind should have asked me to set a password, but I never got that. Is something going wrong? Thanks


texts: Is it possible to exchange bitcoins into PayPal credit?

texts:
I'm aware that PayPal's terms of conditions do not allow for purchase of virtual currencies such as bitcoins, however, is it possible to sell bitcoins and receive PayPal credit in return? MtGox allows you to exchange BTC > USD, but there's no way to withdraw it using Paypal or a similar service.

Is there an exchange that supports either MtGox coupons or direct bitcoin transactions to top up a PayPal account, without the use of a credit card or bank transfer? I'm interested in more obfuscated methods/workarounds as well, even with the use of multiple exchanges.


texts: How many computers are connected to the "Ledger" or the Blockchain of Bitcoin?

texts: Somebody asked me about Bitcoin and I explained to him many many computers are connected to the Blockchain to keep records of all the accounts (or to keep addresses of the bitcoin and owner?). But how many computers are connected to it, as of recently or 2020?


texts:
I am sure this has been asked before but I want to be absolutely sure before I start:

Using the Electrum Software I have created a basic default wallet on my desktop. I have a good deal of money stored in it and I plan to leave it there for a year, hoping the price of bitcoin will rise.

My question: If after a year, my computer hard drive fries, I forget the public and private key, I don't remember my Electrum password and I hardly even rememeber what Bitcoin is, will I be able to recover everything with only the 12 word seed I have?

I could even delete my wallet and unistall Electrum, move to Mars and if I had an internet connection and the seed gain all my bitcoin back correct?

EDIT: I just want to add, that I don't wan't to use a paper wallet just in case I decide to temporarily use some of the money although I don't plan on using it I want to have the option.


texts: Where can I find a roadmap of the main bitcoin client?

texts: Wallet encryption is long overdue, and AFAIK is coming in the next client version (0.4.0). What are the next planned milestones in the development of the main client and/or protocol? Where can I find information about that?


texts: Electrum: How to generate hardened public addresses with HD BIP32 wallet

texts:
Please comment on the accuracy of this explanation.

Scenario: The master public key is compromised and so all non-hardened public addresses can be generated and monitored by a third party. This negates the privacy gained from avoiding address reuse. (The third party cannot spend any bitcoins from these addresses however).

Hardened public keys cannot be generated from the master public key, and a priori cannot be attributed to the owner of the non-hardened addresses above.

Is it possible to generate such hardened keys in Electrum, and if so, how?


texts: What are test_bitcoin.exe and test_bitcoin-qt.exe?

texts: These two binaries appeared in Bitcoin Core a few versions ago, but I don't remember ever seeing an explanation of what they are and what you would use them for.


texts: Pools combine power, but all focus on a block? How do they all earn?

texts:
So,
As far as I understand, when you join a pool you help work on the block that they are currently trying to solve and get paid for. I understand that, and how it's all split up....

But with a ton of different pools working on the same blocks... They all seem to pay out EVERY block... How? Surely one is faster than another, and solves the block first, being paid all of the winnings?

How does everyone on different pools get paid for each block? I understand that if it's too slow they'll get nothing... but how?
Thanks.


texts: When using createrawtransaction, are the outputs ordered as they are presented within the request?

texts:
Let say, when I set second parameter of craterawtransaction call as below

[{"demoaddress1": 0.42}, {"demoaddress2": 1.00}]

Is it possible to occur that returned transaction's output is not ordered as same? like below

[{"demoaddress2": 1.00}, {"demoaddress1": 0.42}]


texts: How can i solo mine with antminer? Using local bitcoin core

texts:
I am having trouble setting up mining with antminer.
I have a gpu rig which is successfully mining with 2060 rtx on bitcoin with bfgminer at a hashrate of 1.5gh/s
Obviously 1.5gh/s is nothing compared to what can be achieved with the antminer
So went and got an antminer promising speeds of dozens of th/s
I can do pooled mining with it and get the advertised speed
However i wish to have a go at setting up solo mining with my antminer
Which software would you recommend to use in conjunction with the bitcoin core client? It seems i am unable to use bfgminer with my antminer for solo mining
The information i have access to so far with google search and searching on this website is very limited or most of it is outdated
No comments on how unlikely it is i will profit. I want to get it working so please stay on topic


texts: What does a negative Ripple balance mean?

texts:
I just sold some BTC for XRP, and managed to get a negative balance. WTF?

Transaction ID - E2D1BBD7A602E9D5B16FD79819A0347E18DED7F988F2F4C9EA3854BFCB4D3664


texts: Alternative uses of a blockchain-mechanism?

texts:
Bitcoin's blockchain is basicly just a mechanism to record timestamped entries. Bitcoin uses it as a transaction ledger, but it could be used for many other things.

For example, one could create a chain for a decentral chess-game, where each move is an entry in the blockchain. All nodes can verify if the players turns are by the book, and in the correct order, and decide who is the winner.

Can anyone think of other examples of alternative chains?


texts: Why is the Bitcoin Wiki protected against editing?

texts:
I recently found an error on the Bitcoin Wiki, when I noticed that I could not edit it.

I made an account a long time ago, so I logged into it, but still I am not able to edit pages.

Why is this? A wiki is supposed to be community-driven.

Who does have access to the wiki pages?


texts:
Sorry for the noob question I'm pretty new to crypto coins and all this stuff. :)

I wonder why the formula <your hashrate> / <coin difficulty> gives the mined coins as a result...Formula mentioned on xmg.minerclaim.comQuote:

  "XMG/Day" is calculated by the current Hashrate/Difficulty. Due to the
  fact that difficulty is constantly changing, this is only a rough
  estimate.

Example (from altcoin Coin Magi):

If I have a hashrate of 3.211 MH/s and the coins difficulty is 2.599 (approximately) then my earnings per second (because it's H/s) should be

  3,211,000 / 2.599 = ~1235.47 coins per second

and

  1235.47 * ( 60 * 60 *24 ) = 106744608 coins per day

How can this be? The 'fastest' miner (highest hashrate) has 3.211 MH/s and is 'only' earning 32.892 XMG per day?

Did I do something wrong? Is minerclaim wrong? And what's a good formula to calculate mined coins per day?

Thanks in advance!


texts:
How do I use my wallet.dat on my windows 8 bitcoin qt?

Someone posted this

C:\Documents and Settings\YourUserName\Application data\Bitcoin (XP)

C:\Users\YourUserName\Appdata\Roaming\Bitcoin (Vista and 7)

but I'm on windows 8, so i don't know what to do


texts: How can I sell my Bitcoin Gold? Do any exchanges support BTG deposits?

texts: Given I have Bitcoin Gold in my own wallet, what practical ways are there to trade this, either to other crypto-currencies or to fiat? Is there a list of exchanges that support Bitcoin Gold deposits?


texts: How do I host an testnet Electron Cash (Electrum fork) server or where can I find a working one that is online?

texts:
I have not been able to find any working nodes for Electron Cash in testnet. Does anyone know of an existing node that is up to date and matches the height of a tesnet Bitcoin Cash explorer: https://www.blocktrail.com/tBCC

Thanks!


texts: How do I create a new genesis block for an altcoin?

texts:
I'm trying to clone the Blackcoin sourcecode just for the hell of it but I can't seem to generate a genesis block. I can do it on normal coins, but not here. The Blackcoin developers seem to have shifted a lot of code into weird places.

For example, all of the coins major parameters are in chainparams.cpp. However, there is no code in the link above or in main.cpp to create a genesis block.

How do I make a genesis block for this coin?


texts: Each BIP (Bitcoin Improvement Proposal) has a assigned number. For example BIP-2, BIP-42 and BIP-152. How does this number get assigned and by whom?


texts: How to ./configure a built for Raspberry Pi?

texts:
I want to use this guide to set up a headless bitcoin core full node and came across the line:

./configure CPPFLAGS="-I/usr/local/BerkeleyDB.4.8/include -O2" LDFLAGS="-L/usr/local/BerkeleyDB.4.8/lib" --disable-wallet

Unfortunately, the blog does not explain why he uses this.

First of all, I want to use my node with wallet. Second, I want to configure it to be usefull with a Raspberry Pi which has only 1GB of RAM and is also running other stuff, for example my Logitech Media Server for audio streaming. So I would like to make the node as lean as possible.

I know that I can use a config file for running  bitcoind with entries for upload limit and other setups. Do I need to run the skript also with options or are both setups interchangeably?

Also, I get the error Found Berkeley DB other than 4.8 upon configure. Can Ihave a wallet with the BDB other than 4.8? The error message suggests, that 4.8 is needed for "portable wallets".

Here I found out about dependencies for the wallet and also about the option to built without GUI. Unfortunately, I cannot successfully ./configure with those neither, because BDB 4.8 is also not found this way.

However, to do it without GUI the option --without-guican be used, which is very usefull.

EDIT: I encountered another problem while make:

/usr/bin/ld: cannot find -ldb_cxx-4.8
collect2: error: ld returned 1 exit status
Makefile:4779: die Regel für Ziel „bitcoind“ scheiterte
make[2]: *** [bitcoind] Fehler 1
make[2]: Verzeichnis „/home/pi/Downloads/bin/bitcoin/src“ wird verlassen
Makefile:12975: die Regel für Ziel „all-recursive“ scheiterte
make[1]: *** [all-recursive] Fehler 1
make[1]: Verzeichnis „/home/pi/Downloads/bin/bitcoin/src“ wird verlassen
Makefile:776: die Regel für Ziel „all-recursive“ scheiterte
make: *** [all-recursive] Fehler 1
19:07:10 [pi@raspberrypi bitcoin]$ /usr/bin/ld: cannot find -ldb_cxx-4.8
-bash: /usr/bin/ld:: Datei oder Verzeichnis nicht gefunden

Here I found an answer to a related error and I used ld -ldb_cxx-4.8 --verbose and got this:

attempt to open //usr/local/lib/arm-linux-gnueabihf/libdb_cxx-4.8.so failed
attempt to open //usr/local/lib/arm-linux-gnueabihf/libdb_cxx-4.8.a failed
attempt to open //lib/arm-linux-gnueabihf/libdb_cxx-4.8.so failed
attempt to open //lib/arm-linux-gnueabihf/libdb_cxx-4.8.a failed
attempt to open //usr/lib/arm-linux-gnueabihf/libdb_cxx-4.8.so failed
attempt to open //usr/lib/arm-linux-gnueabihf/libdb_cxx-4.8.a failed
attempt to open //usr/local/lib/libdb_cxx-4.8.so failed
attempt to open //usr/local/lib/libdb_cxx-4.8.a failed
attempt to open //lib/libdb_cxx-4.8.so failed
attempt to open //lib/libdb_cxx-4.8.a failed
attempt to open //usr/lib/libdb_cxx-4.8.so failed
attempt to open //usr/lib/libdb_cxx-4.8.a failed
attempt to open //usr/arm-linux-gnueabihf/lib/libdb_cxx-4.8.so failed
attempt to open //usr/arm-linux-gnueabihf/lib/libdb_cxx-4.8.a failed
ld: cannot find -ldb_cxx-4.8

Now trying with sudo apt-get install gcc-4.8 g++-4.8. That did not help.

Maybe I have to try this guide: https://medium.com/@meeDamian/bitcoin-full-node-on-rbp3-revised-88bb7c8ef1d1


texts: Calculating the target from the hash leading off bits

texts:
I'm implementing my own cryptocurrency and I found it that saving the "hash difficulty” as the leading off (0) bits of a 256 bit number in a SHA-256 hash is the most intuitive.

I'm struggling to find a way to calculate the bitcoin equivalent “target” from that number.

Additionally I wonder why it is not implemented that way in the bitcoin protocol? Does it cause too harsh steps of difficulty?


texts: How is the value of a forked currency being determined?

texts:
As in the case of Bitcoin's hard fork Bitcoin Cash, what determines the value of the forked currency?

Say before the fork I had X BTC; then now after the fork I have X BTC and X BCH. What does affect the value of my X BTC? What does affect the value of my X BCH? What does determine the market caps of both currencies? Is it a group of big backers that come to an agreement on shifting their assets to the forked currency? Can you think of it (in the bigger picture) as: post_fork_BTC_market_cap = pre_fork_BTC_market_cap - initial_BCH_market_cap? Or otherwise the forked currency's market cap is "imported" from a combination of different market caps?

Note: I used Bitcoin and Bitcoin Cash as an example, without loss of generality.

Another approach that comes to my mind is to think of it as an ICO funding. Let's say that there is currently a circulating supply of 800,000 FOO (Foocoin), and now I'm creating a fork of Foocoin called Barcoin (BAR). I funded 200,000 FOO for this purpose at an exchange rate of 1 FOO = 500 BAR, so the initial circulating supply of Barcoin is 800,000 + 200,000 * 500 BAR = 100,800,000 BAR, so that eventually each one of the funders has lost some value, while each one of the FOO holders has gained some value in the form of an "airdrop".

For example someone who had ~2000 FOO now also has ~2000 BAR that equal to ~4 FOO; this is without correlation to the market cap of FOO. But if this person funded Barcoin using Foocoin, then it is resulted in less profit out of the fork. But then nobody will fund this project unless it's completely necessary from the person's viewpoint.

Is it something like this?


texts: How vulnerable are offline users of bitaddress.org, who don’t use Ubuntu?

texts:
By not installing Ubuntu and not removing the hard drive, I suppose I am vulnerable when I open bitaddress.org offline and enter the 64 random hexadecimal characters I have generated without a computer to find corresponding public address.

Yes, I clear the browser before re-connecting to the net. I never use the mouse to copy the private address (or indeed keep any computer record of it) but, if malware can pick up the 64 random hexadecimal characters which I typed in or if it can take a screenshot of the private WIF address I am screwed.


texts: How thoroughly has Segregated Witness been tested?

texts:
I've encountered claims that Segregated Witness was "not really tested" and is being "rushed".

It is my understanding that SegWit had been running on Elements for more than half a year already, and that it is currently being run on its own testnet.

Has development of SegWit been rushed?
What level of testing has been performed on Segregated Witness?
Is it reasonable to expect SegWit to be sufficiently tested and ready for deployment in April?


texts: What is the current computing speed of performing an elliptic curve multiplication?

texts:
Hi I was just looking for some information on how long it would take to crack a private key in bitcoin using a brute force approach and I couldn't find a very good answer for how long it takes to check whether one specific key (or every key) would work.

So essentially what I am asking is how long would the elliptic curve multiplication process take to check whether a single private key would work for a given public key (on average), thanks :)


texts: Will the amount of electricity used for mining be huge if Bitcoin is widely adopted?

texts:
A quick and very rough estimation: If the USD/BTC exchange rate grows to $1000/BTC (not that far-fetched if Bitcoin is actually widely adopted) bitcoins for a value of $300000 would be produced every hour, given the current rate of 50BTC each 10 minutes. This should mean that the amount of money spent on mining is roughly the same, $300000/hour.

Given an electricy price of $0.01/kWh that means that 3GW, i.e. a rather large power plant, would be used solely for mining.

Is there anything fundamentally wrong about the above calculation? Is it a problem?


texts: What are realistic expectations for an ethereum miner on AWS?

texts:
I've configured the large (8x) GPU image on AWS at 2.60/hour. I ran it goes few hours after setup and mined nothing.

This was my first foray into mining.

Does this size instance give me a reasonable chance of being able to successfully mine? Or am I so underpowered that the probability is too small?

It may also be that I don't fully understand the concepts so feel free to tell me so :)


texts: What is the best way to pull miner's fee associated with a list of transactions?

texts: I have a spreadsheet containing the transaction ID, datetime, and BTC amount of 800,000+ transactions associated with a BTC address (includes both sent and received transactions). Now I am trying to add another column listing the fee paid for each of those transactions. What is the (1) fastest (2) easiest (3) most efficient way to do that? Please explain in detail if technical know-how is required, because I am a novice in coding.


texts: Practical application of Electrum's Encrypt/Decrypt message feature?

texts:
It's pretty clear how signing a message with a Bitcoin key can be useful in proving ownership of funds.

However, it's far from clear how encrypting a message with a Bitcoin key can do anything useful. This feature is available from Tools/Encrypt/decrypt message, and appears to use ECIES or some variant of it:

https://en.wikipedia.org/wiki/Integrated_Encryption_Scheme

It seems that at least one developer is doubtful about the security of such schemes:

https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2014-August/006581.html

Security aside, what practical reason would anyone have to encrypt a message with a Bitcoin key?


texts: How can the transaction history be checked when new addresses are generated?

texts:
When a new transaction is executed via a Bitcoin-client, the sender will have a different address than the ones used in previous transactions. I also know that all the full nodes in the Bitcoin network maintain a ledger, which is basically a history off all Bitoin transactions ever made so the nodes can check the integrity of the system and the current amount of bitcoins people have available in their wallets.
How is it even possible to check all the transactions when there are constantly new addresses being generated? You can't even link a current transaction to the previous. Is there something I'm missing?


texts:
I'm still new to all this, but would like to know how to make a clone of bitcoin, including required files and sources.
Thanks


texts: How does the Segwit2x fork implement replay protection?

texts: The creators of the Segwit2x fork claim that they are working on some sort of replay protection. What replay protection do they have and how does this replay protection work?


texts: More than 1000 CPU solo mining = bitcoin?

texts:
If I have 1000 (or more) machines with CPU (and no GPU) solo mining (12 hours/day), will it be profitable?

Forget about the costs of electricity, etc...

I want to know if doing more than 1000 machines solo mining (CPU) will win any bitcoin?


texts: Calculation for transaction input-output balling:

texts:
To roughly calculate transaction send size in bytes we do:

((numberOfInputs*148)+(numberOfOutputs*34)+10)

  We want to make a transaction using two inputs of 0.01BTC (Amount to send = 0.015BTC, change left over = 0.005BTC). Number of outputs in this case will be two; as we have two inputs, one of which we are 'tearing-in-two' creating change that will be sent back to us (we are the second output so the change is not lost).

So to calculate the fee

We calculate the value of each input in BTC multiplied by the age of the input in blocks
Add up all the answers into a total priority
Divide the priority by the size of the transaction in bytes
If this gives a number less than 0.576 then the transaction requires a fee
Also if the transaction size exceeds 1000 bytes it requires a fee

If both inputs were 1000 conformations old, a fee would be required:

((0.01*1000) + (0.01*1000)) = 20 //priority
((2*148)+(2*34)+10) = 374 //bytes
20 / 374 = 0.053475935828877004

If both inputs were 11000 conformations old, a fee would not be required:

((0.01*11000) + (0.01*11000)) = 220 //priority
((2*148)+(2*34)+10) = 374 //bytes
220 / 374 = 0.5882352941176471

Is this correct?

If one input was old dust and the other new and large (this looks free to me):

((0.00001*11000) + (1*1000)) = 1000.11 //priority
((2*148)+(2*34)+10) = 374 //bytes
1000.11 / 374 = 2.6740909090909093

Does this explain how you can put a dust-input with a large-input to rescue dust?

Will the threshold of 0.576 change in the future and if so how will we find out?


texts: I received multiple transactions at one address, but may have screwed up wallet. Not sure what my options are.

texts:
Some years ago, as an experiment, I took part in a mining pool and received a number of Bitcoin payouts, all to the same address. Then I stopped mining. I didn't spend any of the balance I had accrued.
However today for the first time in years I decided to fire up my wallet software and after sync'ing (yes, it took ages!) it appears to have zero balance.
I can look on https://blockchain.info at the receiving address I'd originally used and see all the payments that took place originally, with the total value that I expect. But somehow it looks as though I've screwed up whatever connection there was between these and what I thought was my wallet.
I'm completely lost in the complex world of blockchain, wallets, addresses, keys etc. I thought I had all the info I needed to 'prove my ownership' of these Bitcoin payments I'd received, but clearly something's missing in what I've done.
Can anyone suggest a way that I can 're-acquire' these payments somehow?
Apologies if the terminology I'm using isn't entirely appropriate - I seem to have forgotten whatever little I once knew about Bitcoin :(


texts: Is anyone mathematically adding a Brain Wallet key with a hosted wallet (like vanitygen) for extra security?

texts:
This question is inspired by how the Vanity Gen pool operates.  Basically there are two sets of keys and addresses: one that is stored at the Wallet hosting provider, the other set is derived from a Brain wallet.

In order to sign the transaction, the keys are combined by adding the two keys (as hex numbers) together (Pubkey + Pubkey) and (PrivKey + PrivKey).  Although I think there is an alternate implementation that multiplies the keys.

My question is, has anyone explored the concept of using a Brain Wallet in conjunction with a hosted wallet for additional security?


texts: Why is the value field 8 bytes in transaction output when it can be achieved with 7 bytes?

texts: Bitcoin uses a 8 bytes value field in the transaction output. However, the total supply of bitcoin is capped at 21M. Theoretically, even if all the 21M bitcoins are transferred to a single address, the output, after converting to satoshis, can be effectively represented with 7 bytes of data. This means, we are adding at least 2 bytes of redundant data (one for the spend address and other for change address) for every transaction stored in the blockchain. Is there a particular reason why a size of 8 bytes was chosen or was this a design flaw that was overlooked by Satoshi? Is it possible to bring a change to this via a soft-fork or does changing this require a hard-fork?


texts: Creating multiple clients inside a single lnd node

texts: I am trying to create hot wallets using the lightning network but I don't want to create a new node for each user. Is there a way to have multiple users be able to use a single lnd node?


texts: Is it possible to use a PGP key as a bitcoin address?

texts:
Both bitcoin and encrypted emailing are based on public key cryptography. However, they use different implementations, so I assume that a public PGP key cannot be used as a bitcoin address directly.

But would it be possible to convert a public PGP key to a bitcoin address in such a way that it can be accessed only with the corresponding private PGP key (or something derived from it)?

If such an algorithm existed it would allow for sending coins to people without them knowing anything about Bitcoin, as long as they have a PGP key (e.g. for giving someone a little incentive to learn something about Bitcoin).


texts: How find own address in testnet using bitcoin-cli?

texts:
I have bitcoin-core installed, I am running it in testnet mode. Now if I want to fund my wallet, I need to know the receiving address. How do find my receiving address, so that I can fund it and then complete a transaction.
I am using bitcoin-cli -testnet , what is best way to fund my own wallet so that I can send some coins to another address?


texts: How would I be able to show 24 open, high & low on my site made with php

texts:
I'm a self thought designer/developer that knows basic photoshp/css3/html5 and a little python/php. I have never used an API to fetch  stats, so can you please point me in the right direction?

I would love to show the 24 hr open, high & low price of BTC on my php site, here is the api reference: https://docs.gdax.com/?php#get-historic-rates

Could any of you make a .php file with the necessary code for me? It would be such a great help.

I got this code to get started:

<?php

// get the HTTP method, path and body of the request
$method = $_SERVER['REQUEST_METHOD'];
$request = explode('/', trim($_SERVER['PATH_INFO'],'/'));
$input = json_decode(file_get_contents('php://input'),true);

// connect to the mysql database
$link = mysqli_connect('localhost', 'user', 'pass', 'dbname');
mysqli_set_charset($link,'utf8');

// retrieve the table and key from the path
$table = preg_replace('/[^a-z0-9_]+/i','',array_shift($request));
$key = array_shift($request)+0;

// escape the columns and values from the input object
$columns = preg_replace('/[^a-z0-9_]+/i','',array_keys($input));
$values = array_map(function ($value) use ($link) {
  if ($value===null) return null;
  return mysqli_real_escape_string($link,(string)$value);
},array_values($input));

// build the SET part of the SQL command
$set = '';
for ($i=0;$i<count($columns);$i++) {
  $set.=($i>0?',':'').'`'.$columns[$i].'`=';
  $set.=($values[$i]===null?'NULL':'"'.$values[$i].'"');
}

// create SQL based on HTTP method
switch ($method) {
  case 'GET':
    $sql = "select * from `$table`".($key?" WHERE id=$key":''); break;
  case 'PUT':
    $sql = "update `$table` set $set where id=$key"; break;
  case 'POST':
    $sql = "insert into `$table` set $set"; break;
  case 'DELETE':
    $sql = "delete `$table` where id=$key"; break;
}

// excecute SQL statement
$result = mysqli_query($link,$sql);

// die if SQL statement failed
if (!$result) {
  http_response_code(404);
  die(mysqli_error());
}

// print results, insert id or affected row count
if ($method == 'GET') {
  if (!$key) echo '[';
  for ($i=0;$i<mysqli_num_rows($result);$i++) {
    echo ($i>0?',':'').json_encode(mysqli_fetch_object($result));
  }
  if (!$key) echo ']';
} elseif ($method == 'POST') {
  echo mysqli_insert_id($link);
} else {
  echo mysqli_affected_rows($link);
}

// close mysql connection
mysqli_close($link);

Thanks!


texts: Compiler optimizations for self-compiled Bitcoin Core

texts: If I compile Bitcoin Core using the instructions in the README, does the C++ compiler use compiler optimizations for my current CPU, or will it output a "generic" binary, that can run on almost any CPU? For example if my CPU supports the AVX-512 instructions, will the compiler automatically output a suitable binary or does it not take into account any CPU features at all? If so, how can I make sure I have the optimal binary running on my machine?


texts: Can i convert BAR ( Tidex ) to XRP ( Binance ) ?

texts: I need some advice, I do have some BARS with me on Tidex but I would like to send them to my Binance account but in other coin format e.g BARS to Ripple. Is it possible to do so, if any option please do let me know.


texts: Can you make altcoin vanity addresses out of those of Bitcoin?

texts:
I generated a Bitcoin vanity address having a string “TEST” in it.

> vanitygen -v -1 -F pubkey -C BTC 1TEST
Generating BTC Address
Prefix difficulty:            264104224 1TEST
Difficulty: 264104224
Using 16 worker thread(s)
BTC Pattern: 1TEST
Pubkey (hex): 0488ee6eb5f11979685086810a148f3cc25573e6b86572e8e79fc22ec7d9dc9d561e490b7f61d438eef870343e524d1f44518ed3cc86922b2ba3cff74e69e6c7b3
Privkey (hex): F0EFC073E94C15DFAF10660005B5DF0E9654636A7A9E97738524C0896092D871
BTC Address: 1TESTUYn69qjvxwmHAXWCdDL7vRDJxAo8
BTC Privkey: 5KePyu3mmr9TJxmFsqGxDR1kS8W28PKgfs4SCALi2Yf5D4UFyF8
[2.54 Mkey/s][total 184456984][Prob 7.4%][50% in 1.1min][Found 1/1]

I want to make such ones for other coins, too. If I could make altcoin vanity addresses of the same key pair preserving the “TEST,” that would save some computational resources for me.

Some altcoins seem to have similar address generation steps with Bitcoin, but not sure if there’re any cases where this idea works.

Are there any? If so, which coins, for example? If never, why is it?


texts:
How does a light node know which block its transaction got included in?

Say a light node sends out a transaction spending its UTXO. Does it get some sort of notification when its transaction is mined in some block or does it need to manually ask a full node if its transaction is present in every new block that is mined after it made the transaction?

Also, say a wallet program was loaded after a month of inactivity. Now the wallet needs to know the balance of its address? How does it go about reconstructing its balance after downloading the latest block headers?

Note here that I'm asking about the low level apis and not any service like a block explorer!


texts: Multisig refund transaction flaw in Lightning Network talk

texts:
I was watching Tadje Dryja's talk at SF Bitcoin Devs conference on transaction malleability, which formed part of the basis behind the Lightning Network.

At 17'45", I saw this example. Prior to SegWit and even before considering malleability, how is it possible to even sign a refund txn without knowing the TX-fund signatures? The funding signatures from both parties are required to create the txid that is referenced in the TX-refund input. However, if this information is known, one of the parties can send the funding txn to the network before a refund txn is ever signed, thus forcing the other party's funds into the multi-sig contract. Am I missing something?

(I think SIGHASH_NOINPUT was introduced to get around this exact limitation.)


texts:
I'm wondering about what the best practices are around generating and maintaining key pools for a wallet.

What is the maximum number of keys/addresses that can be created for a single wallet? Phrased another way, what is the largest value one can safely put for the keypool option in bitcoin.conf?

If I generate some keys with bitcoind keypoolrefill then generate some new addresses and then call keypoolrefill again, will the original addresses still work, and will my private key now work for all addresses I've ever created?

Is there some way to determine how many keys are left in the current key pool?

The Bitcoin documentation says that this feature is actively being phased out. When will this happen and what will the new system be?

This wallet type is being actively phased out and discouraged from being used due to the backup hassle.

Answers to any of these questions is greatly appreciated.

Gavin Andresen (Bitcoin's Chief Scientist) has to say on the topic:

Backup every 30 sendtoaddress or generatenewaddress and you'll be fine-- you should always have at least 3 backup copies of all your keys.
If you're running a very busy service so backing up every 30 is too often, then run with -keypool=1000 and backup at least every 300 sends/generates.


texts: I've started to implement my bitcoin client to learn the protocol and faced a problem to see debugging output. When I start bitcoind with -debug option, it start to print so many debug messages in such speed that i can't see whats wrong with my client implementation. How can I start the bitcoind program in such way that it will not sync and just listen to new connections from local machine?


texts: How would you give away free bitcoins by letting the user just scan a qr code?

texts: I'm currently trying to build a game where if the user reaches a certain amount of points they get rewarded with btc at the end of the game. But the thing is I would like the QR code to show up on the screen and the user would just have to scan it and they would receive the btc. Is there an application that can do such a thing? I'm guessing it would show the private key of the qr code. But is there a better method of doing this?


texts: How do I implement an escrow service using Bitcoin contracts?

texts:
I can see that Bitocin can provide escrow contracts. https://en.bitcoin.it/wiki/Contracts#Example_2:_Escrow_and_dispute_mediation

Can someone provide a worked example or even better a pointer to a code example.


texts:
I am trying to buy bitcoins, and I have just recently got my bank account verfied on coinbase.com, and I am trying to buy bitcoins.

When browsing the buy page,  I got the following message

  Note! We've exceeded our normal buy limits for today. If you would
  still like to purchase you will receive the market price of bitcoin on
  Tuesday Apr 16, 2013 at 08:24AM PDT after your funds have arrived.
  read more

When I click read more, it just tells me

  Due to higher than normal buy volumes, we are unable to provide exact
  price quotes right now.

  Instead of pausing buys entirely, we decided to give people the option
  to purchase bitcoin at the market price in a few days. Once your USD
  funds arrive, we will exchange them to bitcoin at the market price at
  approximately Tuesday Apr 16, 2013 at 08:24AM PDT.

  Note that you can cancel your order at any time up until your bitcoin
  arrive from the transfer history page.

  The market price of bitcoin changes frequently. Below are some recent
  prices to give you an idea. These do not guarantee what the price will
  be in a few days.

It looks like it's allowing you to put yourself in a queue to buy bitcoin, but I have no idea how to take advantage of this feature.

Am I correct about what this feature is? and If I am, how do I take advantage of it?


texts: Can someone explain in detail how p2pool payout works?

texts:
From reading the wiki on https://en.bitcoin.it/wiki/P2Pool#Donating_to_P2Pool_miners I got the impression that the pool members included each of the share payments directly in the coinbase generation transaction as multiple txouts.  But after spending some time looking at  example p2pool blocks (for example this one:
https://blockchain.info/block/000000000000000007508100b6d96c3e1d1016835db41a32532d53ebd0207039)
I see that the whole output goes to one wallet (starting with 1KFEH7...). (EDIT: My error this was a F2Pool not P2Pool. Actual P2Pool coinbase do pay to multiple txouts.) In some blocks I do see this wallet sending money to many people  (but not in this example one) but this leads to a couple questions:

1) How does the system enforce these payouts?
2) How does the system get it's intitial seed money for the first payouts?


texts: Running a Bitcoin client with tor with a Debian based Linux OS

texts: I've received a question asking how to setup a Bitcoin client using Tor on a Debian based Linux system. Could someone provide a rough overview and perhaps a link to a tutorial?


texts:
It was the burn address with the most BTC received in 2017 according to
http://bitcoinwhoswho.com/blog/2017/12/30/8-97-bitcoins-burned-in-2017/. It's Hash160 is 0000000000000000000000000000000000000000. In Sept 2015 it served as a 40 BTC proof-of-burn address for Blockstore.

So, why did it receive 14,270 inputs of BTC dust in 2017 totaling 8.70069482? Why does "unable to decode output address" accompany this address on every transaction on Blockchain.info? https://blockchain.info/address/1111111111111111111114oLvT2

In this transaction it appears similar to a change address:
https://blockchain.info/address/16HBq938GwQkpWKWFkAomt4KpQeWUqXsZR


texts: How UNL is created,Can we create a own network and validate all our transactions?


texts:
Jan Moritz Lindemann graciously educated me that difficulty is used not only to regulate the creation rate of a cryptocurrency but also to allow for block propagation thus prevent orphaned blocks.

Since consumers of a cryptocurrency could be presumed to desire instantaneous transaction verification, is near instantaneous transaction verfication possible and secure?  If so, how?


texts: Why was the maximum target set to 0xffff0000000...?

texts:
Is there any specific reason why the initial target was set to this:

00000000ffff0000000000000000000000000000000000000000000000000000

Why not the maximum value for a 256 bit number:

ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff


texts:
I started bitcoind -datadir=/mnt/btc but everytime I try to use bitcoin-cli it says :

  error : incorrect rpcuser or rpcpassword (authorization failed)

I can't find bitcoin.conf (neither in the default datadir ~/.bitcoin neither in /mnt/btc).

Any idea how I can generate one and if it will help the original problem ?


texts:
I've generated a testnet address like this:

const btc = require('bitcoinjs-lib');
const bip32 = require('bip32');
const bip39 = require('bip39');

var root = bip32.fromSeed(
    bip39.mnemonicToSeedSync('my-twelve-word-seed...'),
    btc.networks.testnet
);
var pubkey = root.derivePath("m/44'/1'/0'/0/0").publicKey;
console.log(btc.payments.p2pkh({pubkey}).address);

and for my troubles I end up with this value: 14kwGTShacA5hT4uAes7dkNvreuHXuRRf7

however, when I test that with BlockCypher (or Blockchain.com or some other explorer), it doesn't seem to recognise it:

curl https://api.blockcypher.com/v1/btc/test3/addrs/14kwGTShacA5hT4uAes7dkNvreuHXuRRf7/balance

yields

  {"error": "Address 14kwGTShacA5hT4uAes7dkNvreuHXuRRf7 incompatible
  with current block chain: BTC.test3"}

notice that according to BIP44 the derivation path for testnet coins is m/44'/1' vs. m/44/0' for mainnet

so what is wrong here?


texts: Why are adresses not showing up in gettxout?

texts:
I have a bitcoin node but whenever i try to gettxout i get this response:
user@bitcoin:~# bitcoin-cli gettxout "0e3e2357e806b6cdb1f70b54c3a3a17b6714ee1f0e68bebb44a74b1efd512098" 0
{ "bestblock": "0000000000000000007c11ddb3e10be41ef0f6a2a5dbc2915937df8a608c4af6",   "confirmations": 385308,   "value": 50.00000000,   "scriptPubKey": {
    "asm": "0496b538e853519c726a2c91e61ec11600ae1390813a627c66fb8be7947be63c52da7589379515d4e0a604f8141781e62294721166bf621e73a82cbf2342c858ee OP_CHECKSIG",
    "hex": "410496b538e853519c726a2c91e61ec11600ae1390813a627c66fb8be7947be63c52da7589379515d4e0a604f8141781e62294721166bf621e73a82cbf2342c858eeac",
    "type": "pubkey"   },   "coinbase": true }
user@bitcoin:~# bitcoin-cli gettxout "0e3e2357e806b6cdb1f70b54c3a3a17b6714ee1f0e68bebb44a74b1efd512098" 1

I have txindex=1 in my config file and it's reindexed. Anything else i can try?


texts: Double spend in transaction with multiple inputs

texts:
Lets assume we have transaction with 2 inputs, each worth 1 bitcoin, and we send these 2 bitcoins to one address.

What happens if there is successful double spend attack on bitcoins in our first input?
How many bitcoins recipient gets, one or zero?


texts: What is a simple way to sign a message to verify that you possess the private key for a specific public address?

texts:
I need to explain to somebody step by step how to go through the process of signing a message to verify they own the private keys associated with an address containing funds. This is to ensure ownership before a sale is agreed.

What is the simplest and easiest way to do this (so that I can get them to understand my instructions and be able to follow through)?

I know this can be done a number of ways (bitcoin core, Electrum, Using a Ledger or Trezor, or a browser based tool .

I appreciate any input.

Thanks.


texts: Able to send 0.2BTC from old to new wallet w/o fee as of 2016?

texts:
Good evening everyone. I've been out of the cryptocurrency scene for a couple of years and I've stumbled into a minor issue. I've been trying to figure out if it will be viable to move some Bitcoin from one wallet I own to another without a fee. Specifically, I'm trying to send 0.2BTC from an Armory wallet to an Electrum wallet (latest stable versions of each client).  The 0.2 BTC is all I have in that Armory wallet at the moment and I'd ideally like to get it to Electrum intact if possible and thus without fee.

When I try to send at 0 fees with Armory, it warns me I need 0.00012407 "for the size and priority" of the transaction. I am not sure how it calculated this or if it is a baseline estimate (which is pretty close to the default 0.0001 fee.), but it will allow me to send at 0 against its advice.

Reading over the description of how transaction fees are calculated my transaction seems to miss some of the "gotchas" that the protocol requires a fee (ie 0.2 BTC is not small enough to require fees),  the coin itself is definitely old enough as the transaction that granted it to me was from 2014 and I haven't moved it from Armory since then etc.. but when I read over a variety of articles and posts there is a lot of variety in the confidence that such a transaction would be actually be validated sans-fees.  Some older posts from 2013/2014 don't seem to be of use any longer, as it seems that transactions were more likely to be processed without a fee back then compared to now.  Others suggest that at the value I still shouldn't have much trouble or to just give it a try and see

So given the current state of Bitcoin in 2016, should I attempt to send the 0.2 BTC to myself without any fees and have a reasonable expectation of timely (within a few days ) processing?     Should I send without fees and my transaction goes unconfirmed for days, what would be the best way to "cancel" it and try again?  Is there another way around the problem that I've not yet considered?

Thank you in advance