texts: How do you create a merkle tree that lets you insert and delete elements without recomputing the whole thing?

texts:
I have a merkle tree. The elements of this tree are in sorted order, so that anyone can create a proof that something isn't in the tree. So far, so good.

However, I also want to be able to add and remove elements from the tree. If I use a normal merkle tree, I have to recompute most of the tree. For example, I have the following merkle tree:

                    395
          /                     \
        85                       310
    /        \               /        \
  23          62          137          172
 /  \        /  \        /   \        /   \
1    22    23    39    60     77    82     91

(I'm using addition for the hash function, as an example.)

I insert 50 to the middle of the merkle tree.

                               445
                       /                  \
                    354                    91
          /                     \           \
        85                       269         91
    /        \               /        \       \
  23          62          110          159     91
 /  \        /  \        /   \        /   \     \
1    22    23    39    50     60    77     82    91

Every merkle branch after the 50 changed. I had to run the hash function 5 times. This would get pretty unwieldy for very big merkle trees.

I'm looking for a merkle tree with these properties:

Fast. I shouldn't need to recompute the entire thing (or half of the entire thing) to insert or remove something from the middle.
Authentic. If I have a merkle root, there should be only one tree that corresponds to that merkle root. Changing any part of the tree
should cause the validation to fail.
Deterministic. (Optional) This is essentially the opposite of the previous statement. If I take the elements out of a merkle tree, and
build a new merkle tree from those elements, I should get the same
root hash.
Proof of existence. Someone with enough of the tree should be able to make a proof that an element is in the tree, if that element is in the tree. This proof should be reasonably small.
Proof of non-existence. Someone with enough of the tree should be able to make a proof that an element is not in the tree, if that element is not in the tree. This proof should be reasonably small.


texts:
When mining Bitcoin, the nonce is included in the header, which is then hashed and checked to see if it is below the target threshold.
Everybody can verify that the header does indeed hash below the threshold. However, in merged mining, according to the wiki, the hash of the auxiliary chain's header is included in the parent's coinbase txin script without the opportunity to change the nonce in the auxiliary chain. The parent's nonce is incremented as usual but the aux hash remains the same.

How can we then verify the auxiliary chain?

is it because the parent nonce makes its way into the auxiliary chain through the parent header's hash? even so it seems that this would not help for verification because the aux chain's hash no longer need meet any threshold criteria.


texts: What can a dishonest node do (or try to do)?

texts:
Except this kind of attacks: https://en.bitcoin.it/wiki/Double-spending

For example can he simply create a new block that includes some invented transactions that steal money from real address? Without possessing the private keys of those addresses?


texts:
I've read that an OP_RETURN opcode allows up to 80 arbitrary bytes to be used in an unspendable transaction.
My question is, how is it possible that in this famous transaction (d29c9c0e8e4d2a9790922af73f0b8d51f0bd4bb19940d9cf910ead8fbe85bc9b) are being pushed 983 bytes?

In detail:

 Push data having size of 893 bytes. OP_CODES:

     6a             4d                    d7 03
 OP_RETURN    OP_PUSHDATA2    (03d7 = 983 following bytes)


texts: How can the compressed UTXO set be stored in just 4GB?

texts:
According to S. Delgado-Segura, C. Pérez-Sola, G. Navarro-Arribas, J. Herrera-Joancomartí, "Analysis of the Bitcoin UTXO set", Financial Cryptography and Data Security, pp. 78-91, 2019, the distribution of the UTXO set as of 2017 was:

No of UTXO                  52,543,649   100%      Size
Pay-to-PubkeyHash (P2PKH)   43,079,604    81.99%   147-179 bytes
Pay-to-ScriptHash(P2SH)      8,987,799    17.11%   40 - ? bytes
Pay-to-Pubkey(P2PK)             66,759     0.1%    113 bytes
Others                         409,487     0.8%    114-1483 bytes

There are 66.6 million UTXO in April 2020. Assuming the same distribution, the size of UTXO set should be approximately:

No of UTXO: 66.6 million = 100%
Pay-to-PubkeyHash (P2PKH)   81.99%    147-179 bytes   7.475712318GB
Pay-to-ScriptHash(P2SH)     17.11%    40 - ? bytes    0.424506515GB
Pay-to-Pubkey(P2PK)          0.1%     113 bytes       0.007008947GB
Others                       0.8%     114-1483bytes   0.056567788GB
Total                                                 7.963795569GB

Per statoshi.info the serialized UTXO set is 4GB as off April 2020.

I understand UTXO data does not have lot of leading zeros. How can the serialized UTXO set be compressed to 4GB?


texts: Are Bitcoin ASICs Optimized for Fixed Length Messages?

texts:
Bitcoin block headers are 80 bytes.

int32_t nVersion;       // 4 bytes
uint256 hashPrevBlock;  // 32 bytes
uint256 hashMerkleRoot; // 32 bytes
uint32_t nTime;         // 4 bytes
uint32_t nBits;         // 4 bytes
uint32_t nNonce;        // 4 bytes
                        // total: 80 bytes

A SHA256 ASIC is specifically designed to (double) hash theses fields over and over until the resulting value is below the difficulty level, which is encoded by nBits.

Since it is a double hash, the ASIC has to be able to hash initial messages of length 80 and 32. After the padding required for SHA256, the byte strings that will be hashed have lengths 128 and 64, respectively. So, bitcoin ASICs obviously have to able to hash messages of length 128 and 64.

But say I have a file on my computer that is considerably longer (10,000x longer). Could I hash it with a SHA256 bitcoin ASIC?

Does it vary from SHA256-ASIC to SHA256-ASIC depending on how they are made?


texts: Why Ethereum is growing in USD but decreasing in BTC?

texts: Please explain to me why the ETH/BTC price is decreasing but ETH/USD price is increasing. How does that work? Why it costs less in bitcoins but more in USD?


texts:
As a vendor, how do you detect a double-spend? I'm happy to tell end-users that I'm proceeding with a transaction on 0 confirms, simply assuming everything is fine. I'm selling physical goods and so I don't ship them until I actually have 6 confirmations. I only alert the customer if I actually discover a problem. But I still need to have a way to detect if a transaction is stuck vs a malicious double-spend.

At what point does a transaction become suspicious? Besides manually looking up transactions on blockchain.org, how do you know a transaction is a double-spend? Monitoring all transactions happening on the network in order to match transaction inputs (as does blockchain.org) seems excessive. I'm looking for a solution I can implement using the bitcoind API.


texts:
I was considering running a small test using Bitcoin transactions when I ran into the stress-test / DDOS that Coinwallet.eu conducted in July 2015 (and maybe September too, I am not really sure) where they bombarded the network with small transactions.

Were there any similar tests done? Are their results available? I am trying to find more information on what happen to transaction propagation times, block propagation times, etc, in presence of high volumes of transactions. Pointers to the right directions will be highly appreciated.

P.S. I am studying the behavior of crypto networks, so testnet tests are not really representative, in general, because of their small scale and different bandwidth characteristics, to the best of my understanding.


texts: Is the "double geometric" payout method for pooled mining fair to part time miners?

texts: The "double geometric" payout method as used on the Ozco.in pool is supposed to be fair and prevent pool hopping, but is this method fair to miners that only mine for a few hours per day, as opposed to miners that mine 24/7?


texts: How do you know your public key from a private key?

texts:
In my understanding, when you create a public-private key pair, first, you create a pair of complementary keys by using cryptographic software. Then you give one key the name public key, and give the other key the name private key.  You keep the private key for yourself and give your public key to everyone else.

Then I was reading Mastering Bitcoin, I found this sentence:

  Paper wallets are bitcoin private keys printed on paper. Often the
  paper wallet also includes the corresponding bitcoin address for
  convenience, but this is not necessary because it can be derived from
  the private key.

I don’t understand how it is possible to derive the corresponding bitcoin address(the hash of a public key) from the private key.

If the public key can really be derived from the private key, isn’t the opposite true? I mean, we can choose whichever is the private key when we generate them.


texts:
This is a question regarding the probability of orphaned blocks depending on the block interval. I am using Bitcoin vs Litecoin as an example.

Assuming equal hash rate and number of transactions, what is the relative increase in the probability of orphaned blocks for Litecoin, given that its block interval is a quarter?

The answer might be as simple as 4, but I'm wondering what is the quantitative justification?


texts: Bitcoin public key pre-0.6 length before hashing

texts:
As I understand, since bitcoin 0.6.x, compressed and uncompressed public keys are supported. And the process from the public key to the address has the step that puts a byte in front of the public key before hashing, like:

0x04<256bit x><256bit y> = buffer before hashing the uncompressed public key

or

[0x02|0x03]<256bit x> = buffer before hashing the compressed public key

That implies that the buffer before the hashing is either 33bytes long or 65 bytes long.

My question: pre-0.6, all the way back to the first public version of bitcoin, is the buffer pre-hashing always 65 bytes long, since compressed keys were not supported? Or was it 64 bytes long (just <256bit x><256bit y>) and there was no byte for the version prepended before hashing?

If it was just the 64bytes of the public key on clients pre-0.6, that means that for the same public key, if I ran that public key through the code path of both pre-0.6 bitcoin client and current bitcoin client (uncompressed fomat), the final bitcoin address would still be different, since the modern client would prepend the version byte?


texts: BFGMiner, what will be displayed when solo mining?

texts:
I have started solo mining with BitcoinQt and BFGMiner on my Block Erupters.

I would first like to determine, if indeed I am doing this right, what I should see, and to make sure if on the rarest chance ever I find a block I actually get paid.

From what I can tell and my experience everything is spot on except for this long-poll stuff, do I need to tell BitcoinQt to poll "better"?

BitcoinQt .conf file (started with -server)

rpcuser=User
rpcpassword=Pass
rpcallowip=*
rpcport=8332

BFGMiner Arguments

F:\PATH\bfgminer.exe -G
-o http://localhost:8332
-u User
-p Pass
--coinbase-addr 14tdCy1xBk78nVGQj26YCMPRBWiZSpvpiJ
-S all --icarus-options 115200:1:1 --icarus-timing 3.0=100

With 14tdCy1xBk78nVGQj26YCMPRBWiZSpvpiJ being one of the recieve addresses in my BitcoinQt wallet

BFGMiner Screen after about 5 mins:


texts: Import multiple watch-only addresses using importaddress?

texts:
With the importaddress RPC command it is possible to import one watch-only address.
But how can I do that with, let's say, 100?


texts: Where/How does Bitcoin-qt check for receives to it's addresses?

texts: How does Bitcoin-qt technically check for receives to it's own addresses. I know it has a list of addresses loaded in from the wallet.dat, but when a new block or new transaction arrives, what logic increments the wallet balance you see and how? I've been told that it uses some merkle tree stuff.


texts: Specific instance of Tx using a malformed null byte vector for P2SH; insight req

texts:
From Biteasy's API for TXID fccf964964c34994e5dbbb9ff7f914159b524b0831f6eea12255aa424b39090e we can see the following info regarding inputs (for a P2SH Tx):

"script_sig_string": "[] [3044022016c09f09b6c55....]
"script_sig": "ff473044022016c09f09b6c55....

I do know a null byte vector (OP_0) is required for the off by 1 error for multisig Txs. But it's the raw hex where ff is representing the OP_0 (empty array) that is confusing me.  Is this being read as 2's complement of 0x00 or is it reading OP_INVALIDOPCODE as outlined on the Bitcoin Wiki Script page (quoted below)?

OP_PUBKEYHASH      253  0xfd    Represents a public key hashed with OP_HASH160.
OP_PUBKEY          254  0xfe    Represents a public key compatible with OP_CHECKSIG.
OP_INVALIDOPCODE   255  0xff    Matches any opcode that is not yet assigned.

FYI, this Tx caused issues with the core software parsing the blockchain awhile back; that much I am aware. However I have yet to find an explanation online (omitting github/C++ code, which I am not well versed in reading)


texts: Lightning network: how are "only X can broadcast" transactions implemented?

texts:
The Lightning paper states on page 12 (emphasis mine):

  This can only be enforced if one is able to ascribe blame for
  broadcasting an old transaction. In order to do so, one must be able
  to uniquely identify who broadcast an older transaction. This can be
  done if each counterparty has a uniquely identifiable Commitment
  Transaction. Both parties must sign the inputs to the Commitment
  Transaction which the other party is responsible for broadcasting.
  Since one has a version of the Commitment Transaction that is signed
  by the other party, one can only broadcast one’s own version of the
  Commitment Transaction.

How is this technically implemented? How do I make two transactions, both of them signed by Alice and by Bob, such that each of them is valid only if broadcast by Alice or by Bob respectively?


texts: update to 0.17.0 broke several rpc api calls that worked under 0.16.3, how to migrate correcty my code?

texts:
After updating from Bitcoin core 0.16.3 to 0.17 I've found several RPC calls are now broken, and I'm not sure on how to migrate/update my code (PHP).

Things broken so far:

getbalance : does not detect unconfirmed balance, this command shows only confirmed balance where it used to (and should) show confirmed+unconfirmed balance. Expected to work like in 0.16.3.

$btc->getbalance("*", 0);

listunspent: does not detect unconfirmed inputs, showing nothing and returning error stating "Invalid amount". Expected to work like in 0.16.3.

$btc->listunspent(0, 9999999, array(), true, array("minimumAmount" => 0.00005));

I will add more to the list as they get discovered.
There is no mention of these issues online, in the 0.17 changelog or anywhere else I could find.

Already updated some other php code that used validateaddress deprecated call and a couple more, probably still missing some editing here.

How to restore functionality as expected?
Thanks.


texts: Withdraw from a BTC wallet Ucoincash 24hours is still pending?

texts: I wanted to withdraw 0.62 Bitcoin back to my wallet and I did try to verify the receive wallet address as I submitted the request and it is still pending 24 hours later? On the blockchain, I see no transaction or received BTC? This request was sent Saturday Evening November 18th, 2017 at approximately 11 pm and it is 11 pm Sunday, November 19, 2017


texts: Is there a way to get the public key of a given wallet.dat to check the balance in the blockchain to avoid having to install the wallet and read all blocks?


texts: restore wallet using hd seed before 0.17.0

texts:
Hd wallets are supported from v0.13.0.
Currently it is easy to save hd seed and restore a wallet from it (due to changes in v0.17.0 and v0.18.0):

dumpwallet (read hdseed from it)

createwallet (blank wallet)

sethdseed (set hdseed on a blank wallet)

How to do this using v0.16.3?
Problems I encountered:

I cannot find hdseed in dumped wallet file, so I don't know hd seed to backup
creating new wallets is done by starting bitcoind and passing -wallet option, but I don't see a way to specify hd seed when creating a new wallet

Is that even possible without upgrading?


texts: Is there a standard wallet format that can be read with different bitcoin clients, and that is likely to be compatible to future bitcoin clients as well and thus is usable for long term storage of bitcoins? Or how am I supposed to transfer bitcoins between different bitcoin clients/computers/client versions?


texts: Does solo mining with multiple computers require different generation transaction addresses?

texts: I've heard that what prevents the fastest computers from almost always dominating pools is that each miner is hashing different data because of the generation transaction. However, if I solo mine with many of my own computers running miners connecting to a bitcoind I'm running, it seems like I'm going to redo the same work across all miners because the generation transaction address would be the same. Or should each miner have its own address? Or should bitcoind generate a new address for each getwork request?


texts: Can I start a Bitcoin Private Node using bitcoin-qt?

texts:
Currently I am starting a private node using:
bitcoind -regtest -port=11111 -datadir=.\data -rpcport=11112

I can't find the -regtest option in qt.


texts:
I have seen some people on the bitcointalk forum looking for hashing power to rent (here is one example) and usually they pay more to rent the rig than they would earn by selling the mined coins at market price.
It seems to me that they are losing money with the deal so why would someone want to do this? Are there other uses for the hashing power besides bitcoin generation?


texts:
Currently my understanding is that if new version of Segwit script is introduced, you are free to create whatever crazy rules you want there as long as they do not go against any valid consensus rules. Is that correct or are there any limitations that I'm missing?

For example, if I propose version 9 of script and convince enough nodes and miners that it is a good idea then we could soft fork to it. And the rules it would use would be exactly the same as version 0, except that the witness would be only one item instead of N items and I would say that you need to parse the actual items from this one item given that the separator is 0xdeadbeef and that the whole value is XORed by 0x11 and that the very first value is a new one that is to be discarded, but before it is discarded it has to be equal to the value used in the last version 9 script transaction +1. And with these rules I would be only limited with the size limitation of the witness. Is that correct?


texts: How can i check bulk BTC address balance?

texts: I'll appreciate some suggestions for online resources or software that can be used to check/monitor a few thousands of BTC address. Thanks


texts: Is there a comprehensive list of Gateways' IOUs and fees associated with using them?

texts: I am looking for information about the various IOUs issued by Ripple Gateways and what fees are associated with using them - namely fees to get the IOUs and transit fees.


texts: I need a full Bitcoin node running on a server. It's a Windows server - is there any advantage to running bitcoind over bitcoin-qt? I need the JSON API, to they need the server flag, I just figured that if something goes amiss it would be easier to take a quick look at the wallet if the GUI us running as opposed to the console.


texts: How can i locate my deceased husbands bitcoin?

texts: My husband passed away 4 years ago and he bought a lot of shares in bitcoin when it first became a thing.  How can i find out who he purchased these through in order to accuquire about his shares?


texts: Tried to fix unconfirmed transactions, remaining balance gone!

texts:
apologies if some of the details aren't relevant, I'm not quite sure what's going on and I'm getting desperate!

I'm using the latest version of MultiBit HD. 2 days ago I bought some BTC (I already had a little in my wallet) and tried to make 3 payments. They appeared at blockchain.info pretty quickly, and I could see in MultiBit that they had been seen by peers, but remained unconfirmed. The transaction fee for each was set to the default (0.0001 BTC), making the fee-per-byte 19.231 sat/B for one transaction and 44.444 for the other two.

As I couldn't work out why it was taking so long I tried to cancel the transactions, so that I could resend with a higher fee, but the option to reset the blockchain & transactions (as per the MultiBit manual) doesn't seem to exist in the current version. Restarting MultiBit did nothing, neither did reinstalling.

I then tried "repair wallet", hoping that this would have the same effect - instead, my remaining balance disappeared! A small amount of BTC has appeared as unconfirmed though - has my balance just somehow become unconfirmed? Why/how do I avoid this in future? And, what should I do about the outstanding transactions? The intended recipients are starting to get annoyed with me, and I can't just buy more BTC and send that with a higher fee in case the old transactions suddenly decide to work!

Any help would be extremely gratefully received - even if it's just to tell me how not to make the same mistake again! Transaction ids:

d86bc86b30495d4150a0fb1733038cb0c3fced57803de0e91ad4c13326b28d58
2a8191e9ab4f3d96cdf5a557146d470a0c78a4c7b1b64051c0f90417407019a3
b854be622f4e4fa7229c14b2054b62e4ddd4441e993085fe9f229798e7215f16

TIA :)


texts: I forgot my bitcoin core passphrase. Is there anyway I can recover?

texts:
I've tried brute forcing it. Doesn't work.

0.02 BTC in the wallet.


texts: How to ask donors to send bitcoin if they are not bitcoin enthusiasts?

texts:
Have idea for wonderful service many would want to donate to see happen. Those who donate though know nothing of bitcoin. Google reveals much trouble with bitcoin<->paypal or bitcoin<->creditcard gateways.

Exists any credible and reliable service that does this?

Bitcoiners too small group to expect enough from them, bitcoin system too difficult for non-bitcoiners to donate. Non bitcoin donations undermine concept.


texts: Active connections and sync-ing my wallet issues

texts:
I have been trying to sync my wallet with the network for around 3 months, and it is still only at 45.29%. Any ideas?

I am using Bitcoin Core version v0.15.0.1 (64-bit). I have UPnP enabled, I am also port forwarding on 8333. The machine is a macbook pro running sierra 10.12.1. The wallet is on an external HDD.

I can not get more that 7 active connections to the network. Most of the time I only have 1.

I would have give up on this if I hadn't accidentally sent bitcoins that I have mined to this address already, before the sync completed. ( I had no idea I would have these problems, I have, in the past, sync'd with no problems, using the same machine, same internet provider).

Any ideas on how I retrieve my lost coin, or make the sync process possible? I've exhausted the few ideas I had.

Thanks.
Pete


texts: Convert WIF to Witness PubKey Hash Address in Go

texts:
How can WIF be easily converted to WitnessPubKeyHash in Go?

We need to get the public key from WIF and than calculate witness program as ripemd160(sha256(compressed_pub_key)).

But is there a function in btcutil to convert the public key to witnessProg required by NewAddressWitnessPubKeyHash function:

func NewAddressWitnessPubKeyHash(witnessProg []byte, net *chaincfg.Params) (*AddressWitnessPubKeyHash, error)


texts: I got this error connecting to blockchain.info, does anyone know what that means?


texts: Mining a transaction with a 0 BTC output

texts:
It is possible to mine tx that has a 0 BTC output?
In theory it is non-standard but valid, so it is not relayed but it can be mined.
How to mine it in practice? Are there nodes that accept it? I tried Eligius' 192.3.11.20 but it rejects it.

EDIT: i want to do p2pkh transaction


texts:
I am going to activate a Bitcoin Core full node on my PC. Selecting a custom folder in which to save the blockchain, however, I get the error message:
"A fatal error occured. Bitcoin can no longer continue safely and will quit.".
The only button I can press is "OK", after which the Bitcoin Core application crashes / closes and restarting it, the same error appears again each time. Is it a bug or is it something wanted by the developers not to be able to change the save destination folder of the blockchain?
My OS is Ubuntu 18.04, my Bitcoin Core version is 0.19.0.1 (Snap).

Thank you.


texts: I was investing bitcoins in Coin Controller but I need the time to send it because they only give you 10 minutes. So I want to know how to calculate the time to send bitcoin with for an example 0.00005 transaction fee. I know that you can't calculate it but do you know how long it would take if I send 0.00015 and the transaction fee is 0.00005 (the half of a normal transaction fee).


texts: How to access my bitcoin gold without compromising my hardware wallet?

texts:
I have my bitcoins in a hardware wallet(trezor and nano ledger s) and I want to keep it that way, my mnemonic seed is stamped in metal and stored securely, so I won't change it, and I will keep it airgapped. According to bitcoin gold, they have support in three wallets:

Coinomi Guarda Freewallet

As far as i can understand, none of theese wallets have hardware support, and trezor or nano won't support bitcoin gold natively either. What are my options here?


texts:
According to bip65
https://github.com/bitcoin/bips/blob/master/bip-0065.mediawiki

I can use expressions like IF ... ELSE ... ENDIF
Here is example script from this document:

IF
    HASH160 <Hash160(encryption key)> EQUALVERIFY
    <publisher pubkey> CHECKSIG
ELSE
    <expiry time> CHECKLOCKTIMEVERIFY DROP
    <buyer pubkey> CHECKSIG
ENDIF

But when I trying to spend transaction with the following script:

OP_IF
    OP_SHA256 4bf5122f344554c53bde2ebb8cd2b7e3d1600ad631c385a5d7cce23c7785459a OP_EQUAL
OP_ELSE
    10 OP_CHECKLOCKTIMEVERIFY OP_DROP OP_SHA256 dbc1b4c900ffe48d575b5da5c638040125f65db0fe3e24494b76ea986457d986 OP_EQUAL
OP_ENDIF

https://tchain.btc.com/dbf477b700b7e159c07f15e1b6f5917e1247175e055fe533068a6fbc4ce2c374

I get error:

bitcoin-cli -testnet sendrawtransaction 020000000174c3e24cbc6f8a0633e55f055e1747127e91f5b6e1157fc059e1b700b777f4db000000000151ffffffff01c0d401000000000023a820dbc1b4c900ffe48d575b5da5c638040125f65db0fe3e24494b76ea986457d9868700000000
error code: -26
error message:
mandatory-script-verify-flag-failed (Operation not valid with the current stack size) (code 16)

Where is my error ?

P.S.

  SHA256 from 1 ->
  4bf5122f344554c53bde2ebb8cd2b7e3d1600ad631c385a5d7cce23c7785459a

  SHA256 from 2 ->
  dbc1b4c900ffe48d575b5da5c638040125f65db0fe3e24494b76ea986457d986


texts: How are public & private keys in an address created?

texts: I understand the high level concept I am more interested specific details.   How is a private key generated.  How exactly is public key generated, how is address generated from public key.


texts: Internet speed required to run the Bitcoin client

texts: What is the rough estimate of internet speed needed to run the standard client? Does a faster Internet connection increase the client performance (by that I mean how fast it updates its blockchain, sends transactions, and how well can it function as a node in the network)?


texts: How can I avoid the "Amount too low" message in my wallet for payout from Cloud mining service?

texts:
1) I have a Bitcoin-wallet called "Copay" on my IOS-device
2) I have joined the cloud mining-service "Genesis mining". For trying out the service I started with 50 $ from my credit card.
3) here is a list of payments I received from them and the fees which yielded always the "Amount too low" message

11th July 2017 3,243 bits   fee 0,00044277 BTC
31st July 2017  1,750 bits   fee 0.02086374 BTC
14th August 2017 1,615 bits  fee 0.00224983 BTC

There is another transaction where I went to a bitcoin shop and bought 10 Euro in Bitcoin which gets the "Amount too low" message.

As a newbie I have some questions

1) Is there a possibility to recover any of these funds without paying fees which are high (e.g. the fee from 31st July amounts to around 100 $) ?
2) Would switching to another wallet remedy the situation
3) Is this a general problem of the Bitcoin network that the fees are rising and thus it is not suitable for transactions below 20 $ ?
4) Would there be a possibility to stop "Genesis Mining" from sending me micro transactions but instead accumulating the funds until a reasonable sum is reached ?

Sorry for having so many questions, I would be grateful for any input

Regards


texts:
# server=1 tells Bitcoin-QT to accept JSON-RPC commands.
 server=1

 # You must set rpcuser and rpcpassword to secure the JSON-RPC api
 rpcuser=bhhtufhrt
 rpcpassword=ferhrhh

im trying to connect to my bitcoin thats my conf file but i cant connect to

http://127.0.0.1:8832/

im running on my local machine


texts: On quering the blockchain, can someone read what transaction took place?

texts:
Like considering the Alice Bob ex where Alice is the customer and Bob is the merchant. If Alice and Bob signed a contract where alice will pay bob on the delivery of a service. The transaction took place at time "t".

Can some one query the blockchain at time "t+10" and see what was the actual contract signed between alice and bob?


texts: Was libbitcoin a part of bitcoin core in the past?

texts:
I am trying to use c++ code from the book of Antonopoulos for some time now and I seem to lack an include named bitcoin/bitcoin.hpp.

To compile the code the g++ compiler gets a pkg-config input with libbitcoin. So I suspect I would have to install this library.

Since the book does not mention to install anything else then bitcoin core I really wonder if parts of libbitcoin have originally been part of bitcoin core and have been excluded at some point.

The other explanation would be that the author forgot to mention it. But it seems a bit overload that I have to install another complete system for a full node (libbitcoin) to be able to run the code since the book explicitly says that running a full node with bitcoin core should suffice.

It is just a minor thing and probably laughable for an expert in the field but I am also learning how to use pkg-config and the compiler by doing this.

There have been suggestions to just install parts of libbitcoin but the developers said it is advisable to install the full thing with the automatic install skript.

Also, there is libbitcoin-dev, which is a package in debian (I run Raspbian Buster), but I was not able to compile the code with it.


texts: Bitcoin mining process-the leading zeros before the hash-how is the mining puzzle solved exactly?

texts:
Can someone please explain:

In Bitcoin proof of work, mining is done to create and validate new blocks. Who becomes the sole block producer is subject to winning a "mining puzzle".

As I understand, the difficulty is that the solution of this puzzle must have a specific number of leading zeros in the resulting hash.

My questions are:

1) must the hashing result have X number of leading zeros, or is the constraint more like "less or equal X number of leading zeros"?

2) If the mining puzzle's solution has a hash as a result, what is then the input parameters for doing the hashing? What are the miners exactly hashing, what are all the input factors?  As i understand, input factors are e.g. the Nonce, previous Block's hash, etc...

3) I understand a hash function is only one way function. You have an Input which produces a unique hash. This means that if multiple different parties are hashing the same input then their hash results must be identical, right?

Given this definition, I really do not understand how the situation of orphan blocks in Bitcoin can happen? Because orphans happen for example when 2 miners at the same time solve the mining puzzle. But both are solving the exact same mining puzzle right? This means, they both have dealt with the same difficulty level of the puzzle and arrived at the same number of leading zeros for their hash, right?

How is the blockchain then distinguishing between those 2 miners, who has "put more work into the mining" if they have solved the same thing? On which parameters is the network looking to determine which of the two miners should get the reward?

Thanks


texts: Is there a bitcoin source, fork available that does not include a GUI?

texts:
I would like to try to download and compile a barebones variation of the Bitcoin daemon.  Specifically, I'd would prefer to not have a copy of the code with any GUI implementation.

Does such a reliable, and maintained, forked project exist on Github or any where else?


texts: Is it possible to pay part of a Bitcoin to someone?

texts: Bitcoins are over $800, I need to pay someone about $200. Is it possible to pay someone with a partial bitcoin?


texts: Is there a service where you can generate public/private keys without anyone knowing? Like a tamperproof digital envelope

texts:
Is there a service where it generates a BTC address with public/private key, but no one knows it until someone pays a fee to reveal it? The idea is basically, some script or some other decentralized system will generate a btc private key, then encrypt it somehow. And in order to decrypt the encoded private key, a certain fee has to be paid. But the public key is exposed publicly.

I guess the idea is akin to generating a btc paper wallet private key, and then putting a few bitcoins in it. Then seal it inside a tamper proof envelope and then display the public key on the outside of the envelope. Now you can give this envelope to anyone physically without it showing on the blockchain.

But is there a service like this?


texts: I am looking for a step-by-step Guide to create a new Cryptocurrency, based on Bitcoin code

texts:
I am looking for a step-by-step guide on creating a new CryptoCurrency using BitCoin Code, particularly on Fedora.

Can someone help?

Thanks in advance.


texts:
This is a follow-up post to this question.

I am using Electrum to send Bitcoin. From what I can gather, it doesn't seem like there is a way to know your "inputs" upfront. The inputs are the various addresses the different chunks of bitcoin are coming from... I think? So the inputs, as I understand, will depend on the source.

I am trying to figure out the best way to calculate the fee I can charge the client for the transaction. So my questions are:

Is there any way that I can assume 1 input for my calculations? Or find another way to get a more accurate fee calculation?
I can't have a fixed fee of, for example, 0.0005, because that will probably work fine for small amounts, but if someone sends a large amount, the fee could easily be more than this. Is there a way to know what the worst case cost could be for sending 0.01 BTC versus sending 20 000 BTC?
Is there a maximum or "worst-case" formula I could use to work out what the absolute highest a fee could be for a specific scenario?


texts: What kind of bug does bitcoin core possess that have to be replicated

texts:
In order to build a bitcoin client accepted by the current bitcoin nodes we to have to emulate the C++ code present in the bitcoin core client, with all its attributes even the bugs.

For example the same function written in C++ will not work exactly the same as one in Python.

Do we have example of those bitcoin core bugs or attributes that has to be present in a bitcoin client?


texts: Verifying that a transaction is in the blockchain

texts:
Let me first start off by saying im just learning about blockchain and the technical aspects.

From my understanding, each transaction is cryptographically hashed, the hashes are paired and hashed until a single root hash is generated. The miners hash the entire block containing the root hash, previous hash, timestamp etc. If the hash meets the target difficulty then the block is added to the chain. Cryptographic hashing makes it infeasible to obtain the input from the hash output.

Q. If say, I wanted to go back to block X and see which transactions it contains, how is that possible if all the hashes are cryptographic and its infeasible to find the input from the hash output?

Thanks in advance.


texts: How much time it takes to verify a Bitcoin signature in the Satoshi client?

texts:
Assuming:

An average modern computer
Using a single thread, as the current Satoshi client does
Using the OpenSSL library, as the Satoshi Bitcoin client does
The signature is not in the signature cache

I speculate that the time may be between 1 and 10 msec.


texts: How to block certain IP address from bitcoind or using ufw

texts:
Certain IP is brute forcing my node for rpc access. I tried ufw to deny that IP but did not work.
Looked for any black list conf entry or param to bitcoind and found none.
Any suggestions?


texts: Blockchain removing invalid transactions

texts:
Currently, I have the following architecture:

Multiple honeypots for VoIP which detects voice attackers.
These honeypots collect IP and SIP information.
Using a Publisher/Subscribe model (Observer pattern), Publisher notifies clients or subscribers, about attackers in order to update their infrastructure firewalls or by adding VoIP rules blocking attackers dialed number. Example:

I detect an IP from France is scanning my network trying to place calls to a number in Dubai. I notify agent which in turn will update firewall access list and my VoIP software to create a block rule to that destination.

As I want to partner with other companies, my goal is to have a shared database where we can access the information we are collecting, the risk is that as it grows, attacker can insert valid IP addresses or valid numbers, (Example block IPs from our major ITSP, or block the number to our most important customer)
While a whitelist can easily solve this issue.

What I would like to know is if Blockchain will be a valid use case where information containing only suspicious IPs and dialed Telephone numbers/SIP URIs are validated by all parties and shared. I started a prototype based on this Blockchain.

The idea is that each Honeypot submits a transaction with IP/SIP attacker data. The transaction is mined and added to blockchain. But how can I remove an IP which is no longer valid? Any suggestions?

Flow:

1) Honeypot detects attacker

2) Honeypot submit new transaction to Blockchain:

curl "localhost:5002/transactions/new" -H "Content-Type: application/json" -d '{"sender": "honeypot-2", "recipient":"twilio", "amount": 111, "hosts": ["192.99.38.121"]}'

3) Transaction is mined.

curl "localhost:5002/mine"

4) It is detected that 192.99.38.121 is no longer a threat, how to remove it from blockchain securely?


texts: How does intial block download work at P2P layer?

texts:
A simple DOS attack while IBD could be as follows:

The fresh client is currently downloading block 100.
Then it is offered 10 blocks at height 101, each claiming they are the heaviest chain
9 out of 10 alternatives are
    with fake PoW but still the client will waste time in getting the
    entire block and validating their PoW.

How does the current implementation of P2P protocol in bitcoin-core handle this sort of DoS attack?


texts: I can't send a transaction uses BitGo API

texts:
I have a test BitGo account, and there are test wallets. One of this wallet has 1.1000 TBTC (test btc). I want to send transaction uses BitGo API.

I do this request:

http://localhost:3080/api/v2/tbtc/wallet/"my_wallet_id"/sendcoins

with this headers:
Content-Type application/json
Authorization Bearer "my_token"

and this body:

{
    "address":"address_where_i_send",
    "amount":0.1,
    "walletPassphrase":"my_test_passphrase"
}

and I get this response:

{
    "error": "sub-dust-threshold amount for 2N4ebmhA3FDuPiULXUEu1jBdPc3y2hk1NrD: 0.5",
    "message": "sub-dust-threshold amount for 2N4ebmhA3FDuPiULXUEu1jBdPc3y2hk1NrD: 0.5"
}

Can somebody explain why I have this response, and how fix it?
(I have V2 BTC wallet)

Thanks!


texts: Why does Bitcoin Core take up so much space?

texts:
I have downloaded Bitcoin Core and the blockchain has nearly filled my local storage. Can i move the wallet to a hard drive and then delete Core from my computer?
I'm a newbie lol


texts: can someone explain what i did wrong here? (btc transaction with fee not confirming)

texts:
https://blockchain.info/tx/c782b48bba09dea21896b7c58292abaec81d7ce2db2975f30b77176dddad492c

was the fee not high enough? i have never had an issue with fees using the recommended amount that bitcoin core suggests before but now this one, for some reason is just sitting there unconfirmed.


texts:
I have seen several folks selling "bitcoins" on Ebay and the like - but they are made of base metal and have no real connection with the bitcoin concept other than the symbol.

I'm wondering if some number of bitcoins could be permanently assigned to a coin (i'd plan on about 10 bitcoins impressed into a one ounce silver round).  I'm thinking of having a public registry of bitcoins assigned permanently to individual coins.  Said bitcoins could be reassigned only in the instance of the "surrender" of said silver round.

I appreciate the fact this reduces the portability of bitcoins, but it would be an interesting method of storing value.


texts: message signing: is it safe to publish the address, message and hash

texts:
I want to use message signing in another application to prove a particular wallet owner did in fact make the transaction.  This as I understand it is what message signing/verification is for.

I just want to confirm that making the address, the message, and the hash fully public (open for the world to see) does not compromise the wallet security.  Also if I did this thousands of times on the same address, but each with a unique message and hash, the private keys would remain secure.

Thank you.


texts: Do some Bitcoin wallets fail to support sending to multi-signature addresses?

texts:
The Satoshi client has support for multi-signature transactions through the JSON-RPC API since version 0.6.1rc2.

My understanding is that a multi-signature transaction creates an address which is special only in that spending from it requires multiple signatures, and its prefix is '3' instead of '1'.

As Gavin said on bitcointalk.org, "you can then send funds into that 2-of-3 transaction using the normal sendtoaddress/sendmany RPC commands, or the GUI (or anything that's been updated to recognize multisig addresses)."

What I read from that is that all wallet clients and web wallets might not yet support sending to addresses with a '3' prefix. How wide is that support currently?


texts:
I'm working on my SPV library and I still have a hard time figuring how to approach the BIP32 + Bloom filters combination. Here's how I currently sync an existing HD wallet (after fast catch-up):

Generate a number of watched look-ahead addresses (say 10).
Load a Bloom filter with all used addresses plus look-ahead (N used + 10 look-ahead).
Download filtered blocks with getdata.
Mark watched addresses as used if they're found in any block transaction.
Ensure that the last watched address wasn't used in a transaction.
If so, generate new look-ahead addresses, reload the Bloom filter and download last block again to rematch it. By using a new receive address for each transaction we may have missed other transactions in the same block.
Otherwise, go back to 4 and download new blocks.

Now this sounds quirky and overcomplicated to me. Several discussions on the web talk about "scanning keys" when coming to wallet sync and I don't really understand if they assume a full node or a lightweight SPV node, because I have no idea of how to "scan keys" without a global UTXO database. Also the gap limit only seems to make sense for a full node.

I'm stuck, thanks.


texts: Why is BIP32 root key different for different standards(purposes)?

texts:
When generating key on https://iancolemen.com/bip39/, the BIP32 Root Key changes as I change the derivation path tab, e.g. BIP32, BIP44, BIP39 etc. Why is this the case? Isn't BIP32 Root Key the m at the beginning of the derivation path and the different standards are subsequent purpose that should not affect the root key?
Contrary to the above, when I generate addresses with the following code in go, the master key printed always matches the BIP32 Root Key on iancolemen.com. And changing the purpose does not affect the address generated in the end, it is always a BIP32(legacy) address, instead of a segwit which I would expect from BIP84.
m, err := hdkeychain.NewMaster(seed, chainParams)
if err != nil {
    panic(err)
}
fmt.Println("bip32 root", m.String())

purpose, _ := m.Child(hdkeychain.HardenedKeyStart + 84)
coin, _ := purpose.Child(hdkeychain.HardenedKeyStart + 1)
account, _ := coin.Child(hdkeychain.HardenedKeyStart + 0)
receiving, _ := account.Child(0)
index, _ := receiving.Child(0)
fmt.Println("address", index.Address)

EDIT: The wrong address printed in go was a result from not properly encoding the addresses to bech32 and by default they are interpreted as legacy addresses. The keys themselves are alright.


texts: How do I scan my bitcoin receipt into my wallet?

texts: I bought Bitcoins from the Robocoin ATM (I'm told it's the only one) and it gave me a receipt with a QR code to scan into my wallet. I downloaded Blockchain, but don't see where in the app I can scan the receipt to add to my wallet. Help!


texts: Bitcoin-cli 0.19.1 Wallet not Sending from Addresses with Closest Amount?

texts:
I have a weird issue that I thought was fixed a few years back with Bitcoin wallet to reduce fees. I guess not, or I am missing something...
My wallet received a transaction for the amount of 0.54530200 BTC, yet when I went and sent 0.51986042 BTC out using bitcoin-cli sendtomany to 16 outputs, the wallet used 856 inputs to send the amount that was available and cleared with at least 400+ confirmations in the first address.
The above TX cost me 0.03600705 BTC to send when it should have cost me a fraction of the amount had it used the address that contained the closest amount to the amount it's sending out...
Bitcoint-cli version 0.19.1
Any ideas what I could be doing wrong or what I could be missing?


texts: I have a few BSD-based systems sitting around serving away, but for the most part they're idle CPU-wise. Does anyone knew of a bitcoin client that I could run on these machines to make them more productive while they wait for requests?


texts:
I have a question.
Right no I'm running litecoind + pushpoold + mmcFE (as the front-end), it's a smal sized pool with peaks at around 3000kh/s so far, but we're growing rapidly.

However, some users are getting a LOT of invalid/stale shares. People have been saying their miner can stop for a while, and start subimitting only stales for a couple of minutes, then it goes back to submitting valid ones. Me myself only gets around 10% which seems fair while using getwork.

Now to the question:
Is it difficult to switch from pushpoold to say... poolserverJ? I heard it's preferred since it uses GBT (getblocktemplate). This would decrease the amount of work our server does, whilst eliminating invalid shares.

Are the shares saved if we switch back-end? (We haven't found a block yet, we're up to a total of about 200k shares so far)
Will our users notice any difference on their end?
Is poolserverJ compatible with mmcFE for litecoin?

Some help would be awesome!


texts:
I'm aware that LiteCoin is (was?) the "silver" to bitcoin's "gold".

The question is:

  What was the first altcoin? Was it actually LiteCoin or was there something else?

For the purposes of "alt coin"

What was the first fork of bitcoin
What was the first altcoin that more than, say, 10 people mined?


texts: Is there some kind of draft to support a chain split+merge, like Version Control systems do?

texts:
Currently, if I didn't misunderstand, in case of a network split when the two networks merged again only one of them would be "valid" and everything else would be discarded.

This seems overly simplistic and un-technologic for me: a smart system able to handle splits and merge like distributed version control systems do (like hg or git). Of course that wouldn't be easy to do properly, and it's totally understandable it hasn't been done yet, but I would be surprised if nobody even bothered to draft some kind of proposal about it.

Does such a draft exist?


texts: Bitcoin "Quits unexpectedly" everytime but only on my account

texts: Everytime i try to open Bitcoin QT it quits unexpectedly, however if i log out and log in using another account on the same Mac, it works fine.  Can i use the other account (where my Bitcoin QT opens fine) to transfer bitcoins to from MtGox as it is still the same computer or do have to fix this issue of it quitting all the time?


texts: importprivkey in bitgold-cli not importing the expected address

texts:
I'm in the process of trying to import an existing paper wallet BTC private key into a Bitcoin Gold node I setup so that I can grab the BTG that was airdropped there, however whenever I try to importprivkey the public address associated doesn't match what I had generated, and there are no funds there (they are there if I have the right address in the BTG block chain explorer) I tried:

Generating a random new address on bitaddress.org
1MiXQPkKZersaFrPmteiUexGbyLEATxD8x / Ky324ikVv9HAjeoz7CVWQN2zA8bVY3aDU1gJq8tJjpEQRmUgJXCK
Importing that address in the cli - ./bgold-cli importprivkey "Ky324ikVv9HAjeoz7CVWQN2zA8bVY3aDU1gJq8tJjpEQRmUgJXCK" "test" true
Get the address for the private key I just imported bgold-cli getaddressesbyaccount

I'd expect to get 1MiXQPkKZersaFrPmteiUexGbyLEATxD8x but instead get:

bgold-cli getaddressesbyaccount test
[
  "GeZSpX5GYWUAej9ghqJpuRJAX985Ayn99A"
]

What am I doing wrong here?  Why is my public address getting morphed?


texts: Meaning of confirmation within n blocks?

texts:
I have a hard time understanding the meaning of below sentence:

"To confirm within 48 blocks, a transaction fee of 1 satoshi/byte is required."

I have 2 questions here:

1) Does this mean that the first confirmation of the transaction will probably happen within attachment of the next 48 blocks?

2) As soon as the first confirmation is received, is it guaranteed that this confirmation will increment with all future block attachment (which is every 10 mins)?


texts: How do I properly shut down bitcoind on Windows? I get error: EnvShutdown exception: DB_RUNRECOVERY: Fatal error, run database recovery (-30974)

texts:
I am running bitcoind in Windows (interactively) and pressed "control c".  The following error was displayed:

EnvShutdown exception: DB_RUNRECOVERY: Fatal error, run database recovery (-30974)

Is this a bogus error, or could it lead to serious issues?
Did this delay my restart time?

This is the output after I restarted bitcoind:

Bitcoin version v0.7.1-beta (2012-10-09 13:22:09 -0400)
Using OpenSSL version OpenSSL 1.0.1c 10 May 2012
Startup time: 12/09/12 02:35:45
Default data directory C:\Users\Administrator\AppData\Roaming\Bitcoin
Used data directory C:\Users\Administrator\AppData\Roaming\Bitcoin
dbenv.open LogDir=C:\Users\Administrator\AppData\Roaming\Bitcoin\database

ErrorFile=C:\Users\Administrator\AppData\Roaming\Bitcoin\db.log
Bound to [::]:8333
Bound to 0.0.0.0:8333
Loading block index...
LoadBlockIndex(): hashBestChain=0000000000000451ad20  height=193797  date=08/14/12 03:38:39
Verifying last 2500 blocks at level 1
 block index          158518ms
Loading wallet...
nFileVersion = 70100
 wallet                  858ms
Rescanning last 3 blocks (from block 193794)...
 rescan                   47ms
Loading addresses...
Loaded 12371 addresses from peers.dat  78ms
RandAddSeed() 164540 bytes
mapBlockIndex.size() = 193799
nBestHeight = 193797
setKeyPool.size() = 100
mapWallet.size() = 0
mapAddressBook.size() = 1
Done loading
send version message: version 60002, blocks=193797, us=0.0.0.0:0, them=0.0.0.0:0, peer=127.0.0.1:0
sending: version (100 bytes)
ThreadRPCServer started


texts: What are the three values in the csv graph of price history?


texts: Does any documentations with mathematical description of Bitcoin exist? Some documentations like YellowPaper in Ethereum?


texts: I generated a paper wallets with offlineaddress.com. Is there a way to check if the private key corresponds to the public key without compromising the wallet by loading it onto an online computer?


texts: Is there a way to mine with many graphics cards without having a PC for each one (or two)?

texts:
I have a serious stash of radeon cards, some great, some fairly crap. I figure with them all running it all adds up.

Problem is, running a PC for each card will get expensive, so is there any known rig or way to mine using a bunch of cards and NOT have them all plugged into a PC of their own?


texts:
I love the idea of a powerful alternative to bitcoind, and especially the ability to subscribe on blockchain events and easily process them on the server side.

However, I see the last activity on the BitcoinJS code is 7-10 months ago.
Does anybody know the status of the BitcoinJS projects or can suggest alternatives?

Update: I'm now looking into bitsofproof supernode, a project that looks really promising.


texts: Bitcoin RPC works in bitcoin-cli but not in python-bitcoinrpc: No JSON object

texts:
I'm running a testnet node. I can use bitcoin-cli just fine:

>bitcoin-cli.exe getinfo
{
    "version" : 100000,
    "protocolversion" : 70002,
    "walletversion" : 60000,
[... snipped]

But when I run this python code:

from bitcoinrpc.authproxy import AuthServiceProxy, JSONRPCException
import logging

rpc_user = "rpcuser"
rpc_password = "xxxxx"

logging.basicConfig()
logging.getLogger("BitcoinRPC").setLevel(logging.DEBUG)

rpc_connection = AuthServiceProxy("http://%s:%s@192.168.1.39:8332/" % (rpc_user, rpc_password))
print(rpc_connection.getinfo())

I get this error:

DEBUG:BitcoinRPC:-1-> getinfo []

Traceback (most recent call last):
  File "<path>\rawtransactiondemo\raw.py", line 11, in <module>
    print(rpc_connection.getinfo())
[... snipped]
  File "C:\Python27\lib\json\decoder.py", line 384, in raw_decode
    raise ValueError("No JSON object could be decoded")
ValueError: No JSON object could be decoded

This is my bitcoin.conf:

testnet=1
rpcuser=bitcoinrpc
rpcpassword=xxxxx
daemon=1
rpcport=8332
rpcallowip=192.168.1.39
bind=192.168.1.39

I'm using the python-bitcoinrpc library.


texts: I don't understand why people need to create alternatives to Bitcoin such as litecoin. Why were these created? What's the point? You can't answer those questions using the same arguments for why Bitcoin was created.


texts: Why don't miners charge more for high value transactions?

texts:
I know high and low value transactions take up the same amount of space in the blockchain.
But wouldn't btc be more economical and fair if miners deliberatly chose transactions based on the value/fee ratio?
That way small transactions became cheaper and more viable


texts: What if my Transaction is in differently assembled blocks

texts:
I understand, that the miner decides which transactions she chooses to include in a block. Often dependent on fees.
So the blocks that are mined in parallel might include different transactions. Say my transacting is in two blocks ... Then one bock is confirmed ... Will it be taken out from the other attempt to mine the block? #transaction


texts: How to read the transaction pages on blockchain.info?

texts:
I read the original Bitcoin paper and think I understand it but I'm having a hard time relating it to the transaction pages on blockchain.info.  For example, sometimes there are 2 outputs and neither of them is back to the sender (what the paper would call "change") which seems to violate the rules of splitting and combining described in the paper.

Is there a good guide on how to read these diagrams?


texts: Why exchanges show Bitcoin price higher than actual value?

texts: I trade crypto on indian platform WazirX and CoinSwitch. Both are currently showing price of 1 Bitcoin to be 44,78,353 Indian Rupees ($ 60,605.51) while the price shown on google as well as Binance right now is only 41,37,198.19 Indian Rupees ($ 56,000.78) . Same for other crypto. Could someone please explain this huge difference in pricing, I would really appreciate it ?


texts: What is the point of a permissioned blockchain?

texts: As far as I understand, the whole point of a blockchain is to prevent failures of the kind where a node produces arbitrary data with malice - i.e., to guard against the case you don't trust some nodes of the network. If your nodes are trusted, though, a blockchain isn't necessary at all, you know the code isn't malicious. So what is the point of a permissioned blockchain?


texts:
I'm building a webapp that needs to update account info and send a message when an account's address gets a deposit, and/or confirm withdrawals.

I'm not sure what the best way to do this is. Would you have a separate application keep sending API calls to blockchain.info until a new transaction comes through? Then initiate the right callback function?

Using blockchain.info seems flimsy since it's a 3rd party service. How would you do this monitoring the bitcoin network? It seems like using any bitcoin client would rely on some commandline action. Would the best way be continuing to send the commandline action out until the returned data is different, and then initiate the callback? Is there a better design pattern that I am missing?


texts: Risk to Bitcoin balance when making Bitcoin Gold transactions

texts:
If Bitcoin Gold fails to implement replay protection, will I risk losing my Bitcoin when I make a Bitcoin Gold transaction?

Assuming replay protection is not implemented properly, how can I protect myself?


texts: Can I retrieve my bitcoins from years ago that I never received?

texts:
How can I get hold of my bitcoins that never made it to my wallet years ago?

I purchased some bitcoins years ago (have got my receipt and all emails from who I purchased). I downloaded Bitcoin-Qt 7, synced it, got an address for the seller. It went through, but I could never sync it again as I was using prepaid internet credit. So, the bitcoins never got to my wallet! I gave up for a few years, but now I have unlimited download. Now Bitcoin-Qt 7 has a download issue. I switched to Bitcoin Core 11 now. I would like to know how I can get hold of my bitcoins?

Ther was no data transferred over to Bitcoin Core 11 sadly. Please can any one help me?


texts: Why does Ripple needs to have a long ledger?

texts: Why does ripple need to maintain a long ledger? Why is it not enough to maintain only the most previous transaction details? What is the purpose of having a long history ledger?


texts: Mycelium - more than one unused Bitcoin HD account

texts: Why can't I have more than one unused Bitcoin HD Account? What if I want to use a Bitcoin mixer that allows for 5 destination addresses?


texts: Is it possible to add a label to a sent bitcoin transaction using the bitcoin-cli?


texts: How much Bitcoin did I mine in December 2013?

texts:
I just realized I had a bitcoin mining program installed back in November/December 2013.

I am trying to figure out if it's worth going through all my backups to see if I can still find the wallet file.

I assume that based on the duration, the date and my MacBook Pro specs, I should be able to get a rough estimate on how much I had mined. Maybe someone can help me figure out, what the difficulty was back then, and based on the MacBook Pro specs, how much I could have mined.

Starting date: 25. November
Ending date: 22 December

Hardware: MacBook Pro (Mid 2012) - 2.5 GHz (3210M) Intel Core i5 Ivy Bridge -  Nvidia GeForce GT 650M with 512 MB

I had my MacBook on pretty much 24/7.

I am just looking for a rough estimate.


texts: bitcoin payment accidentally sent to Bitcoin-Qt application's sending address

texts:
My father accidentally sent a bitcoin payment to his Bitcoin-Qt application's "sending address". Are the bitcoins lost? or is it possible to recover them somehow? When checking on blockchain.info, the funds are visible but I have no idea how to recover them into the Bitcoin-Qt wallet.

I thought it would be visible after his Bitcoin-Qt wallet synchronized but no luck. When referring to "sending address", when you go to sending address in the Bitcoin-Qt client it has one address (you can have multiple) but this was the address he sent the funds to. Unfortunately the bitcoins did not come back to his wallet. This was done 2 days ago. If I look up the same address on blockchain, the exact amount is just sitting there.

Does anyone have a suggestion? Thanks!


texts: How do I get the public bitcoin address from a given private key in wallet import format offline?

texts: I have made paper wallets. And I continually send what bitcoins I get to them. I'm paranoid that I've been sending bitcoins to the paper bitcoin addresses where somehow at sometime my saved private keys got corrupted. So from time to time I want to run a script, python or whatever, to check if my private keys do correspond to the public address that I've been sending bitcoins to. I want an offline solution so things like the satoshi client would not do. Is there a small script written by someone that can solve this?


texts: Is there a way to import my wallet from Bitcoin.org's client into the much lighter Multibit or Electrum?  The disk space & bandwidth consumption (not exactly well presented to a beginner) quickly made it unfeasible on home computers.


texts: Pool mining website need to be logged in?

texts: Do i need to be logged in on the website mining pool to mine coins? Can i log off the pool mining website and just leave cudaminer running and still mine coins in the mining pool?


texts: Run bitcoin-qt at startup of Windows server

texts:
I am running bitcoin-qt on my server. I use .Net library to query it through windows services.
It all works when I start bitcoin-qt manually.
But if the server is restarted, I see that it is running in task manager (bitcoin-qt.exe), but it is not available for services.
I also tried to run it as administrator using the scheduler, but this did not help.


texts: BitcoinLib SignRawTransaction JSON-RPC returns false when using private key

texts:
This is a repost of (JSON-RPC signrawtransaction returns false when using private keys) but I could not comment because of my reputation (new user).

I've been using BitcoinLib via Litecoin Testnet for a week now and I got stuck with SignRawTransaction. It returns false but when I use the RPC call via litecoin-cli

litecoin-cli.exe signrawtransaction 020000000152cf5e76f1ac0fd42e97ec60db30406b019621da497601b430e7adf5642e1fa20000000000ffffffff02e09c4100000000001976a914fbb4b6ef02914490e99f899cb8538b03105331df88acc095a905000000001976a91471efff92af2740dd4fe088fc3de98ceebaa4c13488ac00000000 "[]" "[\"cQ3HSi45qrfGGZjYAci22gATWfhb1QhWR8JGBHBbzbPsD8Uuu2n2\"]"

the result is OK.

This is how I use the SignRawTransaction (Sample):

SignRawTransactionRequest signRawRequest = new SignRawTransactionRequest("020000000152cf5e76f1ac0fd42e97ec60db30406b019621da497601b430e7adf5642e1fa20000000000ffffffff02e09c4100000000001976a914fbb4b6ef02914490e99f899cb8538b03105331df88acc095a905000000001976a91471efff92af2740dd4fe088fc3de98ceebaa4c13488ac00000000");
signRawRequest.AddKey("cQ3HSi45qrfGGZjYAci22gATWfhb1QhWR8JGBHBbzbPsD8Uuu2n2");

SignRawTransactionResponse signRawResponse = coinService.SignRawTransaction(signRawRequest);

Has anyone encountered this problem before?


texts:
root@i-M116V:/var/www/cpuminer-2.2.3# ./minerd
[2013-12-27 15:22:35] 2 miner threads started, using 'scrypt' algorithm.
[2013-12-27 15:22:35] Binding thread 1 to cpu 1
[2013-12-27 15:22:35] Binding thread 0 to cpu 0
[2013-12-27 15:22:35] HTTP request failed: Failed connect to 127.0.0.1:9332; Connection refused
[2013-12-27 15:22:35] json_rpc_call failed, retry after 30 seconds

I'm using a laptop with no GPU.

root@i-M116V:~# netstat -anp | grep 9332
root@i-M116V:~#

i@i-M116V:~$ cd /home/i/デスクトップ/cpuminer-master/cpuminer
i@i-M116V:~/デスクトップ/cpuminer-master/cpuminer$ ./minerd -o ltc.give-me-coins.com:3333 -u sukarutinohu.1 -p 1


texts: Do full nodes store the complete merkle tree or do they regenerate it when creating a merkle proof?

texts:
I understand what the merkle root is for. And I understand that blocks don't store the merkle tree.
Question 1) Is there any place that the complete merkle trees get stored? I don't mean the merkle root hashes since I know they are in the block headers.
Question 2) Let's say a full node starts proving to a light node that a specific transaction is in Block J. How does the full node send the merkle branch to the light node? Does it loop through the transactions again to get the hashes and then sends the interior node hashes of transactions, or do full nodes already have the complete merkle tree (whole tree and each internal hash) stored somewhere?


texts: Why does this transaction results in only 2 unspent output (and no spent output)?

texts: This transaction is from one of the latest block. However I don't understand why it seems to be just dividing a single transaction without being spent and transferred to someone else.


texts:
Here is the Q/A related to: How is a wallet's balance computed?.

Based on this:

[Q] What is the Big-O complexity to retrieve the balance for a user?

Is it O(n), so basically do I have to iterate all utxoset to find matching outputs which correspond to public keys that it has the private key for ("your keys")? or is there any hash machanism that returns all outputs when I just provide my public-key?

Thank you for your valuable time and help.


texts: Ledger Nano Mnemonic Generation and Questions

texts:
From the ledger documentaion we have

The device generates a sequence of 256 random bits using the true random number generator (TRNG) built into the device’s Secure Element.
The first 8 bits of the SHA-256 hash of the initial 256 bits is appended to the end, giving us 264 bits.
All 264 bits are split into 24 groups of 11 bits.
Each group of 11 bits is interpreted as a number in the range 0 - 2047, which serves as an index to the BIP 39 wordlist, giving us 24
words.

The result of this process is that your device will generate a single
mnemonic seed out of 2^256 possible mnemonic seeds (That’s one of 115
792 089 237 316 195 423 570 985 008 687 907 853 269 984 665 640 564
039 457 584 007 913 129 639 936 possible mnemonic seeds). Note that
while the first 23 words are completely random, the final word was
derived from 3 random bits and 8 calculated bits from the SHA-256
hash. This means that the final word can act like a checksum - if you
input an incorrect seed into the device while recovering it, it is
possible for the device to detect that the inputted seed is invalid.

What was the motivation to move 8 bits to the end and use 2^11 possible words instead of move no bits and use 2^8 words with a 32 word mnemonic resulting in a bijective correspondance between the set of permutations of words and the set of possible 256 bit sequences.
Because of the dependence of the last word on the first 8 bits, there are (2048)^24 - 2^256 \approx 2.95 x 10^79 invalid 24 word mnemonics. Does anyone know what would happen if you tried to input on of these into a ledger during recovery mode? Mathematically it should give a random 264 bit sequence and then either 1) check that the first and last 8 bits are the same - if not, error. 2) throw the last 8 bits away to obtain a valid 256 bit seed that would correspond to a different mnemonic, where the # corresponding to the 24th word began with the same 3 digits.
"The device generates a sequence of 256 random bits using the true random number generator (TRNG) built into the device’s Secure Element." This is the only part that startles me a little. I feel like I remember reading in the past that a lot of attacks happen because random number generators can be exploited because they are not truly random. How is the randomness of this TRNG tested?


texts: How can coinbase charge less than the average transaction fee?

texts:
As of this writing, the average bitcoin transaction fee is over $30, according to this chart.  However, I just bought $20 worth of bitcoin on coinbase, and they charged me a fee of $1.49.

My understanding of the fee for a transaction is that it is a function of market forces, the number of bytes in the transaction, and the time you are willing to wait for your transaction to be added to the blockchain.  Overall however, I had the impression that at a given time these fees are relatively constant per transaction.  So I would expect that coinbase would have to spend something around $30 in fees to give me my $18.51.

What don't I understand?


texts: Can someone explain those free 0.00000001 BTCs?

texts:
I've just noticed an odd transaction to my wallet address. 1LnNQDKV6DiMnZ2rZ9yXpcnnTh7my1WusP seems to be giving me a free 0.00000001 BTC.

Investigating further shows that I'm not the only one receiving the free 0.00000001 BTC. Take a look at the blockchain transaction.

What is happening? Is this guy using blockchain's public note as an advertisement spam?


texts: Adding Comment on Bitcoin Transaction (After Sent)

texts: Is it possible to add a comment to a bitcoin transaction after it has been sent?


texts: Automatically restarting bitcoind five minutes after reboot on ubuntu

texts:
How can I run bitcoind automatically five minutes after restart?

So far I have crontab set up to reboot my computer every morning at 4AM (it runs into issues when it stays on for more than a couple days). I also have tried to use crontab to restart bitcoind on @reboot, but haven't had any success with that.

I am currently using Ubuntu 18.10, and bitcoind v0.18.0.0.
Here is my current crontab:

0 4 * * * /sbin/shutdown -r +5
@reboot /usr/bin/bitcoind -daemon -conf=/home/<username>/.bitcoin/bitcoin.conf


texts: What does Bitcoin Core's "Coin Control Features" do and how do I use it?

texts:
What is Bitcoin Core's "Coin Control Features"?

How do I use it, and what can I do with it?


texts: Do exchange rates between countries' currencies have an influence on Bitcoin exchange rates?

texts:
Are the exchange rates of each country a factor in the worth of a Bitcoin? Is the use of Bitcoin similar to traveling to another country and having a exchange rate between paper monies?

Basically, are bitcoins affected by the exchange rates of each country or the web exchange?


texts: Generate Bitcoin address with privatekey

texts: I am able to create new bitcoin address using jsonrpc by accessing the bitcoind client, where I am able to get only the account name and address but I could not get private or public key.  Is there anyother approach to create new bitcoin address with private and public key.


texts: What are the 3 arguments called in function SHA256?

texts:
void sha256(struct sha256 *sha, const void *p, size_t size)
{
    struct sha256_ctx ctx;

    sha256_init(&ctx);
    sha256_update(&ctx, p, size);
    sha256_done(&ctx, sha);
}

I'm trying to call this function in c-lightning but I'm confused to what the function arguments are.


texts: Can Bitcoin mining with my current specs break my PC?

texts:
I use the Windows Store app mining program. Will it harm my computer if I'm using the following specs:

Intel i5 3.2Ghz
NVIVIDA GeForce 730
8GB RAM
2TB Hard Drive

Thanks in advanced!


texts: Stable coins differences? (USDC - Coinbase / Circle, GUDS - Gemini, TUSD - Trust Token, PAX - PAXFUL, USDT - Tether)

texts: There has been a release of many stables coins recently. What are the differences from each? So far I know that Tether (usdt) is based out of the US banking system and everything else is in the US banking system and regulated. Also I read that the USDC and GUSD has a back door system to freeze and hold accounts if they wanted to. I wasn't sure if PAX had this same thing. What are all the listed pros/cons of each stable coin?


texts: I am business man but I am not tech savvy.  Recently, I have needed to use bitcoin for a few business transactions and so I asked my IT guy to buy the bitcoins for me and take care of the transactions.  He told me that due to various fees the $2000 dollars that I gave him only amounted to $1,400 after said fees.  My question is: am I being ripped off?


texts: What happens when a transaction script for mining is used for fund transfer?

texts:
So, through an odd bug in hacking some stuff onto Bitcoin, I encountered a peculiar thing.

Basically, I managed to generate an transaction with 2 outputs. The first output was a typical  txout

DUP HASH160 20:905a...a998 EQUALVERIFY CHECKSIG

However, a bug caused the second output (the change output, to send it back to myself) to be a mining generate transaction script:

33:025c...6718 CHECKSIG

This was not considered a non-standard TX, and as far as I can tell, was interpreted as a valid transaction for sending coins and block explorers see it as being sent to the proper address.

What exactly is the difference between these two scripts? What is the significance of using a mining script for a transaction?


texts: How do I determine my transaction fee in an automated way?

texts:
When I send Bitcoins through Electrum, I just pay whatever transaction fee the software recommends. Now I'm writing a program that will have to determine the size of the transaction fee on the fly.

How is this computed? It looks like Electrum is consistently recommending .0002 BTC for each transaction but I read elsewhere that resolving the fee amount depends upon the size of the transaction. In an extreme example, if I wanted to redeem 15 tiny unspent outputs and send them to 2 destinations (the receiver + my change address), would the unusually large number of inputs for the new transaction justify a larger transaction fee? If so, how much larger?


texts: How do I know I can trust the head of the blockchain

texts:
I'm trying to understand how the mining process works. Specifically, my understanding is the local miner works on blocks and add them to their local blockchain if they succeed. It may turn out that this isn't the longest chain of blocks (because there are other miners working in parallel) and when that longest chain arrives at the miner, the miner will discard its local (shorter) subchain in favor of the new one.

My question is if the local node (who's also a miner) is asked for information from the block chain before that longest chain arrives, how would it know that these blocks may still change in the future and shouldn't necessarily be trusted?

I apologize if the whole question seems confused. It's only a reflection of my own confusion on the topic.


texts: P2Pool Missing BTC Reward in Block History

texts:
I have been studying the block history for P2Pool here:

http://p2pool.org/stats/?blockoffset=40

over the last several days.  I noticed that bitcoin reward for each recent block is blank until 459871 and previous blocks (which appears after scrolling through several pages of block history).  Once you get to block 459871, it shows mining rewards as I'd expect.  Can someone help me understand why this is?  I have been mining on the site for quite some time with some S9s and still haven't received a reward.  I'm wondering if this might be the cause?


texts: Proof-of-Stake: What if a bad enactor is chosen by random?

texts:
My understanding of proof-of-stake is the following:
The node that mines the next block is chosen, randomly in proportion to the amount of nodes they have in the network (ex. person who who owns 5% of all the tokens in the ecosystem has a 5% chance of being selected to mine the next block)

The block gets broadcasted throughout the network.

However, based on this principle of randomness, what if a bad enactor is chosen by chance.

What if a person wants to submit a block w/ fraudulent transactions (ex. instead of Bob sending Alice 1 cryptotoken, the fraudster changes up the transaction to make Bob send Alice 100 cryptotokens - assuming Bob owns 100+ cryptotokens)?

Thanks!


texts: Why do exchanges provide ask/bid transaction data like the NYSE and NASDAQ?

texts:
Bitcointicker.co provides a very slick, very active display that purports to be all the ask/bid transactions on several exchanges (Gemini, Kraken, Coinbase, and others).
Where does it get its data?  AFAIU all the bitcoin transactions inside an exchange are just bookkeeping they do and the only real blockchain-recorded transactions are when you send bitcoin into the exchange, take bitcoin out of the exchange, and all the balancing activity the exchange needs to do to buy and sell actual bitcoin to keep themselves balanced.  So none of these can be actual bitcoin-network transactions (appearing in the mempool), right?
Only thing I can think of is that somehow when you become an SEC regulated exchange you've got to provide public visibility to the market - just like the NYSE or Nasdaq.  Is that the case?  Or is it something else?
I do see from the tag ticker that different exchanges provide different APIs for this.  So my actual question is: Why?  Are they required to?  Because if it isn't a (legal, regulatory) requirement on them I can't see why they do it.


texts: Does it make sense to use BitCoin to transfer money to yourself internationally?

texts: If you have a bank account in the US and an account in the UK, and you want to move money from one to the other, is Bitcoin a sensible way to do it, or are you better off using TransferWise or just doing an international wire transfer?


texts:
I'm asking about how to turn bitcoins into cash (USD or EURO) that you hold in your hands, so I can use it in real life not on the internet.

I don't have a credit card, and I'm in a country (IRAQ) where banking services aren't so profound and people don't use credit cards.

What do I need to do this?


texts: If most G20 nations ban bitcoins, would that effectively kill bitcoin?

texts: If the G20 nations (or most of them) ban bitcoins doesn't this effectively kill bitcoin? My thinking is that a normal person would no longer have any means of converting bitcoins to the local currency. The only other way this would work, were if most places took bitcoin (coffee shops, grocery stores), but if it's banned then most of the places would stop taking it.


texts: What is the typical size for an extended public key?

texts:
What is the typical bytesize range for an extended public key?

An extended private key?


texts: Script - Is it possible to build an addresss that allows retrieve a certain amount per address?

texts:
Is it possible to define a multi signature address that allows spending only certain percentage to each signature?

For example, three different people with different public-private keys build an pay to script address with a script that allows spending only 34% of the total amount.

So instead of requiring multiple signatures to spend the amount, it define limits on each signature.


texts: What would happen if I try to broadcast a transaction being funded by segwit outputs with a bitcoin unlimited node?


texts: Why do large blocks increase the probability of chain reorgs?

texts:
After the recent two chain reorgs taking place in Bitcoin Cash SV, I am finding a number of developers stating that large blocks are the reason for the reorgs:

"Almost each time someone is trying to produce a very large block on the $BSV chain, there’s a reorg." Nikita Zhavoronkov, lead developer at Blockchair

“This is basically exactly the problem the BU gigabock testnet identified. At sizes > 100mb the mempools were so out of sync that blocks were basically transmitted as full blocks.

"BSV had ONE 128mb block and it caused a six block reorg. On the BU testnet sustained 128mb blocks caused a total breakdown of the chain where there were so many reorgs that every node had a different view of the state of the blockchain. And would you believe barely a day goes by where the BSV supporters don’t mock me pointing this out as if it’s sooooo obvious how wrong I was.” Chris Pacia, CEO of OpenBazaar

What is it about the nature of large blocks that makes it more likely that the blockchain will reorganise itself?


texts: Does Bitcoin Blockchain solves Byzantine General Problem?

texts:
If bitcoin blockchain solves byzantine general problem, can you give an example of how it solves it?

Thanks


texts: If a wallet has multiple addresses, is the money in the wallet or in the address?

texts:
In the standard bitcoin client (Bitcoin-Qt), they tell me the total money in the wallet. However, should I be able to see how much money is in each address?

Does bitcoin money belong to an address or on a wallet?


texts: Set up eclair wallet 0.3.1 but cannot send onchain funds

texts: I filled my wallet with some btc then wanted to send coins onchain and it seems there is no that possibility ?


texts: What determines SHA256 performance on different types of hardware?

texts:
I know the answers to many questions on here briefly touch on this point, but I'd like to get a consolidated answer that really touches on the key differences between different types of hardware which allows SHA256 to perform better, instead of the less-related tangents other questions discuss. While my immediate concern is with Bitcoin, I know that some other crypto-currencies use different algorithms, so feel free to reference them if it helps make your point.

Why does the Bitcoin hash algorithm, SHA256, perform better on different types of hardware? What makes an ASIC/FPGA capable of computing more H/s than a GPU, a GPU than a CPU, etc?
What is "the complexity of the cores?" Is this a reference to the number of cores, or to the actual die complexity? In both cases, why is this not a factor in SHA256 performance? Referencing David Perry's answer here:

  It's important to note, by the way, that the one thing that won't buy you more hashes per second is the complexity of the cores. This is why Nvidia may make great cards for gaming purposes, but they suck for mining - games make better use of exotic new instructions than SHA256 does.

Can SHA256 be optimized at all to perform better on a per-architecture basis? Can any optimizations be made to the double-hashing process?


texts: BIP 84, BIP 173 Implementation in BitcoinJ

texts:
Can BitcoinJ (Java) supports complete implementations of BIP 173, BIP 84?
How can segwit address can be created using BitcoinJ for SPV wallet?


texts:
Can I test that I've correctly recorded the seed by "restoring" my wallet in a desktop wallet like Electrum by using the seed given to me by my Nano S?  It would mirror my hardware wallet, correct?

Is this safe / right way ?


texts: How to use -txindex to enable blockchain transaction queries?

texts:
I am trying getting the raw of transaction. But I am getting the following error with following command and  RPC call as well.

  bitcoin-cli getrawtransaction ad844933ceb9cf990fd75ebd2f6731527885e31d1a4c9ea292db235bcd64bdbe

Error
No such mempool transaction. Use -txindex to enable blockchain transaction queries. Use gettransaction for wallet transactions.


texts: Is it safe to run bitcoind on another server

texts:
I'm making first, rough concepts of some ideas for bitcoin-enabled services I have in mind.

One thing that I wonder is, is there a best-practise approach on running bitcoind on another server that acts as backend for a particular other server?

I thought of something like that:

I have a vServer A and a plain and simple PHP-Webspace at another host B.

A runs my bitcoind-deamon and only allows RPC-calls from Bs IP.

B makes its RPC-calls to A in a server-proccess which was not triggered by a client/website-visitor.

How safe would you ensure such a scenario? Is it possible that nodes, connected to my vServer A, identify the servers purpose from the transactions and try to attack him?

Even if they do, they would have to use a MiM-attack, because A only accepts Bs IP.

What else can I do to make the communication more secure? HTTP-Auth, SSL?


texts: I'm using bitcoin-cli and I need to get the public key of one of my SegWit addresses. My first attempt was to use 'validateaddress' command and take the 'scriptPubKey' field but that doesn't seem to be the public key of the address. Any ideas?


texts: Can transaction inputs reference outputs of pending transactions?

texts:
The inputs of a transaction reference outputs of previous transactions. These previous transactions

must already be present in the block chain, or
can also be pending transactions?

I don't know if the term pending transactions has some meaning I'm not aware of. In this context, I mean transactions that are not yet in the block chain, but are present in the block containing the new transaction.

Example: A particular block B contains multiple transactions including a transaction X and a transaction Y. The transaction X references the output(s) of transaction Y. Transaction Y is not yet in the block chain, but it is present in block B as well. Is this possible since transaction Y is not yet confirmed?

Note: I'm not using the term unconfirmed transaction because as I understand these are transactions not appearing in any block; and in this case transaction Y would be in a block, the same block as transaction X.


texts: Can someone explain what exactly is derived address?

texts:
Let's say my mnemonic words are

  army van defense carry jealous true garbage claim echo media make
  crunch

When I used https://iancoleman.io/bip39/#english, the section, Derived Address, showed me a lot of addresses. Among them, I found an address that my wallet showed, but the address would change time to time?

Why does my address change?

I understand that Derived Address are children of Account Extended Private/Public Keys, but why isn't my wallet showing me all of those addresses that I can use?

What is the maximum number of Derived Address for m / 44 / 0 / 0 / 0 / * ?

Are all the address valid and working? Meaning, can I send a payment to any of the address from the Derived Address and will I still get the cryptocurrency?

If I import any listed Derived Private Key to another wallet, can I use the funds in there?


texts: In my quest to learn about cryorocurrency, as fast as I possibly can, I have registered with about seven wallets, all with one goal, to deposit Bitcoin into one of them, I am yet to do this but I was thinking that maybe working with only one wallet would be easier, anyone, can you PLEASE help ?


texts:
I create a transaction with inputs from a given address / public key without signatures. Every input needs to be signed. I use a different method to generate the signatures so I can't provide a private key to sign the transaction.
Much like the blockcypher API I want to extract a list of strings (called "tosigns" in blockcypher API), sign them externally and combine them with the partial transaction I generated before.
Question 1: What field(s) do I have to take out of the bitcoin transaction json and how do they need to be processed to receive a string (or list of strings for multiple inputs) that just needs to be signed?
Question 2: How do I intergrate the generated signatures with the transaction object to receive a valid, signed transaction, that can be send to the network.
Any JS libraries that help with it are appreciated.


texts: How does the mathematical problem get harder for bitcoin mining over time?

texts: How does it become harder for miners to extract bitcoin as time passes (excluding increasing computer capabilities and the competition between miners accordingly)? Is related to the amount of bitcoins that could be extracted at that timestamp?


texts: What type of smart contacts will be available on Lightning Network?

texts: What kind of contacts will we be seeing eventually on LN? Will it be anything like what Ethereum has?


texts:
What is a wallet in the context of Bitcoin?

What are wallets used for?
What relation do wallets have to other concepts such as addresses, private-keys, client-software, and Bitcoin balances?


texts: Is transaction validation in Ripple trust-based or trust-less?

texts:
In Ripple consensus,

(1) Each validating server maintains a list of trusted servers known as Unique Node List (UNL).

(2) Servers only trust the votes issued by other servers which are contained in their UNL.

(3) Ripple enables different institutions (e.g. banks which run their own servers) to reach a consensus with respect to the fate of financial transactions.

From (1), (2), (3) :

(a) Can we conclude a a bank which runs its own server will reach a consensus on its transactions via only servers trusted by that bank ?

(b) And if so, can we say transaction validation in Ripple is trust-based and not trust-less?


texts: Reset bitcoin blockchain checkpoint to mine 0th block

texts:
I want to start a new block chain and mine the 0th block, but I guess the hardcoded checkpoint in chainparams.cpp won't allow that.

I guess I need to reset the checkpoint hardcoded as follows before starting a new blockchain.

    checkpointData = (CCheckpointData){
        boost::assign::map_list_of
        ( 0, uint256S("000000000933ea01ad0ee984209779baaec3ced90fa3f408719526f8d77f4943")),
        0,
        0,
        0
    };


texts: Why isn't transaction replacement supported?

texts:
The wiki article on contracts talks about the best stuff you can do with delays and replacement. (Lock time and sequence numbers, respectively.) But according to the documentation, replacement isn't supported yet. Why not?

(If the answer is "it's not implemented yet", why hasn't it been?)


texts: Delegated Proof of Stake (DPOS) vs. Proof of stake?

texts:
What is the main difference between Delegated Proof of Stake (DPOS) vs. Proof of Stake? Is there any significant advantage for security? (since PoS in general suffers security problems.) And which DLTs / Blockchains use DPOS?

P.S. the link mentioned in THIS ANSWER about DPOS does not exist any more.


texts: How many signatures are there in one non-multisig transaction

texts:
I checked this How is a transaction's output signed?.

I need clarification for:

For each input there is one signature, so there are as many signatures as there are inputs?

Why is that so and not use just one master signature per transaction, is it because sender of transaction can use funds from more than one address he controls?

Is there also a master signature that signs entire transaction or just the per  input signatures mentioned before?


texts: Is there an on the fly service to exchange physical currency for BTC for payment processing?

texts:
I want, as a merchant, to receive money from my customers in the form of
bitcoins, to avoid the 2~4% fees. But many of my customers don't have
BitCoins. I was wondering if there is a service that would allow for a customer to
spend X amount of USD (or any other currency) to buy the corresponding
amount of BTC "on the fly", without requiring customers to have BitCoins or
even a BTC wallet.

Is there such a service?


texts: Trying to figure out the two-part authentication process. Can anyone give direct instructions?

texts:
I'm using btc-e.com verification, in the Finances section.
It supplies two key codes and has a square bar code to scan.
I've set up my google account for two-part verification, and google is ALSO supplying a keycode.
I've downloaded the bar code reader, but apparently I have to do something with these 3 keycodes before the bar code reader will give it's 6 digit code for me to enter in the btc-e.com security/finances section.

Can anyone tell me where I enter the google security code?  And also tell me where I'm supposed to enter the two btc-e.com security codes?
I need explicit step by step instructions, which I can't seem to find online.
thanks,
PS. I am a complete noob at this.  I've read similar questions and answers on this forum already, but they don't explain WHERE these codes are really supposed to go.


texts: What happens once the mining reward gets cut in half?

texts:
Sometime around the end of 2012 the mining reward is expected to be cut in half from 50BTC/block to 25BTC/block.

What effect will this have? Doesn't this mean that it will be less economic to run a Bitcoin miner? Will the hashing power be severely reduced? Will BTC prices soar (or alternatively, crash)?


texts:
Need help!! anyone there..
How to Deduct transaction fee always from 1 receiver address if sending some BTC amount to 2 different receiver addresses in single transaction


texts: Is it possible to reverse mistaken transactions?

texts: I'm referring to the challenge Bill Gates raised as a shortcoming of Bitcoin. Could it ever be possible to reverse a bitcoin transaction mistakenly sent to the wrong address?


texts: Privacy issues with storing entire information in blockchain

texts:
I have been learning about how blockchain can be implemented in IoT, or health where entire information of patient is stored in blockchain, or in case of governments having info about citizens.

However, I have a question. What could be the privacy issues in the long run and the implications. I am just curious.


texts: How to let a peer connect to a peer's peer?

texts:
I'm testing a new altcoin that I've created between several computers in LAN but encounter a situation as follow:

Computer A's client connects to computer B's client through the B's IP in the addnode field in the config file and only B's IP is specified in it. The same thing happens between B and C as C only knows B through the config file. It seems that there is no connection between A and C since the the command getpeerinfo in both A and C doesn't show the other's IP. Indeed, when I shut down the client on computer B, the two clients on A and C become disconnected to the network.

So my question is: what should I do to make A and C connected since they share a common peer's connection? (assuming that the new common connections are random, not known in advance to be included in the config file)

I've read somewhere that there are seed nodes which stores IPs of clients which have connected to them and that they usually don't need to keep connecting to those new nodes, just save the addresses in the database and disconnect. In case of new peer connects to the network, those seed nodes will help to provide list of peers' IPs. So how can I configure a node to be a seed node? Is it in this case the DNS seed? (I guess it's not)

Thank you in advance and all kinds of help will be highly appreciated.


texts: How do you choose the correct fee with Bitcoin Core?

texts: I have the same problem with unconfirmed transaction and I already know how to solve it. But I don't know how to define transaction fee so that it doesn't happen again. I'm using the Bitcoin Core wallet and I chose the recommended option for transaction and fastest confirmation time. When I sent the transaction, a lower fee was applied than recommended and now the status of transaction is: 0/unconfirmed, in memory pool, broadcast through 1 node(s).


texts: How to generate transaction history from all addresses that are part of common xpub/ypub without having the xpub/ypub?

texts: I have 20 addresses generated  which are part of a common xpub/ypub. I want to create a combined transaction history of all addresses similar to that of how trezor has the export CSV function. I understand that trezor generates it from the xpub, but in my case I have the addresses but not the xpub.


texts: Can the price of Bitcoin ever be stable to the USD?

texts: It seems like the only way to sell BTC for products/services is to have the BTC reflect how other currencies are doing. I'm not great in economics but can it ever be stable?


texts: Where is the Mycelium wallet file stored?

texts:
I have a fairly straightforward question that's still unanswered after googling for days for a definite answer, I hope you guys can help me out with this one here.

Background: I have Mycelium Bitcoin Wallet installed on my Android phone [ROOT], I have backed up my HD wallet which also contains Local Trader account, and have been successful in restoring said backup[s] (by means of un-installing app, wiping it's old data and re-installing / loading wallet from backup (Master seed)). I also have redundant backups of the app and it's data (I assume that includes the wallet file?) made with Titanium Backup.

Question: I however still do not know where Mycelium's wallet resides, is it on my SD extCard? SD Card? Data  partition? Protected Storage? Is it just determined by the Master Seed and hence resides nowhere?

Final Note: I'm eagerly awaiting this piece of information to be at ease with my policies, knowing that  I can manually backup/encrypt my wallet file (if there is one) is really important to me.

Thanks in advance!


texts:
Sorry guys & gals - yet another "unconfirmed BTC transaction..".

Looks like the fee was too small, but this was sent 72 hours ago now (at the time of writing)

https://blockchain.info/tx/f81760ebe76ad0e64374ee3d243f0549fe809d61285c5631c01def84848dcdb2

Do I just need to be more patient?

Edit:12/06/16 - It has been over 120 hours now, are there any options for me to retract the transfer and re-submit with a higher fee?


texts:
For a newbie like me, I am still confused about how this bitcoins works. And I don't mind if someone can help me get a clear sight on how this thing works.

Thanks


texts:
I've been looking at the Bitcoin Core PR review club sessions on fuzz testing here and here.
Can you explain at a high level what is fuzz testing?


texts: Coinbase transaction smaller than .001 btc? & Blockchain says my Bitcoincore wallet is invalid

texts:
I'm trying to figure out how to send tiny transactions, like 10 cents.  Coinbase says the minimum is .001btc.  That seems rather large.  Is that just a coinbase requirement?
Also, my blockchain wallet says that my bitcoincore wallet receiving qr code is an "Invalid Bitcoin address: "  Why?


texts: Can you specify a date in the future for the Bitcoin transaction

texts:
I just came across this Transaction: https://blockchain.info/tx/cf77c2b888916c0debfb801d3d129ba5b7f6445e0dd6db9238b313b51369024c

Received Time:  2063-08-04 05:00:33

Raw Transaction: https://blockchain.info/rawtx/cf77c2b888916c0debfb801d3d129ba5b7f6445e0dd6db9238b313b51369024c

Is it just one case, maybe some kind of bug, which has already been solved, or is this a normal behavior?

Is there any official information regarding this topic?