How address balance is calculated?

It does not seem practical to scan every transaction on a block chain to determine the balance for an account. As the block chain grows this seems even more difficult and resource consuming. Perhaps all the transactions are grouped into what we used to call a record, specifically a variable length record.
address..trans1, trans2, etc…transN for the last transaction.

What prevents Dash miners from refusing to pay to masternodes?

I struggle to understand the repationship between Dash miners and masternodes. The proposition is that masternodes provide additional services to the network and automatically get paid a part (45%) of the block reward. What I don’t understand is how this share is enforced.

From the Dash whitepaper:

When mining on the network, pool software (websites that merge the
efforts of individual miners) use the RPC API interface to get
information about how to make a block. To pay the Masternodes, this
interface must be extended by adding a secondary payee to
GetBlockTemplate. Pools then propagate their successfully mined
blocks, with a split payment between themselves and a Masternode.

What prevents miners from simply ignoring the masternodes and assigning 100% of block reward to themselves?

Edit: from Dash documentation:

If a miner tried to take the entire block reward for themselves or tried to run an old version of the Dash software, the masternode network would orphan that block, and it would not be added to the blockchain.

But the question remains: what does it mean for a masternode to orphan a block?

Calculate fees with Blocktrail/ SDK

First of all hi and thanks for your support and your time.

I want to calculate the fees of a blocktrail transaction with blocktrail SDK, before making the transaction, in order to let the recipient pay fees.

Here is what I tried:

$FEES = $wallet->coinSelection(\Blocktrail\SDK\Wallet::normalizeOutputsStruct(['66f4dec6ab29cd056ce1814c6fdfee05e1524b36' =>'100000']),false,false,\Blocktrail\SDK\Wallet::FEE_STRATEGY_LOW_PRIORITY;
echo "$FEES";
$fee = $FEES['fee'];
echo "$fee";

But this don’t work, it says this: Fatal error: Uncaught Blocktrail\SDK\Exceptions\BlocktrailSDKException: Address not recognized how can I fix this error? Thanks for read, hope that you’ll have a nice day 🙂

Slow sync running Bitcon full node on Mac Mini OSX

It is Jul 2018, I need help after several attempts to sync a full node running on a Mac Mini.

I have tried several times and Bitcoin-qt starts pretty well for the initial sync, downloading with progress that ranges from 1% per hour up to 3 % per hour. But when sync goes around 30% (blockchain around 50 GB) sync slows down to 0.2% per hour so it’d take weeks.


  • 1.4GHz dual-core Intel Core i5
  • OSX 10.13.6
  • 500GB (5400-rpm) hard drive
  • RAM 4GB of 1600MHz LPDDR3 memory
  • Good internet speed.


  • Installed Bitcoin Core implementation 0.16
  • I tried both, installing the .dmg for mac and also tried to homebrew
  • Both successful in the beginning, and then sync goes down

I get good connections, and I have the port 8333 opened so I have no clue of what is going on, whether it is problem with the hardware (mac works fine) or the implementation.

Actually I have been running Litecoin and Monero nodes in the same hardware, implementing OSX builts and those worked fine, but Bitcion Core doesn’t .

I hope someone can help me, if faced the same difficulties with bitcoin.
I really would like to succeed in this and support the network

Restore from 24 words seed

I have used bitcoinj for createting wallet. I made some changes and try to generate 24 words seed instead of 12 words seed.

When I try to restore from 24 words seed, at that time I am using 3 method as mentioned in bitcoinj documentation.

Fast catchup.
Bloom filtering.

According to documentation, by using these methods you can easily decrease restore time.

But it takes maximum 20 to 25 minutes to complete restore.

Please help me who knows this process.

PoW 51% attack vs. BFT 1/3 attack?

So from what I understand, Bitcoin’s PoW is prone to 51% attack, but as a distributed system it is also prone to BFT’s 1/3 attack right? I think it’s mathematically proven that in a distributed system, if you have more than 1/3 bad nodes collaborate together, then you cannot safely reach a correct consensus no matter what?

So for Bitcoin, there are two types of possible attack scenarios, one is if a miner node consistently has more than 51% computing power of the whole network then it can double-spend indefinitely and basically has unlimited cash to spend.

The other is if more than 1/3 of the nodes in the whole network are bad guys working together with modified malicious node code then they can potentially stop the correct block being accepted and make it impossible for others to know which is the correct longest chain, thus prevent valid transactions being processed and recorded.

So are my understandings correct?