chain reorganization – Rewriting the blockchain?

The main bitcoin blockchain (the chain that miners choose to work on) is the chain with the most proof of work (“heaviest” chain). Currently, the cumulative proof of work on the bitcoin main blockchain is about 2^94 hashes.

I have a few questions here:

(1) How is the cumulative proof of work on a bitcoin chain calculated? Are they calculated by checking the timestamps (and thus the difficulty)?

(2) Let’s say an adversary has an alien supercomputer he stole from Area 51. He uses this alien supercomputer to rewrite the entire bitcoin blockchain from the genesis block – by mining a private chain that is heavier than the current chain. Does the current bitcoin network have any method of defending against this kind of attack? (I know that checkpoints can prevent such an attack, but checkpoints are no longer in the current bitcoin protocol, as far as I know)

(3) What would be the consequences of a bitcoin blockchain rewriting attack? An instant crash in bitcoin price? Would bitcoin be essentially dead forever, or does the bitcoin network have a way to recover and go on?

blockchain – bitcoin block time after halving?

I would like to know why the bitcoin block time is taking longer than 10 minutes, I know that bitcoin halving had decrease reward and increase difficulty but according what I read the blockchain itself will regulate the block time by adjusting difficulty to create a new block in order to have the same block time as first block was ever mined.Now block time are taking even hours what is it ?

thanks a lot

blockchain – Unable to make custom Bitcoin command

To add a new RPC, you need to write the function the implements it’s action, add the function to the dispatch table, and update bitcoin-cli‘s type conversion table.

At the bottom of the RPC file you added your function to (in this case, src/rpc/blockchain.cpp, you will see a table that has all of the RPCs in that file as well as some extra information about them like category, name, and argument names. Add your new RPC to that table.

Next, if your command has any arguments which are not strings, open src/rpc/client.cpp and add those arguments to the vRPCConvertParams list there. In that list, you give it the RPC name, the index of the argument that needs to be converted, and the name of that argument.

The World’s First 100% Decentralized Ethereum Blockchain Matrix Project – Cryptocurrencies Corner



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With regard to this, many companies have resorted to incentivizing tasks and promotional activities to give their consumers a fraction of a specific cryptocurrency. Ethereum is the second most popular and lucrative cryptocurrency in the world right now; which is potentially predicted to surpass Bitcoin someday. 

The main idea behind blockchain is to set up a decentralized network that would need a large number of users. Nevertheless, Ethereum has joined forces with many online incentive programs to give a little taste of their cryptocurrency to the users who are still having difficulties establishing themselves in the crypto market. 
Unlike many other incentive programs, Forsage is based on a Smart Contract Crypto earnings structure. There are no time limits, incentive caps, or any sort of time-sensitive pressure related to this program. What’s better is that you do not need any prior knowledge about blockchain or cryptocurrency! 

This program enables you to earn long term residual income by simply providing a referral to 3 or more friends, and asking them to follow the same process. In a way, this is a type of marketing program that is associated with Ethereum. Since it is based on the ‘Smart Contract’ structure, it cannot exploit any user. 
What is a Smart Contract? 
Smart Contract is a developed blockchain technology that involves an automated digital contract of sorts, which is unbreakable and unchangeable. One of the best features of this automated blockchain is that even if the host i.e. Forsage closes its website or shuts you out of it, the blockchain will still register you as an active participant and will constantly reward you for the efforts you put in. 

So, the chances of you being scammed are negligible. Also, this program was intentionally inclined towards a marketing and network marketing niche. This gives an advantage to people who have prior experience in marketing. Because of its overall technology, scams and fraud are practically non-existent. 
How do I Join? 
To join Forsage, you would initially need to pay a one-time payment of 0.055 Ethereum, which is less than $10.00 USD for registration. Once you set up an account and start referring to friends and the cycle continues to expand, you will see the funds in your crypto wallet increase. 

Forsage works with one of two major wallets. This again depends on which medium you use it on. Either Trust works best for mobile, tablets, and laptops and Metamask works best for computers and rigs. 
Forsage is indeed the new wave of incentivized network marketing. The Smart Contract structure makes it scam-free, giving crypto network marketing a revolutionary and much-needed change. Being a blockchain entity, privacy and security are at the top priority of Forsage and the inexpensive initial fee is literally and figuratively a small price to pay. So, what are you waiting for? Go get that Ethereum! 

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blockchain – Replace-by-fee issue – Bitcoin Stack Exchange

Ok so i recieved a 50$ transaction and it was on my account ( the bottom transaction) and 2 days later i have 0 $ on account and all funds from that transaction apparently got replaced by fee, am i gonna get it back eventually or , what does this mean, i tried googling it but language barrier is kinda messing up things for meenter image description here – Authentication error with Blockchain Wallet API

I successfully integrated the blockchain-wallet-api into an application which is currently on production. The challenge I’m having is that even though I was able to disable email login authentication from my wallet settings and added the shared hosting ip to ip whitelist, I still get the error

Array ( (error) => Wallets that require email authorization are currently not supported in the Wallet API. Please disable this in your wallet settings, or add the IP address of this server to your wallet IP whitelist. )

I don’t know what else to do.

blockchain – I made a payment of bitcoin into escrow for services that were not deivered and bitcoin not returned

You can contact the service provider, and the escrow agent to request a refund, but beyond that there is likely nothing that can be done. If you have lost a substantial amount of money, you could file reports with your local law enforcement agency, but understand that there is almost no chance they will be able to help you recover the funds.

Bitcoin transactions are not reversible, once confirmed several blocks deep in the blockchain history, the chance of that transaction being removed or replaced is basically zero. The only way those funds can be returned, is if the person who now controls them decides to send a transaction paying you back.

Sorry for your loss here, it is unfortunate to hear that even after employing an escrow agent, your trade did not go as planned.

blockchain – Problems Setting a Transaction Fee on a Per Transaction Basis Bitcoind

I’ve spent hours and hours trying to find a solution to this problem, with no success.

Using Bitcoin Core on a Linux machine, so using bitcoin-cli to process commands back to the daemon.

Here’s what I want to achieve: I want to send a transaction and be able to specify a custom transaction fee in Bitcoin/KB on a “per transaction basis”.

So far, I haven’t found a solution. These are the areas I have been looking at:

Change the paytxfee global variable and then just send the transaction. —> If I do this, the resultant fee once the transaction has been sent is about 40% lower than what I specified in the paytxfee variable. Why is it smaller?

So…. does anyone please have any ideas how I can just send a transaction and specify a custom fee which is the actual fee used when the transaction is broadcast to the network?

Thanks in advance for your help.


Hi. Thank you for your reply. I’m panicking a bit as I have to get this sorted by tomorrow. I’ve tried setting “paytxfee” with the “settxfee” command. In the last example I sent a dummy transaction using “sendtoaddress”. I entered “0.00170” in the “paytxfee” global variable (170 satoshis per byte). Having looked at the resultant transaction on explorer, only 114 sat/B were used instead of the requested 170. When I used “fundrawtransaction” and specified a “feeRate” option, it was calcultaing the fee on the virtual size rather than the total size, so once again I was getting about a 40% reduction in fees once the transaction was broadcast. I now have loads of transactions stuck!! Anyway, that’s not a problem as they were only tests… Any ideas how I can resolve this? Happy to send screenshots or maybe we can email/use messenger? Desperate to get this sorted …. Thank you so much!