Basic smart contracts are already possible as is.


More complex smart contracts might be enabled by the likes of Simplicity:

https://bitcointalk.org/index.php?topic=2338626.0

So far it's just a concept, but it's an example of work being done on enabling more complex smart contracts on top of the Bitcoin blockchain. Note that Simplicity is explicitely not Turing complete, as allowing Turing complete scripts being run on top of blockchains is arguably a not-so-smart idea and leads to the likes of the DAO disaster and the two Parity mishaps, ie. lacks the stringency needed for immutable transactions that include a financial incentive if exploited.


A bit closer to completion is rootstock, which would run as a sidechain and aims to offer Turing complete smart contracts on a merge-mined blockchain using 2-way pegged tokens:

https://www.rsk.co/

 

Soft forks don't lead to a blockchain split, otherwise the SegWit activation would have lead to an alternative blockchain. SegWit transactions still look valid to legacy nodes, it's just that legacy nodes lack the ability to properly interpret them under the new rules that the soft fork brings with it. Now if you were to disable SegWit again -- ie. have a signifcant number of nodes handle SegWit transactions like legacy nodes -- that then would require a hard fork, since SegWit nodes would deem such transactions as invalid while legacy nodes would process them, leading to a chain split.

In short: Soft forks only require a hard fork (ie. blockchain split) when rolling back the change, not when first deploying the update. Not requiring a blockchain split on deployment / activation is pretty much the definition of a soft fork.

It doesn't. To be fair, the case for PoS is energy savings, not improved decentralization. Seeing how PoS is likely to make centralization of both power and wealth worse by simply replicating the old system of gaining money by owning money, I personally don't have much love for PoS. But that's a different matter. Point being, be aware of future Ethereum milestones when planning to invest in Ethereum mining.

1) It's impossible to come to a solid conclusion about which coin will grow by how much -- or decline, for that matter.

2) Alts surpass each other all the time. Of course there's a certain psychological effect to being the king of the hill, but still: Except for FOMO, what difference does it make if some other coin turned out to be more profitable as long as you made a profit yourself?

3) Since we apparently have a tangent about Ethereum mining -- didn't they plan on getting rid of mining altogether and switch to PoS? I'm aware that they postponed the difficulty bomb, but it's still in the cards, is it not?

4) The platform argument is kinda silly. What's their definition of a platform? The internet is a platform. MySpace was a platform. Without proper context it's just as meaningless a term as "blockchain". Merely defining it as something that Amazon and Facebook have in common doesn't help much.

It's when you fork the code of a repository, for example on Github. If you're unfamiliar with basic software development concepts such as forks and version control you should probably start with something else than cryptocurrencies.



Anyone can provide their computational power to any network. Question is whether they want to.



If you just fork the code without changing any of the protocol rules, then you simply have a Bitcoin client that interacts with the same blockchain and you can send and receive transactions like everyone else.

If you fork the code and change any of the protocol rules, or start from a new Genesis block, then you're on your own blockchain and won't be able to send transactions to or receive transactions from the Bitcoin blockchain.

Ah, I guess I misread your initial post. I thought you meant "rewriting" a block 3 blocks deep into the blockchain. If you only want to rewrite the last block you of course only need to beat the network by that one block and the subsequent one.

What you are describing sounds like an Alternative History Attack as described here:

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

Basically, in your scenario, an adversary would need to have enough hashrate to outrun the rest of the network between block 3 and block 4. In other words, they have roughly 10 minutes to mine 3 valid blocks -- the block with the double-spend and 2 blocks on top. Once they own the longest chain, the rest of the network follows and "their" blockchain is the canonical one.

The chance of such an attack succeeding depends on the hashrate of a would-be adversary. If an adversary controls more than half the network, the chance of success is 100% -- the infamous 51% attack. However the chance for success diminishes pretty quickly the smaller a percentage of the network the would-be adversary controls.

You can calculate some scenarios here, if you like:

https://people.xiph.org/~greg/attack_success.html

An attempt to outrun the 3 confirmations of your scenario with eg. 30% of Bitcoin's hashrate, would succeed with 32.5% probability. With only 10% of the network you're already down at 1.3% success probability.


Keep in mind that these attacks are very costly, as every failed attempt results in forfeited block rewards and transaction fees for each block you tried to outrun.

There are (code) forks and hard forks. There are also soft forks, but let's leave these out for a minute.

Code forks happen when someone bases their code on an existing project (eg. Bitcoin) and starts their own project -- or in this case cryptocurrency (eg. Litecoin). Those kind of forks have nothing in common except for parts of the code. No shared transaction history, nothing. Thus, everyone starts with a zero balance and early adopters stand to gain more coins than latecomers (assuming Bitcoin-like block reward halvings or similar mechanisms that reduce the block reward over time).

Hard forks usually also require a code fork, but in essence are simply an disagreement on the network. That is, parts of the network want to introduce a new rule that other network participants disagree with (eg. a max blocksize increase as was the case with Bitcoin Cash). What then happens is these coins share the same transaction history until the point of disagreement. Which is why everyone who held coins on the original part of the fork, also holds coin on the forked part.

I'm not sure what you mean by "acquiring the mainnet". If you mean "acquire significant hashing power from the original chain" -- this requires the hardforked chain to be more profitable to mine than the original chain.

Bitcoin's power usage is a function of 1) the current block reward, 2) the current Bitcoin price and 3) the current electricity prices according to the region where mining is taking place. Using hashrate as basis for the calculation of Bitcoin's power usage is a futile exercise since the productive hardware mining being used is changing all the time.

GPU mining has been out of the picture for Bitcoin since 2013.



Most bitcoins have already been mined -- about 80% of the final amount. Current mining operations are merely competing over the last few scraps and transaction fees. It follows that most coins that are currently being traded are "old" coins and not freshly mined ones, thus the influence of current mining operations on the currency in circulation is limited.



Becoming richer and expanding your operation is part of running a business.



Exponential hashrate growth does not translate to exponential hardware purchases. It's called Moore's Law.



You stated worries based on uninformed assumptions without acknowledging any of the counter-arguments to your initial proposal.

It won't.

China is leading in clean energy:
https://www.theguardian.com/environment/2018/jan/10/china-on-track-to-lead-in-renewables-as-us-retreats-report-says

US electricity usage is stagnant:
https://www.vox.com/energy-and-environment/2018/2/27/17052488/electricity-demand-utilities

Russian power companies are looking for ways to monetize excess energy:
http://bitcoinist.com/russia-power-sell-energy-bitcoin-miners/

Cryptocurrencies are unlikely to lead to rising electricity costs, as mining operations tend to flock around places with low electricity costs ie. places that have a surplus of electricity already.

If electricity prices rise, whatever the cause may be, mining operations either move to cheaper places still or get simply shut down due to decreased profitability.



Such a law is neither desirable, nor definable, nor executable.

Depending on your setup you either want to have a utility like daemontools watch the process and restart it on a crash:

https://unix.stackexchange.com/questions/336501/how-to-restart-a-process-automatically-when-it-killed-in-linux-centos


Or add a loop to your script that retries the same command until it succeeds:

https://serverfault.com/questions/80862/bash-script-repeat-command-if-it-returns-an-error
https://stackoverflow.com/questions/12321469/retry-a-bash-command-with-timeout

In case you're new to shell scripting: When an application (or command) runs successfully it returns a status code = 0; if it fails it returns a nonzero error code. These loops retry the same command with a slight delay inbetween (sleep) until it returns the status code = 0, ie. succeeds.

PayPal's initial value proposition was allowing users to pay online without the need for a credit card, similar to Bitcoin's banking the unbanked. We all know that PayPal failed in that regard. Whether Bitcoin manages to "bank the unbanked" remains to be seen, but it's definitely a struggle for now.

Where PayPal succeeded however was lowering the entry barrier for merchants to accept payments online. Before PayPal came along it was close to impossible for small shops to accept online payments, so despite all the flak that PayPal gets they played an important role in enabling widespread ecommerce. Hell, before Bitcoin came along it was close to impossible for the average consumer to send and receive money internationally without getting crushed by banking fees. Despite its volatility Bitcoin improved on a lot of the issues that PayPal failed to resolve. In other words, cryptocurrencies stands to lower the entry barrier for ecommerce even further, possibly enabling new business models and especially further enabling international P2P / C2C transactions.

So regardless of their current dominance, looking at the big picture there's a lot of room of improvement over current credit / debit cards and PayPal. Whether Bitcoin and friends manages to sustainably improve on those shortcomings remains to be seen of course, but there's only one way to find out.

Usually you can use the arrow keys up / down to navigate through your command history, if that's what you're looking for. This is true for both Linux and Windows machines. Or are you talking about writing a script that repeats the most recent command in case of a failure?

Unless an AI is successfully trained to create ever more efficient ASIC layouts that then get cast into silicon that's not how any of these technologies work.

Because it won't stay that way and the transaction count that needs to be handled is only going to grow.

Even with off-chain 2nd layer scaling solutions in place we need to utilize what little blockchain space we have as best as we can. Apart from improving Bitcoin's scalability both approaches would also help improve Bitcoin's privacy -- Schnorr signatures are beneficial for CoinJoin and Bulletproofs allows sending hidden transaction amounts.

So I see the Three Body Problem books are popular with Bitmain



Running endless iterations of conway's game of life !== Machine learning

Deep learning / AI in the sense that is currently being applied for eg. autonomous vehicles !== consciousness

AI has taken enormous strides but is yet to grow beyond the hyper-specialized applications we see today. We're still far off from generalized AIs that would count as conscious, intelligent beings, let alone having this all emerge from a blockchain's PoW scheme. We're barely able to create programs that pass the Turing test without relying on special tricks such as having the program pretending to be a 13-year old Ukrainian boy [1], let alone creating an algorithm that goes beyond pretending.

So while it's incredibly important to start discussing the implications of possible future developments in the AI space -- knowing that society takes decades to adjust to new ethical challenges -- we're still far away from what could one day become the singularity.

[1] https://www.theguardian.com/technology/2014/jun/08/super-computer-simulates-13-year-old-boy-passes-turing-test

SegWit is not necessary for implementing Lightning Network, only fixing transaction malleability is (the very same issue that enabled the MtGox hack back in the day).

As for now, however, SegWit is the only available fix for transaction malleability on affected blockchains (I'm not sure if Ethereum is facing the same issue with Raiden, for example) so as a consequence SegWit is currently prerequesite for Lightning Network to work.

Never. Even if cryptocurrencies succeed on every possible metric, fiat currency markets will likely always be larger than crypto markets; if only due to the wider availability of fiat currencies for the general populace. Think about it -- even if the crypto market were as large as the stock market, the trading volume of fiat / crypto currency pairs would count toward the day-to-day volume of both crypto assets and fiat. So unless traditional stocks and bonds get more trades in crypto than in fiat, fiat will always be a step ahead.



"Blockchain the technology" is more often than not a term devoid of meaning, approaching vague problems with undefined solutions; so naturally this platonic ideal of a technology falls apart upon closer inspection.

Cryptocurrencies, a concrete application of blockchains, have left the lab a long time ago. And they are facing real world adversaries over and over again.

Only some people know that I'm fairly familiar with cryptocurrencies and of these even fewer actually know that I have a personal stake in it. So crypto discussions usually don't affect me personally and I just get to be the bystander and watch the Dunning-Kruger effect unfold.

Whenever people dismiss Bitcoin as a bad investment (which is their right to do) I just smile to myself, knowing that most of them either have been dismissing Bitcoin since 2013, are invested in questionable alts or sometimes both. It's their loss, not mine. Or maybe in the long run crypto will utterly fail and they will be proven right after all, but it doesn't matter really. I made my choices, they made theirs, bitching or gloating about either decision is just bad form.

Bitcoin is beating capitalism at its own game. The generations before us choose capitalism and reaped most its gains. The generation now is simply entering the next level of play, that's all there is to it.

The idea behind bulletproof transactions is that the content of the transaction is encoded in a way that only the sender and the receiver know the amount being sent, with an external observer merely being able to verify that no money has been generated out of thin air (ie. input minus output equals zero). Since the balances are only the sum of inbound and outgoing transactions it follows that the balance of addresses that receive / send bulletproof transactions will not be known to an external observer.

For MimbleWimble, which uses a similar technique, not even the sending and receiving addresses are visible to external observers. To be honest I'm not sure if that's the case with Bitcoin bulletproofs as well. Either way it will probably still take a while until we see bulletproof transactions coming to Bitcoin, if this approach will actually be pursued at all.

A bit closer to real life usage is the privacy that comes with Lightning Network. In this case it's more of a side-effect and the settlement balances of each respective address is still public, but at least the transactions that lead to the final state are not. Given enough data an adversary could probably correlate at least part of the transactions that are happening, but it at least gives slightly more privacy than mere on-chain transactions.

There's also CoinJoin btw, which is basically a built-in tumbler / mixer for Bitcoin transactions. Not sure what the state on that front is though.