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Topic: Limitations of Blockchain. What are they? - page 2. (Read 1037 times)

jr. member
Activity: 126
Merit: 3
The data is written to the block chain, waiting at least 10 minutes, all nodes synchronize data, and more time is needed! Block chain transaction data is delayed.

The generation of blocks requires the miners to carry out numerous meaningless calculations, which are very energy-intensive.

jr. member
Activity: 140
Merit: 2

WRONG.  Bitcoin no longer has a block size limit.  Segwit replaces the block size limit with a block weight limit, set to 4000000 bytes:

Code:
/** The maximum allowed weight for a block, see BIP 141 (network rule) */
static const unsigned int MAX_BLOCK_WEIGHT = 4000000;

Yes splits it between two files giving a total of about 3.5meg but they did not need to mess thing up by
coming up with vbytes to muddy the waters and should stick with plain old bytes because we all know
what they are.

Someone posted about the signature not having to be tested by lazy miners looking for a bit more speed
because it is in a separate file but apart from that I am OK with Segwit but will never be OK with Lightning
and its banking hubs that like you say is taking shape and it's not looking like any mama & poppa type home
banking that I have ever seen before. https://lnmainnet.gaben.win/



 

Yep. I've read a lot about Segwit and the main detractors of Segwit are the miners because it cheapens the incentives they get through mining. But as someone who wanted to improve the blockchain, I am pro to it.
member
Activity: 210
Merit: 26
High fees = low BTC price

WRONG.  Bitcoin no longer has a block size limit.  Segwit replaces the block size limit with a block weight limit, set to 4000000 bytes:

Code:
/** The maximum allowed weight for a block, see BIP 141 (network rule) */
static const unsigned int MAX_BLOCK_WEIGHT = 4000000;

Yes splits it between two files giving a total of about 3.5meg but they did not need to mess thing up by
coming up with vbytes to muddy the waters and should stick with plain old bytes because we all know
what they are.

Someone posted about the signature not having to be tested by lazy miners looking for a bit more speed
because it is in a separate file but apart from that I am OK with Segwit but will never be OK with Lightning
and its banking hubs that like you say is taking shape and it's not looking like any mama & poppa type home
banking that I have ever seen before. https://lnmainnet.gaben.win/



   
copper member
Activity: 630
Merit: 2614
If you don’t do PGP, you don’t do crypto!
Well it really depends on which implementation of the blockchain you are referring to, if you're looking at the bitcoin core blockchain one of the limitations is the block size of 1Mb, meaning only 1Mb of transactions can be included in the next discovered block, thereby limiting the total of number of transactions the network can process at once.

WRONG.  Bitcoin no longer has a block size limit.  Segwit replaces the block size limit with a block weight limit, set to 4000000 bytes:

Code:
/** The maximum allowed weight for a block, see BIP 141 (network rule) */
static const unsigned int MAX_BLOCK_WEIGHT = 4000000;

Perpetuating the obsolete notion of a 1MB block size limit is often part of wider disinformation against Bitcoin, and certainly feeds into it.

It is true that the block weight limit does constrict the transactional capacity of the network.  It is estimated that with full Segwit adoption and the types of transactions typically seen on the blockchain, blocks should average a bit more than 2MB in size.  Further scaling will be achieved by (0) off-chain vertical scaling by adding another layer, with Lightning Network, (1) on-chain efficiency improvements such as Schnorr signatures, and (2) what I call “horizontal scaling” with sidechains/Drivechains.  Lightning Network is already live and running, albeit still in its early stages; as it matures, its scaling effects will be hugeN.b. that by taking transactions off-chain, it makes blockchain limitations less relevant.

Another limitation is the the ledger is publicly available, meaning that anybody can go and check your balance, your transaction history and who you've been dealing with, something that most people probably don't want probing into.

This is true, although blockchain analysis is not quite so easy as you say.  Bitcoin is not anonymous.  Use appropriate technical measures to protect your privacy.
jr. member
Activity: 350
Merit: 1
Although the blockchain is an emerging technology, all the technologies that make up the blockchain are the technology developed in the last century. Whether the dependent encryption algorithm can be deciphered with the development of the computer, can the data network synchronization be realized?
sr. member
Activity: 616
Merit: 263
Well it really depends on which implementation of the blockchain you are referring to, if you're looking at the bitcoin core blockchain one of the limitations is the block size of 1Mb, meaning only 1Mb of transactions can be included in the next discovered block, thereby limiting the total of number of transactions the network can process at once. Another limitation is the the ledger is publicly available, meaning that anybody can go and check your balance, your transaction history and who you've been dealing with, something that most people probably don't want probing into.
newbie
Activity: 1
Merit: 0
Hi

  I know the block chain limitations

 1.Network error
 2.Network speed and size and transaction cost
 3.Human error
 4.unavoidable security flaw
 5.politics
jr. member
Activity: 140
Merit: 2
February 26, 2018, 12:49:02 PM
#22

However this is not a significant threat as quantum computing isn't that advanced yet, there are better easier targets than bitcoins (or other cryptocurrencies), and bitcoin can always move to a quantum resistant algorithm.


At least this is comforting to know. As of the moment, I will put my trust on the people behind improving the security of bitcoin. Nothing is ever perfect, but the goal is to minimize the risks. That is why it is important to ask the difficult questions, while people are taking care to be balanced in opinion as well, so that unecessary fear is avoided. The reason why I didn't check out on quantum physics here in this forum is because I didn't think it was an issue for the blockchain until you opened it up.
copper member
Activity: 630
Merit: 2614
If you don’t do PGP, you don’t do crypto!
February 23, 2018, 07:01:06 PM
#21
In addition to the aforementioned limitations of blockchain as enumerated by some contributors here on this forum,i would like to say that there are fears that that future development in cryptography may leave the blockchain vulnerable,ie hackable.That is why there is so much fear about the development of quantum computers,which may become commercially available 10-20 years time frame.Part of the solution to this future vulnerability is to use a bitcoin address only ONCE.Thanks to experts who already see the future.By the way,the world will have bigger problems to deal with when quantum computers become mainstay-sensitive military installations for example.

(Boldface is here added to question-begging.  Smart, well-informed people don’t have “so much fear” about quantum computers; thus, there is no “why”.  I have never beaten my wife; therefore, I have never stopped beating my wife.)

This is new info to me. Forgive my ignorance about quantum computers, but how will it be a huge threat to blockchain? i mean, i just can't see the point why blockchain will be vulnerable. I thought people are aiming to improve it?

There are a lot of threads on Bitcointalk about the threat of quantum computers on bitcoin.
http://lmgtfy.com/?q=quantum+site%3Abitcointalk.org

Yes, so very many threads.  Behold the power of Quantum FUD®, superposition of which is entangled across the forum!

The gist of the matter is that quantum computers can break ECDSA which bitcoin uses for digital signatures and will be theoretically able to calculate private keys from public keys.
This is prevented by not reusing addresses because addresses are not public keys but a hash of them and quantum computing can't do anything with them. (An address's public keys are exposed whenever a transaction is made with that address)

Xynerise, you seem generally well-informed; but here, I think you are sorely mistaken in picking up an unfortunately popular meme.  Quoting one of my better Jr. Member posts from way back when, in the context of a thread about Bitcoin and quantum computers (bracketed clarification added):

As a general point, I will worry about disclosing Bitcoin public keys at the same time I start to worry about disclosing my long-term PGP public key.  (For those in the peanut gallery:  The latter would be entirely useless without public disclosure.)

There are excellent reasons to avoid address reuse; but this [QC resistance] is not one of them.  I say this as a paranoid security nut:  The security of publicly disclosed public keys is just fine.  That is why they are called public keys.  The only exception I would here make is if you have coins which you intend to potentially leave in cold storage for decades.  Then, yes, you will want the extra security margin of the key being unpublished.  That’s not only a concern about quantum computers:  Unexpected cryptanalytic techniques could develop over the course of many years.  For cryptography which really needs to stand the test of time, reducing your security requirements to a hash is simply good security hygiene.

Also apropos, in a distinct context (whereas FUD can only be distinct without difference):

The security of exposed Bitcoin public keys is just fine for general usage.  They cannot be hacked.  [...]  But there is a different, unrelated reason to avoid address reuse:  Privacy.  Avoiding address reuse gives you a modicum of privacy.  That at least makes Chainalysis work for their pay.  Re-using addresses makes transaction linkage trivial, child’s play.

A public key is called a “public key”, because it is secure when exposed in public.  I publish my PGP public keys (and if I didn’t, PGP would be useless).  I am not worried about that.  Each and every time you connect to an https website secured by TLS, the server’s public key is exposed to you—and your symmetric session key is derived from a key-agreement process based on the hardness of the same DLP as is the fundamental basis of most widely-used public-key cryptography other than RSA.  I am not worried about that, either!  Likewise, I am not worried about the security of my Bitcoin public keys.

Evidently, I am not the only one to be of the opinion that “hash public keys for quantum resistance” is a regrettable meme.  Quoting from discussion of Taproot on bitcoin-dev, 2018-01-23:

You had better be worried about being killed by a flying fire hydrant than about [the security] of Bitcoin’s cryptographic keys.  It has happened at least once somewhere that a man was killed by a flying fire hydrant.

Please.  You don’t worry about being killed by a flying fire hydrant.  Whereas to be killed by a flying fire hydrant is not only possible, but astronomically more probable than any cryptographic break of Bitcoin security.

At some point, after the size of 2128 is explained for the 2127th time, anti-Botcoin FUDsters realize that FUDding Bitcoin security in the present just makes them look absurd.  So, they upgrade to Quantum FUD® technology:  Point to an uncertain future, oversimplify complex technological questions much debated by experts, and then beg the question of “why there is so much fear about the development of quantum computers”.

Practical, usable quantum computers do not exist.  Their present is fantasy, and their future is unknown.  Some experts are of the opinion that a practical quantum computer capable of useful computation may be impossible—scientifically, physically, mathematically impossible.

E.g., quoting from one of my Newbie-rank posts, q.v.; see also the ensuing discussion between myself and haltingprobability:

A quantum computer is not a sure thing!

I should preface this by saying, I’m not endorsing the opinions of Scott Aaronson.  I’m only citing him as someone who is not a moron, and wrote a book on quantum computing (which I have not read).  I seem to recall some wager on his blog over the (im)possibility of quantum computing, but I can’t find it right now; anyway, D-Wave has a long history (2013) of drawing his ire (2017), to say the least.

See how he discusses skepticism of quantum computers:

Quote
What I did is to write out every skeptical argument against the possibility of quantum computing that I could think of. We'll just go through them, and make commentary along the way. Let me just start by saying that my point of view has always been rather simple: it's entirely conceivable that quantum computing is impossible for some fundamental reason. If so, then that's by far the most exciting thing that could happen for us. That would be much more interesting than if quantum computing were possible, because it changes our understanding of physics. To have a quantum computer capable of factoring 10000-digit integers is the relatively boring outcome -- the outcome that we'd expect based on the theories we already have.

[...]

As for myself, I account myself moderately skeptical of quantum computing; I’ll believe it when I see it, but meanwhile I think it’s a good idea to move to PQ crypto.  I would be more surprised if quantum cryptography can deliver on its promises.  I don’t like the hype around any of it, especially when it’s sometimes used to FUD Bitcoin.

On that note, in closing, I will repeat in this Quantum FUD® context what I said more generally about Bitcoin’s public-key security:

I strongly recommend that anybody not deeply involved in developing Bitcoin’s long-term security should absolutely not worry about the strength of Bitcoin’s public-key security.  It’s worse than useless worry:  It is a distraction from real problems.  Worry instead about your computer security, your operational security, and your financial privacy.  (Nobody can target you for theft or coercion if nobody knows you have anything significant to take.)

It is as if many people are keeping their coins in a safe with an unbreakable door (the cryptography—all of it) and walls made of tissue paper (the malware-infested PC, privacy leaks which may allow thieves to identify you and know what money you have, etc., etc.).  Then, they obsessively worry about the security of the door!  Don’t do that.



I think Xynerise concludes correctly:

However this is not a significant threat as quantum computing isn't that advanced yet, there are better easier targets than bitcoins (or other cryptocurrencies), and bitcoin can always move to a quantum resistant algorithm.
sr. member
Activity: 322
Merit: 363
39twH4PSYgDSzU7sLnRoDfthR6gWYrrPoD
February 23, 2018, 04:56:22 PM
#20

This is new info to me. Forgive my ignorance about quantum computers, but how will it be a huge threat to blockchain? i mean, i just can't see the point why blockchain will be vulnerable. I thought people are aiming to improve it?
There are a lot of threads on Bitcointalk about the threat of quantum computers on bitcoin.
http://lmgtfy.com/?q=quantum+site%3Abitcointalk.org

The gist of the matter is that quantum computers can break ECDSA which bitcoin uses for digital signatures and will be theoretically able to calculate private keys from public keys.
This is prevented by not reusing addresses because addresses are not public keys but a hash of them and quantum computing can't do anything with them. (An address's public keys are exposed whenever a transaction is made with that address)

However this is not a significant threat as quantum computing isn't that advanced yet, there are better easier targets than bitcoins (or other cryptocurrencies), and bitcoin can always move to a quantum resistant algorithm.
jr. member
Activity: 140
Merit: 2
February 23, 2018, 01:25:30 PM
#19
Blockchain is a new kind of database - block or records connected to another block. That's the simplest explanation. However, I want to ask the hard question.

What are the limitations of blockchain? I know this is a really good innovation and I highly support it, not because I join the bandwagon, but because bitcoin will not exist if not because of it.... But I want to have a better understanding of the blockchain (in layman's terms please) if I want to get really serious about cryptocurrency and ICOs. My second question is, what are the things experts do to improve blockchain?

In addition to the aforementioned limitations of blockchain as enumerated by some contributors here on this forum,i would like to say that there are fears that that future development in cryptography may leave the blockchain vulnerable,ie hackable.That is why there is so much fear about the development of quantum computers,which may become commercially available 10-20 years time frame.Part of the solution to this future vulnerability is to use a bitcoin address only ONCE.Thanks to experts who already see the future.By the way,the world will have bigger problems to deal with when quantum computers become mainstay-sensitive military installations for example.

This is new info to me. Forgive my ignorance about quantum computers, but how will it be a huge threat to blockchain? i mean, i just can't see the point why blockchain will be vulnerable. I thought people are aiming to improve it?
legendary
Activity: 2898
Merit: 1823
February 23, 2018, 01:45:29 AM
#18
The blockchain works great for currency systems, and to an extent, smart contracts (provided they are not needlessly complex, or else you risk losing all stored funds to a bug/hack/unintentional loophole). Alas, there are not many other practical uses for the blockchain, owing to the fact that the very premise of the blockchain requires distributed nodes (which usually requires monetary incentive or a token), and it also requires the transparency of data.

Is transparency really a requirement? I believe the Bitcoin blockchain was only transparent because there was no one developing any implementation for Bitcoin that can mask the sender's address, the receiver's and the amounts at that time.

We do now.

Quote
Now, it's very fun to think of big banks and companies using the blockchain for all of their transaction, but if this was implemented in the real world, the idea falls flat on its face. Why? Because no bank/company in their right mind would reveal all their information publicly, no bank/company in their right mind would let third (or even second) parties control their nodes. They would implement what is commonly known as a private blockchain. A private blockchain is also known as a database.

Not only that. A real "blockchain" is inefficient and slow. It's better if they stop joining the bandwagon and use Bitcoin.
legendary
Activity: 1372
Merit: 1252
February 22, 2018, 12:36:33 PM
#17
I think the most damage done to Bitcoin has been done by those that were promising challenging centralized payment methods such as VISA while doing it on-chain. This is a limitation of a blockchain that pretends to be decentralized. It's just going against physics basically.

The only way we can ever compete against a centralized system is via second layer solutions. Do we really need to?

I never saw the need for Bitcoin to be seen as a viable way to pay for your groceries when I understood the problems it had and how it was better suited as censorship resistant decentralized electronic gold of sorts. But maybe at this point we can't afford not being both, or at least attempting to be both. Is this possible? We'll have to find out. If LN is a success and on-chain transactions are still viable for "gold-tier" transactions, we will have both and this promise of "banking the unbanked" will actually become real, since some poor guy in Africa is better off with LN than with nothing else, the problem is again, if this will become a problem and make on-chain transactions non-viable at some point... again, we will need to find out.
legendary
Activity: 3430
Merit: 3080
February 22, 2018, 05:37:27 AM
#16

Right. I'd like to think that tech like the above could be leveraged to create a database of author attribution (although I must stress: not the laughable "copyright" concept). It'd be a great way to promote the generalised use of cryptographic signing keys; anyone who believes their idea might be falsely attributed to someone else can submit a signed hash of their original works to a blockchain.



One of the side-effects of the rise of ASICs has been that Bitcoin is sharing its PoW scheme with only a handful of coins, signifcantly reducing the number of possible targets to alternatively point hashing power at. Nonetheless it is of course impossible to predict how the world and cryptocurrencies will look like a 100 years from now, given the latter still exist.

And this is one facet of a very significant reason to not switch POW algorithms.  Thank you.

Don't you mean this is the reason not to be holding any coin using the PoW algo to which Bitcoin's PoW algo is switched?

No.  First off, the existing investment in ASIC hardware benefits Bitcoin security insofar as it locks miners into mining Bitcoin (or scamforks—hmmm).  If Bitcoin miners were forced to dump their existing investments in the trash and restart from scratch, they may very well decide to play the market with altcoins—especially since they might feel betrayed (and in the case of some of the better miners, they might have a point).  Moreover, the existing ASIC base provides a formidable hashpower which could not be rebuilt overnight.  Meanwhile, network would be relatively weak.  Lesser hashpower equals lesser resistance to anybody obtaining 25%/33%/51% of it.

There is a trade-off involved:  Mining is now much too centralized; and installed base obviously benefits incumbents.  But on the other hand, a switch would most benefit whomever could rapidly build out a new installed base.  That very well could be the same incumbents.

Eventually, kakistocracy could overwhelm Bitcoin. S2X only failed because not enough people are presently foolish enough to swallow stories about politically motivated emergency hard-forks to different consensus rules defined by a different dev team. At some point, the balance of fools running Bitcoin nodes could be right for that to happen. PoW change is the only possible way to fight that scenario.

Although I hope that won't be necessary, I can see how some kind of technological improvement in semiconductor fabrication could decentralise mining with SHA-2 PoW. I would also point out that it would be surprising to me if SHA-2 has infinite longevity, but maybe that's a long-term problem.


Any alt already using the hypothetical new Bitcoin POW would be potentially crushed out of existence, unless the new POW could be merge-mined.  Then, both blockchains would share a mutually beneficial symbiosis; and the existing alt would receive a security boost from the flood of new miners.  Of course, I don’t see great prospects for this unless the coins are not economic competitors; observe that Namecoin, inventor of merged mining, does not compete with Bitcoin as a currency.

Yes, this is what I meant. Unless other cryptocurrencies using a hashing algorithm that Bitcoin uses have some in demand use-case that isn't duplicated by Bitcoin, then they're set to lose significant amounts of hashrate (assuming Bitcoin is still the dominant cryptocoin)
copper member
Activity: 630
Merit: 2614
If you don’t do PGP, you don’t do crypto!
February 21, 2018, 06:27:17 PM
#15
The blockchain works great for currency systems, and to an extent, smart contracts (provided they are not needlessly complex, or else you risk losing all stored funds to a bug/hack/unintentional loophole).

This can be summed up by saying that blockchains are only useful for abstract information that benefits from being uncensorable, of which money and contracts are examples. Other examples I would include would be ID systems and data timestamping (Satoshi proved this in an inverted way by adding the famous "The Times 3.1.2009, Chancellor approves 2nd bailout" text to the genesis block, any data referenced in a blockchain can be verifiably proven to have existed at least after a verifiable time/date).

Clickbait for hardcore Bitcoiners:

https://petertodd.org/2016/opentimestamps-announcement

https://opentimestamps.org/

But when the 21m BTC supply was mined, miners will surely shift to a more mining-profitable coin that can lead to a lower Hashing power.

One of the side-effects of the rise of ASICs has been that Bitcoin is sharing its PoW scheme with only a handful of coins, signifcantly reducing the number of possible targets to alternatively point hashing power at. Nonetheless it is of course impossible to predict how the world and cryptocurrencies will look like a 100 years from now, given the latter still exist.

And this is one facet of a very significant reason to not switch POW algorithms.  Thank you.

Don't you mean this is the reason not to be holding any coin using the PoW algo to which Bitcoin's PoW algo is switched?

No.  First off, the existing investment in ASIC hardware benefits Bitcoin security insofar as it locks miners into mining Bitcoin (or scamforks—hmmm).  If Bitcoin miners were forced to dump their existing investments in the trash and restart from scratch, they may very well decide to play the market with altcoins—especially since they might feel betrayed (and in the case of some of the better miners, they might have a point).  Moreover, the existing ASIC base provides a formidable hashpower which could not be rebuilt overnight.  Meanwhile, network would be relatively weak.  Lesser hashpower equals lesser resistance to anybody obtaining 25%/33%/51% of it.

There is a trade-off involved:  Mining is now much too centralized; and installed base obviously benefits incumbents.  But on the other hand, a switch would most benefit whomever could rapidly build out a new installed base.  That very well could be the same incumbents.

So as for what I meant.  As for what you said:

Any alt already using the hypothetical new Bitcoin POW would be potentially crushed out of existence, unless the new POW could be merge-mined.  Then, both blockchains would share a mutually beneficial symbiosis; and the existing alt would receive a security boost from the flood of new miners.  Of course, I don’t see great prospects for this unless the coins are not economic competitors; observe that Namecoin, inventor of merged mining, does not compete with Bitcoin as a currency.
legendary
Activity: 3430
Merit: 3080
February 21, 2018, 03:48:00 PM
#14
The blockchain works great for currency systems, and to an extent, smart contracts (provided they are not needlessly complex, or else you risk losing all stored funds to a bug/hack/unintentional loophole).

This can be summed up by saying that blockchains are only useful for abstract information that benefits from being uncensorable, of which money and contracts are examples. Other examples I would include would be ID systems and data timestamping (Satoshi proved this in an inverted way by adding the famous "The Times 3.1.2009, Chancellor approves 2nd bailout" text to the genesis block, any data referenced in a blockchain can be verifiably proven to have existed at least after a verifiable time/date).


But when the 21m BTC supply was mined, miners will surely shift to a more mining-profitable coin that can lead to a lower Hashing power.

One of the side-effects of the rise of ASICs has been that Bitcoin is sharing its PoW scheme with only a handful of coins, signifcantly reducing the number of possible targets to alternatively point hashing power at. Nonetheless it is of course impossible to predict how the world and cryptocurrencies will look like a 100 years from now, given the latter still exist.

And this is one facet of a very significant reason to not switch POW algorithms.  Thank you.

Don't you mean this is the reason not to be holding any coin using the PoW algo to which Bitcoin's PoW algo is switched?
copper member
Activity: 630
Merit: 2614
If you don’t do PGP, you don’t do crypto!
February 21, 2018, 02:44:06 PM
#13
Thanks for all of your answers! I am enjoying reading your replies and it gives me more realistic understanding about blockchain. At first, I thought that this technology will be the magic bullet to every technological problem.

Core developer gmaxwell is prophetic.  In one of the earliest posts to which I awarded merit, he wrote of how DHTs...

...get invoked in ignorance to every distributed systems problem because they're the first distributed systems tool people have heard of (sadly, "blockchain" is seems to be stealing this role), much as "neural network" has infested lay understanding of machine learning, or perhaps in other times "XML" was treated as a magical solution for inter-working serialization in places where it made little sense.

There is no such thing as a “magic bullet to every technological problem”.  Unlike DHTs, the blockchain is actually robust and secure (including Sybil-resistant) in the use case for which it is the right tool for the job.  The blockchain is a work of genius.  But it is still only the right tool for the right job.

Don’t believe the hype.  Ignore the buzzwords.  Know the facts—I am pleased that this thread has helped you do that.

But now, I know that blockchain is not for everyone. But when used correctly according to its purpose and strength, it is indeed a formidable technology.

Exactly.
jr. member
Activity: 140
Merit: 2
February 21, 2018, 01:37:54 PM
#12
Thanks for all of your answers! I am enjoying reading your replies and it gives me more realistic understanding about blockchain. At first, I thought that this technology will be the magic bullet to every technological problem. But now, I know that blockchain is not for everyone. But when used correctly according to its purpose and strength, it is indeed a formidable technology. For example, a pen was invented for transcribing and recording data on paper, but it is useless as a chopstick or to stab on something - sure, you can use it as that, but its full potential will not be realized. See the picture? I'm not saying that people should limit the use of blockchain, though. That's why we have developers. 

This is what people should be educated about: the pros and cons of everything, and to have a realistic and healthy expectation about blockchain and cryptocurrency.
legendary
Activity: 3122
Merit: 2178
Playgram - The Telegram Casino
February 21, 2018, 03:38:33 AM
#11
Blockchain is a new kind of database - block or records connected to another block. That's the simplest explanation.

It’s an oversimplified explanation.  The blockchain forms a Merkle chain of unalterable history, whereby correct knowledge of the present can be used to verify correct knowledge of the past.  Adding a Hashcash-style POW function for transaction ordering, it becomes a Byzantine fault-tolerant distributed database with no central authority or trusted “supernodes”.  That’s the simplest explanation I can provide in two sentences.

Thank you for this post. It's always mildly infuriating how people focus on the boring part of blockchains -- ie. the database aspect -- while completely ignoring the interesting part -- ie. achieving consensus.

Now one may argue about the up and downsides of PoW, but one thing should be clear to everybody -- a blockchain without a decentralized, permissionless, trustless way to reach consensus is only half the fun.


:)1. There is no customer protection on the blockchain.
=> Blockchain technology operates as a push-based settlement system. This means the individual holds power over the resource they want to verify on the blockchain. This could be cryptocurrency, certificate authentication, land titles, etc. The problem with this is if a transaction goes sour after it has already been verified on the blockchain, the only feasible way of returning the transaction is if the parties agree to reverse it. Using a centralized system like a bank. However, there is a procedure in place to be able to dispute trades after they are complete.
     Some trade technologies that settle on a blockchain have used an arbiter system to fix this problem, an example of this is the Open Bazaar P2P trade network. This way a trade occurs between two people, and one impartial moderator.

Customer protection is a legislative responsibility, not a technological one. If you use cash or Bitcoin to pay a law-abiding merchant they will still honor your rights as a customer. If you wire transfer money to a nigerian prince customer protection will do shit for you.


:)2. Settlement on a blockchain is slow.
=> A cost of settling a transaction on the blockchain is that all the nodes in the network need to come to an agreement that the transaction is valid. This is a far slower process than having a bank verify your transaction in an instant.
     Transactions can be made instantaneously, however until the block in which the transaction is inserted in has been verified, it is classified is untrustworthy. In the time between a lodged transaction is made and when the block settles, a bad actor could launch fraudulent transactions to trick the network into what is known as a double-spend.
     A very exciting upcoming technology that could solve this problem is the lightning network. This solution acts as a layer 2 of blockchain technology; it can be applied to any public blockchain. It will enable instantly verified transactions for a fraction of the cost of today’s settlement.

Traditional payment methods may seem instant, but behind the curtain settlement is way slower than Bitcoin's or that of other cryptocurrencies'.

Wire transfer / SEPA transactions can take 1-2 days to settle. Direct debit can take up to 14 days to settle. Credit cards / PayPal can take even longer.


:)3. Miners can be selfish
=> The mining process on the blockchain is an innovation which uses game theory economics to incentivise people to commit computer power for securing the network for a profit. The down-side of this is generally miners won’t care about settling as many transactions as possible; they will make the most money by finding and verifying a block in the fastest way possible.
     This leads to a problem of miners finding empty blocks and validating. There is also another problem known as Selfish Mining, which is a situation where a miner or mining pool finds and validates a block and does not publish and distribute a valid solution to the rest of the network.

Selfish mining is a potential attack on the network but an uneconomical one at that. Unlike mining empty blocks, it has nothing to do with mining incentives being misaligned.
jr. member
Activity: 42
Merit: 2
At your service
February 20, 2018, 08:04:05 PM
#10

 Roll Eyes Hello I was able to browse the following list of weakpoints of Blockchain Technology (big thanks, credit goes to the author ROB BLASETTI from his article 5 Weak Points of Blockchain Technology   https://blockgeeks.com/public-blockchain/ );

 :)1. There is no customer protection on the blockchain.
=> Blockchain technology operates as a push-based settlement system. This means the individual holds power over the resource they want to verify on the blockchain. This could be cryptocurrency, certificate authentication, land titles, etc. The problem with this is if a transaction goes sour after it has already been verified on the blockchain, the only feasible way of returning the transaction is if the parties agree to reverse it. Using a centralized system like a bank. However, there is a procedure in place to be able to dispute trades after they are complete.
     Some trade technologies that settle on a blockchain have used an arbiter system to fix this problem, an example of this is the Open Bazaar P2P trade network. This way a trade occurs between two people, and one impartial moderator.

 :)2. Settlement on a blockchain is slow.
=> A cost of settling a transaction on the blockchain is that all the nodes in the network need to come to an agreement that the transaction is valid. This is a far slower process than having a bank verify your transaction in an instant.
     Transactions can be made instantaneously, however until the block in which the transaction is inserted in has been verified, it is classified is untrustworthy. In the time between a lodged transaction is made and when the block settles, a bad actor could launch fraudulent transactions to trick the network into what is known as a double-spend.
     A very exciting upcoming technology that could solve this problem is the lightning network. This solution acts as a layer 2 of blockchain technology; it can be applied to any public blockchain. It will enable instantly verified transactions for a fraction of the cost of today’s settlement.

 :)3. Miners can be selfish
=> The mining process on the blockchain is an innovation which uses game theory economics to incentivise people to commit computer power for securing the network for a profit. The down-side of this is generally miners won’t care about settling as many transactions as possible; they will make the most money by finding and verifying a block in the fastest way possible.
     This leads to a problem of miners finding empty blocks and validating. There is also another problem known as Selfish Mining, which is a situation where a miner or mining pool finds and validates a block and does not publish and distribute a valid solution to the rest of the network.

 :)4. The growing blockchain size
=> With every new block, a blockchain grows. This can be an issue because each node that is validating the network needs to store the entire history of the blockchain in order to be a participant. This is a hard enough problem with the bitcoin blockchain where the transaction size is only a few bytes, the total blockchain size as of January 2017 is 98GB. Given that at the same time in 2016 the size was 50GB, and the use of the blockchain is continuing to increase, this is a growing concern.
      One of the biggest debates in the bitcoin space is if the block size should be increased. If a blockchain has bigger blocks the blockchain size will increase faster, thus weeding out the solo miners eventually. This is a big issue because the health of a blockchain network is partially dependent on the amount of nodes in the network, and the spread of those nodes across the world. The counter argument for this issue is that with sufficient advancement of technology hard disk space will be very cheap in the future and will stay ahead of the blockchain size. The debate is ongoing.

 :)5. Eventually settlement on the blockchain will not be cheap
=> On any public blockchain, space in a block is a finite resource. Necessarily as the network is utilized more the amount of transactions that will want to settle in a block will exceed the storage capacity. Public blockchain networks have a solution built in for this which is that transactions with a higher miner fee attached will get precedence to be included in a block. This makes sense because the miners want to maximize their profit so that they will include transactions with the highest fees first.
     This is not a bug, but a feature. If it were free to settle on the blockchain, there would be far too many ways of attacking the blocks with dust transactions and clogging up the network. Originally the bitcoin blockchain had no block size limit; this was eventually set to 1MB to avoid a Sybil Attack on the network.

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