Thanx, yup, indeed. I‘ll add it to my list  What I missing now is a way that shows, how to manually create the conditional scripts with regtest and bitcoin-cli. I haven‘t found much, seems like this is covered in libraries, but no precise info can be found in a step-by-step approach  |
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I would rather want to see independent unbiased Peer review from the general public that are skilled enough to do this Peer review, than some government with hidden agendas and zero transparency in their review criteria.
When looking at bitcoin, the credo is „be your own bank“ and „no need to trust anyone“. Hence the open source, and everyone to be able to look at the code. Trusting in „white hats“ is against the principle. And creating a list of „approved“ white hats, that would verify the code? Who watches the watchers? This involves a new set of trust complexity, one should be aware of. |
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What is the best method to monitor?
Not sure what might be "the best" method, as no criteria is given...  I have a running unixoide script using "bitcoin-cli getblockchaininfo", and redirect it e.g. into /tmp/getblockchaininfo.tmp It is running a 0.14 and 0.15 daemon, not yet on the latest 0.16 bitcoin daemon. Then I do: - grep "main", to be sure we are on live blockchain - grep "blocks", the current block on my node - grep "headers", the number of blocks known by the bitcoin world - "verificationprogress", a number >= 0.99 when in sync, otherwise this number indicates "trying to load old blocks to get in sync" I have some more scripts to put this all into a monitoring solution. It is run by a crontab daemon every 5min. There is one thing to pay attention to: if running on a slow (weak CPU) system, the RPC call can take more than 5min to come back, while the chain is not sync'd. So if you crontab the process, need to check first, if the process is still running, before calling again. Otherwise the NAGIOS solution proposed by Coin-1 is a good approach as well. |
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This confuses me, because I thought I was setting the lock time to a block height of 1, which should have already passed.
You talk about the last field in a tx (nLockTime), or the stack item before the CSV command? I think that nLockTime must not be set to the „relative“ block height of one... could you show the raw tax, so far as you got? The wiki explains to set nLockTime field to a higher value than the stack element for CSV, see here: https://en.bitcoin.it/wiki/ScriptI meant I read somewhere (just can‘t find the link), that LockTime cannot be the default „ffffffff“, it must be s.th. else. |
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The majority of Africans are unbanked, and I personally feel that introducing them to the formal banking sector will not alleviate any difficulties that they face. Most financial institutions do not actually have an long term "Africa" strategy because they do not perceive it as an attractive retail/corporate banking market, or they rip their customers off. so true  Africa has a history of economic dysfunction and suffers from frequent occurrences of hyperinflation. For instance, South Sudan struggles with an inflation rate of over 280%, or Nigeria, where inflation was ‘only’ 15.37% in 2017. one could add Simbabwe and probably other countries as well, I see were you go. It looks better in countries, which share a common currency (like the CFA). Burning 150KWh of electricity to process a single transaction is insane. We're talking about communities where people use pay-as-you-go solar because they don't have the capital to pay $200 for their own solar panel, where their income might be $3 a day, and they'd think themselves fortunate if they could use 150KWh in a year. I was wondering, how the 150kWh per tx are calculated. To process a single transaction, you don't need this power. Every PC can process/verify a transaction, even mobiles could do so. Only when it comes to mining, then a transaction goes into a block, and calculating the block's nonce requires so much energy. From my point of view the miners provide a service to the network, and they must not be resident in Africa? The idea of localization is so 19th century, when talking crypto. Anyhow, an Antminer S9 consumes 2kw, so if you run it 24 hours, you consume ~50kWh, three days = 150kWh. Of course there is no garantee, that your Antminer created a valid block. But this is a bit off topic. In general I fully agree, the bitcoin world is consuming too much power to be a solution for poor countries. At prices, where a kWh costs 1/4 of a daily income, it is simply way off... But as I said, mining doesn't need to be in Africa. I can send money from the US to my cousin in the Congo, and he can take the money and go buy himself something nice from the shop. Six African countries rely on remittances for 10% or more of their GDP, with 19 countries relying on diaspora remittances for 3% or more. For instance, in Kenya, diaspora remittances reached $1.95bn in 2017, up over 13% from 2016. As cryptocurrency transactions are subject to lower fees compared to traditional international money transfer alternatives, cryptocurrency transfers would be significantly preferable. Doing the same with Benin and Togo :-) Hence my business model is, to allow people to pay in bitcoin in Europe, if their family members need some urgent medical support. Imagine you need the money Friday evening... It is not perfect. It might be unworkable in its current state but through discussions with individuals on the internet, I hope to come closer to a solution. I am a young optimistic man, hence the naivety in my prose is very apparent. yes please, continue this work!  Everyone willing to support Africa and Crypto is doing good for the world. The inequality of richness distribution over the globe cannot be a basis for future living. Hence I love to see, how the US declines, and China grows, and will pass the US this year in many, many areas (patents, school/training, one day also GDP, ...). So this is the east/west distribution, next step must be South/North equality. There are a plethora of issues on the continent, but you start with the small problems (as outlined above): the relative lack of financial sophistication on the continent, and then allow people build solutions that utilise the protocol to meet their own needs e.g. new microfinance solutions etc. I agree to the step by step approach, can't save the world in a day :-) Microfinance was one of the worst things brought to 3rd world . The interest rates in microfinance were 30-50%, driving many poor people to commit suicide (especially India). I think this interest based money system is like cancer to humanity, and a new system is ready to come in. I hope crypto will help us to get there. |
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I'd start from the point, which problem it shall help to resolve. A "me too" product only copies existing systems, but for sure it is highly questionable, if the reasons for the product in northern hemisphere is the similiar to what can be seen in poor countries. With Bitcoin, the problem to solve was the financial freedom, that a currency is not forgeable, and can't be manipulated by a single authority. I understand it is not an immedeate need in northern hemisphere, but highly welcome to gain some independency. People obviously share being uncomfortable, when all their financial transactions can be monitored, and history shows, that this is no good (even in trustful countries). So yes, financial autonomy was/is driving this system, and many other drivers have joined via alt coins. Just "throwing" an altcoin over poor countries shall help to solve what? An alternative currency can address the volatility associated with fiat currency on the African continent and reduce friction amongst illiquid currency pairs (which leads to the non-convertibility of some currencies). Most observers judge that these problems are linked to civil conflicts, corruption and undisciplined fiscal policies. These conflicts are a good point - who brings the conflicts into these countries? Whose weapons are killing? What benefit has the population of precious metals in countries, where war is happening? Where do these precious metals go to? A common currency will allow businesses across the continent to enjoy frictionless transactions, thereby promoting more economic growth and job placements within individual markets. There are countries sharing the same money (french based CFA), and there is no sign that they have a better economy... However: Ghana is showing tremendous growth since they started to eradicate corruption. Yes! What about other countries, who have been ex-colonnies, like in South-East Asia? They stopped corruption as well, and began to develop their economies. Yes! So it looks to me as a primary driver... but who can help the remaining poor countries to stop corruption, and become a reliable business partner for northern hemisphere countries, so that also the country can benefit from their precious metals/ressources? The creation of a digital currency decoupled from the pervasive governance failures, which are a staple element in numerous African countries, will prove to be a stable asset which performs its function as a means of exchange, a unit of account and a store of value because its purchasing power is stable. Moreover, as it stands, trade between African countries accounts for a woeful 10%, compared to 40% and 60% between North American and European countries respectively. yes... as long as there are interests of foreign countries in ressources, and weapons to different groups, paired with corruption, what's the purpose of having a stable currency? It will not make people rich. The weapons will come back and destroy everything... So an understanding of a common sense of freedom is to be developed, like we see it in Europe for the last 60 years. I hope for Africa, and Bob Marley already was on the way to sing "Arfrica unite". Create partnerships in Africa? Where people envy each others... I'd like to stipulate, in Europe, 1+1 equals 3, in Africa 1+1 equals 1.1 or even 0.9... Therefore, a single currency will boost investor confidence and promote trade amongst intra-continental markets. The cryptocurrency will have to be decentralised, operating on the blockchain, working without the need for a central repository or single administrator. Due to lack of centralised control, the currency cannot be shut down by any one country. I am not yet convinced, that simply a technology change will bring growth or prosperity... It is cheaper for investors to promise weapons to different groups, these groups are eager to govern the country, create a kind of civil war, and make the ressources very, very cheap for northern hemisphere... No need for a centralized, non-forgeable currency? The issue of capital outflow from Africa and the absorption into Western economies deserves our attention and effort. In order to challenge this monopoly over currency, the cryptocurrency should only be transacted within the geographical boundaries of the African continent. Huh, you want to define rules on how to use the money? Noooo, I don't think so... The "today's" technical problems (limited infrastructure) are addressed correctly in an approach with technical solutions, still the root cause problem (what for crypto currency?) is unanswered. Really I think it boils down to the question, what problem can be solved with crypto. One cannot define a set of (complicated) rules, and say if then all rules are followed, growth and prosperity will establish itself... Change must come from internal forces! And development aid as of today is aligned at interests from foreign countries, not interests of the receiving countries. I think South-East Asia is a very good example, Ghana is a very good example, and other countries should follow them. |
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Bump
Maybe no reply cause some things are missing, like frequency of updates, amount (size) of data set, Numbers of nodes, private or public blockchain... A first shot: we see that fees and mining costs on bitcoin network can play a vital role. So you may put the public data into relation. Is the public data worth the expected costs of a bitcoin like blockchain? At the end bitcoin was done with monetary values in mind, not for public data... The same holds true for Ethereum - where there the point is, do you really need the blocks created every minute? Then there is FACTOM, a blockchain designed to do this proof of publishing. There are certainly others ... Last recently there were promising things to hear from a system built on Erlang, called Aeternity. I am not quite sure, if this is a me too project, or really bringing new things - they are aiming for high throuput with smart contracts. I guess the litecoin/Monero “thingies“ are out of scope. And then there is the dag type of systems, which looks interesting. The costs would need to proof, that they are below established blockchain systems though. But there is IOTA, the Angle, DagCoin, ... |
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... Second bolded part: The block size is not 4mb, it is 1mb. It would take a hard fork to increase this. Segwit did not increase the block size one bit (or byte  ), it is still 1mb. Segwit moved stuff around so more txs can be put into that 1mb. It's block weight is 4mb I believe, but block size is still 1mb just as its always been. There must be a misconception, looking at the code: https://github.com/bitcoin/bitcoin/blob/master/src/consensus/consensus.h/** The maximum allowed size for a serialized block, in bytes (only for buffer size limits) */ static const unsigned int MAX_BLOCK_SERIALIZED_SIZE = 4000000; /** The maximum allowed weight for a block, see BIP 141 (network rule) */ static const unsigned int MAX_BLOCK_WEIGHT = 4000000; |
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But the private keys is the same? So multiple public keys can be derived from the same private key?
edit as per comment from DannyHamilton below, unstructured comment, wrong quotes, low level, low quality and misleading - standing guilty :-) This is true for non deterministic wallets/keys.
More standard today is use of HD keys, that allow to derive a set of public keys from a single private key.
It is also referred to as extended pubkeys. More on it can be found under the keywords "HD Wallets" and "BIP-32" or "BIP-44". Without going into details (this thread is about signatures), a quick research in the forum reveals all the details, and as usual Andreas' book "Mastering Bitcoin", section 5 "Wallets". |
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The bitcoin system has a locking and unlocking mechanism. The locking mechanism is in the pubkey script (some refer to it also as the spending condition), where you need to provide the pubkey to a corresponding hash. The author of a tx defines the target address (to whom the tx shall go), and the spending condition(s). When then the receiver of the tx wants to spend the tx, he/she/it needs to fulfill the condition (usually by showing the pubkey in hex format). And the unlocking is done with the sigscript of the transaction: signing the tx with the priv key. Your point seems to play with the condition placed in the pubkey Script. You got it correctly: the OP_EQUALVERIFY would leave a false value on the stack, and as such the tx would not be processed furher. So as I see OP_CHECKSIG does not make any sense This statement is only true, if - and only if - there is a possibility to circumvent the previous step in bitcoin logic, which basically means to find a hash for the previous condition (to satisfy the OP_EQUALVERIFY). Clearly this is impossible to today's knowledge. At that time you would have broken bitcoins security concept for transactions. So, what happens when you have messed around with the transaction, and you place another sig/pubkey into the tx. You would have to send this tx to another node, and then eventually to a miner. Both of them would do transaction justification along the rules: point 16 here: https://en.bitcoin.it/wiki/Protocol_rules#.22tx.22_messages. Now let's assume the first forwarding node and the miner have "non validating software" installed, and forward the malicious tx to others. Then other nodes will mark the tx as invalid, and the miner has the risk of creating a false block and loosing his incentive. And on top, other nodes might even ban these malicious nodes, by blacklisting them (not accepting further tx). Also very good reading: Andreas' book "Mastering Bitcoin" in section 6 "Transactions". |
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The transaction gets sent across the miners network
The miners don't have their own network. It's the same network that everyone else uses. Hint: there is the FIBRE network, a low latency network ( bitcoinfibre.org). I am not sure if this is a specific miners network, but I think I read somewhere in a post, they use it a lot. From the webpage: The Fast Internet Bitcoin Relay Engine (FIBRE) is a protocol and implementation designed to relay blocks within a network of nodes with almost no delay beyond the speed of light through fiber. Its design is based on several years' experience operating and studying the Bitcoin Relay Network and functions incredibly well even when faced with suboptimal internet conditions. |
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Mining drains money from the Bitcoin ecosystem. If miners pay x million dollars per day on electricity, someone else has to put x million dollars into Bitcoin.
This is an interesting perspective: when you say "drain", it sounds like something got lost. I think the opposite is true, something with value is created. miners convert electrical power into bitcoins. And as with nearly all things in economy, the process of refining (adding value) is a standard. Wether it is an electrical device (like smartphones), a tool (like a hammer) or food processing, everywhere "low level material" is converted by some processing steps into something that has higher value. And of course people are ready to pay for it. Same is true in bitcoin / crypto space. The cheap energy is converted into bitcoin, which has a higher value and people find use cases for it (facilitating payments). |
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What if the links between the most important miners were compromised in a similar way? Is this a real danger with respect to the normal functioning of the network, and what could the potential response be?
First of all let's say this is not an attack on bitcoin, this is an attack on the liberty of transmitting/receiving data over the internet. And when you block this, it is not only an attack to bitcoin... You may want to change the headline a bit :-) Once certain traffic is disallowed, you have censorship. Bitcoin was made with censorship resistance in mind. So when all the major miners in one location of the globe are disconnected by a government, there is a high chance that any other person in a different part of the world starts to mine blocks (it becomes beneficial suddenly!). The bitcoin system would need some time to adopt to this new situation (adjusting blockheight etc), but would not fall. Only if all Internet is restricted by all governments, then you can "kill" bitcoin. Highly unlikely. |
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Because of the uniqueness of our hash function output, we can use it as a digital signature.
a minor comment on signatures: there might be use cases where you can use a sha256 fingerprint as a digital signature, cause everytime you provide the same input, it returns the exactly same output. Generally speaking in crypto world, digital signatures are based on a different logic, and in bitcoin world the ECDSA logic is used. I would like to say, that for digital signatures the common software is [EC]DSA logic, and sha256 (or other hashing) is seldom used for signatures. Next to the (H)MAC functions (as described above by bob123), the main benefit and use case of sha256 (and other hashing software) is, that you can say, if content of a file/data has been changed. E.g. you transfer data from system A to B. And also you provide the short checksum. Then B can run the sha256 also on the file, once received, and must receive the exactly same hash value. Otherwise file has changed. Same is true for files on your hard drive: you can check them once, store it in a reference file, and run every day/week/month a sha256 again, compare results against the reference file, and see if contents of (important) files has changed -> this allows to detect malicious code/software on a system. |
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Are you sure that they are tracking bitcoin transactions to de-anonymize users? Have you any proof, link, something? I know that NSA is the evil of this world but why should they track BTC only and all cryptos? There are quite a few millionaires invested and holding other cryptocurrencies. Why only BTC? If NSA is after big wallets they will know about all of them, I think.
I think his thread is going into a wild speculation. The purpose of the NSA is to certainly protect the „land of the free“, and they are not behind some millionaires having cryptos. They are behind players, which don’t respect the rules, or might pose a thread or somehow a danger for the interests of the US and their integrity. Why would they want to get the money of some crypto holders? Whereas I don‘t like the behavior of people in this organization (like in any other large orgs as well), people tend to believe they have power and use it over (more or less) innocent individuals. Like getting shot by a policeman, cause you have African roots... this is what makes us fear these organizations, especially if we have something to hide (taxes are a recurring pattern). If they had really hacked the curves with backdoors, then the millionaires are the lowest level of interest. They could do much better with this power. |
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