Hot answers tagged

29

It takes the median time of the other clients connected, but only 1. if there are at least 5, and 2. if the median time does not differ from system time by more than 70 minutes. For specifics, we look at AddTimeData, in timedata.cpp. Note: I have edited it down for length void AddTimeData(const CNetAddr& ip, int64 nTime) { int64 nOffsetSample = ...


11

From this blog post describing the timejacking attack: Each node internally maintains a counter that represents the network time. This is based on the median time of a node's peers which is sent in the version message when peers connect. The network time counter reverts to the system time however if the median time differs by more than 70 minutes from the ...


10

As individual clients may have an arbitrary timeshift, the Satoshi client will use the median of its neighbors times alongs with its own time to find an offset to the local clock. This offset will then be used throughout the client wherever an accurate time is needed.


9

You probably don't want to download the blockchain The blockchain currently weighs in at about 144 GB (check current size) Assuming you have solid 2 megabytes per second download speed, it would take around 20 hours just to download them. In practice, this takes much longer, as your computer will verify every block individually, which takes some time. ...


8

As the coins "age" they will have a higher priority. I don't know the algorithm, but believe it is roughly like a day or so and then the age of the coin no longer is a factor. So if you are seeing minimum fees for coins more than a day after you've received them, it is because of other reasons, such as having outputs at amounts below 0.01 BTC.


5

All timestamps are in UNIX format, that is: the number of seconds since januari 1st 1970, 0:00 UTC.


5

BIP 113's goal is not to aim for a specific offset. Its goal is guaranteeing monotonicity (treating every block's timestamp as strictly larger than the timestamp of each of its ancestors). It does this by leveraging the existing consensus rule which states that the median of the timestamp of a block has to be strictly larger than the median of its 11 ...


4

In short: don't. The hardware comparison page on the (mostly outdated) Bitcoin wiki does not have information on the Titan XP card, but lists around 200 Mhash/s for the GTX 590. A GTX 590 has 1024 CUDA cores, while the Titan XP has 3840. Extrapolating using this, we can estimate the performance at around 750 Mhash/s. At the current difficulty, that amount ...


3

It is a median, not an average, thus it selects the 6th block's timestamp after sorting. If you're a non-native English speaker, international maths heuristics can be quite tricky. Double-check on the Internet before translating into your head.


3

Bitcoin has been in the news a lot, recently. There have been talks about a Bitcoin ETF: http://www.cnbc.com/2017/02/24/bitcoin-hits-record-high-above-1200-on-talk-of-etf-approval.html There haven have been articles (e.g. http://www.pantagraph.com/business/investment/markets-and-stocks/is-bitcoin-finally-a-serious-currency----or/article_2c5e9474-e135-5e85-...


3

I know people tend to get obsessed about the confirmation time, but the important factors are the number of nodes and the speed at which any given transaction is seen by the network as a whole. I believe this is under three seconds for a transaction to be seen by the entire bitcoin network. Why is this measure important? Because this is the so-called "...


3

The Ripple server has SNTP support to tolerate system clocks that are inaccurate. The consensus process also builds a consensus network time. Each validator pulls the consensus network time a bit closer to their local time. This consensus network time becomes the close times included in ledgers that support features like expiring cross-currency offers.


3

Block finding is random. The number of blocks in a period of time follows the Poisson distribution. If the average is 10 minutes per block, then the chance of at least 9 blocks in a given 24 minute period is roughly 0.086%. Not a lot but it can happen occasionally. Also, if momentarily the hashrate has increased without the difficulty catching up, the rate, ...


3

Blocks have timestamps, transactions don't. The time of a block creation is known, the time of the transaction can only be guessed. Most clients use the block's time for transactions, and if they're still in the transaction mempool (not in a block) they use the time the transaction was first seen by the client.


2

Transactions do not have timestamps, so the timestamp that blockchain.info displays is whatever time their node received the transaction. The time shown will also change to the time that it was included in a block. In general, it is not reliable to trust the timestamp given for an unconfirmed transaction on blockchain.info as it is entirely dependent on ...


2

It all depends on the speed of your connection, CPU, and HDD. I downloaded the entire bitcoin blockchain from the network in an hour or so on my amazon ec2 machine. My old laptop took a few days to fully download it though.


2

Finding blocks is a memoryless process which means: times between blocks can vary significantly the probability to find a block is not influenced by how much time has elapsed in order to surpass the difficulty once, the work necessary is expected to be 10 minutes at the current difficulty, therefore the six blocks in 10 minutes provide the average work of ...


2

If at least two of the partners are cooperative with each other, they can move the funds at any time, even before the 30 days have elapsed. They can spend the output at any time using the second redeem path, with at least two signatures, for example: 0 <Mohammed's Sig> <Zaira's Sig> TRUE TRUE So to 'renew' the time, they just need to spend the ...


2

They 'reset' the clock by moving the funds to a new output before the period ends.


2

For all transactions, "transaction time" is effectively 0. A transaction is created nearly instantaneously and broadcast to the network with no noticeable delay to a human. What you are confirmed about are confirmation times. The time it takes to get a confirmation is only related to the transaction fee rate paid and the time it takes to mine a block. The ...


2

How dependent is Bitcoin on the clock? A lot less than many other applications. A timestamp is accepted as valid if it is greater than the median timestamp of previous 11 blocks, and less than the network-adjusted time + 2 hours. https://en.bitcoin.it/wiki/Block_timestamp AFAIK this means that a block can have a timestamp that is earlier than that of ...


2

You seem to misunderstand how transaction validation and finality works. Nodes validate transactions as they receive them in the mempool or in new blocks - these validations check for standardness (for mempool txs), and consensus compliance (ensuring there are no double spends, valid utxos, etc). However, a transaction is not final simply because a number ...


1

Conceptually, orders arrive at the exchange and are processed one at a time. The fate of your order depends on the previous orders which are on the books when yours is processed. So what matters is the state of the market at the instant when your order "arrives" at the exchange. There will of course be some delay between the instant at which you place the ...


1

The days of individuals having a decent probability of solo mining bitcoin are long gone because of reasons mentioned by the first two answers. Yet bitcoin prevails as the crypto currency 90% of people initially encounter when delving into digital currency. So many still consider mining bitcoin, almost pointlessly, and that’s the lifeblood of btc mining ...


1

At current difficulty, you aren't going to be able to mine an entire bitcoin in 6 months with even the Antminer S9 ($3000 each), you'd probably need two of them, are you sure you don't want to just buy 1 BTC and a cheaper miner for the show?


1

Bitcoins aren't mined individually; they're awarded to miners who discover a block. This process is like a race that restarts every ten minutes when a new block is mined (the miner gets a block reward plus transaction fees). In order to have a shot at winning these races, mining operations use expensive arrays of custom hardware. So, without that, you ...


1

A long time. It's not really feasible to mine bitcoins with gpus anymore as there are special purpose asic chips now used to mine. According to this link CPU mining eventually gave way to GPU mining (where 1 GPU = ~28 CPUs)¹ GPU mining eventually gave way to FPGA/ASIC mining (1 ASIC first-gen = ~33 GPUs)¹ ASIC mining rapidly improved until running ...


1

Basically, transactions just sort of get put in a backlog until there is space enough for them to be processed. That's the usual case anyway. The more extreme case is when there are too many transactions to even keep in the backlog. To understand what would happen here, you need to know a little bit about the software/people that put transactions into ...


1

The initial sync only needs to happen once, launches after a full synchronization will just catch up on the data that you've missed.


1

The times that you are looking at are using a format known as unix time or Epoch time. It is represented as the seconds since 00:00:00 UTC on 1st of January 1970. Most programming languages have classes dedicated to format them into human readable times. For example in python you can use datetime.


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