Questions tagged [timestamp]
Collects questions about the rules, precision, and utility of the timestamp in block headers.
71
questions
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16 views
TSA: Why singing hash(hash(data),t)?
Why does a TSA first appends the timestamp and hashes the combination of timestamp and data? This product is then signed and send to the client back with the timestamp. Why not signing hash + ...
0
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1answer
30 views
Retrieve number of OP-RETURN transaction
Is there a possible way to extract the bitcoin transaction protocoll with Python and extract specifically OP RETURN transaction?
I want to plot the number of those over the course of time to derive ...
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2answers
34 views
How does this time-stamping system work?
There is an online tool called Proof of Existence which uses the bitcoin blockchain to time-stamp documents. I'm reading the documentation but I fail to see how it works. I understand that it adds ...
0
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1answer
23 views
How do nodes come to consensus on whether a timestamp is valid?
From bitcoin wiki:
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.
If a miner submits a block ...
0
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0answers
28 views
Is it possible to get a block by timestamp?
I use Bitcoin Core API and I can retrieve a block by header hash as parameter using the getblock method.
I need to get a block by given timestamp (median time).
I found some solution.
...
0
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1answer
141 views
Bitcoin Pro API - How do you format start/end time for Historic Data?
I don't understand how to format the start and end time per https://docs.pro.coinbase.com/#get-historic-rates
The sample time is "1415398768" which makes no intuitive sense to me, and when I tried ...
2
votes
1answer
351 views
January 19th, 2038: RIP Unix Timestamps
Is there a plan in place for when the inevitable 32-bit overflow of Unix timestamps occurs?
How much will this impact existing blocks that are timestamped with Unix Epoch times?
1
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1answer
33 views
When update mining difficulty, Is the timespan of the past 2016 blocks approximated value?
I know how to calculate difficulty, and I know it is increased or decreased by checking the timespan of the past 2016 blocks.
and I found actual code for calculating timespan: https://github.com/...
3
votes
1answer
843 views
How does timejacking enable double spending?
http://culubas.blogspot.com/2011/05/timejacking-bitcoin_802.html
I went over this blog, but I am still not clear how double spending is achieved by this attack. From what I read, the attackers submit ...
0
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1answer
87 views
Network Time of Bitcoin
Bitcoin uses UNIX time for timestamp. Unix Time is really accurate. I want to know why there is a "70 minutes" offset is allowed in Bitcoin network adjusted time. Is there any distribution used to get ...
5
votes
1answer
418 views
From where does the 2 hours limitation on bitcoin time stamp come?
Bitcoin wiki says that:
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
My question is why 2 ...
1
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3answers
69 views
What prevents DoS based on near-valid block timestamps?
Upon receiving a newly mined block, the block timestamp validation is performed here:
https://github.com/bitcoin/bitcoin/blob/master/src/validation.cpp#L3263-L3270
Q1: As for the second check (block ...
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1answer
519 views
How is PSZ Timestamp encoded in Bitcoin core code?
In Chainparams.cpp of the Bitcoin Core source, the encoded PSZTimestamp is as follows
...
3
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2answers
387 views
Why does the median-past time average the last 11 block timestamps and not the last 12?
As described in BIP-113. Wouldn't the last 12 blocks bring us closer to a one-hour offset (ie 120min, midpoint 60)?
8
votes
1answer
1k views
What prevents similar time-warp attacks in Bitcoin as happened to Verge?
Right now (may 2018), Verge (an altcoin with proof of work) was attacked by time-warp attack. More can be read here
https://blog.theabacus.io/the-verge-hack-explained-7942f63a3017
What exactly ...
0
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1answer
70 views
Would mining future bitcoins break the bitcoin?
assuming an bitcoin miner with very much hashrate like bitmain would decide to mine "future" bitcoin blocks and provide them within very short time to the network, would this break the bitcoin?
As i ...
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vote
2answers
57 views
What roles has the TIME information play in the bitcoin header?
What role does the time play in the bitcoin header? Is it ok to set it to 1 sec after the last block and never change it while calculating? Will the block be rejected when the gap is to large?
If 2 ...
0
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1answer
75 views
What is happening to the none approved transactions?
Every 10 minutes only 1MB of transactions are been approved, so what happened to the rest of them? Let's say my transaction was not entered into the block, can I be sure that no one is going insert it ...
4
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2answers
3k views
The role of timestamp
In Satoshi’s original paper, it is written that “we need timestamp to prevent double-spending”.
However, I think timestamp is unnecessary, because every block has a previous block hash and merkle ...
3
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1answer
429 views
Rewriting the entire blockchain: is it possible to spoof block timestamps of a privately mined chain?
According to fork.lol and Pieter's bitcoin.sipa, it would currently take ~200 days for an attacker with 100% of the current hashpower to rewrite the entire btc blockchain. My question pertains to how ...
0
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1answer
72 views
Bitcoind Testnet time/timereceived constantly changing?
I've got a small question: over a week ago I did some transactions on the Bitcoin testnet as I am developing a new GUI header for full nodes. When continuing development today, I noticed that when ...
1
vote
1answer
62 views
From the Whitepaper: Timestamps prove that the data must have existed at the time"
The whitepaper says exactly this: "The timestamp proves that the data must have existed at the time, obviously, in order to get into the hash. Each timestamp includes the previous timestamp in its ...
2
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1answer
25 views
Are there performance implications using the “timestamp” property of ImportMulti in the following way?
Based on the Developer Reference for importmulti, it seems the the timestamp property is purely used to determine how far back to rescan. If I have, say, 100 addresses and I simply set all of their ...
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162 views
What is the purpose of Bitcoin timestamps
Why do we even need timestamps on the blocks?
Has it something to do with the consensus?
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1answer
246 views
How do nodes agree on timestamps?
While re-calculating the difficulty every 2016 blocks, how do nodes agree on the new difficulty? There is no unique timestamp on the p2p network, because nodes can lie about their time stamps. Let us ...
2
votes
1answer
831 views
How to calculate block generation time from block's data?
I'm working on paper Double-Spending Attacks on Fast Payments in Bitcoin.
And I see they give out the result :
block generation time is approximately 10 minutes (9 minutes and 54
seconds), the ...
0
votes
1answer
55 views
Proving the margin of error of a block timestamp
In the Bitcoin wiki:
Block times are accurate only to within an hour or two.
is a bit vague. Is it possible to prove that an arbitrary accepted block timestamp is within x seconds of the real-...
3
votes
2answers
1k views
timestamp different block explorers are not the same
I'm kind of confused why the timestamp of a block is different when checking different block explorers. I think normally this is the time the block was found, no?
So, when I check a transaction in ...
1
vote
1answer
120 views
Why do we need two transactions for CommitCoin scheme
I am studying BitCoin recently.
I noticed a method called CommitCoin for secure timestamping. It requires two transactions to send coins back with the same randomness so that others can compute the ...
5
votes
2answers
226 views
Can a blockchain from the future be synchronized today?
If one or a few computers with blockchains from a future time line were connected to the Internet today, what would happen? This other question in Worldbuilding focus on possible consequences, but ...
2
votes
1answer
121 views
Why do testnet blocks have future timestamp?
I am playing experiments with testnet blockchain, and it seems like the best block is always set about 2 hours into the future.
For example, now, the block has timestamp 90 minutes into the future. I ...
2
votes
0answers
70 views
Source for accurate block timestamps?
Is there a source of historical data which assigns a relatively consistent and accurate timestamp to each block? This might take the form of a server having precisely logged when they first heard ...
4
votes
1answer
2k views
where do the timestamps on blocks come from?
A stork brings them... or...
One of the basic principles on a dist. system is lack of a global clock.
So how are the timestamps assigned to blocks, by the machine that mines it? Couldn't it just ...
4
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1answer
2k views
How does a time warp attack work?
I more or less understand how an attacker (with less than 50%+1 of the hashing power) can artificially lower the block difficulty by messing with timestamps. I also understand how such an attacker ...
2
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1answer
721 views
Bitfinex get credits and convert timestamp to JS Date
I'm fetching my active credits in BFX and trying to discover when I'll have my funding back. This is a response example:
/v1/credits
[{
amount: "294.4316181",
currency: "USD",
id: ...
0
votes
1answer
99 views
Is there a way to get the node's local time when a block was received?
As in, not the miner's timestamp in the blockheader which can be +/- 2 hours, but the receiving node's local time. My concern is the real-world time that elapses between blocks.
2
votes
1answer
72 views
Finding the timing of blocks, afterwards?
I understand that the timestamps on blocks are not fully accurate. Given only that information, it's efectively impossible to do retrospective analyses of timing of blocks. (For example, this; http://...
4
votes
2answers
386 views
Is Bitcoin a decentralized time-stamping authority?
Can Bitcoin/blockchain be thought of as a decentralized time-stamping authority (TSA)? Is there true consensus in the Bitcoin network on a mined block's time, or just that the block was mined?
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1answer
285 views
Using the blockchain for providing other services, besides bitcoin transactions
What I have in mind are proof of existence software, than are a kind a non-centralized and virtual notary service. They time-stamp digital information submitting a hash to the blockchain.
I know ...
3
votes
2answers
674 views
blockchain.info transaction timestamps set into the future
There seem to be some irregularities with Blockchain.info's transaction timestamp (aka Received Time) for a set of blocks. The transaction times are recorded with unix timestamps well into the future ...
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1answer
152 views
bc.info transactions with no timestamp
The last transaction in blocks 219882, 219888, and 219892 don't have a timestamp. And by last transaction I mean the last transaction shown in the json file.
219882
219888
219892
I find this to be ...
5
votes
2answers
840 views
How could a time warp attack be prevented?
jarpian explains what a time warp attack (AKA zeitgeist attack) is:
This is a 51% attack where the attacker sets the block timestamps artificially to lower the difficulty, allowing him to profit ...
0
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2answers
196 views
Why use OP_RETURN for long-term timestamping if they are pruneable?
There are some timestamping services such as proofofxistence.com that use OP_RETURNS transactions to store a document's hash, so in the future a 3rd party can verify the existence of the hash (and the ...
1
vote
1answer
356 views
Is the block timestamp reliable enough to timestamp the hash of a document?
In using the blockchain to timestamp the hash of a document, so to prove that it existed before a certain time.
Is it reliable? Do you think it can stand on court? (IANAL and probably you neither) ...
5
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2answers
228 views
Why is two hours the maximum acceptable offset for Bitcoin blocks?
As far as I understand, Bitcoin transactions include a timestamp, but the only requirement is that they don't differ for more than two hours.
But why two hours? For computers that are constantly ...
3
votes
2answers
3k views
How do we check the time when a transaction hits x confirmations?
Consider the transaction 948a427.. which has 3341 confirmations as of now:
We can see that the time the relay is received at 8:36:30 and it has one confirmation at 08:50:04 (after 14 minutes).
How ...
0
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1answer
52 views
How exactly is network time sampled?
How exactly is network time sampled?
Is it as simple as one node stamping data right before being sent, the receiving node logging the current time before all other activity, and taking the ...
3
votes
1answer
572 views
Ripple ledger time format?
I am wondering what is the format used in Ripple ledger time? For example, one of the most recent ledgers had close_time of 447299110. I initially thought it was UNIX time, but the current time was ...
8
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3answers
1k views
How accurate is Bitcoin network time?
Have any observations been made to conclude the accuracy of Bitcoin network time?
It would be interesting to know if NIST or any other authority has tracked the phenomenon.
0
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1answer
234 views
Can an old block be inserted into the blockchain?
I've been shown how network time is enforced, but I'm still having trouble understanding how a false old block cannot be inserted into the blockchain with the entire chain remined or how a powerful ...
