Collects questions about the rules, precision, and utility of the timestamp in block headers.
Questions tagged [timestamp]
106 questions
32
votes
9 answers
Why don't the timestamps in the block chain always increase?
The timestamps starting at block 145044 are:
145044: 2011-09-12 15:46:39
145045: 2011-09-12 16:05:07
145046: 2011-09-12 16:00:05 // ~5 minutes before prior block
145047: 2011-09-12 15:53:36 // ~7 & ~12 minutes before 2 prior blocks
145048:…
Mocky
- 937
- 1
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- 11
26
votes
2 answers
How does Bitcoin figure out what time it is?
Bitcoin needs to know the current time in order to validate blocks. How does it decide that?
Note that I'm talking about the Satoshi client specifically.
Nick ODell
- 29,184
- 11
- 69
- 129
21
votes
1 answer
Gaming the "off-by-one" bug (difficulty re-target based on 2015 instead of 2016 block time span)?
In this forum post from Gavin Andresen he writes:
Second: I've written 'discourage blocks' infrastructure:
https://github.com/gavinandresen/bitcoin-git/tree/discourageblocks
(code reviews welcome)
... which should give us the ability to…
kirian
- 3,279
- 1
- 24
- 36
19
votes
1 answer
Was a timejacking attack ever performed?
The timejacking attack appears to be a pretty straightforward attack to pull off successfully. I was wondering, whether it was ever performed and documented somewhere, or was it just theoretically described?
ThePiachu
- 42,931
- 25
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12
votes
0 answers
How can an earlier block have a later timestamp?
Block #180966 has a timestamp of 2012-05-20 23:02:53.
Block #180967 has a timestamp of 2012-05-20 23:02:13.
How has the software permitted a later block to have an earlier timestamp than its predecessor?
Peter
- 441
- 3
- 10
11
votes
2 answers
Transactions with a wait time (using nLockTime)
I'd like to know if there are transactions that can only take place at some predefined moment. In principle, it should be possible to use the parameter nLockTime to wait for a particular block…
halftimepad
- 1,408
- 11
- 16
11
votes
4 answers
how can I insert an arbitrary sha256 hash into the blockchain?
If I want to prove that I wrote a particular document before a certain point in time, it would be sufficient to generate the sha256 hash of the document and somehow arrange for that hash to appear in the blockchain.
Is there an easy way to do that…
Chris Moore
- 14,745
- 6
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- 87
10
votes
1 answer
How is locktime enforced in the standard client?
I am trying to study the locktime feature of transactions ( https://en.bitcoin.it/wiki/Protocol_specification#tx ). I have created some raw transactions in the testnet with different locktimes, but, when I send them, they are confirmed as usual. I…
halftimepad
- 1,408
- 11
- 16
10
votes
3 answers
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.
user5107
10
votes
2 answers
What are acausal blocks?
In this forum post the poster (2112) writes:
It is my understanding that at least Eligius pool isn't a "honest node" and intentionally produces acausal blocks (or at least as close to acausal as they deem practical).
What is an acausal block? Or…
kirian
- 3,279
- 1
- 24
- 36
9
votes
1 answer
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 prevents from similar attack to happen to Bitcoin?…
Karel Bílek
- 2,655
- 3
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- 45
8
votes
3 answers
What format is the time of a Bitcoin transaction stored in?
This may be a very simple question to answer, but I haven't been able to quickly find it. Regardless, if you were to deconstruct a transaction in the blockchain, and pull out the time value of the transaction, what format is the time stamp in?
In…
RLH
- 2,162
- 5
- 24
- 35
7
votes
1 answer
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?
apt-getschwifty
- 313
- 1
- 10
7
votes
2 answers
Why the timestamp component of the block header?
What is the reason for the timestamp field in the block header? Surely the nonce should be the only property that changes? Should the nonce reset to 0 everytime the timestamp changes?
Anonymous
- 473
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6
votes
2 answers
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 tree root and these are enough to check if a…
Rubertos
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