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Questions tagged [locktime]

Defines the block number or timestamp until this transaction is locked, or 0 if the transaction is always locked.

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Are attempts to spend from a timelocked UTXO rejected?

Background I was reading a bit about Bitcoin time locked transactions within the context of the Lightning Network. One thing that was never explained is what happens when one tries to prematurely ...
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Difference between using nLockTime and CLTV in a penalty transaction

After opening a payment channel, a penalty transaction must be exchanged between parties involved so that in case the channel was not closed properly nobody will lose their money. If a channel was ...
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Coinbase transaction UTXOs are prohibited until 100 confirmed? By what?

I notice that many coinbase transactions(like in block 720,815) with locktime=0x00000000 and sequence=0xFFFFFFFF, which means UTXO could be spent immediately. There seems to be no limit to coinbase's ...
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UNIX END TIME January 19, 2038 - Will it affect Timelock nLOCKTIME smart contracts past that date?

So UNIX END TIME is January 19, 2038. What will happen then to the btc TX that looks at Unixtime for nLOCKTIME transactions? Will any Locktime transaction past that date, say to 2040 be an issue? Or ...
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8 votes
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Miners setting locktime in coinbase transaction

Some coinbase transactions have locktime values set. One such recent example is: { "txid": "5166cb509a5d786db33963a269ea08ff82a1c40d37d4fb828a394b0465cd5efd", "hash": ...
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1 vote
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P2TR Scriptpath failing (Timelocked contract)

Goal is to archive the following logic: $alice = A; $bob = B; pk($bob) || (pk($alice) && older(10)) I went through The Taproot Workshop and came up with the following code: from io import ...
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Why are OP_RETURN transactions discouraged? Does using version or locktime make any difference?

Why are OP_RETURN transactions discouraged? Are they paying less fees compared to other transactions? Will it make any difference if same thing is done using version or locktime when data is either 1 ...
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Is it possible to change `their_to_self_delay` after a channel is open?

Rene said here that a c-lightning node is safe for around 24 hours to be offline (depending on the locktime). This is set with watchtime-blocks in the configuration file of c-ligthning. But this will ...
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Best way to store fund on the lightning network

Suppose that someone want to store 0.1 bitcoin on the lightning network for a period of 1 year to use services such as buying and selling things but doesnt know which one and with who yet. What would ...
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4 votes
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what if the timelock is in the past?

I just started learning about bitcoin scripting and wonder: what if the timelock in CLTV is in the past? what if the timelock in nLocktime is equal to 500.000?
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Should the nodes of a channel have the same Time Lock Delta?

Consider this channel https://1ml.com/channel/612829298476056576 : Node 1: Caffeine Time Lock Delta: 10 Node 2: HODLcat.com Time Lock Delta: 144 How is an HTLC passing through this ...
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non-mandatory-script-verify-flag (Locktime requirement not satisfied) (code 64)

I'm attempting to redeem the following htlc ( the python script below ) via timeout, however the redemption tx errors out upon validation with the error below: bitcoin.rpc.VerifyRejectedError: {'code'...
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At what block height may locktimed transactions get included?

Transactions with outputs whose sequence is smaller than UINT_MAX are interpreted as locked until the timestamp or block height specified in nLockTime is reached. Specifically regarding the block ...
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Are both CSV and nLocktime unnecessary in Eltoo?

The Eltoo paper says "Notice that we could use nSequence for this purpose, but due to the interplay with OP_CSV we opted to use nLocktime". Now that Lau showed CSV not to be necessary, does that mean ...
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In Lightning commitment transactions, what do the upper 8 bits of sequence and locktime represent?

In Bolt 3 of the Lightning Network specs, for commitment transactions it states: locktime: upper 8 bits are 0x20, lower 24 bits are the lower 24 bits of the obscured commitment number. sequence: ...
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What does the 'n' in nLockTime and nSequence stand for?

I know what nLockTime and nSequence do, but I'm just curious about where the 'n' comes from. Thanks
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nLockTime in Bitcoin Core

Currently, the Bitcoin Wiki states: A part of the original Bitcoin implementation, nLockTime is a field that specifies the earliest time a transaction may be added to a valid block. A later Bitcoin ...
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Strange LockTime values in Electrum transactions?

Electrum includes a locktime in all transactions by default. Usually the value is equal to the current block height, eg 592918, however it sometimes drops perhaps 20 or so blocks. What is going on ...
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1 vote
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How to make a transaction with locktime on testnet?

I tried to make transaction with nLocktime on bitcoin testnet. I am not able to broadcast it. Can someone please help me to make a basic transaction with 1 input and 1 output, so that I can broadcast ...
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403 views

What is transaction "finality"?

bitcoind IsFinalTx() as seen here checks the properties of a transaction in this order: Is nLockTime exactly 0? That's final. return. If it's not 0, is it below the current block height / time? If so,...
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How can I make transaction output time locked?

Is it possible to submit some coins to some address and make them spendable after some period of time? Like I want submit 1btc to address 1Kc24m... and make that output to be spendable after january ...
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The nlocktime parameter in createrawtransaction seems not work using Bitcoin Core Wallet GUI

If I add the CLocktime (e.g 20) at the end it always gives: Error: Error parsing JSON:{"12CxqQHzhFxCm2TkGkKHdFFPyUerFXcSte":0.008,"1DBDDvpcHv66LD7sWz1mCitPALW1qfrga7":0.012}, If I delete the ...
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1 vote
1 answer
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Where is a tx located before finalized with the sequence number or locktime?

My understand, for a tx, before it finalized with the locktime, it can not go into mempool. But, which specified location is the tx to stay for waiting the locktime come. Similiar, for before the ...
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How does one lock their own Bitcoins for X amount of blocks and prove that you locked it?

Is there a method of locking Bitcoins for X amount of blocks and also being able to prove its locked? How would one do this and with what wallet? Mobile wallet possible? Reason why is I'd imagine one ...
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1 vote
1 answer
162 views

Create a transaction spendable in a specific block height

I am new in Bitcoin and I try to create an address in Bitcoind and send a transaction that the amount will be spendable in a specific height of the blockchain. Here is what I have done: privateKey = ...
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Why CHECKLOCKTIMEVERIFY and CHECKSEQUENCEVERIFY opcodes have to be succeeded with DROP Opcode?

Opcodes that end in VERIFY generally do not leave anything on the stack. What's so different and the reasoning when designing these opcodes that CHECKLOCKTIMEVERIFY and CHECKSEQUENCEVERIFY opcodes ...
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2 votes
1 answer
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How to spend a multisignature, CLTV time-locked UTXO?

I am using this locking script with libbitcoin explorer to create a bitcoin testnet transaction: bx script-to-address -v 196 "[efa716] checklocktimeverify drop 2 [...
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2 answers
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Reference an UTXO of a transaction that has not been yet mined

How to reference an UTXO that has not been yet mined? I want to prepare a transaction and, before spreading it, use its UTXO as input for another relative timelocked transaction. Then, spread the ...
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3 votes
2 answers
696 views

How does nSequence/Check Sequence Verify work?

How does relative timelock work? I mean, I know the theoretical description, but how to use nSequence concretely ? Can you do me a practical example with 2 sample transactions one of which locked with ...
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4 votes
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Is the bit encoding format for the graphic in BIP 68 implicitly little-endian?

CLTV (OP_CHECKLOCKTIMEVERIFY - absolute locktime) and CSV (OP_CHECKSEQUENCEVERIFY - relative locktime) utilize BIP 68. Is the locktime for those two operations implicitly encoded in little-endian ...
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Is it posible to create a transaction output that can either be reddemed by privK of Addr A or by privK of Addr B AFTER certain blockheight?

I am thinking about how to secure your Bitcoin savings. One idea I had was to create sort of a "backup" address B for an address A which stores the bitcoins. So what I want to achieve is that you ...
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1 vote
2 answers
95 views

BIP 113 - monotonic guarantee

BIP 113 mentions: Existing consensus rules guarantee this value to monotonically advance, thereby removing the capability for miners to claim more transaction fees by lying about the timestamps of ...
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2 votes
3 answers
153 views

CHECKSEQUENCEVERIFY After x time of last transaction

Is there a way where i can have a multi-sig address which will allow one of the signers to use only their single key after a set amount of time after each transaction/update on the address? I want ...
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2 votes
0 answers
278 views

Locktime requirement not satisfied when locktime set to 1 in p2sh

I've created the following script on testnet: OP_IF 2 <pubkey1> <pubkey2> <pubkey3> 3 OP_CHECKMULTISIG OP_ELSE 1 OP_CHECKSEQUENCEVERIFY OP_DROP <pubkey1&...
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1 vote
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Which wallet provide lock-time feature?

I try to understand how the lock-time and sequence number work, but I got many different explanations, it is really confusing. I like to send a Bitcoin with lock-time to myself, but I don't know how ...
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2 answers
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TX nLocktime and mempool

Where is a broadcasted TX located at before it's nLocktime reached? in mempool or not? I have tried a lot can't figure out. Help please.
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1 answer
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Understanding BIP 143 [hash computation, lockTime, sequence number, witness format]

I'm trying to grasp some of the concepts presented in BIP 143. These are the things I'm stuck on: (1) A new hash format is presented. This new format is used to create a hash, which when signed with ...
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2 votes
1 answer
272 views

Simple explanation of how a hash timelock function works with an atomic trade of bitcoin / litecoin trade without a 3rd party?

From my understanding a hash timelock function trade or atomic swap involves 2 transactions one separate blockchains. The BTC user named Bob is making a trade with Alice for her LTC. Assuming its a 1 ...
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1 vote
2 answers
191 views

Encrypted message with nLockTime

I know you can delay a transaction's accepted date by using nLockTime. I'm still looking for the simplest way to generate a transaction with nLockTime, but that's another topic. I'm wondering if ...
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5 votes
1 answer
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Sequence number semantics

Reading the following BIPs: 68, 112, 125, I got a few questions about the sematics of sequence numbers. As far as I understood, in version 1 transactions, sequence numbers have the following meaning: ...
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yesterday evening I send out 0.97 BTC. I checked transaction and It says : " lock time 459355"

are my coins lost ? please help It says Lock Time: 459355 and still unconfirmed since yesterday
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3 votes
2 answers
1k views

Understanding GreenAddress nLocktime/recovery transactions

What I understand is that Greenaddress locks a recovery transaction to be spend 90 days in the future. Whats the advantage in doing this? Why not creating a recovery transaction without nLocktime?
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4 votes
2 answers
862 views

Is it possible to combine multi-sig and locktime?

Is it possible to create a 1 of 2 multi-sig address in which only one of the keys is time-locked and the other can sign any time?
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2 answers
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Is it safe to keep ONLY a time-locked tx?

What if the tx become incompatible with future versions of Bitcoin? In which cases it would just stop being compatible? If there is no compatibility guarantee, how can this be useful at all?
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9 votes
1 answer
3k views

Why Bitcoin core creates time locked transactions by default?

I've noticed recently that Bitcoin Core is producing transactions with non-zero lock-time and sequence numbers of inputs being 0xFFFFFFFE, even though I didn't instruct it to do so. The lock-time ...
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3 votes
2 answers
942 views

Can you "undo" an nlockTime transaction by spending a single UTXO of it before lockTime's block happens?

Let's say I have a wallet X with money from 3 unspent outputs (UTXOs) A, B and C. I make an nlocktime transaction to spend 2 of my 3 UTXOs (A & B) to wallet Y, 1 month in the future, sign it, and ...
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2 votes
1 answer
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Which clients support nLockTime?

I want to use nLockTime, but I don't know what clients support it?
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8 votes
3 answers
12k views

What does "lock time" mean?

I got a transaction that is still not confirmed for about one week, and I can see a field called "Lock Time" that says: Lock Time Block: 419382 https://blockchain.info/en/tx/...
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1 answer
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What happens when relative and absolute lock times are used in the same transaction?

BIP 68 redefines the input sequence number field as bit vector that encodes a relative lock time. A transaction can be encumbered with an absolute lock time by setting the nLockTime field to a non-...
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1 vote
1 answer
174 views

If transaction has impossible locking script, are coins lost?

If a bitcoin transaction's outputs have a locking script that is basically unsolvable, are the bitcoins lost, or can the transaction be invalidated? (Or something else?)
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