Questions tagged [script]

This tag should be used for questions regarding Bitcoin transaction scripts or scripting languages used in transactions of altcoins such as Solidity. Scripts are a set of instructions on how to complete a transaction.

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47 views

Which parts of a bitcoin script are embedded in the blockchain?

I assume the scriptPubKey is contained in a UTXO, and therefore embedded in the blockchain. Since, this is the script used to unlock the input. Is a scriptSig also embedded in the blockchain? Or is ...
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2answers
106 views

Verifying a digital signature that a transaction is going to an output with value X inside a script

Edit; after writing this post i have found that OP_CHECKDATASIG is basically this in a nutshell. It is implemented on Bitcoin Cash and may soon be on Bitcoin Core as well. Someone has even written ...
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1answer
101 views

In the bitcoin scripting language, how can I access other outputs of the transaction? Or how else can I limit how the coins may be spent?

Is there any way to add an opcode to a UTXO that prevents how the coins are spent? For example, in order to to spend the output, a person must send X number of bitcoin to Y address within the ...
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1answer
124 views

What’s the opcode sequence for doing the reverse of Multisig?

With a multisig wallet, several public keys are needed to spend an amount. But how to perform the reverse with time ? I’m talking about this case where Alice performs a transaction where the output ...
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2answers
112 views

How to search for a transaction using a specifc OPCODE?

I have several OPCODES where I need real worlds examples… However they are rarely used. So how to search and disassemble an existing mined transaction using it ?
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1answer
81 views

How to disassemble a bitcoin script?

There are many explorers which allows to dissamble a transaction back into opcodes. But what about scripts which aren’t broadcasted yet like this redeem script :...
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1answer
34 views

Destination address(es) when redeeming an HTLC

Starting from this text at https://en.bitcoin.it/wiki/Script: "The script for a typical Bitcoin transfer to destination Bitcoin address D simply encumbers future spending of the bitcoins with two ...
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1answer
111 views

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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1answer
183 views

ScriptCode field in P2SH-P2WPKH BIP-143 Test Vector

I'm trying to understand the meaning of scriptCode in the context of spending a P2SH(P2WPKH) UTXO. I've already read the following answer to a similar question, but it does not fully address my ...
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2answers
171 views

Can someone help me understand what these scripts mean?

Could someone explain what the commands i have in bold do? if possible. Thank you. Transaction URL www.blockchain.com/btc/tx Input Scripts- ScriptSig: PUSHDATA(71)[...
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7answers
5k views

Online Bitcoin Script simulator or debugger?

Is there an online simulator that would allow me to step through, debug, or simulate the execution of a Bitcoin script?
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0answers
55 views

Uniquely identifying a UTXO

I see two ways: Txid + index Txid + script hash Pros of the txid + index: Simple and short Cons of txid + index: It relies on array iteration being deterministic and all third party ...
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1answer
169 views

what is the use of OP_PUSHBYTES

what is the meaning of this SCRIPTPUBKEY: OP_DUP OP_HASH160 OP_PUSHBYTES_20 xxxxx....xxxxxxxx OP_EQUALVERIFY OP_CHECKSIG in particular I searched for some documentation on OP_PUSHBYTES_X which only ...
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2answers
3k views

How to manually verify a signature given scriptSig and scriptPubKey?

First transaction Given a transaction on the blockchain: 3a1b9e330d32fef1ee42f8e86420d2be978bbe0dc5862f17da9027cf9e11f8c4 One of the outputs transfers 424,242.42424242 BTC to ...
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0answers
36 views

Check an outpoint's scriptPubKey against known scripts

So I would like to check if coin.out.scriptPubKey is part of GetScriptForDestination(mypubkey.GetID()) A simple comparison isn't possible as the scriptPubKey (when I decode it) contains only the ...
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1answer
457 views

Bitcoin Script: mandatory-script-verify-flag-failed Script failed an OP_EQUALVERIFY operation

I try to spend a P2SH transaction (in regtest) with a timelockscript of 200 blocks. I got the following error: mandatory-script-verify-flag-failed (Script failed an OP_EQUALVERIFY operation) (...
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1answer
488 views

PUSHDATA4 unnecessary?

Any data push greater than 520 bytes in a Bitcoin transaction is not allowed (https://github.com/bitcoin/bitcoin/blob/v0.10.0rc3/src/script/script.h#L18). The opcode OP_PUSHDATA4 specifies, that the ...
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1answer
49 views

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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1answer
116 views

Maximum standard input script size

What is the maximum size for an input script so to be considered standard ? Looking at the Bitcoin Core source code it appears to be 10'000 byte, however reading here and there, it appears to be 1650 ...
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1answer
4k views

Why does the default miner implementation use pay-to-pubkey?

Looking at the v0.9.3 source in miner.cpp: CBlockTemplate* CreateNewBlockWithKey(CReserveKey& reservekey) { CPubKey pubkey; if (!reservekey.GetReservedKey(pubkey)) return NULL; ...
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1answer
180 views

What is the meaning of in-script and out-script in standard bitcoin transaction?

I am new to bitcoin world and I am reading this paper: Secure multiparty computations on Bitcoin https://eprint.iacr.org/2013/784.pdf The author said on page 7 that the standard bitcoin transaction ...
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2answers
48 views

Valid public key check in transaction output

Let's say I build a P2MS output script using uncompressed public keys, and let's say too that these public keys are not valid, i.e. they do not represent a valid EC Point and they don't start with ...
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1answer
155 views

Possible to check who signed the transaction in a multi-sig transaction case?

Say you have a multi-sig tx that originated from a 2-of-3 P2SH address. Is it possible to say who signed the transaction? i.e. you can get access to the redeem script once the tx is broadcasted, and ...
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1answer
189 views

Transaction still unspendable with CLTV

Previously I generated tx with CHECKLOCKTIMEVERIFY Here is the transaction https://tchain.btc.com/bb1415c166fd9f767c06d34d539f4b110ef4445f74a76c5ffad1ded33032e872 It lock funds before block 1442909. ...
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1answer
96 views

Create simple and secure transaction without checksig?

According to my previously asked question (P2SH secure spending. How?) creating transactions without signature checking is probably not secure. Anyway, I see many transactions (for ex.:...
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2answers
47 views

In theory could a pubkeyhash script be solved without the public key in the scriptSig?

When signing a pubkeyhash UTXO, it is required to provide both a signature and a public key. The public key is duplicated and one copy is provided to op_checksigverify to ensure the signature is valid,...
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1answer
29 views

Script - Is it possible to build an addresss that allows retrieve a certain amount per address?

Is it possible to define a multi signature address that allows spending only certain percentage to each signature? For example, three different people with different public-private keys build an pay ...
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2answers
409 views

Operation not valid with the current stack size

According to bip65 https://github.com/bitcoin/bips/blob/master/bip-0065.mediawiki I can use expressions like IF ... ELSE ... ENDIF Here is example script from this document: IF HASH160 <...
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1answer
262 views

Why this transaction is invalid?

I issued this transaction on testnet (for a homework later solved with another script). python-bitcoinlib validates the transaction but when i submit it to blockcypher it gets rejected with error: {"...
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1answer
139 views

MULTISIG Verified transaction don't get mined on testnet

I'm trying to check the following simple MULTISIG P2SH script on bitcoin testnet (using python-bitcoinlib): Redeem = CScript([2, J1_public_key, J2_public_key, J3_public_key, 3, OP_CHECKMULTISIG]) ...
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2answers
387 views

Non-standard transaction scripts broadcasting

I'm developing an application on Bitcoin blockchain, and I use output transaction scripts that are not standard according to the classic payment methods. However, even so, on Tesnet everything works ...
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2answers
2k views

Is there a maximum size of a scriptSig/scriptPubKey?

Previous research: Transaction's maximum size What is the maximum size of a transaction? The maximum size of a standard transaction is 100k bytes. Are there any consensus rules that prohibit ...
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1answer
250 views

Why is 20 the maximum public keys in a multisig transaction?

In script.h the following limit is set: MAX_PUBKEYS_PER_MULTISIG = 20 I'm wondering: Why is the limit set to 20? How would one would construct a script that allows n more than the current OP_16? E....
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1answer
97 views

nSequence win OP_CSV in child tx must be equal to nSeq parent tx?

When I create OP_CSV transaction I need to set nSequence to the same number (in blocks) e.g. 3 OP_CHECKSEQUENCEVERIFY nSequence = 3 But when I trying to spend this tx (after 3 blocks confirmation)...
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1answer
795 views

Script evaluated without error but finished with a false/empty top stack element

I'm trying to spend coins from this tx https://tchain.btc.com/ad7a1ed858eecdd146d9c932779aecae4b33f068d29cf794fad6de20f5a5d449 The scriptpubkey is simple: 1 OP_CHECKSEQUENCEVERIFY OP_DROP ...
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1answer
116 views

Cant spend input with non-standart redeemscript (OP_CSV)

I'm playing with OP_CHECKSEQUENCEVERIFY. Here is my transaction that I'm trying to spend: https://tchain.btc.com/e79d469698915aa6724288ae3a4141a31706d081f39fb7fd0b956a73a9044b22 which has the ...
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1answer
6k views

How is a Transaction ID generated & when does it change? (with a new sequence ID?)

I'm creating a non-mainstream client that processes and validates Bitcoin transactions and need to track transactions in my database. How is the TxID generated and when does it change? ...
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1answer
72 views

OP_CHECKLOCKTIMEVERIFY . Include / reject or will not included in block?

What happened if I translate to network transaction with the folowing redeem script: [now + 3 months] CHECKLOCKTIMEVERIFY DROP DUP HASH160 [Bob's Public Key Hash] EQUALVERIFY CHECKSIG This tx will ...
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1answer
74 views

Is it safe to store bitcoins on p2sh (no multisig)?

I've just generated p2sh btc address and look in the output script: HASH160 PUSHDATA(20)[e5c32bdc7f7fb1e6ae7aa1baf42a429803054d2c] EQUALVERIFY while normal (legacy btc address) transaction has ...
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1answer
179 views

scriptcode, scriptsig, pubkeyscript confusion

I've been banging my head on a desk for a few days trying to understand the segwit protocol properly. Another roadblock has thrown me off-guard and I am struggling to grasp the concept of "scriptCode:...
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2answers
129 views

How are blocks verified?

I see in the bitcoin wiki there is something called "script" which compiles down to some bytecode to be run by a very very basic virtual machine. Does this mean that each block is actually just a ...
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1answer
104 views

Finding Transactions with seldom used opcodes for testing

I'm trying to implement a script evaluator and would like to get some real testing data from the blockchain (testnet or mainnet). Are there transactions whose input scriptSigs combined with the ...
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1answer
41 views

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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1answer
41 views

Is it possible to write a script, which can allow spend only own inputs except all of them?

Let's imagine: We have just one BTC address. Users send some coins to this shared address. And can spend only own inputs. P.S. If someone can provide some example script for this I'll be very ...
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3answers
784 views

Is there any way to make an UTXO that cannot be spent until a certain block #?

In bitcoin, each transaction has an nLockTime integer to specify the earliest allowed block number/time that the transaction can be added to the blockchain. In addition, each transaction input has an ...
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4answers
2k views

How to decode very huge (!) raw transactions?

I'm parsing the blockchain to extract certain information I need for a script. One thing I do is parsing transactions. What I do is: getrawtransaction <tx> decoderawtransaction <rawtx> ...
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2answers
2k views

Is sha-1 used in Bitcoin?

The Bitcoin scripting language has OP_SHA1 as one of its opcodes. However, I'm not able to find any usage of this opcode (it is not used in any standard scripts nor in any other procedures such as ...
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1answer
19 views

One more question about scripting

Is it possible to write a script that would allow withdrawal of money only to a specific address? Is it possible to write a script that would allow withdrawal only specific amount? Any examples ? ...
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2answers
151 views

Getting Started With Script

I would like to manually write a few locking and unlocking scripts to get a deeper feel for that part of the network. What is the simplest step-by-step set of instructions to set up everything needed ...
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2answers
2k views

How to get addresses from scriptPubKey in segwit transactions?

I'm running through raw transaction data, and I'd like to be able to gather addresses (where possible). So far, I've made this diagram to help me understand when it's possible to figure out addresses ...

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