Within the context of Bitcoin, scripts are a set of instructions on how to complete a transaction. The default send/receive actions are scripts but the protocol can be extended through the creation of new scripts, such as the DNS replacement abilities of NameCoin.
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How vulnerable is bitcoin to quantum algorithms?
Assuming that quantum computers are implemented some time in the near-ish future, how vulnerable is Bitcoin to decryption via quantum algorithms? For example, Shor's algorithm enables a quantum ...
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88 views
An explanation of transaction scripts
https://en.bitcoin.it/wiki/Script
I'm trying to wrap my mind around them. Could anyone provide a bit more intuitive understanding?
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53 views
Instant confirmations with pre-published, locked, transactions
(Clarification: This is not an attempt to solve the problem of a vendor taking the money and running without handing over the merchandise. Problems like that can't be solved without some third party. ...
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64 views
What is “Script Hash” address exactly and how does it work?
I found out this address playing with blockchain
https://blockchain.info/address/3NukJ6fYZJ5Kk8bPjycAnruZkE5Q7UW7i8
I found out it's something called "scripthash". How does it work exactly? How does ...
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53 views
Signature in scriptSig
I'm a bit confused about the signature contained in the scriptSig of a transaction. My question is: what do we really sign? is it the hash of the previous transaction?
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1answer
70 views
How OP_EQUALVERIFY works in a standard transaction?
3 weeks ago I began learning about Bitcoins, and now I'm analyzing how it works internally. My problem is that I can't understand what two public key hashes are compare to use de OP_EQUALVERIFY, ...
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251 views
What is relation between scriptSig and scriptPubKey?
Scenario: A is sending 1 BTC to B.
scriptSig appears in the Input Script.
scriptSig = <sig> <pubKey>
Here, public key is the Public Key of the sender, A. (this is the public key ...
4
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1answer
101 views
How is the Output script formed?
I read about Input and output scripts on the wiki here:
https://en.bitcoin.it/wiki/Transactions
Let's say, I use my Bitcoin - QT Program, I go to "Send Coins" tab, enter a Bitcoin Address, BTC ...
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3answers
492 views
Can I use single address for all my transactions?
Can I always use single public key (addr1) for all my transactions and when I spend every time protect it with different scripts / keys (key2, key3, etc.), so that spending requires at least two keys ...
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59 views
How do I list all unique scripts from blockchain?
How do I list all unique scripts in the block chain, and their count (n-times-used)?
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76 views
In Bitcoin scripting, can you have an IF within an IF?
In bitcoin, you can create a script like this:
OP_1 OP_IF OP_RETURN OP_ENDIF
But could you place another if statement inside the first?
OP_1 OP_IF OP_1 OP_IF OP_RETURN OP_ENDIF OP_ENDIF
I grant ...
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1answer
171 views
How can a Bitcoin Oracle ensure that the money can't be respent?
Suppose I modify the requirements of the Inheritance Scripting Sample where I need to make sure that the prior BTC is "guaranteed" to be available and not reduced or re-spent prior to either of the ...
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2answers
106 views
Is the scripting system an incalculable security risk?
Why does Bitcoin have a complicated scripting system?
https://en.bitcoin.it/wiki/Script
https://github.com/bitcoin/bitcoin/blob/master/src/script.cpp
I guess because it makes fancy contracts ...
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1answer
183 views
Bitcoin charity fraud - is it illegal?
So we're all aware of services like CoinAd, but what if someone took advantage of that? Imagine if someone had a video game on facebook or something and had people fill out a CAPTCHA before they could ...
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1answer
60 views
How do I read a script? How does the processor separate “data” from “commands”?
I'm trying to understand how a script works but am having trouble reading a script (the output of one Tx... and the input of a second Tx) and figuring out how the computer (bitcoin-qt) knows which ...
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119 views
How should a Bitcoin Oracle verify a transaction prior to signing?
What are the specific parts of a transaction(s) that need to be signed in the "inheritance scripting sample". Specifically, can someone provide more detail on what exactly is signed of the ...
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2answers
141 views
Can I send message inside the transactions script?
I would like to send transactions with messages as described in the wiki. In Transaction with slightly changed script is never relayed, someone answered that non-standard transactions are not relaid ...
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1answer
56 views
Can someone explain this [outdated] BIP12 OP_EVAL exploit?
I understand that BIP12 was withdrawn, and probably because of this exploit below. Can someone explain how this attack would have worked and the effect it would have on the network?
for (;;) {
...
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1answer
138 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
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Are all the *coin networks consistent in which script actions are permitted and disabled?
The reference Bitcoin client disables several script commands (the programming within a transaction) due to possible implementation issues in the network. I think it's possible that a forked client ...
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3answers
130 views
Is there a listing of strange or unusual scripts found in transactions?
I'm studying scripts and am looking for strange or unusual scripts that have appeared in any of the *coin networks..(outside the standard ones listed on this page)
Is any one person, or website ...
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2answers
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Will general non-standard transactions ever be allowed?
To the best of my knowledge, currently "Satoshi" client relays and most pools accept only standard (transfer or generation) transactions. Besides, community is working on M-of-N transaction type. ...
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1answer
143 views
Password-based bitcoin transactions
I have been reading about the role of script in transactions and I gather it should be possible to do a Bitcoin transfer to a receiver who knows a password. Instead of checking an address, the script ...
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Bitcoin contracts. Are there good examples in the blockchain?
I have been checking the Bitcoin wiki for script and Bitcoin contracts and I have some doubts about advanced contracts.
For instance, I have seen in many places references to password controlled ...
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3answers
258 views
How do you get the OP_HASH160 value from a bitcoin address?
I'm trying to sign a coinbase transaction. I know I need to use 76 A9 14 (HASH160) 88 AC but I don't understand how to create the HASH160 (20 byte) from a bitcoin address.
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2answers
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What is the format of coinbase input scripts?
The input script of the coinbase transaction of block number 1 (right after the genesis block) looks like this: 04ffff001d010b
How do I recognize this as a coinbase transaction?
Do I simply know ...
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113 views
Can a scriptPubKey have multiple addresses?
When working directly with bitcoind, I can getRawTransaction for any transaction in the network. The vout has multiple outgoing addresses usually which contain a scriptPubKey. The scriptPubKey has a ...
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146 views
Did P2SH (BIP 16) get accepted?
Based on this, it seems like it did http://blockchain.info/p2sh but it seems I can't find a definitive answer.
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Transaction with slightly changed script is never relayed
I am playing with bitcoin transaction a bit now.
I have a question. Normally, the output script looks like
OP_DUP OP_HASH160 (hash) OP_EQUALVERIFY OP_CHECKSIG
Now that is understandable. However, ...
4
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1answer
83 views
Why do some generation transactions use pubkey, instead of hash?
At BlockExplorer I can see that (edit: some) generation transactions use a pubkey in the script (<key> OP_CHECKSIG), while ordinary transactions use address/hash (OP_DUP OP_HASH160 <hash> ...
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3answers
112 views
Custom validation logic for transactions/ custom script extensions
Is it possible to add a hook for custom validation of transactions with a special script "tag" in them? If so, How? In essence, I want to add something similar in functionality to bitcoin script, but ...
3
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2answers
299 views
In which Block was Len Sassaman memorialised?
It has been mentioned a couple times here and there that Len Sassaman was memorialised somewhere in the Block Chain. I was able to find a dump of of the tribute to him, but I can't seem to find where ...
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54 views
What does script operation “OP_IFDUP” do?
According to the wiki page, OP_IFDUP will duplicate the top of the stack "if the input is true or false". It seems to me that everything is true or false when interpreted as a boolean.
According to ...
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194 views
How did these 3 tx make it into a block in the main chain?
http://blockexplorer.com/block/000000000000051b42fd09195c75da7a084df7593f47ad18139cdc9cd83a112e
The last three tx have a inputs with script_sig "1". This is invalid right?
According to protocol ...
4
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2answers
176 views
Can Scripts be used to implement Chargebacks?
I went ahead and wrote this semi-detailed post about how to implement Chargebacks, when I hit my head and said "Doh, maybe this can just be implemented more cleanly with Scripts".
So ... is there a ...
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3answers
238 views
Why is Script needed?
As I see it, the script feature is one of the most complicated features in the entire protocol. It features
$ cat src/script.h|grep '^ *OP_'|wc -l
118
instructions, and requires a stack to ...
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1answer
101 views
Will any of the proposed Scripts (OP_XXX) allow subscription/recurring type payments?
Is it possible to implement a subscription/recurring payment type using Bitcoin scripts?
For example, you could send a payment for a service where there is a monthly subscription say, and each month ...
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2answers
626 views
How to know if a transaction is valid?
I understand there are a couple things that need to be checked for a transaction to be valid - the previous transaction had to be correct, no OP can invalidate the transaction, etc, but is there a ...
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1answer
54 views
Script - OP_IF etc. clarifications
Description of the OP IF is a bit vague on the wiki. Where does one get statements for the op for? Are they coming from the stack, or from somewhere else? Are there any available examples of how a ...
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45 views
Script - OP_SIZE
Does the OP_SIZE operation in Script push one item onto the stack (length of the string), or two (string and its length)?
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Script - true and false values
In the Script, when one is checking whether a value is true of false, should the length of the expression be checked? For example, 0x01 is evaluated as true, but can the same be said about 0x0001, ...
2
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1answer
84 views
Script - OP_PUSHDATAs
When using OP_PUSHDATAs in different Scripts, how are the next bytes denoting the amount of bytes to be pushed encoded? Are they to be treated as unsigned integer, or signed (like the data that is ...
3
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1answer
408 views
Bitcoin script example
Is there some good example on how to process a basic tx's scriptsig and get the recipient's address from the raw transaction?
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1answer
129 views
How are transactions in discarded forks merged back into the blockchain?
It sounds like transactions in discarded blocks are propagated back to the network to be included in the next block to be generated, is that the case? If so, is that triggered in the client when it ...
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525 views
How do Scripts work?
Bitcoin protocol supports scripts.
How do they work?
How are those implemented?
What are their intended usages?
When are they planned to be used?
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1answer
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How does a recipient know they can satisfy the transaction script to spend their bitcoins?
The wiki page on the transaction script says:
The party who originally sent the Bitcoins now being spent, dictates the script operations that will occur last in order to release them for use in ...
15
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2answers
1k views
Useful alternative Bitcoin transaction scripts
The Bitcoin wiki describes a transaction's script as something that describes "how the next person wanting to spend the Bitcoins being transferred can gain access to them".
The script for "a typical ...
