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Questions tagged [segregated-witness]

This tag should be used for questions regarding Segregated Witness (segwit), an activated softfork that defined a new transaction format which doesn't include signatures in the transaction identifier (txid).

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3
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1answer
350 views

SegWit and SPV-mining. What if…?

Is the following scenario valid? Some unhonest segwit mining pool takes top-1000 segwit utxo and mines a block at height N with a transaction which transfers all funds to his p2pkh address This block ...
3
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1answer
60 views

What is the rationale for inclusion of previous amount in SegWit signing process?

When spending a P2PKH output, the "data" we hash only includes the output script from previous transaction but when spending a P2WPKH (the new serialization) we also include the amount field from ...
3
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2answers
97 views

SegWit Version - is there a proposal for new versions?

I can see transactions with version 0 Are there any other versions of SegWit proposed or in existence?
3
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4answers
2k views
3
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2answers
1k views

SegWit, Bitcoin JSON-RPC and (strange?) addresses

I'm trying to analyse this transaction: https://blockchain.info/tx/a388d6f88373aacf2a5c170eeff4adf51f2c6744da26375d5890f42d653a2e6c I used to be able to just run bitcoin-cli getrawtransaction txid 1 ...
3
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1answer
237 views

What do I have to do after Segwit activates if I'm running Bitcoin Core 0.14.1?

I have my bitcoins on a Linux Server. It runs Bitcoin Core 0.14.1. What do I have to do after Segwit activates?
3
votes
1answer
81 views

Do sigops count towards the block weight in SegWit?

I was just rereading the SegWit benefits page and noticed that the section Moving towards a single combined block limit contains an example in which sigops count towards the blockweight. Did this ...
3
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1answer
542 views

Parsing a SegWit transaction - what is the size of witness data?

I'm parsing s SegWit transaction, I got it done until i reach the witness data. How big is the witness data?
3
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1answer
643 views

After Segwit Activation, what is the largest block size possible?

The code says MAX_BLOCK_SERIALIZED_SIZE = 4000000, but that is actually not a actually consensus rule as stated here: https://github.com/bitcoin/bitcoin/issues/10289 The actual consensus rule is ...
3
votes
1answer
329 views

Does the introduction of Schnorr signatures require segwit?

What is the relationship of segwit and Schnorr signatures? Is segwit a prerequisit for Schnorr signatures? I've read that the transaction versioning of Segregated Witness would allow to just assign ...
3
votes
2answers
801 views

Is there a paper wallet generator for the new bech32 bc1xxx segwit address?

Is there a paper wallet generator like bitaddress.org for the new bech32 bc1xxx segwit addresses?
3
votes
1answer
605 views

How to quickly find the private key from Segwit P2SH address?

I have a very large list of Segwit addresses for bitcoin, starting with '3' and do not know the corresponding legacy '1' address for them. How can I quickly find the corresponding legacy address to ...
3
votes
1answer
309 views

how to get address from transaction with empty ScriptSig?

look here https://blockchain.info/tx/d4223672c9043c17a2775abde858778fca38b53152e165757188ab747850770e why does address start with bc1q... ? Is it some standart? How can I derive this value from ...
3
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1answer
371 views

What is 'ScriptCode'?

I don't understand what the 'ScriptCode' thing is. Is it a part of transaction format? The wiki https://en.bitcoin.it/wiki/Transaction describes scriptPubKey and scriptSig, mentioning nothing about '...
3
votes
1answer
135 views

What are the risks of a lower-than-95% activation threshold for soft forks (particularly SegWit)?

95% seems exceptionally conservative, especially given the evidence of vetoing by a subset of Bitcoin miners. What risks does, say, 60% over a longer activation period hold vs 95% for SegWit?
3
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1answer
46 views

Is SegWit similar to/ derived from Hyperledger Fabric?

Segregating the witness (signature) data from the transactional data is similar to the structure used in Hyperledger Fabric. Curious about the derivation of SegWit?
3
votes
1answer
455 views

Why does SegWit offer P2SH nesting?

I'm reading about SegWit and the BIP 141 in particular and I don't understand what is the motivation behind the P2SH nesting. At first I thought the P2WPKH is not valid on non-upgraded nodes, so ...
3
votes
1answer
653 views

How much does SegWit affect transaction size?

I know that SegWit transactions are bigger than normal transactions. But how much? 10% or 15% or..?
3
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1answer
279 views

What new JSON-RPC calls are available with SegWit activation?

For example, I can see getblock now returns two fields for a block's size: size (all data) and strippedsize (base block size, NOT including witness data) Are there any more RPC updates to interact ...
3
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0answers
295 views

HD Wallets - Generating P2SH-P2WSH Addresses from a ypub-type mpks in PHP?

I am writing a webapp in PHP that needs to generate Bitcoin addresses from their mpk. I have successfully done it for P2SH addresses (starting with a 1, with a xpub mpk) using the BitWasp php library,...
3
votes
1answer
755 views

Can Bitcoin Diamond be claimed on Segwit addresses?

I currently have my Bitcoin (BTC) on a Trezor hardware wallet with Segwit (Not in a "Legacy account"). Can I claim Bitcoin Diamond (BCD) with this or not? In general: Should I move my BTC to a ...
3
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0answers
353 views

Scrypt CPU miner supporting segregated witness (for Litecoin testnet4) [closed]

I am interested in CPU mining on the Litecoin testnet (testnet4); the difficulty level is currently low enough to make this feasible. The standard Litecoin client no longer supports CPU mining. The ...
2
votes
3answers
349 views

Why does the decode function of the segwit bech32 encoder/decoder take a hrp (human readable part) as input?

Looking at the code referenced in bip-0173, specifically for example here: https://github.com/sipa/bech32/blob/master/ref/javascript/segwit_addr.js function decode (hrp, addr) { var dec = ...
2
votes
2answers
369 views

How do virtual size, stripped size and raw size compare between legacy address formats and native segwit?

This answer states that SegWit doesn't reduce transaction size. If this is true, why is it cheaper to send a SegWit transaction?
2
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3answers
2k views

Calculate Segwit address from public address

I would like to calculate the segwit address of a public address. First step: take the compressed public address: 1L88S26C5oyjL1gkXsBeYwHHjvGvCcidr9 do a sha256 on that address: ...
2
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1answer
296 views

Are “1” , “3” and “Bech” Addresses (BTC) forward and backward compatible?

Wondering if lets say someone has funds in Bech32 and they send to a "1" or "3" address due to less characters to remember ect.
2
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1answer
3k views

What is the difference between BTC and Bitcoin Core?

To my understanding BTC and bitcoin core are the same, when mentioned against S2X/B2X. Is that the case? (Bitcoin Core is BTC in the post segwit2x world?)
2
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2answers
88 views

Calculating the witness size of a transaction

I want to calculate how many % of a block, and thus, transactions that are witness data. I need to calculate the size of the witness data in bytes in every transaction. And as I understand it, I ...
2
votes
2answers
202 views

Why non-SegWit nodes do not reject SegWit block since there is no witness?

SegWit is meant to be backward-compatible. When a SigWit block is relayed to a non-SegWit node, the witness part is stripped. If this is the case, wouldn't it be invalid since the non-SegWit node sees ...
2
votes
1answer
345 views

BIP91 is activated, why BIP141 is still dormant?

The moment is BIP91 activated non-SegWit signaling blocks will be orphaned. Since BIP91 is now activated won't that immediately boost BIP9 to 100%? Why is it not happening?
2
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2answers
265 views

Can there be a half segwit, half normal Bitcoin transaction?

I was wondering if it's feasible to compile a bitcoin transaction that is somewhere in between (segwit and non-segwit), maybe one of these scenarios. I'll call the non-segwit inputs, normal inputs ...
2
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3answers
423 views

When is the earliest we will see SegWit transactions on main net

I am assuming that only after SegWit activation SegWit txs will be on mainnet, what i cannot determine is the date for that event. Can anyone help? So far i have seen references to late August.
2
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1answer
107 views

Why does P2SH-P2WPKH use DER encoded signatures?

If we simply assumed 32 bytes of r and s each, then signatures can be 64 bytes. Now they are on average 71 bytes in DER plus an additional byte to declare their size, effectively making them use 72 ...
2
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1answer
697 views

SegWit address to Non-SegWit addresses

If I send from a segwit wallet to a non segwit wallet, does the tx not show up in the other wallet until there is a confirmation?
2
votes
1answer
176 views

What are the positives and negatives of “Flexible transactions”?

What are the positives and negatives of Bitcoin Classic's Flexible Transactions? (related BIP 134) Why aren't they used instead of Segwit? It seems that they solve the exact same issues as Segwit, in ...
2
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2answers
219 views

Which kinds of transactions show quadratic signature-hashing scaling?

It has been stated: A major problem with simple approaches to increasing the Bitcoin blocksize is that for certain transactions, signature-hashing scales quadratically rather than linearly. https:/...
2
votes
1answer
355 views

How to compute double sha256 shown in examples of bip 143?

How do I compute the double sha256 shown in example of bip 143? The example in Native P2WPKH hashPrevouts: dSHA256(...
2
votes
1answer
37 views

Why is a library's signature of a segwit tx different from Bitcoin Core signature?

I have been writing a (yet another) Bitcoin python library primarily for educational purposes; for me and my students. Signing a non-segwit transaction results in a signed tx that is identical to ...
2
votes
1answer
140 views

What does it mean if TXID and WTXID are the same?

I'm having a tough time understanding what exactly WTXID is and what it means when WTXID and TXID are the same (and vica versa). What I understand is that WTXID includes the witness data. Since non-...
2
votes
1answer
346 views

In simple terms, what are the major differences between P2WPKH and P2WSH bech32 addresses?

I've read over the bip173, bip141, and bip143 specifications and they're a bit too technical to get at the simple answers I'm looking for.
2
votes
2answers
101 views

Do legacy nodes receive the witness fields of a Segwit transactions?

My question comes from not understanding how BIP 144 works? Regarding the BIP what I ask is, whether legacy nodes support the new parser, so that they treat Segwit tranasctions as valid? There it is ...
2
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1answer
488 views

OP_RETURN in a coinbase transaction?

Hey looking at this transaction I'm confused why there are two outputs and why one of them is labelled with OP_RETURN
2
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1answer
130 views

Extract lightning network funding transactions with python bitcoin blockchain parser lib

My ultimate goal is to parse funding transactions (as well as channel closes in a later step) from the blockchain. In order to do so I wanted to start with a funding transaction and disect it. ...
2
votes
2answers
953 views

Why is my segwit private key generating a 3 address vs a bc1 address like how I originally generated?

I have the following btc private key that I generated from another application: 5KCPzu4tEAnFqwLrXUbW3GKMDSnUYY8CMie2HMRuHouSvrFhXA9 That application gives me the following segwit address: ...
2
votes
1answer
354 views

Creating a new electrum 3 wallet file with an imported segwit private key

I have a segwit private key that I generated from another app. How can I create a new electrum wallet file with just this private key in there? I tried creating a new electrum 3 wallet with this ...
2
votes
1answer
195 views

Why is there an output with op-return in regtest mode?

Here is an output from getrawtransaction: { "txid": "a2b9e3aa4adeb68a9b8b8b0bbc8d4890585cd711e89cda83e7f236397fac6218", "hash": "6d96c04d49eefe3eab4934188841ef3592c818bf789517b90b1f71ff75a14c26",...
2
votes
1answer
110 views

Bitcoin Core - When is fAllowWitness evaluated to true?

In Bitcoin Core, when is fAllowWitness evaluated to true? transaction.h const bool fAllowWitness = !(s.GetVersion() & SERIALIZE_TRANSACTION_NO_WITNESS); In particular, I cant figure out the ...
2
votes
1answer
268 views

Legacy blockchain after upgrade to SegWit

Let's suppose I run a legacy (non-SegWit) node after SegWit gets activated. My blockchain doesn't store any SegWit data. What happens when I upgrade my node? Will I have to re-download the blockchain ...
2
votes
2answers
341 views

Can BIP91 cause a chain split?

BIP91 forces BIP141 signaling, the blocks that do not signal BIP141 will be rejected by those who are pro-BIP91. The minority of miners that do not support BIP91 (and by extension BIP141), could start ...
2
votes
1answer
84 views

Once SegWit is implemented, could updated miners still choose to ignore SegWit transactions?

Regular transactions can be ignored. What about SegWit transactions?