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Questions tagged [spv]

refers to Simplified Payment Verification, a scheme by which thin clients can check whether the network trusts a transaction.

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Light clients transaction verification

How does a light node know which block its transaction got included in? Say a light node sends out a transaction spending its UTXO. Does it get some sort of notification when its transaction is mined ...
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1answer
14 views

How to get output linked to input in SPV node?

We're working on bitcoin SPV wallet. After setting bloom filter, we only get merkle blocks, and transactions that match the hashes we set plus some false positives. If a transaction is where we SEND ...
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What are the lightest (smallest) SPV clients available?

I need to embed a Bitcoin client into another P2P program so I need it to occupy the least disk space possible. What are the best options around? How do they compare (in terms of space) to Bitcoin in ...
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1answer
58 views

How to make a persistent SPV wallet? (bcoin)

I created a wallet on a SPV node. The wallet is initialized from a mnemonic. After receiving some transactions, the wallet's balance looks like: { account: -1, tx: 3, coin: 3, unconfirmed: 136300, ...
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How does supporting additional 'Address Chains' impact resource usage for an SPV wallet?

On Reddit I encountered a user claiming that implementing Segwit support for an SPV wallet would require supporting an 'additional address chain', but I'm not sure what exactly that entails. I would ...
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2answers
95 views

Can SPV clients offer “proof of absence” of a transaction?

So light SPV clients give the user the ability to obtain merkle proofs (from a full node) that a given transaction is included in a block. Is there some cryptographic mechanism by which an SPV client ...
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11 views

Open Source SPV client with sendTransaction functionality

Are there any open source SPV clients (ideally in C#) that have sendTransaction functionality? I am creating a C# mobile application to send bitcoins and receive bitcoins, but the application ...
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34 views

Which light wallets actually connect to nodes?

AFAIK, most light wallets are not members of the P2P network, but rather connect to a centralized server run by the wallet developers, which broadcast users' transactions to the actual network. Which ...
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1answer
102 views

How exactly does SPV work?

Here is what I have so far: A mobile connects to a node using rpc. The mobile then asks the node, to give him a set of transactions for a set of public keys. The node, then looks for any ...
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1answer
136 views

How is the Leaf node weakness in Merkle Trees exploitable?

Recently a weakness in leaf nodes of merkle trees was disclosed and it is claimed that this issue is exploitable to trick SPV nodes. How does the weakness make SPV nodes vulnerable to attack? What ...
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1answer
37 views

My spv node received in a nTx = 2 in headers message

I am coding an spv node for dogecoin. I am syncing the headers and I am exceping to have nTx=0 for all the headers received but for one of the headers i have a nTx = 2 and some weird data following... ...
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1answer
58 views

does bcoin support simplified payment verification (SPV)?

Does bcoin support simplified payment verification (SPV)? I can't seem to find anything about it online
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2answers
122 views

Who gives SPV nodes merkle path to do validation for small subset of transaction?

From Mastering bitcoin: Merkle trees are used extensively by SPV nodes. SPV nodes don’t have all transactions and do not download full blocks, just block headers. In order to verify that a transaction ...
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24 views

What are the proposed solution for SPV scaling?

Apart from Client Side filtering, are there any other solutions regarding how to scale light clients? Maybe having centralised services hold the UTXO list, the problem would then be how to anonymise ...
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1answer
39 views

On SPV clients and Segwit

An article released by Blockstream claims that after Segwit, SPV clients can verify that transactions have been accepted by the network without having to download the signatures/witness-data. I'm ...
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87 views

Building a simple spv android wallet for an altcoin Please help!

I am currently trying to build an android wallet for an altcoin that was forked from litecoin. I have been looking at the loafwallet to change the parameters: https://github.com/litecoin-foundation/...
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22 views

Why do SPV clients need to store the headers?

Can SPV clients store only the last 10 block headers or just one day's worth of blockheaders for example. Instead of keeping each one?
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1answer
53 views

If 30% of the network are malicious, how many nodes would an SPV need to connect to, to be sure?

If we assume that 30% of the network is malicious and colluding together to trick an SPV client, by telling him wrong information. How many random connections would the SPV client, need to connect to ...
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1answer
151 views

SPV Wallets vs API Wallets - Pragmatic

From what I know, the only advantage of an SPV node compared to a API Node, is the increase in privacy. SPV nodes take up more bandwidth, in order to stay synced with the current chain and in some ...
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23 views

State of privacy-preserving light clients

Currently, it is trivial to operate a SPV wallet in Bitcoin at the cost of a lot of privacy due to the necessity to connect to full nodes that offer SPV services. Neutrino, currently being worked on ...
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1answer
114 views

Bitcoin wallet on smart phone drains battery a lot?

I downloaded Android Bitcoin Wallet (version 6.17) on my android phone, and realized that the app drains battery a lot. The system showed 40% of battery was used to the wallet. Does anyone have same ...
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1answer
205 views

What is the difference between an SPV wallet and an API wallet?

I understand what an api wallet is, but I'm unfamiliar with what an SPV wallet details. I'd like a technical explanation on what an SPV wallet is, how it differs from traditional thin clients and how ...
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1answer
73 views

Query publicly available full nodes

I don't want to run a full node yet, but I want to build an application. How and what do I use to query publicly available nodes? What nodes besides blockchain.info are publicly available for me to ...
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106 views

Bitcoin SPV-based wallet using Cordova Ionic and bitcoinjs-lib

I am trying to build SPV-based bitcoin wallet app using Ionic Cordova. I want to integrate the bitcoinjs-lib in Ionic app, to implement the full wallet functionalities and transactions in peer-2-peer ...
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46 views

Does an SPV download the block headers from other nodes than the one that is servicing him?

If I understand correctly. The SPV downloads the block headers, from somewhere? It then uses the merkle root in the block headers, to validate any transactions that the full node servicing him ...
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2answers
101 views

Deserializing merkleblock message

I've been struggling the past couple of days to deserialize a merkleblock message. I'm writing a go app that uses the bitcoin rpc client to call gettxoutproof, but only need the merkle proof (array of ...
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1answer
181 views

how does a node searches a transaction among various blocks in blockchain?

Let me express what I have got to know about blockchain and where am I stuck. Transactions are stored in the form of merkel trees inside a block. (I know how a merkel tree is made). A merkel root is ...
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1answer
50 views

How could the Bitcoin protocol be modified so that pruned nodes could still participate in BIP 37 SPV?

According to Jameson Lopp (https://www.coindesk.com/spv-support-billion-bitcoin-users-sizing-scaling-claim/), allowing pruned nodes to advertise that they support BIP 37 would be impossible without "...
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1answer
67 views

Bitcoin full clients checks all the blockchain every time they receive bloom filter?

I assume that an spv client like bitcoinJ requested transactions related to the client one week before and the client has been offline for a week. When the spv client come online, does it just request ...
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2answers
365 views

Why does Electrum's SPV require proprietary servers?

What does an Electrum server do that a regular Core full node doesn't do? If the wallet downloads block headers and verifies transactions using SPV and bloom filters, why does it require special ...
2
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1answer
681 views

BTG wallet or exchange with BIP39 seed import

Can anyone recommend a Bitcoin Gold exchange or SPV wallet for Linux that supports importing wallets from a BIP39 seed? The best I’ve found so far is a fork of Electrum that supports BTG for Windows ...
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2answers
140 views

Segwit2x/btc1 block header changes: wipeout protection for SPV nodes?

Are there any current plans for segwit2x/btc1 to change the block header in a backward-incompatible way, either permanently or with a signal block (e.g., "hard fork bit"), before it goes live? This is ...
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1answer
119 views

What indexes does a Bitcoin Core node maintain to serve Bloom-filtered requests and SPV peers?

The Wiki makes this statement: It [getdata message] can be used to retrieve transactions, but only if they are in the memory pool or relay set - arbitrary access to transactions in the chain is not ...
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1answer
709 views

Understanding SPV, pruning and its downsides, as well

First of all, sorry by not asking an objective question, it's because I can't resume this one and I didn't find information even in the "mastering bitcoin" book. The large texts in this question are ...
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1answer
1k views

The use of Bloom filter in SPV nodes

I know what Bloom Filter (BF) is, and I'm aware of this post and this paper. But I don't understand how it's used in bitcoin. I can imagine that an SPV node encodes the transaction(s) it's ...
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0answers
244 views

Understanding simplifying payment verification

I'm studying the paper "Bitcoin: A Peer-to-Peer Electronic Cash System" and I've gone through many questions on this site. Still I cannot fully understand the contents of the Simplified Payment ...
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1answer
526 views

How does SPV prevent double spending of UTXO?

I am new to Bitcoins. I have read about how double spending is prevented in Bitcoins. Suppose A, a peer, receives 'B' BTCs from various transactions: B1,B2,B3, etc. Also, A had spent 'S' BTCs in ...
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817 views

How does merkle tree verification of transaction work?

From what I have read, suppose B sends 1 bitcoin to C. C wishes to verify B's payment and asks C for the block number (location) that input transaction is located at. (Is this correct understanding/...
2
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1answer
479 views

Bitcore full node list with Wallet service enabled?

Is there any Bitcore full node list out there? I wanted that in order to use the Wallet Service while not being dependant on only one server. edit: quote on their website: You should now be able ...
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0answers
195 views

Privacy risks with a hardware wallet

I'm trying to understand the privacy risks with a hardware wallet like a Trezor, Ledger, or similar. I understand the common workflow with these wallets is that you use an SPV bitcoin client which ...
2
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1answer
175 views

SPV clients - how much does occupy the full blockchain headers?

Does a spv client need to download the full blockchain headers? how much does it occupy? is it better for security? I saw a blockchain-headers file in my android wallet that only occupies -30MB.
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97 views

Payment Transaction Validation

I want to build a app which takes transaction id, source and destination address as input and need to validate the transaction (the specified amount is sent from address1 to address2. What is the ...
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1answer
81 views

Privacy approach for a light-weight wallet

I am looking for an approach to build a privacy centric lighter weight wallet. By privacy centric I only mean: network observers should be unable to guess the addresses belongs to the same wallet. So ...
3
votes
1answer
550 views

Are there any POS coin open source mobile wallets implementations?

Specifically, I'm interested in the thick clients with Simplified Payment Verification. Haven't found these so far, do they even exist? Why are the POS mobile wallets such poorly distributed ...
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1answer
372 views

Copay wallet problem: “Could not update Wallet: Network connection error”

Apparently BitPay's servers must be down because I can browse the internet but my copay wallet is stuck in this error: Is there any way to know if it's really an issue on their end and if they're ...
7
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2answers
951 views

How does a node find a transaction in the blockchain?

If a (light) SPV client asks a full node for the Merkle branch containing a specific transaction (or the value of an address), how does the full node find this transaction (or the UTXOs) in the ...
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2answers
3k views

Is there a light (SPV) version of bitcoin core (bitcoind)?

I'm trying to develop an SPV Bitcoin client which makes use of a library requiring bitcoin core (a running bitcoind service). However, from what I understand, Bitcoin Core is full node, meaning that ...
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1answer
202 views

What hardware requirements does a SPV client have?

I read about SPVs here that: [A SPV] client downloads a complete copy of the headers for all blocks in the entire block chain. This means that the download and storage requirements scale ...
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1answer
216 views

How long does it take for a SPV to intermittently sync (order of magnitude)?

Say I have a device that is mostly offline, with a SPV on it. Say once in a while (for instance once a week) I go online for about 20 minutes, and make a large number of transactions (which are ...
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1answer
155 views

BIP 37 automatic filter update not inserting outputs

I'm having a problem with bloom filters when using the getdata message. As I understand BIP 37, setting the bloom filter on a connection using the loadfilter message with flag ...