A Java library for processing Bitcoin, stores blockchain headers only

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C++ Proofofworklimit to bitcoinj util.DecodeCompactBits

What is equivalent bitcoinj util.DecodeCompactBits for below c++. Cbignum(~uint256(0) >>32) Cbignum(~uint256(0) >>20) Cbignum(~uint256(0) >>23) Cbignum(~uint256(0) >>22)
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1answer
26 views

How to send money to set of recipients using bitcoinj

I am creating a wallet app using the bitcoinj library. I have a use-case where I need to send bitcoins to multiple recipients in one transaction. Currently, I am creating multiple send requests for ...
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1answer
65 views

How are Lightning network, duplex channels, and micropayment channels related?

I'm new to Bitcoin and just became familiar with Micropayment channels. But how exactly do they relate to: Lightning network Duplex Micropayment Channels ? I am reading about these but can't find ...
4
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1answer
48 views

Transaction with `OP_RETURN` to a particular address

How do I formulate a Transaction with OP_RETURN to a particular address using Bitcoinj library. SendRequest req; Transaction transaction = new Transaction(Main.getNetWorkParameters()); ...
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1answer
69 views

How to use the BIP-32 keys

I am trying to built an application that uses the BIP-32. But I am not sure on how to use it. I have a passphrase with which I generate the Derived Private Key and Derived Public Key. If I share my ...
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36 views

Get transaction details using bitcoinj library

I am trying to develop an application using bitcoinj library. I want to get the bitcoin transaction details. The details, that I want to extract from a transaction includes the following. 1) Who ...
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36 views

Editing bitcoinJ for Android Altcoin App

So there is an altcoin created by another party and i want to edit the bitcoin-wallet app for android so that it connects to the new network. Is it enough to edit core/params/MainNetParams.java in ...
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1answer
51 views

Not receving Bitcoins to my testnet wallet

I am running the bitcoinj wallettemplate on testnet3. I have this address miAKWcmebJ7TYyZCYUx54djHsatVGdNZA8 , I tried out some websites which sends me testnet coins (Faucet). But I am not receiving ...
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21 views

Connect to regnet from my WalletAppKit Android app

everyone. I'm developing a simple app to learn how to use the bitcoinj library. I'm using the WalletAppKit object to simplyfy the process and I'm following the official documentation. When ...
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50 views

BitcoinJ - How to Create a wallet properly. (seeds, etc…) [closed]

I'm learning this as fast as possible for a project. However the documentation, I find is lacking and/or not super super clear. That said, Using BitcoinJ, I would like to know how to do the following:...
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1answer
43 views

get any transaction in p2p manner using bitcoinj

I'm pretty sure bitcoinj is capable to download any bitcoin transaction from p2p nodes by broadcasting GetDataMessage because that's what its do in peer.downloadDependenciesInternal method. I'm ...
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23 views

check if transaction is spendable in bitcoinj

Is there some kind of check if incoming transaction is normally spendable by the bitcoinj wallet? I mean to check if there is no time lock and it's not multisig or whatever can prevent receiver from ...
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51 views

How can you make bitcoinj not use change addresses?

My question is related to bitcoinj library but not limited by it. bitcoinj will create new change address after every transaction. It will manage them transparently, but let say I want to use this ...
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transaction limits with bitcoinj library

After brief look into bitcoinj library, I found out that wallet class keeps all transactions in one big hash map. That make me think about transaction limits of this library. How many transaction can ...
2
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1answer
43 views

how do I get list of all “used” addresses in bitcoinj

Bitcoinj generates receiving addresses on demand and change addresses after each transaction. So how do I list all receiving addresses ? I guess I have to deal with KeyChainGroup and BasicKeyChain. I ...
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1answer
91 views

How to get list of all transactions in bitcoinj wallet?

I configured bitcoinj library so I can connect to network, replay blockchain, create addresses, receive and send bitcoins. I using FullPrunedDatabase as block store. I'm still missing how to find ...
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22 views

Why does bitcoinj need block headers and how it gets transactions

From log files and database it's obvious, that bitcoinj downloads block headers for whole blockchain history. If I'm not mistaken, it's only 80bytes hash. Why do we need to do this. I understand ...
2
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1answer
79 views

How to get fee in a transaction with unconfirmed inputs in bitcoinj?

I am trying to get the fee of incoming transactions in a wallet with bitcoinj. At times it was the commission using Transaction.getFee(), but this was throwing NullPointerException. I got to do a ...
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1answer
84 views

With Mike Hearn quitting Bitcoin, what seems to be the future or bitcoinj?

Mike Hearn has apparently sold all his Bitcoins. So what is to be expected about the development of bitcoinj? (and Java based clients in general).
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52 views

Send BTC with attachment using BitcoinJ

is there an example of how using BitcoinJ send BTC with an attachment? Lets say I want to write to blockchain "Vaclav Bilek Born 1991". If I understand it correctly, its just about sending minimum ...
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30 views

Wallet loses the money to be restored in bitcoinj

I have a problem when using the library bitcoinj. When I restore a wallet from a backup, if it has received money in some of his addresses to synchronize with the blockchain, the money does not appear....
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34 views

Decrypt my private key using KeyCrypter

I am trying to decrypt my private key bytes using the KeyCrypter interface. But i do not know how to implement and call the decrypt() function. Initially i encrypt the bytes of my Private Key of my ...
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1answer
71 views

ECKey.ECDSASignature creation

I have my ECKey key. In order to create an ECDSASignature object with BitcoinJ, we have to call ECDSASignature mySignature = key.sign(Sha256Hash input). Is the Sha256Hash input my message? Or is it ...
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41 views

Creation of P2SH MultiSig Input Script

In the createP2SHMultiSigInputScript() function of BitcoinJ according to this: public static Script createP2SHMultiSigInputScript(@NullableList signatures,Script multisigProgram) Create a program ...
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41 views

Creation of <20-byte hash of redeem Script> in a P2SH Transaction

According to this example: Redeem Script: 2 PubKey1 PubKey2 PubKey3 PubKey4 PubKey5 5 OP_CHECKMULTISIG Locking Script: OP_HASH160 <20-byte hash of redeem script> OP_EQUAL Unlocking Script: Sig1 ...
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2answers
154 views

Encoding my Bitcoin Address with Base58 encoding

I am trying to convert my Bitcoin Address with BitcoinJ in order to look like a normal address such as this: 1J7mdg5rbQyUHENYdx39WVWK7fsLpEoXZy. I haven't found anything exept for the Base58.encode() ...
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1answer
48 views

Verifing the given R/S pair (signature) against a hash using the public key

According to this function: public boolean verify(Sha256Hash sigHash, ECDSASignature signature) { return ECKey.verify(sigHash.getBytes(), signature, getPubKey()); } I do not understand ...
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25 views

Creating the Pay to PubkeyHash Transaction with bitcoinj

I want to implement the Pay to PubkeyHash Transaction without connecting to a network(for example testnet). I want to create it, to run locally. I don't know how to create my Signature from my ...
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38 views

How to use MySQLFullPrunedBlockStore with bitcoinj-core-0.13-bundled.jar

Initailly i am using bitcoinj-core-0.12.2.jar and bitcoinj-tools-0.12.2.jar on my project.Now i updated it with bitcoinj-core-0.13-bundled.jar because i am assuming that bitcoinj-core-0.13-bundled is ...
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23 views

SPV client unconfirmed transaction handling

Do SPV wallets do any validation for unconfirmed transactions like checking for DER encoding or low-S signatures? Or do they rely entirely on a full nodes mempool?
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1answer
49 views

How to get the MPK using bitcoinj and how to generate the addresses using the MPK?

I am trying to get the MPK of a wallet using bitcoinj. Can I get the DeterministicSeed, which is the seed of the wallet and get the MnemonicCode of 12 words. But I can't get the MPK. As I can make it ...
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91 views

Bitcoin multisig tutorial

I have five private keys (of type java.math.BigInteger) called a, b, c, d, e. Please provide some code template for the following. Create an address that has "3-out-of-5" spendability for the above ...
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35 views

How is a transaction verified in a micropayment channel?

Let's say Alice opens a micropayment channel with Bob and sends $10 into the multi sig transaction. How do we know that Alice has those $10? Or are we taking the risk of her double spending it?
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1answer
84 views

Bitcoin transactions reserve more coins than needed

I have a JavaWebApp wich uses bitcoinj 0.13.2 for sending bitcoins from a wallet to a particular address in a TimerTask. When the job starts, every minute I send 10000 satoshis to the address. The fee ...
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34 views

Differences between MemoryBlockStore and SPVBlockStore

What are differences between MemoryBlockStore and SPVBlockStore in bitcoinj? Which should be used for downloading the blockchain and why? Can I use same SPVChain format file for all wallets?
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54 views

Bitcoinj: Multiple wallets

In my Java application I am now required to handle multiple bitcoin wallets (HD wallets?). This means sending and receiving BTC. Unfortunately bitcoin is quite new for me, so there are some questions: ...
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2answers
93 views

SPV Bloom filter construction, are false positives taken from the blockchain or just due matching with other addresses

It is my understanding that the false positive addresses generated by an SPV bloom filter do not need to necessarily be on the blockchain (ie. be addresses that have been used already). Is that a ...
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0answers
90 views

Bitcoinj: How to fix error “You should use Context.propagate() or a ContextPropagatingThreadFactory”

I'm using bitcoinj from a Scala application... and when I start it, I always get the following errors: [error] o.b.c.Context - Performing thread fixup: you are accessing bitcoinj via a thread that ...
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236 views

Transaction still pending after 12 hours

About 12 hours ago I sent BTC 0.06304568 to my test wallet... and the transactions is still pending: { "receiveAddress": "1KU9VwJ992UisoAYiPbRdSXDRVUCq4wdW1", "balance": 0, "net": "prod", "...
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1answer
132 views

Bitcoinj: How to get notified when coins are received

I need to know when my local wallet receives coins... but onCoinsReceived is invoked as soon as a transaction on my wallet is visible. How do I get notified when coins have been received and are ...
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27 views

Bip70 Server returned HTTP response code: 406 for URL

While reading BitcoinUrl I m getting 406 http error (Server returned HTTP response code: 406 for URL Here is my code. ListenableFuture future=null; if (url.startsWith("bitcoin:")) { ...
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79 views

Why I can't see the balance increasing in my wallet?

I wrote this function using bitcoinJ public Wallet getWallet(ECKey ecKey) { Wallet wallet = walletAppKit.wallet(); wallet.importKey(ecKey); wallet.addEventListener(new ...
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65 views

Implement Bitcoin BIP 70 protocol

I want to implement Bitcoin BIP 70 for an ATM machine. I am bit new to bitcoin technology. What I want to ask is, if any user wants to sell coins then this means we have to generate a QR code of our ...
2
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1answer
148 views

How can I get the input addresses of a transaction in Java?

I am trying to obtain the addresses of entry of a transaction when I receive money, but I have not found the way. I have tried to create an address with the bytes obtained by calling TransactionInput....
2
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1answer
135 views

How to synchronize with the bitcoin blockchain via bitcoinJ

I'am writing my very first application using bitcoinJ api and I got a bit stuck. Maybe somebody can tell me what I am missing. My practice app wants to write a sample contract in the bitcoin ...
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2answers
222 views

Even if transaction fee is set to BTC 0.00001, transactions remain unconfirmed

I'm testing an application based on bitcoinj so I've been sending small amounts for days and it worked fine – transaction fees are set by default to BTC 0.00001. As of yesterday, these small ...
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1answer
135 views

How do I check if an address belongs to my wallet using bitcoinJ?

I'm using bitcoinJ and I want to verify if some of the destination addresses in a transaction belongs to my wallet when I receive a amount of bitcoin. How can I verify it?
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1answer
52 views

How fast is BitcoinJ for getting UTXOs(/UnspentTXOuts)?

I'm making an app where I need to be able to get unspent TX outs very quickly for addresses I do not know beforehand. Now this is supported by Bitcoins architecture in that you can have a pruned ...
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22 views

Q. What happens to dead , or deadended Bitcoins? [duplicate]

NAMASTE! please understand that I am tech challenged! ie. ignorant not stupid! I am trying to learn and sarcastic smartass comments do not help! :-) I am trying to find out what happens to Bitcoins ...
4
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1answer
154 views

How to get balance from a specific address in bitcoinj?

I'm trying to get the balance of a specific address in a wallet by using bitcoinj, but I don't know how. Can someone help me? Thanks in advance!!