Questions tagged [bitcoinj]

A Java library for processing Bitcoin, stores blockchain headers only

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9 votes
4 answers
11k views

Is there a known way to export my wallet private key from the "Bitcoin Android" app (com.bitcoinandroid)?

A while back, I installed the Bitcoin Android app and moved 5 BTC on it. Fast forward to now, new phone, new ROM, and the app seems completely unwilling to update its blockchain, meaning I have no way ...
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  • 193
11 votes
2 answers
3k 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!!
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5 votes
2 answers
5k views

How do I create an offline transaction in java to broadcast via blockchain.info?

Blockchain.info has a PushTX API. How do I create & sign a raw transaction in Java for use in this API? Should I use bitcoinj? Are there any code samples?
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8 votes
2 answers
3k views

How to retrieve the from and to wallet addresses of a transaction?

Given a transaction's inputs and outputs, I'd like to be able to extract the wallet address (or addresses) which sent the transaction, and also the address/addresses that will receive the transaction. ...
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7 votes
1 answer
4k views

How to sign raw transaction given a private key and SHA hash (in java)

I have followed the instructions here to build my own bitcoin transaction. Redeeming a raw transaction step by step example required Currently my code can create a transaction and compute the SHA ...
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  • 73
4 votes
1 answer
3k views

How to create raw transaction

I've started creating my own wallet in bitcoinj and I have serious problem. I want to create raw transaction without wallet object. So I wrote this piece of code: //String to a private key ...
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3 votes
1 answer
2k views

Using bitcoinj to discover peers and download the block chain

I'm sorry everyone, I have looked and stared at the API and I'm coming up with nothing. I've got a public static void main (naturally), but have no idea how to: Connect to the network Download the ...
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1 vote
1 answer
746 views

Does exist some library for decode/encode raw transaction?

I want to parse raw transaction into JSON then change some values and encode back to hex. JSON like this: { "addresses": [ "346vcZZ6QV4nr68fybMEuA7qxxQeyKWoPS" ], "block_height": -1, "...
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  • 31
0 votes
1 answer
783 views

How can i switch from BIP32 to BIP44 using bitcoinj

i am working on a wallet that is using BIP32 for creating Accounts, addresses, xpub, public keys, transaction and etc. but now i want to switch from BIP32 to BIP 44. how can i do this using bitcoinj i ...
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  • 548
6 votes
1 answer
459 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 a ...
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  • 641
2 votes
1 answer
736 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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  • 197
2 votes
3 answers
1k views

How to check if user sent me the BTC?

I am developing JSP web. User will be redirected to another page only if he sends the certain amount of BTC, is there any listener which could check if money arrived to my wallet from the certain ...
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2 votes
2 answers
2k views

how can I hardcode a private key in bitcoinJ - ECKey constructor?

Can someone please explain how to use the following constructor (listed here): ECKey(BigInteger priv, org.spongycastle.math.ec.ECPoint pub) Say my private key is: priv = "L4...5". How do ...
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  • 641
1 vote
1 answer
175 views

Errors when building/sending multisig transactions

Going by the example here: https://bitcoinj.github.io/working-with-contracts I believe I've done everything correctly. Yet my program fails either to propagate correctly or because of a tx error and ...
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  • 13
0 votes
2 answers
1k views

Sign transaction with multiple inputs using bitcoinj/peercoinj libraries

Good day for everyone! I have some troubles with adding signed Input to the transaction. Currently, I'm working with altCoin (fork peercoin) currency. I'm trying build the transaction in the ...
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6 votes
1 answer
612 views

Test Network Genesis Block

I am using BitcoinJ for my java application which fetches the test network's genesis block. I referred to the basics mentioned at JavaWorld and BitcoinJ's Google Code wiki. I am able to get it ...
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5 votes
2 answers
523 views

SPV Bloom filter construction, are false positives taken from the blockchain or just due to 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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  • 1,530
3 votes
2 answers
239 views

Accept payments on someone else's behalf without being able to spend them

TL;DR I wish to store some sort of key in my application for each vendor account that allows for my application to generate a receiving address for clients to make payments to. I am writing some ...
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  • 45
3 votes
1 answer
2k views

How to get hex string from transaction in bitcoinj

I want to use this tool: http://blockchain.info/pushtx to push transaction. I don't understand the input data. It says it is hex string representation. I've read information about that in the raw ...
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3 votes
1 answer
2k views

How can I create a raw transaction in hex format with Bitcoinj?

How can I create a raw transaction when I'm given the input scripts, input indexes, input txids, output script, output address and output amount? The method below works but it requires the method ...
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2 votes
4 answers
1k views

What is the best way to download a "recent" UTXO set snapshot?

I am using bitcoinj to listen for payments. I need a way to maintain the entire UTXO set in a local database. Can bitcoinj be used to download every block (I think it downloads only recent blocks ...
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  • 1,313
2 votes
1 answer
148 views

micropayment channels, n-m addresses, interoperability

I just read bitcoinJ's working with contracts tutorial and I am puzzled as: it seems to me that n-m addresses are implemented in Bitcoinj using plain multisig (as defined in this bit of the developer'...
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  • 641
1 vote
1 answer
85 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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  • 135
0 votes
2 answers
1k views

generate wallet addresses from extended public key

i am trying to generate addresses from Extended Public Key using bitcoinj but can't figure out, how can i possibly do this. i need those addresses for watch-only wallet, those addresses were ...
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  • 548
0 votes
0 answers
230 views

Extract all public keys from blockchain [duplicate]

I want to extract all public keys from the blockchain. Those will probably mostly be keys that have been used to sign transactions. How would I do this?
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