Questions tagged [bitcoinj]

A Java library for processing Bitcoin, stores blockchain headers only

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9
votes
4answers
9k 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 ...
8
votes
2answers
2k 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!!
8
votes
2answers
2k 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. ...
5
votes
2answers
4k 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?
4
votes
1answer
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 ...
3
votes
1answer
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 ...
5
votes
1answer
411 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 ...
5
votes
1answer
3k 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 ...
0
votes
2answers
749 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 ...
5
votes
2answers
471 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 ...
5
votes
1answer
503 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 ...
3
votes
2answers
202 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 ...
3
votes
1answer
1k 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 ...
2
votes
3answers
620 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 ...
2
votes
1answer
1k 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 ...
2
votes
3answers
749 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 ...
1
vote
1answer
125 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'...
0
votes
1answer
661 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 ...
0
votes
0answers
121 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?
0
votes
1answer
503 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 ...