Questions tagged [bitcoinj]

A Java library for processing Bitcoin, stores blockchain headers only

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4
votes
1answer
518 views

What is proofOfWorkLimit?

Look at the code below from android bitcoin wallet: proofOfWorkLimit = Utils.decodeCompactBits(0x1d00ffffL); And look at the code from bitcoin qt wallet: static CBigNum bnProofOfWorkLimit(~uint256(...
2
votes
2answers
1k views

How to build a bitcoinj checkpoint file

How can I build a bitcoinj checkpoint file like the Bitcoin-wallet checkpoints?
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 ...
1
vote
0answers
108 views

BitcoinJ without PeerNetwork

I am writing a system which generates wallets on a per user basis. It must be capable to receive and send payments. So I have to keep the private keys encrypted on the system. Generating the ...
1
vote
2answers
320 views

Does there exist a SPV-client in another language than Java?

The only (active) project I know that implements a full SPV client is BitcoinJ, which is written in Java. Does somebody know if there are any SPV implementations in other languages (like C) too?
2
votes
1answer
275 views

Why do my futures keep getting cancelled using BitcoinJ?

I am trying to write an application that queries bitcoin nodes for the results of a particular transaction. I am attempting to imitate FetchTransactions.java, one of the examples that comes with ...
11
votes
6answers
1k views

Accepting Bitcoin payments on my website using bitcoind? Many questions… no apparent answers

I am trying to design a system that lets me accept Bitcoins on my website. I would like to use bitcoind, or bitcoinj. However, I have many questions regarding this setup. FYI, I already read similar ...
1
vote
2answers
467 views

BitcoinJ encrypt message

I came across this in the source code for ECKey.java: "Represents an elliptic curve public and (optionally) private key, usable for digital signatures but not encryption." Why can you not encrypt ...
1
vote
1answer
593 views

BitCoinJ custom transaction

I'm trying to learn a few things about the API. I've managed to send coins on testnet via wallet.sendCoins(Peergroup,Address,BigInteger) so I don't think I have a network problem. Here's what I'm ...
3
votes
1answer
213 views

In bitcoinj, why is MemoryBlockStore not used by default?

My understanding of bitcoinj is that it is used to implement a "thin client" that doesn't store the entire blockchain- just the headers. When I use the WalletAppKit, it creates a file "default....
3
votes
0answers
142 views

Does a bitcoinj SPV node forward transactions for itself?

The bitcoinj library offers a rather convenient WalletAppKit class, which I'd like to accept payments from customers. In order to facilitate the payments I'd offer the customers to send the ...
2
votes
0answers
192 views

DnsDiscovery vs SeedPeers in bitcoinj

First look in screenshot number one of davlik debug monitor server after running Bitcoin Wallet: http://piccy.info/view3/5090102/7074a1d99a96e67bdbea36a04073c21f/orig/ I suppose, that is normal work ...
3
votes
1answer
2k views

Creating Base58 public key & private key in Java?

How can I create a base58 private key and public key in Java? I'm pretty familiar with Java and I have the bitcoinj-minimal code, but it's not clear to me how I can generate a base58 key pair from the ...
1
vote
1answer
19k views

How to use my own web hosting server to mine a bitcoin? [duplicate]

I have a web hosting with unlimited bandwidth and unlimited disk space, Cpanel and much more. Can anyone guide me. How to mine a bitcoin by using my own web hosting?. Then there is any mining software ...
0
votes
1answer
125 views

BOP: Not authorized to receive from the temporary destination

I'm trying to run my own BOP (BitsOfProof) server and connect to it. I appear to be able to connect, but I am unable to execute any commands. I am connecting with the following: ...
1
vote
2answers
2k views

Security advise on setting up a gambling Bitcoin site

I have written a Bitcoin gambling site and am planning on the best approach to host it/manage it securely. The site is implemented in Java using the BitcoinJ API and servlets etc are handled via the ...
5
votes
2answers
533 views

What is the difference between bitcoinj and BitsOfProof?

bitcoinj is a bitcoin library, bitsofproof is a full server (standalone 'exe'). Beyond the above - can anyone elaborate on the difference between them? What problems they were designed to solve, ...
6
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2answers
2k views

Tutorials for BitcoinJ

Beside the examples that come with BitcoinJ and the documentation on Google Code, does anyone know of any tutorials for using BitcoinJ?
3
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 ...
1
vote
1answer
983 views

How to receive transaction in bitcoinj wallet

I am a real noob with bitcoin and bitcoin. I have a lot of questions and I don't know where to start. Let me try. I have a bitcoin-qt client and I downloaded the chain (took me one day) and now I am ...
0
votes
1answer
450 views

Open bitcoin-qt wallet with bitcoinj

I try to open the bitcoin-qt wallet with bitcoinj, I write this code: private static final File WALLET_FILE = new File("C:\\Users\\Bapt\\AppData\\Roaming\\Bitcoin\\wallet.dat"); public static void ...
2
votes
0answers
248 views

Bitcoin-qt database for BitcoinJ downloadBlockChain()

I am using bitcoinJ to develop a bitcoin based payment module for my project. I have the complete block chain downloaded/in sync with the network on the bitcoin-qt client. Is there a way I can use ...
5
votes
1answer
2k views

How to run Bitcoinj on Heroku?

Does anyone know where I might find a tutorial on how to deploy a bitcoinj server (essentially a replica of a bitcoind server with an rpc API) on Heroku?
5
votes
1answer
533 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
235 views

BitCoinJ for Cloud based application

I am currently working on a cloud based project that will be accepting payments using bitcoins. I intend to use BitCoinJ to handle the payment. Unfortunately the only help I am able to get is from the ...
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?
10
votes
3answers
2k views

Getting balance/downloading blockhain with bitcoinj

I am playing around with bitoinj and I can't seem to even get the most basic functionality running. What I want to do: I have one wallet with one address. I want to dowload blockchain and from that, ...
5
votes
1answer
738 views

Load a transaction with bitcoinj

I am developing simple Bitcoin application using the bitcoinj library: The user enters the hash of a transaction and my application should return detailed information about that transaction. How can ...
9
votes
4answers
10k 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 ...
2
votes
1answer
581 views

How to get destination address from bitcoinj TransactionOutput?

I believe TransactionOutput represents one of the outputs of a transaction. I have a list of such output objects, and a String that represents my own address. I would like to check that this output ...
6
votes
1answer
688 views

How do I generate offline transactions in Java?

I'd like to develop a Java binding to the Stratum Overlay Network (a server for thin clients). This requires signing on offline transactions. Can I directly use bitcoinj's API to do this? Can I copy-...
4
votes
1answer
289 views

How can you find how many keys you wasted in bitcoinj?

Supposed you create a new wallet and pre-populate it with 100 keys (so you don't need to back it up after each transaction). How do you know, given an instance of Wallet, which keys have been "used ...
12
votes
2answers
4k views

Java library for Bitcoin Client Application

are there Java libraries for Bitcoin available to develop client applications?

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