A Java library for processing Bitcoin, stores blockchain headers only

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How to extract the signature of a transaction using bitcoinj

I am trying to extract the signatures from a transaction. What is the best way to do this given a com.google.bitcoin.core.Transaction object I just received from the network?
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1answer
48 views

How to manually disconnect a peer from peergroup?

Here is my code. params = TestNet3Params.get(); blockStore = new MemoryBlockStore(params); chain = new BlockChain(params, blockStore); chain.addWallet(newwallet); final ...
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1answer
72 views

How do we verify the signature on a raw transaction using Bitcoinj?

I managed to create a raw tx using Bitcoinj but not able to figure out how to verify its signatures. Assuming I know the addresses corresponding to the (supposedly) unspent outputs used as inputs to ...
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1answer
25 views

In BitcoinJ, do I need to run downloadBlockChain() again after adding a new key?

I added a Wallet instance to PeerGroup instance and executed downloadBlockChain() method. Now if I add a key(s) to that wallet, do I have to execute downloadBlockChain() again to get a current balance ...
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178 views

java.lang.NoClassDefFoundError: Could not initialize class com.google.bitcoin.core.Block when dealing with Bitcoin address

I have a private key bigInt of type bigInteger and I would like to generate the address corresponding to this private key. I implemented the following function public String get_address () { Address ...
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1answer
78 views

Sending bitcoins to same address

I am using the BitcoinJ API to create my wallet. When I create a transaction, I provide the change address to which change should be sent. For example: let there be 1 bitcoin at address A; then I ...
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0answers
46 views

BitcoinJ seems to be calculating balance incorrectly

My application is using bitcoinj-0.11.3. I am using Wallet.getBalance(balanceType) to read wallet balance. For AVAILABLE I get 8.94106037 This is supposed to include all confirmed transactions. For ...
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1answer
34 views

In BitcoinJ, what is the purpose of Peer?

In BitcoinJ, there is PeerGroup and Peer. I understand there are differences such as one is related to a group of peers while other is related to a single peer. When should I use which construct? ...
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1answer
102 views

Bitcoinj always gets 0 balance

I am trying to use Bitcoinj for my app. I am using regtest mode. I have a balance of 42 BTC on my account: bitcoin-cli -regtest getbalance mirko3 -> 42.00000000 My code follows: public class ...
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1answer
50 views

Key exported from BitcoinJ is different from the key shown by bitcoind

I am quite new to Bitcoin. I am trying to use Bitcoinj with regtest mode. I have created the following application: public class TestBitcoinj { private final static BigInteger ONE = new ...
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1answer
34 views

How to export bitcoinj wallet

I am working on an app which uses bitcoinj. I want to implement export/import functionality to a standard format which can be shared with as many as possible wallet apps. Is there a standard format ...
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49 views

bitcoinj, unknown confidence level

I've got a bitcoin address A with its relative encrypted key K stored in a persistence storage. I am launching bitcoinj through the WalletAppKit class and calling awaitRunning to wait for the ...
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1answer
58 views

How to find a block containing a transaction using transaction hash only?

Well, the title says it all. I have a transaction hash and I want to find this transaction in the blockchain. I am working with bitcoinj. I am probably missing something very obvious here, but I ...
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1answer
96 views

How to get senders address with bitcoinj (no duplicate)?

I am using bitcoinj (java implementation). I have read many answers here but none of them answers my question. How to get senders address using bitcoinj? I have transaction variable tx. I can get ...
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0answers
44 views

multiple wallets in bitcoinj ?

Is there a possibility of using multiple Wallets, that are running synchronous in Bitcoinj? I've alredy tried to use several WalletAppKits but this does not work.
2
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3answers
103 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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0answers
158 views

Howto partially sign a multisig rawtransaction with BitcoinJ?

I am trying to partially sign a 2of2 transaction which I created in bitcoind. Unfortunately I am not seeing a valid raw output after signing. The expected raw output is: ...
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0answers
54 views

Can't broadcast transaction

I am trying to create android wallet for some cryptocurrency (litecoin similar). My altcoin wallet is based on bitcoinj-0.10.1. Everything works except transactions broadcast. There are logs from my ...
2
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1answer
73 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 ...
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1answer
425 views

How to build a bitcoinj checkpoint file

How can I build a bitcoinj checkpoint file like the Bitcoin-wallet checkpoints?
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1answer
268 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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0answers
57 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 ...
0
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2answers
139 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 in Java. Does somebody if there are any SPV implementations in other languages (like C) too?
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1answer
122 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 ...
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6answers
550 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 ...
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2answers
121 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 ...
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1answer
113 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
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1answer
112 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 ...
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56 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 ...
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0answers
98 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
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1answer
420 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 ...
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1answer
5k 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
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1answer
88 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
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2answers
1k 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
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2answers
351 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
709 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?
2
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1answer
223 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 ...
0
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1answer
309 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
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1answer
257 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
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0answers
156 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
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1answer
567 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?
2
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0answers
275 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 BitCoins Google Code wiki. I am able to get it running ...
3
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1answer
123 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 ...
4
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2answers
1k 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?
6
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3answers
845 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, ...
4
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1answer
208 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 ...
7
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3answers
4k 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
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1answer
322 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 ...
5
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1answer
491 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 ...
4
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1answer
258 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 ...