Questions tagged [java]

Java is a programming language.

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2
votes
1answer
608 views

How to sign a transaction using BitcoinJ

I am having problem signing the transaction using BitcoinJ library without the Wallet instance, I only have the Transaction class instance and the ECKey in order to sign the transaction. Is there a ...
5
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1answer
531 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 ...
0
votes
2answers
24 views

How to verify signature in java using message and public key?

I was trying different things to verify the signature but couldn't succeed. I have got the following: message in string or decimal array (ASCII code for each char) public key in decimal array (which I ...
1
vote
1answer
532 views

can i use one Mnemonic Code to create both(TestNet and MainNet) wallets

currently i am using bitcoinj library to create wallet for both Main-net and Test-net using Mnemonic code(Mnemonic Code is different for both), my question is can i create both Wallets(Test-net and ...
0
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1answer
259 views

GDAX Java Limit Order (HTTP Post)

Trying to send HTTP Post request to GDAX with auth. The 'GET' requests work fine and I'm unsure if I am passing the json params correctly as I keep getting Bad Request. private static JsonObject ...
1
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1answer
559 views

How to sign rawtransaction with private key

How to sign raw transaction with private key. this is my raw transaction : ...
0
votes
1answer
34 views

Error message still returned after transaction was indeed broadcast

I use bitcoinj to create the following method to broadcast a raw transacion in testnet, and I did see on bitcoin explorer that it has been broadcast. But even the transaction has been already ...
1
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1answer
286 views

Why does my implementation of hex to Base58check produce different results than the example?

Step 8 of this wiki page gives this hex value: 00010966776006953D5567439E5E39F86A0D273BEED61967F6 Step 9 converts it to this base58 string:16UwLL9Risc3QfPqBUvKofHmBQ7wMtjvM I'm trying to implement ...
1
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1answer
267 views

Is there anything I can do to speed up the synchronization of litecoinj?

I am using litecoinj which is forked from bitcoinj but compared to bitcoinj, the wallet creation and block synching is slow when using litecoinj. So, I searched for a solution and found a post that ...
3
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1answer
1k views

Building Signed Bitcoin Transaction in Java

I have been attempting to build my own raw transaction generator in Java which I can then broadcast on the testnet network. The problem is when I attempt to broadcast the transaction it says there is ...
0
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0answers
11 views

Fail to sign the Segwit Transaction's input in bitcoinj

I want to spend from a segwit address and it has a P2WPH script, I created this transaction just like creating a normal P2PKH transaction, but just changed the address of the input to the segwit ...
1
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0answers
26 views

How to sign a 2-of-2 multisig address?

I want to implement 2-of-2 multisig in bitcoinj, and I implement the methods which are used to sign the first time and the second time. But there is a bug that using the same key for the first signing ...
5
votes
1answer
327 views

How to build Merkle root from merkle branches?

Is there any help/tutorial on how to build the Merkle root from stratum data? The Slushpool's stratum protocol has an example of a mining job but it does not contain any Merkle branches and I don't ...
0
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1answer
44 views

How can Server-less communication take place between clients?

I was thinking to design a application which is not dependent on server and can directly send and receive data to and from other clients.I learned it is possible with UDP but how can new users join in ...
-1
votes
1answer
80 views

Standalone Java Bitcoin Miner - Does it Exist?

I am a java developer, and currently am looking to create a standalone java class that will let people mine Bitcoin using CPU, but I have no idea if such already exists. I have found one for LiteCoin, ...
0
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2answers
113 views

Verify Bitcoin Transaction

Following the great post [Redeeming a raw transaction step by step example required, I came up with code below but the verification failed. // pubkeyBytes, len: 65 // ...
1
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1answer
135 views

How to verify a signed message in Java?

I want to verify, in Java, a signature produced with bitcoin core's signmessagewithprivkey (equivalent to the verifymessage). I noticed a bitcoinj method similar to the bitcoin core's verifymessage - ...
0
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1answer
22 views

what are the dangers of transfering bitcoins between addresses?

So I heard stories about people losing bitcoins because their wallet didn't support a cerain feature.. or bitcoins getting sent to wrong address etc.. how does that happen? As a software developer I'...
1
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2answers
1k views

JAVA JSON-RPC for Litecoin

I am looking for Java Json-Rpc for Litecoin or any implementation for Litecoin
1
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0answers
71 views

How to sign an Altcoin transaction manually with 2 inputs and 2 outputs

So i'm working with the altcoin denarius which has the following raw TX structure. This is a transaction I am try to sign: Original: ...
0
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1answer
75 views

Bitcoin Signature Verification

I am trying to implement the OP_CHECKSIG opcode of Bitcoin and verify whether a signature is valid or not. I have the signature that I recieve from the transaction data and the public key(the hex ...
0
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1answer
106 views

How to sign Bitcoin transactions using JCE?

I need to sign Bitcoin transactions using JCE primitives(no bitcoinj), but my signatures are not considered valid by bitcoinj. I tried to simulate this process. I created a random hash and signed it ...
0
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0answers
173 views

How can I generate public address from an xpub key in Java?

I have an xpub key with which I want to generate all addresses which have been used or will be used and then find out the keys which have balance. Here's a sample xpubkey with balance- ...
6
votes
1answer
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 ...
7
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8answers
6k views

How to communicate between Java and bitcoind?

I am having problems communicating between Java and bitcoind - every JSON RPC library I try has some issues. Can anyone provide a working implementation of even the most basic JSON RPC communication ...
3
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1answer
182 views

ECDSA signature with r value of 31?

occasionally on Android we are generating an ECDSA signature. This turns out to have a "r" length of 31 bytes. Is that valid? For reference here is a nice diagram outlining the ASN.1 structure of ...
1
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3answers
1k views

How to get compressed public key with ECKey

Here some java code. What i need to change to get compressed public address in getPublicAddress? import com.google.bitcoin.core.Address; import com.google.bitcoin.core.ECKey; import com.google....
1
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1answer
116 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 ...
1
vote
1answer
457 views

Bitcoinj wallet can't receive coins in Testnet3

I have a problem with bitcoinj. I have created a wallet and than trying to send coins to it in Testnet3 using this faucet: https://coinfaucet.eu/en/btc-testnet/ Coins sended, transaction confirmed, ...
1
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0answers
51 views

Bitcoinj Spend from a address directly without wallet

I am stuck trying to send coins from arbitary privateKey in bitcoinj. How can I make the following function work without using the Kit or Wallet classes? @Override public String transferCoin( ECKey ...
2
votes
1answer
36 views

How to convert from Ardor time to Unix time?

What is the best approach to convert from Ardor time to Unix time?
0
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1answer
100 views

Cancel pending transaction (bitcoinj)

I'm using bitcoincashj (https://github.com/bitcoinj-cash/bitcoinj) I created a transaction and sent it. But it didn't broadcasted to network. Can I cancel this transaction? Current wallet status is: ...
2
votes
1answer
94 views

Handling fees and setting them

Im trying to get the estimation of how much the fees will be when a final amount is decided on. I would say im getting familiar with bitcoinj but not completely with java so im still learning how to ...
0
votes
1answer
490 views

How to create ECPoint from raw private key

How to create a bouncy castle ECPoint from a raw private key hex string? I am getting a private key using the 'dumpprivkey' RPC and removing the header byte and the 4 bytes of checksum + 1 byte of ...
0
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1answer
110 views

Can't see balance after some time

I'm trying to use bitcoinj library to receive bitcoin payments and monitor the balance on the address. My implementation is based on DeterministicKey watching public key. The code below is working ...
1
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3answers
3k views

Get uncompressed public key from compressed form

A similar question has an answer in Python which links to the bitcointalk forum: How can I get the uncompressed public key from the compressed public key in openssl? https://bitcointalk.org/index.php?...
3
votes
1answer
1k views

How to develop with the Bitcoin cash?

I have a simple wallet created with the BitcoinJ. I can create the address, track the transactions, check account balance etc with the wallet. I would like to extend the wallet for the Bitcoin cash ...
0
votes
1answer
386 views

WalletAppKit creates an address every time Bitcoinj gets initialized

I'm implementing an app using BitcoinJ, but every time I run the code, a new address is created. Is there any way to work with the very first address that was created and stop creating new addresses? ...
4
votes
1answer
5k views

Generating an address from a private key in Java?

I'd like to write a function in Java that takes a private key and generates the address to use in a QR code. I'd like to make this , but I'm not very good with the hashing algorithms. I've checked ...
0
votes
1answer
193 views

Problematic Digital Signature with SECP256K1

I am trying to test out TestNet3 and I have a keypair generated using Java crypto library. The private key is 23F847360E1EB348A212F443C633058080A8EB9F05AD132F8B82D51FE672EADD and the public key is ...
2
votes
0answers
258 views

Broadcasting signed transaction from Watching wallet using bitcoinj

I am working with watching wallet and Offline wallet using bitcoinj, I created Watching Wallet using tpub key of Offline Wallet I am receiving payment on watching wallet Fine, now I want to ...
1
vote
1answer
433 views

Java mining solution

I am a beginner in mining algorithms and I have a general question regarding the mining using Java language. Does it make sense to use Java to develop for example ETHASH algorithm (or any other) and ...
2
votes
1answer
587 views

how to create Watching Address from available xPub key

Watch-only wallet can only receive payments but not spend the available coins. I am using bitcoinj (in Java). Can anyone please tell me that How to create watching addresses from available xPub key? ...
0
votes
1answer
835 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 ...
2
votes
1answer
761 views

How to create an offline wallet on Android only to sign transaction

I am new to bitcoins, I want to create an offline wallet on Android, to scan transaction QR code from online Desktop wallet, Sign that transaction with private key on my offline wallet. 1 Creating ...
0
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1answer
398 views

How to use Signed Hash to Send Coins in bitcoinj

I am very new to bitcoinj library. I am using 0.14.7 version of bitcoinj and developing my own application in java. I have created a watch-only wallet by using the tPub of the Offline wallet. Upto ...
3
votes
1answer
1k views

Bruteforce bitcoin address - I know the words + public address but not the order

I have a long list of 1million+ permutations of a 12 word BIP39 seed. How can I try them all on a bitcoin address? edit: I know the address and the 12 words but i don't know the order of the words
1
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0answers
372 views

Block chain receive payment api not working

I am building a little online app to accept bitcoin payments in my website. I have a blockchain.info wallet and I am following their Receive Payments Api, which can be visited here: http://blockchain....
0
votes
1answer
1k views

Bitfinex api v2 not returning candles

I am using bitfinex websockets v2 api in a Java application, to get the candles from a market. But I don't get any message back from the socket(not even an error). I wonder what I am doing wrong. Also ...
0
votes
1answer
147 views

connect watching wallet with blockchain

i have created watch wallet Wallet wallet = Wallet.fromWatchingKeyB58(params, tPub, DeterministicHierarchy.BIP32_STANDARDISATION_TIME_SECS); How can i link this with block chain i am using ...