Questions tagged [java]

Java is a programming language.

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1answer
31 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 ...
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1answer
58 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 - ...
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1answer
21 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'...
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2answers
73 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 // ...
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1answer
51 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, ...
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0answers
60 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: ...
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1answer
55 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
63 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 ...
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0answers
107 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- ...
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1answer
409 views

How to sign rawtransaction with private key

How to sign raw transaction with private key. this is my raw transaction : ...
3
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1answer
144 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 ...
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1answer
107 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 ...
2
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1answer
34 views

How to convert from Ardor time to Unix time?

What is the best approach to convert from Ardor time to Unix time?
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1answer
372 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 ...
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0answers
49 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 ...
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1answer
414 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, ...
0
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1answer
102 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 ...
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1answer
180 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 ...
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1answer
373 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
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0answers
244 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 ...
3
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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
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1answer
365 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 ...
2
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1answer
91 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 ...
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1answer
140 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 ...
2
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1answer
546 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? ...
1
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1answer
266 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 ...
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1answer
744 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
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1answer
93 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: ...
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0answers
255 views

List of crypto currencies built with java?

Is there a list of crypto currencies that was built with Java?
2
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2answers
696 views

How to find ripple faucet coin for development

I'm developing an app with ripple. I need some faucet coin for ripple. How can I find it?
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2answers
714 views

How do i parse the zeroMQ messages in java?

This is the code that i have. I receive messages from the zeroMQ however a hashtx message for example looks like this --> "hashtx �����v����|(8d �!��v��&�-�k�". Any help in turning that into a ...
3
votes
1answer
2k views

Get Historical Bitcoin Prices on GDAX in CSV Format

I'm looking for minute by minute historical Bitcoin price data for the past year in format: time, open, high, low etc. I code in Java and I'm not familiar with other programming languages (such as ...
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2answers
140 views

Code example for Ardor bundler code snippet to filter transactions of a certain criteria to pay ZERO 0 ignis Fees?

I'm looking to write a custom Ardor bundler to only bundle transactions that have the following properties: Bundle transactions that are being sent to a specific account only. Bundle transactions ...
0
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1answer
257 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 ...
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2answers
102 views

Unable to execute getwork logic in java

I was going through this post in stack exchange How can I code a Bitcoin JSON-RPC “getwork” request in Java? I tried to write a simple snippet for just the getwork json rpc. public static void ...
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1answer
490 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 ...
2
votes
1answer
702 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 ...
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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....
2
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3answers
1k views

Convert between String/Hex/Byte in Java for sha256 - wrong format?

I am trying to convert a bitcoin address and have the following code from here (Calculate Segwit address from public address, 2nd answer): Step1: $ printf 1L88S26C5oyjL1gkXsBeYwHHjvGvCcidr9 > adr....
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vote
1answer
1k views

Java: Base58-encode String

I would like to Base58-encode this String: 56379c7bcd6b41188854e74169f844e8676cf8b8 My current Java code looks like this: String test9 = "56379c7bcd6b41188854e74169f844e8676cf8b8"; byte[...
0
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1answer
148 views

GDAX Java Bad Request

Trying to request private data on GDAX but keep getting bad request. Cannot figure out what I am doing wrong. Please help. private static JsonObject getAuthenticatedData() { try { ...
0
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1answer
139 views

how to convert URI into Bip21

i am trying to convert the URI into BIP21 currently i am generating URI from bitcoinj library, but i want it to be on BIP21 Standard. i have read many articles but didn't found any solution
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1answer
261 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 ...
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2answers
969 views

JAVA JSON-RPC for Litecoin

I am looking for Java Json-Rpc for Litecoin or any implementation for Litecoin
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1answer
491 views

How to generate xPub Key from public key in java

I am working on a Bitcoin Wallet, i have public key but can't figure out how can i genrate xPub key from this.
1
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1answer
1k views

Java: way to convert a 256-bit private key to WIF?

I have a question concerning Java and sha-256. I try to do these steps discribed here to create a WIF key: https://en.bitcoin.it/wiki/Wallet_import_format step: String string = "...
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0answers
370 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....
1
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1answer
205 views

OP_ADD operation in bitcoin script for integers greater than 128 in java

I want to execute a simple series of instructions to implement a bitcoin script in java using bitcoinj API. All I am looking for is performing arithmetic operations for negative integers or integers ...
3
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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 ...
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0answers
119 views

How return transaction hash from wallet to android app after payment?

Scenario: I have my android app where customers can pay by bitcoins. For this I created intent with uri like: bitcoin:[address]?amount=.. and using startActivityForResult it opens wallet with ...