7
votes
Accepted
With Mike Hearn quitting Bitcoin, what seems to be the future of bitcoinj?
Hopefully, bitcoinj will now be maintained by other people that based projects on it. From what I've read and the commit list it seems that Andreas Schildbach, who also initiated the Bitcoin Wallet ...
- 72.8k
7
votes
Accepted
How to sign raw transaction given a private key and SHA hash (in java)
This answer does not attempt to sign a transaction, but simply focuses on successfully calling the sign method of the ECKey class, i.e. making your code work. I am not yet familiar with the ...
- 1,524
6
votes
Accepted
How to retrieve the from and to wallet addresses of a transaction?
Which part / field of the input refers to the hash of the output?
The outpoint contains a txid (32 bytes) and vout (4 bytes), which specify the output you're spending.
This is not the sending ...
- 29.3k
5
votes
Accepted
Encoding my Bitcoin Address with Base58 encoding
Yes.
ECKey key = ...;
String addr = key.toAddress(MainNetParams.get()).toString();
https://bitcoinj.github.io/javadoc/0.12/org/bitcoinj/core/ECKey.html#toAddress-org.bitcoinj.core.NetworkParameters-
- 29.3k
5
votes
SPV Bloom filter construction, are false positives taken from the blockchain or just due to matching with other addresses
Bloom filters are probabilistic, each attempted match you make with it has a specific chance of being a false positive. The rate of false positives is determined by the construction of the filter (how ...
- 15.4k
5
votes
Accepted
How are Lightning network, duplex channels, and micropayment channels related?
Both lightning channels and duplex micropayment channels (DMC) are proposals to create bidirectional micropayment channels, that is, micropayment channels that can be used in both directions (a user A ...
- 1,598
5
votes
How do I sign and send a raw transaction using BitcoinJ?
I'm not an expert in this field by any means (and my error message was different), but I spent last week trying to make Bitcoinj sign a transaction and send in raw form (i.e. without using transport ...
4
votes
How to get senders address with bitcoinj (no duplicate)?
For future reference:
In bitcoinJ (java version) the input/output addresses of transactions are located in TransactionInput and TransactionOutput objects.
For example: for Transaction tx:
List<...
- 41
4
votes
Accepted
How to get balance from a specific address in bitcoinj?
I found the solution for this question. I used this class:
/**
* This class implements a {@link org.bitcoinj.wallet.CoinSelector} which attempts to select all outputs
* from a designated address. ...
- 412
4
votes
How to retrieve the from and to wallet addresses of a transaction?
The scriptPubKey contains the public key used to synthesize the public address. Here are two pedantic approaches, not using bitcoinj, applying bx commands to synthesize the public address of interest ...
- 3,047
4
votes
Problem with full node
From my experience the process of syncing the blockchain is CPU bound, not IO bound (You can check this on Linux by running the top command). bitcoinj has two ways of verifying signatures, either ...
- 1,524
4
votes
Accepted
Why the bitcoin address is not valid in any of the testNet faucet
Testnet uses a different address format than the main network. Testnet addresses start with an "m" or "n".
The address you are using starts with a "1" and is therefore for the main network. This is ...
- 1,598
4
votes
Accepted
How to develop with the Bitcoin cash?
There is a bitcoinj.cash project currently being put together. The code is not ready for use but should be by next week: https://github.com/bitcoinj-cash/bitcoinj
- 56
4
votes
What is the difference between bitcoin core vs bitcoinj vs bitcoind vs bitcoinqt?
bitcoind, and bitcoin-qt are all part of the same program. Bitcoind and bitcoin-qt are both Bitcoin Core and do the same thing except that bitcoind has no GUI. Both are part of the Bitcoin Core ...
- 68.5k
4
votes
convert 12 word seed into 24 word seed
This is not possible.
The mnemonic words are an encoding of the entropy used in the seed, essentially. A 12 word seed has less entropy than a 24 word one, so you cannot get 24 words out of it. ...
- 16.9k
4
votes
Accepted
How can I determine the address from a private key?
Both "1LoVG.." and the other one are valid legacy (1...) addresses made using the same private key. They are different since one of them uses the compressed public key (you might want to ...
- 10.1k
3
votes
Accepted
Verifing the given R/S pair (signature) against a hash using the public key
I suppose you use the BitCoinJ library.
You are not creating a signature the correct way; an ECDSASignature object should be initialized with the ECDSA signature parameters (r,s), not the actual ...
- 146
3
votes
Accepted
Transaction with `OP_RETURN` to a particular address
You can't make an OP_RETURN-based output out to any specific address, since the OP_RETURN opcode marks an output as invalid (thus provably unspendable). In fact, an OP_RETURN-based output will not ...
- 758
3
votes
Accepted
The BTC shows 10^8 times more than what is received in the account
Apparently the app shows the amount as Satoshi (the smallest unit) instead of BTC. For internal calculations that's ok because it avoids rounding errors, but for input and output you should scale by ...
3
votes
Accepted
Sign transaction with multiple inputs using bitcoinj/peercoinj libraries
Good day! Finally I found a solution, I hope it will useful to someone.
The problem was that I tried to sign inputs before adding outputs and other info into transaction. So now I add inputs with ...
- 141
3
votes
Accepted
How to verify a signed message by bitcoin core?
The preimage used when signing messages with Bitcoin Core is a combination of the "Magic" phrase: Bitcoin Signed Message:\n and the Message you are signing. However there is one caveat, being you must ...
- 657
2
votes
Bitcoinj How to create multi-signature address using bitcoinj
you have an exemple in bitcoinj documentation :
https://bitcoinj.github.io/working-with-contracts
Let’s see how to do it:
// Create a random key.
ECKey clientKey = new ECKey();
// We get the other ...
- 1,141
2
votes
Differences between MemoryBlockStore and SPVBlockStore
MemoryBlockStore keeps StoredBlocks in memory and it is used primarily for unit testing.
Whereas SPVBlockStore holds a limited number of block headers in a memory mapped ring buffer. With such a ...
- 146
2
votes
Accepted
Decrypt my private key using KeyCrypter
Attempting to implement the interface KeyCrypter is a worthy exercise but it seems to require more than a few simple lines of code. bitcoinj offers one implementation with the class KeyCrypterScrypt ...
- 1,524
2
votes
how do I get list of all "used" addresses in bitcoinj
This seems to get change addresses:
public List<String> getChangeAddresses() {
List<String> ret = new ArrayList<>();
int issuedKeys = wallet.getActiveKeyChain()....
- 556
2
votes
Get transaction details using bitcoinj library
maybe this helps
private void txHistory()
{
List<Transaction> txx = kit.wallet().getTransactionsByTime();
if (!txx.isEmpty())
{
int i ...
- 548
2
votes
Accepted
Connect to regnet from my WalletAppKit Android app
If you're connecting to a bitcoind regtest node and you're trying to connect as an RPC client to it via bitcoinj, it's possible.
Figure out what your Android's IP address is, say x.y.z.w and use the -...
- 1,337
2
votes
Accepted
how can I hardcode a private key in bitcoinJ - ECKey constructor?
If all you are after is getting an ECKey object for that private key, then Bitcoinj has a DumpedPrivateKey class for just such an occasion.
import org.bitcoinj.core.ECKey;
import org.bitcoinj.core....
- 14k
2
votes
Accepted
How can I create a raw transaction in hex format with Bitcoinj?
Don't build the entire parent transaction, just build the outpoint, which is all that is relevant for encoding a transaction to hex. Specifically use this constructor
EDIT: More specifically, cannot ...
- 1,114
2
votes
How to create raw transaction
Sure :)
My solution was pretty simple:
//String to a private key
DumpedPrivateKey dumpedPrivateKey = DumpedPrivateKey.fromBase58(params,
privKey);
ECKey key = dumpedPrivateKey.getKey();
//...
- 261
Only top scored, non community-wiki answers of a minimum length are eligible