Questions tagged [development]

This tag should be used for questions related to creation and ongoing work for different existing and future Bitcoin-related projects and source code.

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2answers
335 views

How to tell which account an unspent output is in?

When I go to send coins, I want the transaction to ignore the unspent coins in a certain account. I think I can do this in wallet.cpp, but I'm not sure how. Maybe in the AvailableCoins() function? ...
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1answer
153 views

How to best structure Internal bitcoin payments within a webapp?

I'm building out a pet project webapp called CollaboTree, a big part of it is allowing users to set bounties for completing/collaborating on little bits of work. I'd like these micro payments to be as ...
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1answer
282 views

Bitcoin packages

Are there any bitcoin package/librairies in popular langage that would make the recuperation of prices easy ? I have the exemple of the Quantmod package for R that allows you to get market data from ...
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1answer
831 views

Blockchain command line tools

I was under the assumption that the bitcoind server allowed you to query the blockchain and run commands like bitcoind getbalance on any address. I'm finding out that you may query addresses in your ...
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1answer
301 views

What is the incentive behind using platforms such as XDP/Dogeparty?

ELI5: What can one do with XDP that s/he cannot do with DOGE? Is Dogeparty similar to projects such as Ethereum/Ripple? If I understand correctly one receives 1 XDP/1000 DOGE "burned". How are these ...
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1answer
1k views

Get private key from BigInteger

I have a BigInteger that represents a private key. How can I get that private key as a base58 encoded string? The following pseudo code does not work properly: base58.encode(bigInt.toByteArray) // ...
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1answer
145 views

Script for sending funds to a multisig address

Does sending funds to a multisig address require different script than the one used for ordinary addresses? If yes, how should this script look like? (Under multisig address I mean Bitcoin script hash ...
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1answer
218 views

How many bits are in a Bitcoin?

I need to track an amount of Bitcoins in a database. Is a UINT64 sufficient? I'd rather not deal with floating point types, and the rounding errors they end with.
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2answers
83 views

Transaction change calculation

I'm confused about how exactly I should compute a change for transactions. Say, for a given address I have 4 unspent outputs containing 2 BTC each and I want to send 5 BTC to other address. Here's ...
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2answers
218 views

WeaveCoin - Extremely High-Speed AltCoin - Is this Possible? [closed]

I've written a proposal for an extremely extremely high-speed transaction verification algorithm: http://kenthagerman.blogspot.ca/2014/08/weavecoin-high-speed-crypto-currency.html Is this possible? ...
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1answer
210 views

How do cryptocurrency exchanges like Mintpal manage so many?

As there are 100s of crypto coins each with their own QT-client, how do exchanges manage the transactions? Do they use the core client of every altcoin in the servers or will they be programming code ...
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0answers
1k views

Gitian Build Issue - Windows

Got a little issue when compiling Windows QT using Gitian. BTW Im using a Ubuntu 12.04 64bit VPS. So I am using the instructions here : https://cryptocointalk.com/topic/2966-bitcoin-scrypt-v120-...
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1answer
98 views

Other ways to determine the validity of a public key

Public key 3, 4 fits the equation of y^2 = x^2 + 7 Yet this comes up as an "invalid public key". How is that invalid? Sure, it deviates extremely from other numbers, but what other equations are ...
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1answer
392 views

Ripple partial payments

I've read on the Ripple Wiki page for Transactions about partial payments. I am wondering how a partial payment would look when data is polled about an account? Would the transaction amount be ...
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1answer
226 views

How does bitcoind find p2p hosts? [duplicate]

I read the bitcoin references but I can't find a description regarding how bitcoin clients find other host in the p2p network. Would you please tell me?
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2answers
421 views

Modular Inverse for ECDSA in C++

I've seen several variations on "modular inverse" but I can't seem to identify the proper way of utilizing it for C++. I'm not sure how this python code translates into c++: def inverse(x, p): """ ...
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1answer
264 views

Is Block Height 1 is the genesis block?

As the question I asked before, I wanted to make an altcoin. The block height in main.cpp allows you to choose which block gets different rewards. If it does, do txNew.vout[0].nValue = depend on the ...
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2answers
3k views

Got an issue compiling

After working my way through many errors compiling an alt-coin windows qt. Everything compiles fine right until the final stage when the system is putting together the exe. You can find the error ...
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4answers
610 views

Error compiling altcoin-qt for Windows, getting a GCC internal compiler error

I think I managed to get all my dependencies and libraries right (fingers crossed), but now when trying to build blackcoin-qt, the QTSdk compiler gives me this error while building qtipcserver.o: In ...
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1answer
291 views

Programming and the ECDSA equation

I've been implementing point addition into a c++ program I've written but I don't see how this can be done right. When I do slope = (y1 - y2)/(x1 - x2) I get a freaking decimal, which doesn't produce ...
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1answer
409 views

0 Active Connection on my-new-coin

I have compiled my-newcoin-qt and my-newcoind on different platforms (windows, Linux and Mac), with my coin specification based on litecoin. When I run my-newcoin-qt at the first time, I get no error ...
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1answer
165 views

Wallet programming, search transactions by address

This may be a silly question, but I keep running in circles. Using either bitcoind or JSON-RPC is there a way to search all transactions involving a address hash? I understand every wallet and most ...
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2answers
10k views

what programming languages are used to built bitcoin?

I have one very basic question, I would like to know: what programming languages are used to built bitcoin?
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0answers
150 views

Should mining.notify.merkle_branches contain the coinbase transaction or not?

Okay I'm working on a new pool-server though got a question. I'm using litecoin testnet right now to test stuff and here's a getblocktemplate() response I get; { "result": { "version": 2, "...
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2answers
3k views

Bitcoin private key, location on ECC curve

In the ECDSA algorithm, the Bitcoin private key is supposedly a point on the graph (or is it?). But the private key is a single integer, and not x,y coordinates. Is the integer, by itself, the x ...
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2answers
319 views

Does the Bitcoin Core API support high-precision balance display?

I am currently working with a number of altcoins and and I need to support deposits and withdrawals in currencies with very large coin number cap like Dogecoin. I am wondering whether the Bitcoin Core ...
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2answers
690 views

Why don't developers switch from bitcoin-qt to a cleaner implementation?

The "reference client" bitcoin-qt receives a lot of complaints from developers on the messy way it was coded. It seems to require a big overhead to learn, and a lot of time is being spent on ...
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2answers
1k views

Generating Ripple address

I am trying to recreate the Ripple address from Account Family wiki page and I am having some problems. I have the private generator of ...
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1answer
1k views

How does a proof of work limit of `~uint256(0) >> 20` translate into a difficulty of `1 / 2^12`?

In the Litecoin source it is written: static CBigNum bnProofOfWorkLimit(~uint256(0) >> 20); // Litecoin: starting difficulty is 1 / 2^12 How does that compute? ~uint256(0) >> 20 is ...
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1answer
98 views

In what line of what file does the block reward depend on?

I want to make an altcoin and since I am new, I wanted to know what sets the reward of a block after being mined.
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1answer
676 views

Walletnotify under windows

Few questions about Walletnotify under win: 1) Is this the rigt way to write .py script into litecoin.conf: walletnotify=C:\Python27\python.exe D:\LiVe\listener.py %s If not, how it should be ...
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3answers
476 views

Getting sender address, python

Getting senders account Say we got txid by listtransactions: "txid" : "2ca54b92338e52bbb16562dd7a91e8670d9362bb255e21fb568acc13e732b6b7" then getrawtransaction ...
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1answer
1k views

Bitcoin peer to peer network source code

Does anybody know a place to get the source code of the Bitcoin Peer to Peer network? I only need the P2P network portion of the Bitcoin protocol. I am going to implement a new virtual currency. So i ...
2
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1answer
224 views

Why are broadcast checkpoints considered bad?

warren, a LiteCoin dev, said of Peercoin: Good Luck Removing PPC's Centralized Checkpoints Regarding PPC... these amount to empty obfuscating defensive excuses. Sure he wants to remove the broadcast ...
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3answers
365 views

Which altcoins have testnets?

Bitcoin can be run on a public testnet (by using a different port than the real Bitcoin network). This is very useful for development, because you can test software handling Bitcoin without handling ...
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2answers
2k views

How to create a SPV client?

What are the steps a SPV client takes in order to sync? Connect to a peer Set bloom filter for wallet addresses Download all block-headers since latest checkpoint Request every block again with ...
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1answer
464 views

Programming for/modding bitcoin-qt on Windows

In multiple places I've found methods of modifying or adding to the bitcoin-qt(or other coin wallet) source on ubuntu or osx, but how would I do this on a Windows machine? If possible, I'd like to be ...
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2answers
377 views

How can I find out how much bitcoin is in existence with PHP?

I'm running a Bitcoin blog and I'd love to display a ticket of the total amount of Bitcoins in existence. Unfortunately, I'm not sure where I can find a JSON feed for this (now that MTGOX is gone). Is ...
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1answer
378 views

Bitcoin Exchange Api [duplicate]

I need an bitcoin exchange api implemented in my website. Basically there will be one way transactions money->bitcoin and it needs to support major credit cards (visa,mastercard) as well as paypal ...
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2answers
668 views

Bitcoind Performance for production usage

Lets say we have one instance of bitcoind running on the production server. And our exchange software/application interacts with it using RPC callbacks for: address generation withdrawal ...
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2answers
2k views

How do I use Blockchain.info's Receive Payments API with node JS / Express?

Blockchain has great documentation for PHP, but nothing really for node! Does anyone here have any projects,where they used the blockchain.info Receive Payments API, in their node apps, to receive ...
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0answers
238 views

When computing a normalized transaction id, when do I finalize the sha256 hash?

I'm trying to compute the normalized transaction ID so that it matches what is on blockchain.into at the following URL http://blockchain.info/q/hashtontxid/ --- normal TX ID here ---- Given that I ...
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3answers
219 views

So how would someone steal coins from my site?

Nearly every attack I've ever read about has involved bad website coding in one fashion or another. Like that that attack on the Doge wallet site in December, where they allegedly injected the website,...
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1answer
162 views

Can mining puzzles be made socially valuable? [duplicate]

Bitcoin miners work to solve a random puzzle as "proof of work". A huge amount of raw computing power is going into finding the solution to these puzzles, yet the actual solution to the puzzle serves ...
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2answers
1k views

What is the correct Base58 encoding for this uncompressed Public Key RipeMD hash with a zeros in bits 31, 32, or 33?

My understanding is that Base58Checked is always 34 bytes long, and isn't going to be less than 34 bytes even if the first or last bytes of the RipeMD are zero. If this statement isn't true, then ...
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2answers
961 views

What are the differences between the transaction and block versions? (v1, v2, v3, etc..)

If I run command to fetch a block, I see version 2 is returned: getblock 0000000000000000ae22455f90306f43e8c806585fe2dfc3b0e92ac7b7620bff Output { "hash" : "...
3
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1answer
177 views

Mine valid but nonstandard transactions

Is there a way to configure cgminer to accept valid but nonstandard transactions for mining? If not, where, theoretically, would be a good place to look if I was interested in mining nonstandard ...
3
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1answer
178 views

Is there a signature format, or cryptography has *only one* possible S value?

EDIT: This question is not specific to Bitcoin. It's applicable to any other crypto currency that is interested in using a different signature scheme than Bitcoin or the QT reference client. One ...
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1answer
143 views

What parts of Bitcoin (litecoin etc) are Little Endian?

As mentioned on this Hardfork Wishlist, many developers want Bitcoin to be entirely Big Endian for consistency and performance reasons. I'm looking for a concise list of all the areas that Bitcoin ...
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1answer
372 views

What encoding is “pubkey” from the JSONRPC validateaddress command?

I need to convert a public key into a form suitable for use with BouncyCastle. To do this I open the debugger and write: ListAddressGroupings I then pick an address and write validateaddress ...

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