Zergatul
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Transaction Malleability in the blockchain
7 votes

Here is example: https://blockchain.info/tx/683f45578328242a06bc5c54acbcbe6e70a5435b4561fc8b0570a59ab09f8bfa?show_adv=true Look at first input script in raw: ...

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What is the format of the coinbase transaction?
7 votes

Look at block #280963. Look at coinbase transaction d1c6b8...fd08. You can see CoinBase data: ...

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How many characters you need to mistype at minimum to get another valid address?
5 votes

Check sum is a result of 2 hash-functions: SHA256 and RIPEMD160. The length of checksum is 4 bytes. Hash functions are indistinguishable from random oracle, so it is possible, if you make 1 mistake in ...

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How can all possible numbers in 256-bit space be squeezed into 160-bit space?
Accepted answer
4 votes

It's really 160 bit hash (RIPEMD160) of an already hashed (SHA256) public secp256k1 elliptic curve key. And yes, on the average, every address has about 2256-160=296 pairs of private/public keys.

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How to convert a transaction into hex before using the sendrawtransaction API?
Accepted answer
4 votes

You cannot convert json string to hex representation. Transactions have their own binary format (you can read in wiki: https://en.bitcoin.it/wiki/Transactions). To create transaction in hex format, ...

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Bitcoin Address generation
4 votes

Use must use SHA256 on array of bytes, not on a hex-string representation.

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How does difficulty is defined for block '55798'?
Accepted answer
3 votes

How to calculate difficulty from Bits fields (which is stored in block). Convert value to hex: bits=471067731 -> 0x1c13ec53 Split hex value, take 8 high bits (0x1c), and 24 low (0x13ec53) Use ...

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How to fully decode a coinbase transaction?
3 votes

coinbase, scriptPubKey, scriptSig - they are all scripts. You can read in wiki about how to decode script https://en.bitcoin.it/wiki/Script. Coinbase can contain any data, even invalid script. But ...

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Bitcoin QT Rpc Transaction date format
Accepted answer
3 votes

This is a Unix date format. As I understand, you are using c#, so it will be look like: public static DateTime FromUnixTime(uint time) { return new DateTime(1970, 1, 1).AddSeconds(time); }

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Does a bitcoin node broadcast that it is full synced?
Accepted answer
2 votes

No. The nodes notify only about block height in the beginning of connection in version message. When node wants to notify about new block/tx it received/created, it uses inv message. There is no ...

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Why is the target truncated?
Accepted answer
2 votes

Target is stored in block header (it's called Bits), and it takes only 4 bytes. We derive target 256-bit value from these 32 bits. That's why it is getting truncated. There is no need to store all ...

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How can I find the coinbase transactions where the bitcoins involved in a transaction were created?
2 votes

If you have running bitcoin core, you can use JSON RPC and any programming language you want. getrawtransaction <txid> decoderawtransaction <hex> Second call will return all inputs of ...

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Why on bitcoin client sender address is 'undefined'
Accepted answer
2 votes

Yes, it is possible. You can use getrawtransaction <txid> and decoderawtransaction <output from getrawtransaction>. For example: getrawtransaction ...

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Can someone explain to me how do you read the blockchain.info transaction data?
2 votes

Bitcoin addresses on the left are valid addresses from wallet, someone has private key for them. Bitcoin addresses on the right can be any addresses, even addresses, that nobody has private keys for ...

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Proof of address ownership
1 votes

I opened random transaction for this example: https://blockchain.info/tx/c929454d6c83c15ecd9931c005a5a7fbacb1faba69f0a49538ab334d2848c5a1 Input scripts: ScriptSig: PUSHDATA(72)[...

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Duplicate ANY transaction from Bitcoin to Bitcoin Cash.. is it possible?
1 votes

No, transaction will not be approved. There are differences in transaction format. Transactions are not valid between 2 forks.

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Why there is only 8 peers in bitcoind?
Accepted answer
1 votes

You should check if port 8333 is open. If port is closed from internet, bitcoin client will make only 8 outgoing connections. maxconnections parameter works only for incoming connections.

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How to make a "Donate" function with bitcoins?
Accepted answer
1 votes

You can just take any existing receiving address or create new one. Any address can accept unlimited transactions count. Bitcoin clients generate new address every time you want to receive for ...

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Why is it so that if some bitcoin is spent by any user, the rest of his account's amount should also be spent and paid him back?
1 votes

Because on the lowest level of bitcoin protocol there is no accounts. There are scripts inside transaction. The most common script says: show me public key, I will compute Hash160 of it, compare with ...

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Blockchain API Bitcoin transaction list to a wallet
1 votes

Transaction has inputs and outputs. "value" is Satoshi count: "inputs":[ { ... "prev_out":{ ... "value":461323, ... }, ... } ], ... "out":[ { ... ...

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send btc from specific input without running bitcoind
1 votes

You can implement your own very light bitcoin client. It should support version and tx messages: https://en.bitcoin.it/wiki/Protocol_documentation So, you make TCP connection to any bitcoin node with ...

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How to use Bitaddress.org and Blockchain.info with Testnet coins?
1 votes

https://en.bitcoin.it/wiki/Technical_background_of_version_1_Bitcoin_addresses - you can read about how to generate adresses by yourself. You can also use getnewaddress RPC command to generate a lot ...

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Why I cannot get transaction from genesis block
Accepted answer
1 votes

I found answer to my question there: Why can’t the genesis block coinbase be spent? For some reason, Satoshi decided not to add the coinbase transaction from the genesis block to the global ...

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What is the bitcoind command to see how much btc a specific address has?
1 votes

There is no such command. Addresses are like a superstructure over a bitcoin transaction processing. Client does not maintain index with addresses and balances on them.

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Is the asymptotic performance of bitcoin O(n) relative to the block chain length?
Accepted answer
0 votes

You have to traverse entire blockchain. At the lowest bitcoin level there is no accounts, there is concept of "unspent output". Bitсoin clients (excluding light versions) should support index of all ...

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If bitcoin have a 21 milion limit...what happens with the lost bitcoins?
0 votes

Total bitcoins amount will never reach 21 milion, it will continue to approach the limit closer and closer. You can check wiki page for the details: https://en.bitcoin.it/wiki/Controlled_supply About ...

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Check if received bitcoin are in blockchain/not pending without a transaction id
0 votes

I guess exchanger does not give you txid because of transaction malleability. Someone can change this id. It is enough to check the receipt of the Bitcoin amount in a unique account. Third party ...

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How to measure TX confirmation latency
Accepted answer
0 votes

Use can use command getrawmempool from bitcoin-qt console (or through JSON-RPC). This command shows all transactions, that are not confirmed yet. You can run this command every second, and save the ...

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What would happen if you send bitcoins to a non-existent Bitcoin address?
0 votes

I want to note. There is about 2^256 valid private keys. But there is only 2^160 valid addresses. Hash functions are used to convert public key to address. So, it is very-very likely, that for any ...

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