We start creating a new transaction which we hash and sign.
Add four-byte version field: 01000000
One-byte varint specifying the number of inputs: 01
32-byte hash of the transaction from which we want to redeem an output (reverse order): be66e10da854e7aea9338c1f91cd489768d1d6d7189f586d7a3613f2a24d5396
Four-byte field denoting the ...
Sequence numbers aren't shown on the Bitcoin Block Explorer HTML pages because they are not used by the network currently. Non-default sequence numbers would be shown on raw block/tx pages, but I'm not sure whether this has ever happened.
Sequence numbers are intended to be used for replacement. Replacement is currently disabled, but how it would work is:
This is a fun little puzzle on the blockchain, basically. First, you need to know a little about pdf's and how they're structured, which you can find here.
Second, you'll note from section 3.4.1 that all pdf's start with this string:
In hex, that is 255044462d. And indeed that is in the very first output in the very first bare multisig pubkey:
Note that the accepted answer is outdated.
Currently, sequence numbers are mainly used for signaling RBF - replace-by-fee - that allows you to resend a transaction with a higher fee.
See https://bitcoincore.org/en/faq/optin_rbf/ , https://github.com/bitcoin/bips/blob/master/bip-0125.mediawiki
I am developing the ccxt cryptocurrency trading library, check it out on GitHub:
It is a library for cryptocurrency trading and e-commerce with support for many bitcoin/ether/altcoin exchange markets and merchant APIs.
With it you can access market data and trade bitcoin, ether and altcoins with more than 70 (!!!) ...
Current market depth available at
All trades which happened in the last 24 hours available at
Retrieves 100 trades that happend after specified transaction
A script is required to retrive ...
This guy wanted to do the same thing. You can find a solution there.
get a Linux Box/VM with >=8GB RAM
run "./parser allBalances -w 250000 >allBalances.txt"
the parser run take around 2 minutes on my vSphere VM (2x3Ghz Xeon, 16GB of RAM)
now you have a list of the top 250.000 adresses ...
You have two options here:
Check out one of the data providers online. Quandl offers (mostly) free historical data for a variety of pairs and exchanges. Alternatively, if you have bucks to spare, Coinigy offers high-quality data sets on a per-month pricing model.
Roll your own data crawler, using a programming language of your choice and the ...
then you have 25 letters in base58, and that's like 17 bytes.
So, you have to pay like 0.0001 BTC for the transaction fee, and after that you can add data to that transaction at a price of 17bytes per 1 satoshi, by sending satoshis to many addresses that contains the whole data. Imagine if we could store data there forever,.. and ...
Found the data on crypto compare
const endpoint = 'https://min-api.cryptocompare.com/data/histoday?aggregate=1&e=CCCAGG&extraParams=CryptoCompare&fsym='+ ticker.toUpperCase() +'&limit=365&tryConversion=false&tsym=' + currency.toUpperCase();
The wiki describes this:
BlockExplorer will show the raw data. For example:
The number of confirmations is (height of most recent block - height of the block containing the transaction + 1). The contents of the specific block containing the transaction are fixed, while the number of confirmations keeps increasing, so the number of confirmations cannot be in the raw block data.
You can get complete and up-to-date price history here:
You can also get subsets of the data.
For details see: http://bitcoincharts.com/about/markets-api/
What kind of API do you want? Do you mean API with your local Bitcoin Core or do you need web-API?
Have a look to http://webbtc.com/block/000000000000000001f942eb4bfa0aeccb6a14c268f4c72d5fff17270da771b9 (this is an example)
It is possible to download block as [json] / [hex] / [binary] there if you know the hash of the block
block in ...
/** Size of the "block download window": how far ahead of our current height do we fetch?
* Larger windows tolerate larger download speed differences between peer, but increase the potential
* degree of disordering of blocks on disk (which make reindexing and in the future perhaps pruning
* harder). We'll probably want to make this a per-peer ...
Each entry in the new 0.15 format is defined as outpoint:coin, and has the following structure:
Outpoint is formed by: key | tx_hash | index.
Where the key corresponds to b'C', or 43 in hex. The transaction hash in encoded in Little endian, and the index
is a base128 varint. The corresponding Bitcoin Core source code can be found here.
On the other ...
Electrum has a gui form for just that. Also I think brainwallet.org has a web form that works offline and runs off github source directly so you can verify privacy concerns.
Edit: also see:
As referenced in Transaction signature generation
Two new command-line or bitcoin.conf file commands have been added in the 0.8 release that allow for historical transactions to be accessible by recreating the old index:
txindex : maintains an extra index of old, spent transaction ids so they will be found
by the getrawtransaction JSON-RPC method.
reindex : rebuild block and transaction indices ...
I created a fork of blockparser with a 'csvdump' command that will generate a details dump of the blockchain in CSV format. There are also some support scripts in that repository for creation, population and periodic update of a PostgreSQL database.
Be aware that the resultant database is pretty large; you might want to consider PostgreSQL over SQLite for ...
This is actually already implemented: blk0001.dat contains the first two gigabytes of blockchain data, blk0002.dat contains the second two gigabytes, and so on. We just haven't hit two gigabytes of data yet.
SX is a set of modular Bitcoin commandline utilities that admin types can engage with Bitcoin functionality without having to write code.
Using the Mycelium mobile app has to be the easiest method to spend funds from a paper wallet. From the app, select ...
It's been done. It's lame. It's spam. You're incurring cost on the whole network for perpetuity (and no, the fee doesn't pay for that).
If you really can't stop yourself look at OP_RETURN as that's at least a much more network friendly way of doing it.
Any (full) Bitcoin client will download the entire blockchain. It's stored in files on disk which you can look at after it's been downloaded. The current blockchain size is 115 GB of raw data (the size on disk will be a bit larger because of indexes created by the client).
There's a boolean parameter to that RPC call that'll return it as a hex string representing the binary contents of the block.
If verbosity is 0, returns a string that is serialized, hex-encoded data for block 'hash'
getblock 'hash' 0 should return what you want.
The number of transactions in the header is always zero, per the specification. The -gen option has no effect on the getwork RPC call.
I'm not sure what you think is wrong with that information, but if it's just the zero transaction count, that's always that way. If it's the fact that you only get the headers you need to hash, it's always that way. Of ...
Also, there was a Bitcoin Time Series spreadsheet. Scroll to the bottom to see the data sources.