Let’s calculate the classic bitcoin (crypto) block hash from scratch (zero).
Let’s start with the genesis block, that is block #0
with the unique block hash id 000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f.
Note: You can search and browse bitcoin blocks using (online) block explorers. Example:
The classic bitcoin (crypto) block hash gets calculated from the 80-byte block header:
| Field | Size (Bytes) | Comments |
|---|---|---|
| version | 4 byte | Block version number |
| prev | 32 byte | 256-bit hash of the previous block header |
| merkleroot | 32 byte | 256-bit hash of all transactions in the block |
| time | 4 bytes | Current timestamp as seconds since 1970-01-01 00:00 |
| bits | 4 bytes | Current difficulty target in compact binary format |
| nonce | 4 bytes | 32-bit number of the (mined) lucky lottery number used once |
Note: 32 byte x 8 bit = 256 bit
Tip: Find out more about the Bitcoin Block hashing algorithm in the wiki page.
Using the data for the genesis block the setup is:
version = 1
prev = "0000000000000000000000000000000000000000000000000000000000000000"
merkleroot = "4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b"
time = 1231006505
bits = "1d00ffff"
nonce = 2083236893
The challenge: Code a calculate method that returns the Bitcoin hash. Start from scratch or, yes, use any library / gem you can find.
def calculate( version, prev, merkleroot, time, bits, nonce )
# ...
end
To qualify for solving the code challenge / puzzle you must pass the test:
require 'minitest/autorun'
class RubyQuizTest < MiniTest::Test
def test_calculate
hash = "000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f"
version = 1
prev = "0000000000000000000000000000000000000000000000000000000000000000"
merkleroot = "4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b"
time = 1231006505
bits = "1d00ffff"
nonce = 2083236893
assert_equal hash, calculate( version, prev, merkleroot, time, bits, nonce )
end # method test_calculate
end # class RubyQuizTest
Post your code snippets on the “official” Ruby Quiz Channel, that is, the ruby-talk mailing list.
Happy hacking and crypto mining with Ruby.