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Title: How do I perform the SHA-256 hashing on a public key? Post by: sjors on May 09, 2013, 11:47:30 PM I'm trying to understand bitcoin better by trying things out in Ruby. I know some aspects of Bitcoin have already been implemented (https://github.com/lian/bitcoin-ruby) in Ruby, but I'm trying to avoid "cheating" by studying those.
I read the wiki regarding scripts (https://en.bitcoin.it/wiki/Script) as well as addresses (https://en.bitcoin.it/wiki/Technical_background_of_Bitcoin_addresses) and I'm confused as to how to convert between the public key and the bitcoin address. The scriptPubKey of a transaction output usually looks like this: OP_DUP OP_HASH160 <pubKeyHash> OP_EQUALVERIFY OP_CHECKSIG. If I understand correctly, this <pubKeyHash> is the result of Base58 decoding the bitcoin address. In ruby that can be done like this ("step 9" from the address page results in "step 8"): Code: require 'base58_gmp' So far so good (although it took a long time to realize bitcoin uses a non-standard form of Base58). The scriptSig of a transaction input looks this this: <sig> <pubKey>. If I understand correctly <pubKey> here is the thing shown in step 1: "04508 ... 82BA6". Now according to the scripts page, OP_HASH(<pubkey>) should result in <pubKeyHash>, but I'm having a hard time achieving that. OP_HASH is supposed to (https://en.bitcoin.it/wiki/Script#Crypto) only perform a SHA256 hash followed by an RMB160 hash. That looks like step 2 and step 3, but does not include step 4 through 8 (adding network info and a checksum). My guess is that I also need to follow those steps when I see OP_HASH. Unfortunately I'm already stuck at step 2. If I try to reproduce the example in ruby, I get different results for the SHA256 hash. Code: require 'digest/sha2' What am I doing wrong? By the way, I tried searching the forum for similar questions, but search is blocked for several minutes after one or two attempts... Title: Re: How do I perform the SHA-256 hashing on a public key? Post by: sjors on May 10, 2013, 10:10:21 AM Alright, I had to cheat here and peek at bitcoin-ruby. I needed to replace:
Code: step_2 = (Digest::SHA2.new << pubKey).to_s With this, by adding pack("H*"): Code: step_2 = (Digest::SHA2.new << [pubKey].pack("H*")).to_sThe problem was that my code created a sha256 digest of a string and not of the actual hex value. This meant for instance that there was a difference between the digest of pubKey.downcase and pubKey.upcase. Title: Re: How do I perform the SHA-256 hashing on a public key? Post by: Vergil77 on July 04, 2013, 02:01:11 PM what can i do?
Startseite Charts Statistiken Markets Entwickler Wallet Unverbrauchten Ausgänge 1Bv82xxr341Uf7hZfWPy9RiNUkG4hx3CMf Total: 1.33 BTC a31ee8dc42faf6f06ee609a8fa25b69c3eab2768ff3bc455879ee2f45087e0d12013-07-02 14:13:34 OP_DUP OP_HASH160 77bd2ce6db4564c6a640fccd133da6371f89fd96 OP_EQUALVERIFY OP_CHECKSIG (1Bv82xxr341Uf7hZfWPy9RiNUkG4hx3CMf) 344 Bestätigungen 0.6 BTC 242ed4f0f7986ecc13f27ce01d294e22935288ee0c6018e05763813d34b076882013-06-30 13:55:34 OP_DUP OP_HASH160 77bd2ce6db4564c6a640fccd133da6371f89fd96 OP_EQUALVERIFY OP_CHECKSIG (1Bv82xxr341Uf7hZfWPy9RiNUkG4hx3CMf) 653 Bestätigungen 0.33 BTC 2addf8699726fd7def844e9cec615d610a4ff3eb50b0cdd47ce882a910c46c9c2013-06-27 10:26:36 OP_DUP OP_HASH160 77bd2ce6db4564c6a640fccd133da6371f89fd96 OP_EQUALVERIFY OP_CHECKSIG (1Bv82xxr341Uf7hZfWPy9RiNUkG4hx3CMf) 1184 Bestätigungen 0.4 BTC Über uns & Kontakt: Über uns - Status: Ok (566 Knoten verbunden) - Erweitert: Aktivieren - Währung: |