如何在Ruby中生成比特币地址

Question

I'm trying to generate Bitcoin addresses in ruby by using this guide:

https://bhelx.simst.im/articles/generating-bitcoin-keys-from-scratch-with-ruby/

But something isn't quite right, because the addresses being generated aren't coming out quite right.

Here's the class I'm using:

require 'openssl'
require 'ecdsa'
require 'securerandom'
require 'base58'

class BitcoinAddressGenerator

  ADDRESS_VERSION = '00'

  def self.generate_address
    # Bitcoin uses the secp256k1 curve
    curve = OpenSSL::PKey::EC.new('secp256k1')

    # Now we generate the public and private key together
    curve.generate_key

    private_key_hex = curve.private_key.to_s(16)
    puts "private_key_hex: #{private_key_hex}"
    public_key_hex = curve.public_key.to_bn.to_s(16)
    puts "public_key_hex: #{public_key_hex}"

    pub_key_hash = public_key_hash(public_key_hex)
    puts "pub_key_hash: #{pub_key_hash}"

    address = generate_address_from_public_key_hash(public_key_hash(public_key_hex))

    puts "address: #{address}"
  end

  def self.generate_address_from_public_key_hash(pub_key_hash)
    pk = ADDRESS_VERSION + pub_key_hash
    encode_base58(pub_key_hash + checksum(pub_key_hash))
  end

  def self.int_to_base58(int_val, leading_zero_bytes=0)
    alpha = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
    base58_val, base = '', alpha.size
    while int_val > 0
      int_val, remainder = int_val.divmod(base)
      base58_val = alpha[remainder] + base58_val
    end
    base58_val
  end

  def self.encode_base58(hex)
    leading_zero_bytes = (hex.match(/^([0]+)/) ? $1 : '').size / 2
    ("1"*leading_zero_bytes) + int_to_base58( hex.to_i(16) )
  end

  def self.checksum(hex)
    sha256(sha256(hex))[0...8]
  end

  # RIPEMD-160 (160 bit) hash
  def self.rmd160(hex)
    Digest::RMD160.hexdigest([hex].pack("H*"))
  end

  def self.sha256(hex)
   Digest::SHA256.hexdigest([hex].pack("H*"))
  end

  # Turns public key into the 160 bit public key hash
  def self.public_key_hash(hex)
    rmd160(sha256(hex))
  end

end

It outputs something like:

private_key_hex: C96DE079BAE4877E086288DEDD6F9F70B671862B7E6E4FC0EC401CADB81EDF45
public_key_hex: 0422435DF80F62E643D3CFBA66194052EC9ED0DFB47A1B26A4731079A5FF84FBF98FF0A540B6981D75BA789E6192F3B38BABEF6B0286CAEB4CAFCB51BB96D97B46
public_key_hash: db34927cc5ec0066411f366d9a95f9c6369c6e1d
address: Lz3xnxx6Uh79PEzPpWSMMZJVWR36hJgVL

If I plug this address into blockchain.info and similar tools it says that it's an invalid address.

Any help would be greatly appreciated.

Answer 1

In your generate_address_from_public_key_hash method, the checksum should be over the hash including the address prefix . You're not actually using the pk variable at all at the moment after you assign it. The code should look something like:

def self.generate_address_from_public_key_hash(pub_key_hash)
  pk = ADDRESS_VERSION + pub_key_hash
  encode_base58(pk + checksum(pk)) # Using pk here, not pub_key_hash
end

The mistake seems to also be on the page you link to, I guess the author must have made a copy/paste error.

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As an aside, keeping everything in hex strings and decoding back and forth seems an odd way of doing this. I would have thought it would be easier to use raw binary strings, and only encode to hex when printing out values.