Extract bitcoin address and private key from EC PEM certificate to nice and sweet QR codes

generate.rb

#!/usr/bin/ruby

require 'erb'
require 'digest'
require 'date'

B58Chars  = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
B58Digits = B58Chars.split('')
B58Base   = B58Chars.length

def hex2bin(str)
  (0..((str.length/2)-1)).inject([]) do |r, i|
    r << [str[i*2, 2]].pack("H2")
  end.join
end

def bin2hex(str)
  str.unpack("H*")[0]
end

class Numeric
  def to_b58
    if self < B58Base
      B58Digits[self]
    else
      (self / B58Base).to_b58 + (self % B58Base).to_b58
    end
  end  
end


class PrivateKey
  attr_accessor :key
  
  def initialize(hex_key)
    self.key = hex_key
  end
  
  def checksum
    bin2hex(Digest::SHA2.digest(Digest::SHA2.digest(hex2bin("80" + key)))[0, 4])
  end
  
  def to_b58
    ("80" + key + checksum).to_i(16).to_b58
  end
end

pem = ARGV[0]

pkey = PrivateKey.new(bin2hex(`cat #{pem} | openssl ec -outform der`[7, 32]))
@private_key = pkey.to_b58

addy = `cat #{pem} | openssl ec -pubout -outform der | tail -c 65`
addy = "00" + Digest::RMD160.hexdigest(Digest::SHA2.digest(addy))
@address = "1" + (addy + bin2hex(Digest::SHA2.digest(Digest::SHA2.digest(hex2bin(addy)))[0,4])).to_i(16).to_b58

@now = DateTime.now.to_s

`qrencode -o #{@address}.png -s 4 -l H #{@address}` 
`qrencode -o #{@private_key}.png -s 4 -l H #{@private_key}` 
`qrencode -o bbe_#{@address}.png -s 4 -l H https://blockexplorer.com/address/#{@address}` 

text = File.read("./template.erb")
template = ERB.new(text, 0, "%<>")
result = template.result(binding)

File.open("#{@address}.html", 'w') { |f| f.write(result) }