block12.ruby

def base58(binary_hash)
  alphabet = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
  value = binary_hash.unpack('H*')[0].to_i 16
  output = ''
  while value > 0
    remainder = value % 58
    value /= 58
    output += alphabet[remainder]
  end
  output += alphabet[0] * binary_hash.bytes.find_index{|b| b != 0}
  output.reverse
end