block11.ruby

def bitcoin_base58_encode(ripe160_hash)
  alphabet = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
  value = ripe160_hash.to_i 16
  output = ''
  while value > 0
    remainder = value % 58
    value /= 58
    output += alphabet[remainder]
  end
  output += alphabet[0] * [ripe160_hash].pack('H*').bytes.find_index{|b| b != 0}
  output.reverse
end
def bitcoin_base58_decode(address)
  alphabet = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
  int_val = 0
  address.reverse.chars.each_with_index do |char, index|
    char_index = alphabet.index(char)
    int_val += char_index * 58**index
  end
  bignum_to_bytes(int_val, 25).unpack('H*').first
end
def bitcoin_address_decode(address)
  wrap_encode = bitcoin_base58_decode address
  wrap_encode[2, 40]
end
def bitcoin_script(address)
  hash160 = bitcoin_address_decode address
  if address.start_with? '2'
    "OP_HASH160 #{hash160} OP_EQUAL"
  else
    "OP_DUP OP_HASH160 #{hash160} OP_EQUALVERIFY OP_CHECKSIG"
  end
end