neo_key.rb

require 'openssl'

module Neo
  class Key
    ADDRESS_VERSION = '17'
    PUSHBYTES33 = '21'
    CHECKSIG = 'ac'
    WIF_PREFIX = '80' # MainNet
    WIF_SUFFIX = '01' # Compressed

    def initialize
      @key = OpenSSL::PKey::EC.new('prime256v1').generate_key
    end

    def private_hex
      @key.private_key.to_s(16).downcase
    end

    def public_key_encoded
      @key.public_key.to_bn(:compressed).to_s(16).downcase
    end

    def script
      PUSHBYTES33 + public_key_encoded + CHECKSIG
    end

    def script_hash
      bytes = [script].pack("H*")
      sha256 = Digest::SHA256.digest(bytes)
      Digest::RMD160.hexdigest(sha256)
    end

    def address
      Base58.encode(with_checksum(ADDRESS_VERSION + script_hash).to_i(16))
    end

    def wif
      Base58.encode(with_checksum(WIF_PREFIX + private_hex + WIF_SUFFIX).to_i(16))
    end

    def with_checksum(hex)
      bytes = [hex].pack("H*")
      hash1 = Digest::SHA256.digest(bytes)
      hash2 = Digest::SHA256.hexdigest(hash1)
      hex + hash2.slice(0, 8)
    end
  end
end