# File lib/travis/cli/encrypt_file.rb, line 49
      def setup
        super
        self.key        ||= SecureRandom.hex(32) unless decrypt?
        self.iv         ||= SecureRandom.hex(16) unless decrypt?
        error "key must be 64 characters long and a valid hex number" unless key =~ /^[a-f0-9]{64}$/
        error "iv must be 32 characters long and a valid hex number"  unless iv  =~ /^[a-f0-9]{32}$/
      end