UEFI Secure Boot support:

UEFI stands for Unified Extensible Firmware Interface, UEFI will be a specification detailing an interface that helps hand off control of the system after the system is powered on, but before the operating system starts (pre-boot environment) to an operating system, such as Windows O.S or Linux O.S., new security characteristic included in this version of Windows. UEFI is intended to replace the traditional BIOS (Basic Input Output System) as the next-generation firmware interface for PCs. it can make Windows 8 very resistant to low-level malware such as rootkits when the Secure Mode enabled. UEFI defines an OS-firmware interface, which is known as "boot services" and "runtime services", but isn’t specific to any processor architecture. But BIOS is specific to the Intel x86 processor architectures.

Inbuilt Antivirus:

In the History of Windows that first time introduces the antivirus with any windows operating system, you can protect your PCs and Laptops and other devices from viruses, spyware, Trojan horses, rootkits and other malwares, and it can also comes with an updated version of Windows Defender now provide the same protection which is already offered in Windows Vista and similar look and feel to that of the free Microsoft Security Essentials antivirus program (Malware detection, Dynamic/behavioral detection, Disinfection, Rootkits removal, Scan speed, False alarms and etc). And if you want to use another antivirus program or utility in the windows 8 you can disabled the Windows Defender.

New Password Types:

Microsoft introduces the “Two New Password Types” of password in the Windows 8 for authenticate your login in 

1.     Picture Password.

      2.    Four-Digits PIN.

Picture Password:

You select a photo or image and draw three gestures (a combination of circles, straight lines, or taps/clicks) in different places to create your “password”, Picture password gives you a more creative and fun way.

Four Digits PIN:

A PIN offers a faster way to Login, It allows you to setup Windows 8 login password at the most four digits. This password protection option has been added to Windows 8 for tablet users to enter code via touch-numpad, but PC users can also create PIN to logon to Windows 8 using either Windows Live account username and password or PIN code.

Note:

The improved Windows Defender, boot system, and password protection are the most noticeable security improvements in Windows 8.  A few core Windows components (such as the Windows kernel, ASLR, and heap) have been updated to help reduce common attacks and exploits even further.