Android OS has been supporting verified boot system since the launch of KitKat version (Android 4.4). However, Android 7.0 Nougat is going to enforce the verification system much strongly than the previous Android versions. Google calls it as a security measure to protect the device from malware.
The aim of this feature is to notify the user about malware. It alerts the user whenever the virus makes its way to kernel files present on the device. Thankfully, Nougat also boasts error correction feature that is capable of handling many such issues on its own without the need of user input. Nexus users will be the first in the lot to receive this feature.
Even though it is a useful feature for device security, but there are also many cons attached to it. Firstly, data corruption could stop the device from booting up as the verified boot process often runs into troubles that it can't handle. The fault in data could also be a direct result of some software bug or maybe hardware shortcomings.
Also, this security enhancement feature will also affect the users who want to run custom ROMs on their devices. The rooting process involves bypassing the locked bootloader, and the verified boot will detect these changes. However, this will not apply to Nexus devices as they come with an unlocked bootloader.