What is Bitlocker, specifically what function

Bitlocker only has the function of win7 flagship version, and other versions of win7 do not have this function, this function is very easy to use. Let's take a look at what Bitlocker is.
1
What is Bitlocker:
Windows BitLocker Drive Encryption protects the data on your computer by encrypting all the data stored on the Windows operating system volume. BitLocker uses TPM to help protect Windows operating system and user data and helps ensure that computers are not tampered with even if they are unattended, lost or stolen. BitLocker can also be used without a TPM. To use BitLocker on a computer without using a TPM, you must either change the default behavior of the BitLocker Setup Wizard by using Group Policy, or configure BitLocker by using a script. When using BitLocker instead of TPM, the required encryption key is stored on the USB flash drive and must be provided to unlock the data stored on the volume.
2
The specific use of BitLocker driver encryption
In other words, when two operating systems are installed on one computer, or the hard disk with the system is removed and connected to other computers, access the application. When the partition of the BitLocker system is located, a message indicating that the access is denied will be popped up, and the prompt is that the target partition is not formatted, and it is completely invisible to be encrypted. Bitlocker to Go is the expansion and improvement of the Bitlocker function. It allows Bitlocker to encrypt not only the internal hard disk of the computer, but also the U disk, mobile hard disk and other devices.
The above is about what is Bitlocker, what is the function, I hope to let you know more about the features of the Win7 that only the flag version has.