BitLocker is an encryption technology used to encrypt a drive or a partition to protect a computer drive from unauthorized data access when the device or hard drive is lost or stolen.

It provides the best protection when the computer has a TPM chip with version 1.2 or later. You must create a USB startup key to enable BitLocker on older computers with no TPM chip. You can then use the USB startup key to decrypt the drive and start the computer or resume the computer from hibernation.