This month we’ll review BitLocker, a new feature of Windows Vista and the upcoming Windows 2008 Server.
Data on a lost or stolen computer may be accessed by unauthorized persons using specialized software or by transferring the information to a different storage device. Individuals may have financial or personal information on the system that may lead to identify theft. Companies involved in the loss of sensitive data are often exposed to unwanted media attention and complaints of angry customers, along with a potential loss of profit. BitLocker attempts to minimize the likelihood of data exposure on lost or stolen computers by encrypting whole volumes of data.
Encryption is the process of converting plain-text (easily read by people) into cipher-text (requires a key to be read). Windows systems have had encryption on NTFS volumes for some time, but BitLocker takes the process one step further. (NTFS is the most secure method of formatting on Windows systems now available.) Previously, data was encrypted by individual files or folders. With BitLocker, two NTFS volumes are encrypted, and no access is allowed to the system until a key is provided. You may use BitLocker alongside more traditional encryption if you wish.
Currently, in order to use BitLocker, you need to have Vista Ultimate or Enterprise installed with two NTFS volumes: one containing the files that will boot the machine and the other containing your operating system files. Only these two volumes will be BitLocker-encrypted. Additionally, BitLocker is designed to work with TPM 1.2 (Trusted Platform Module), which refers to a chip on a computer that stores keys. Systems with TPM can easily employ BitLocker and will enjoy the additional benefit of an authentication check prior to boot.
Systems without TPM may also employ BitLocker, but only if the system will boot to a USB device, such as a thumb drive. In this case, two USB devices are preferred. The first device stores the “startup key,” which is inserted prior to boot in order to access the system. The second device stores the “recovery key.” The recovery key should be saved on a separate device in case of loss or corruption of the first device.
Finally, BitLocker provides the ability to recover the system with a password key. This numerical password consists of 48 digits divided into 8 groups entered into the BitLocker Recovery Console by using the function keys on your keyboard.
It is imperative that all keys be stored separately from the system so that theft of the computer does not include theft of the key. Access to the system along with any of these keys eliminates any protection otherwise provided.
Systems that use BitLocker should never be the only system containing the confidential data. If the system is stolen, the keys are lost or corrupted or the authentication check fails, the data may be inaccessible. BitLocker is primarily designed for use on system that may hold copies of confidential or sensitive data, but may not always be physically secure. The perfect example of this type of system is a laptop or notebook computer. TPW
