I recently read of this: Key Recovery Attacks of Practical Complexity on AES Variants With Up To 10 Rounds So I was wondering how many rounds Bitlocker AES uses, whether 128bit, 256bit, etc. I read the Bitlocker 2006 spec paper but maybe I didn't understand all that I was reading, because I can't find this information.

Hi Popchoc, Thank you for posting here. Bitlocker supports 128-bit and 256-bit encryption. You refer to the following links to read more information: A Disk Encryption Algorithm for Windows Vista What is the difference between BitLocker Drive Encryption 128-bit and 256-bit encryption? Hope it helps. Best regards, Robinson Zhang TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com

The first link you supplied is the spec sheet I have already read. The second link doesn't say much. What I want to know is how many rounds of AES CBC Microsoft uses for Bitlocker encryption. Thanks

Hi Popchoc, For AES-128, that is 10. For AES-256, that is 14. Hope it helps. Best regards,Robinson ZhangTechNet Subscriber Support in forumIf you have any feedback on our support, please contact tngfb@microsoft.com

Hi Popchoc, How are you? If you have any questions or concerns, please feel free to let me know. I am happy to be of further assistance. :) Thanks! Best regards,Robinson ZhangTechNet Subscriber Support in forumIf you have any feedback on our support, please contact tngfb@microsoft.com