Microsoft announcing hardware-accelerated BitLocker for Windows 11

We know that users desire both security and great performance. Historically, we have strived to keep BitLocker performance overhead within single digit percentage points. However, with the rapid rise in popularity and advancement of Non-Volatile Memory Express (NVMe) drive technology, these drives now achieve much higher Input/Output (I/O) operation speeds. As a result, corresponding BitLocker cryptographic operations can require a higher proportion of CPU (Central Processing Unit) cycles. This makes the performance impact of BitLocker more pronounced, especially on high-throughput and I/O intensive workloads like gaming or video editing.

As NVMe drives continue to evolve, their ability to deliver extremely fast data transfer rates has set new expectations for system responsiveness and application performance. While this is a major benefit for users, it also means that any additional processing — such as real-time encryption and decryption by BitLocker — can become a bottleneck if not properly optimized. For example, professionals working with large video files, developers compiling massive codebases, or gamers demanding the lowest possible latency may notice delays or increased CPU usage when BitLocker is enabled on these high-speed drives.

Balancing robust security with minimal performance impact is more challenging than ever. The need to protect sensitive data remains critical, but users also expect their devices to operate at peak efficiency. As a result, the industry has needed to innovate new solutions that ensure both security and speed are maintained even as hardware capabilities advance.

To achieve this, we announced hardware-accelerated BitLocker at Microsoft Ignite last month. Hardware-accelerated BitLocker is designed to provide the best combination of performance and security.

Starting with the September 2025 Windows update for Windows 11 24H2 and the release of Windows 11 25H2, in addition to existing support for UFS (Universal Flash Storage) Inline Crypto Engine technology, BitLocker will take advantage of upcoming system on chip (SoC) and central processing unit (CPU) capabilities to achieve better performance and security for current and future NVMe drives.

These capabilities are:

1. Crypto offloading – BitLocker shifts bulk cryptographic operations from the main CPU to a dedicated crypto engine. This capability frees up CPU resources for other tasks and helps improve both performance and battery life.
2. Hardware protected keys – BitLocker bulk encryption keys, when necessary SoC support is present, are hardware wrapped, which helps increase security by reducing their exposure to CPU and memory vulnerabilities. This is an addition to the already supported Trusted Platform Module (TPM), which protects intermediate BitLocker keys, putting us on a path to completely eliminate BitLocker keys from the CPU and memory.

When enabling BitLocker, supported devices with NVMe drives along with one of the new crypto offload capable SoCs will use hardware-accelerated BitLocker with the XTS-AES-256 algorithm by default. This includes automatic device encryption, manual BitLocker enablement, policy driven enablement, or script-based enablement with some exceptions. (Please see the Enablement and management experiences section below for more details.)

We have enhanced the architecture and implementation of the Windows storage and security stacks to support these new capabilities as an operating system enhancement that will bring value to all capable PCs over time. Upcoming Intel vPro® devices featuring Intel® Core™ Ultra Series 3 (formally codenamed Panther Lake) processors will provide initial support for these capabilities with support for other vendors and platforms planned. Coordinate with your suppliers and keep an eye on listings from us and other vendors as PCs become available on the market.

How Hardware-accelerated BitLocker works – diagram​

A diagram comparing a software BitLocker to hardware accelerated BitLocker.

These diagrams show data flow for both software BitLocker and hardware-accelerated BitLocker. The type of the arrows indicate if we are dealing with unencrypted data (dotted arrow), encrypted data (solid arrow) or key management operations (dashed arrow).

1. In software BitLocker all the cryptographic operations for I/O (reads and writes) are executed on the main CPU before the I/O reaches the drive.

2. In hardware-accelerated BitLocker all the cryptographic operations for I/O (reads and writes) are executed on the dedicated part of the SoC before the I/O reaches the NVMe drive. Additionally, the BitLocker bulk encryption key is hardware protected by the SoC (if SoC supports it).

Performance improvement over software BitLocker​

According to our tests, storage performance with hardware-accelerated BitLocker can approach NVMe performance without BitLocker encryption across common workloads.

We see performance improvements in storage and I/O metrics like sequential and random writes and reads when comparing hardware-accelerated BitLocker to software BitLocker.

In addition to the better storage performance, hardware-accelerated BitLocker provides on average a 70% savings in CPU cycles compared with software BitLocker. The CPU cycle savings can result in longer battery life.


A bar chart comparing an average number of cycles per IO between hardware-accelerated BitLocker and software BitLocker as opposed to without BitLocker encryption

Note: Test outcomes may differ and are influenced by the platform’s H/W configuration.

Validation​

To check if your device is using hardware-accelerated BitLocker, open a command prompt as an administrator and run manage-bde -status. Look at the Encryption Method section — if you see Hardware accelerated shown, it indicates that BitLocker is utilizing the SoC’s crypto acceleration capabilities.



A command-prompt interface shows hardware-accelerated BitLocker as the encryption method

We are working on improving our tools’ status readout to clearly show which capabilities are used.

Product demo: comparing Software BitLocker and Hardware-accelerated BitLocker performance​

This video compares software BitLocker and hardware-accelerated BitLocker by enabling both via command line, verifying encryption methods, and running benchmarks to assess performance differences. It concludes by demonstrating hardware-protected keys.


Video from the Microsoft Ignite 2025 conference comparing software BitLocker to hardware-accelerated BitLocker.

Note: (0:28 - 0:41) Accelerated for demo purposes, actual times may vary.

Enablement and management experiences​

For BitLocker provisioning during the WinPE (Windows Preinstallation Environment) flow and other offline provisioning scenarios, cryptographic offloading will function as intended provided that the disk is used on compatible hardware with appropriate drivers, and the chosen algorithm and encryption method align with those supported by the SoC.

Hardware-accelerated BitLocker will not be used in Windows if:

• A user enables BitLocker manually through the command line or PowerShell and specifies an algorithm or key size that is not supported by the SoC vendor. This also applies to any automation tools or scripts.
• An administrator applies an enterprise policy (through MDM or GPO) with a key size or algorithm that the SoC vendor does not support (such as AES-CBC-128 bit or AES-CBC-256 bit). We plan to modify this behavior in an early spring update by automatically increasing the key size for new BitLocker enablements, but not changing the algorithm itself. For instance, if the policy specifies AES-XTS-128 bit, it will be upgraded to AES-XTS-256 to enable hardware-accelerated BitLocker on supported platforms. However, if the policy specifies AES-CBC-128 or AES-CBC-256, the algorithm will not be changed to AES-XTS, and hardware-accelerated BitLocker will not be utilized.
• An IT Administrator enables the “System cryptography: Use FIPS 140 compliant cryptographic algorithms, including encryption, hashing, and signing algorithms” policy (link). The use of hardware-accelerated BitLocker relies on whether the SoC reports FIPS certification of its hardware key wrapping and crypto offloading capabilities to Windows.

We encourage you to leverage these advancements to help maximize both security and performance on your devices. Thank you for taking the time to stay informed and proactive about device protection.

Securing the present, Innovating for the future​

Security is a shared responsibility. Through collaboration across hardware and software ecosystems, we can build more resilient systems secure by design and by default, from Windows to the cloud, enabling trust at every layer of the digital experience.

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