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| <title>Android Verified Boot</title> |
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| <p> |
| Android 8.0 and higher includes a reference implementation of Verified Boot |
| called Android Verified Boot (AVB) or Verified Boot 2.0. AVB in a version of |
| Verified Boot that works with <a |
| href="/devices/architecture/#hidl">Project Treble</a> |
| architecture, which separates the Android framework from the underlying vendor |
| implementation. |
| </p> |
| <p> |
| AVB is integrated with the Android Build System and enabled by |
| a single line, which takes care of generating and signing all necessary dm-verity |
| metadata. For more information, see <a |
| href="https://android.googlesource.com/platform/external/avb/+/master/README.md#Build-System-Integration" |
| class="external">Build System Integration</a>. |
| </p> |
| <p>AVB provides libavb, which is a C library to be used at boot time for |
| verifying Android. You can integrate libavb with your bootloader by implementing a |
| <a href="https://android.googlesource.com/platform/external/avb/+/master/libavb/avb_ops.h" |
| class="external">platform-specific functionality</a> for I/O, providing the root |
| of trust, and getting/setting rollback protection metadata. |
| </p> |
| <p> |
| AVB's key features include delegating updates for different |
| partitions, a common footer format for signing partitions, and protection from |
| attackers rolling back to a vulnerable version of Android. |
| </p> |
| For more implementation details, see <code><a |
| href="https://android.googlesource.com/platform/external/avb/+/master/README.md" |
| class="external">/platform/external/avb/README.md</a></code>. |
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