Specify the expected contents of "verifiedBootKey". am: 9caca7e7f0 am: 41839cdb8e

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/3359914

Change-Id: Iaff81f64b059835a6eba898103e3dbe9f89d2786
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>
diff --git a/security/keymint/aidl/android/hardware/security/keymint/KeyCreationResult.aidl b/security/keymint/aidl/android/hardware/security/keymint/KeyCreationResult.aidl
index eb9d83d..2d2f307 100644
--- a/security/keymint/aidl/android/hardware/security/keymint/KeyCreationResult.aidl
+++ b/security/keymint/aidl/android/hardware/security/keymint/KeyCreationResult.aidl
@@ -153,6 +153,9 @@
      * }
      *
      * RootOfTrust ::= SEQUENCE {
+     *     -- verifiedBootKey must contain a SHA-256 digest of the public key embedded in the
+     *     -- "vbmeta" partition if the device's bootloader is locked, or 32 bytes of zeroes if the
+     *     -- device's bootloader is unlocked.
      *     verifiedBootKey            OCTET_STRING,
      *     deviceLocked               BOOLEAN,
      *     verifiedBootState          VerifiedBootState,