diff --git a/security/keymint/aidl/aidl_api/android.hardware.security.keymint/current/android/hardware/security/keymint/IKeyMintDevice.aidl b/security/keymint/aidl/aidl_api/android.hardware.security.keymint/current/android/hardware/security/keymint/IKeyMintDevice.aidl
index bf30999..3f75af6 100644
--- a/security/keymint/aidl/aidl_api/android.hardware.security.keymint/current/android/hardware/security/keymint/IKeyMintDevice.aidl
+++ b/security/keymint/aidl/aidl_api/android.hardware.security.keymint/current/android/hardware/security/keymint/IKeyMintDevice.aidl
@@ -44,10 +44,9 @@
   void deleteKey(in byte[] keyBlob);
   void deleteAllKeys();
   void destroyAttestationIds();
-  android.hardware.security.keymint.BeginResult begin(in android.hardware.security.keymint.KeyPurpose purpose, in byte[] keyBlob, in android.hardware.security.keymint.KeyParameter[] params, in android.hardware.security.keymint.HardwareAuthToken authToken);
+  android.hardware.security.keymint.BeginResult begin(in android.hardware.security.keymint.KeyPurpose purpose, in byte[] keyBlob, in android.hardware.security.keymint.KeyParameter[] params, in @nullable android.hardware.security.keymint.HardwareAuthToken authToken);
   void deviceLocked(in boolean passwordOnly, in @nullable android.hardware.security.secureclock.TimeStampToken timestampToken);
   void earlyBootEnded();
   byte[] convertStorageKeyToEphemeral(in byte[] storageKeyBlob);
-  byte[] performOperation(in byte[] request);
   const int AUTH_TOKEN_MAC_LENGTH = 32;
 }
diff --git a/security/keymint/aidl/aidl_api/android.hardware.security.keymint/current/android/hardware/security/keymint/Tag.aidl b/security/keymint/aidl/aidl_api/android.hardware.security.keymint/current/android/hardware/security/keymint/Tag.aidl
index 7591318..e310b44 100644
--- a/security/keymint/aidl/aidl_api/android.hardware.security.keymint/current/android/hardware/security/keymint/Tag.aidl
+++ b/security/keymint/aidl/aidl_api/android.hardware.security.keymint/current/android/hardware/security/keymint/Tag.aidl
@@ -48,7 +48,6 @@
   RSA_PUBLIC_EXPONENT = 1342177480,
   INCLUDE_UNIQUE_ID = 1879048394,
   RSA_OAEP_MGF_DIGEST = 536871115,
-  BLOB_USAGE_REQUIREMENTS = 268435757,
   BOOTLOADER_ONLY = 1879048494,
   ROLLBACK_RESISTANCE = 1879048495,
   HARDWARE_TYPE = 268435760,
diff --git a/security/keymint/aidl/android/hardware/security/keymint/IKeyMintDevice.aidl b/security/keymint/aidl/android/hardware/security/keymint/IKeyMintDevice.aidl
index 1c503c2..a3260f5 100644
--- a/security/keymint/aidl/android/hardware/security/keymint/IKeyMintDevice.aidl
+++ b/security/keymint/aidl/android/hardware/security/keymint/IKeyMintDevice.aidl
@@ -257,9 +257,6 @@
      *
      * o Tag::ORIGIN with the value KeyOrigin::GENERATED.
      *
-     * o Tag::BLOB_USAGE_REQUIREMENTS with the appropriate value (see KeyBlobUsageRequirements in
-     *   Tag.aidl).
-     *
      * o Tag::OS_VERSION, Tag::OS_PATCHLEVEL, Tag::VENDOR_PATCHLEVEL and Tag::BOOT_PATCHLEVEL with
      *   appropriate values.
      *
@@ -325,6 +322,10 @@
      *        return ErrorCode::INCOMPATIBLE_PURPOSE.  If the provided AttestationKey has an empty
      *        issuer subject name, the IKeyMintDevice must return ErrorCode::INVALID_ARGUMENT.
      *
+     *        If `attestationKey` is null and `keyParams` contains Tag::ATTESTATION_CHALLENGE but
+     *        the KeyMint implementation does not have factory-provisioned attestation keys, it must
+     *        return ErrorCode::ATTESTATION_KEYS_NOT_PROVISIONED.
+     *
      * @return The result of key creation.  See KeyCreationResult.aidl.
      */
     KeyCreationResult generateKey(
@@ -364,6 +365,10 @@
      *        return ErrorCode::INCOMPATIBLE_PURPOSE.  If the provided AttestationKey has an empty
      *        issuer subject name, the IKeyMintDevice must return ErrorCode::INVALID_ARGUMENT.
      *
+     *        If `attestationKey` is null and `keyParams` contains Tag::ATTESTATION_CHALLENGE but
+     *        the KeyMint implementation does not have factory-provisioned attestation keys, it must
+     *        return ErrorCode::ATTESTATION_KEYS_NOT_PROVISIONED.
+     *
      * @return The result of key creation.  See KeyCreationResult.aidl.
      */
     KeyCreationResult importKey(in KeyParameter[] keyParams, in KeyFormat keyFormat,
@@ -713,9 +718,7 @@
      *        contain a tag Tag::NONCE.  If Tag::NONCE is provided for a key without
      *        Tag:CALLER_NONCE, ErrorCode::CALLER_NONCE_PROHIBITED must be returned.
      *
-     * @param inAuthToken Authentication token.  Callers that provide no token must set all numeric
-     *        fields to zero and the MAC must be an empty vector.  TODO: make this field nullable.
-     *        b/173483024.
+     * @param inAuthToken Authentication token.
      *
      * @return BeginResult as output, which contains the challenge, KeyParameters which haves
      *         additional data from the operation initialization, notably to return the IV or nonce
@@ -723,7 +726,7 @@
      *         which is used to perform update(), finish() or abort() operations.
      */
     BeginResult begin(in KeyPurpose purpose, in byte[] keyBlob, in KeyParameter[] params,
-            in HardwareAuthToken authToken);
+            in @nullable HardwareAuthToken authToken);
 
     /**
      * Called by client to notify the IKeyMintDevice that the device is now locked, and keys with
@@ -783,18 +786,4 @@
      *         place of the input storageKeyBlob
      */
     byte[] convertStorageKeyToEphemeral(in byte[] storageKeyBlob);
-
-    /**
-     * Called by the client to perform a KeyMint operation.
-     *
-     *  This method is added primarily as a placeholder.  Details will be fleshed before the KeyMint
-     *  V1 interface is frozen.  Until then, implementations must return ErrorCode::UNIMPLEMENTED.
-     *
-     * @param request is an encrypted buffer containing a description of the operation the client
-     *        wishes to perform.  Structure, content and encryption are TBD.
-     *
-     * @return an encrypted buffer containing the result of the operation.  Structure, content and
-     *         encryption are TBD.
-     */
-    byte[] performOperation(in byte[] request);
 }
diff --git a/security/keymint/aidl/android/hardware/security/keymint/KeyCreationResult.aidl b/security/keymint/aidl/android/hardware/security/keymint/KeyCreationResult.aidl
index c2e21b6..972a6a5 100644
--- a/security/keymint/aidl/android/hardware/security/keymint/KeyCreationResult.aidl
+++ b/security/keymint/aidl/android/hardware/security/keymint/KeyCreationResult.aidl
@@ -66,7 +66,8 @@
      *     provisioned attestation key, and the full certificate chain for that factory-provisioned
      *     attestation key.  Tag::ATTESTATION_APPLICATION_ID must also be provided when the
      *     ATTESTATION_CHALLENGE is provided, otherwise ATTESTATION_APPLICATION_ID_MISSING will be
-     *     returned.
+     *     returned.  KeyMint implementations are not required to support factory-provisioned
+     *     attestation keys.
      *
      * 2.  Asymmetric key attestation with caller-provided key.  If Tag::ATTESTATION_CHALLENGE is
      *     provided and the `attestationKey` parameter on the generat/import call is non-null and
@@ -90,6 +91,110 @@
      * 5.  Symmetric key.  If the generated/imported key is symmetric, the certificate chain must
      *     return empty, any Tag::ATTESTATION_CHALLENGE or Tag::ATTESTATION_APPLICATION_ID inputs,
      *     if provided, are ignored.
+     *
+     * In all cases except the symmetric key, the contents of certificate chain must be DER-encoded
+     * X.509 certificates ordered such that each certificate is signed by the subsequent one, up to
+     * the root which must be self-signed (or contain a fake signature in the case of case 4 above).
+     * The first certificate in the chain signs the public key info of the newly-generated or
+     * newly-imported key pair.  In the attestation cases (1 and 2 above), the first certificate
+     * must also satisfy some other requirements:
+     *
+     * o It must have the serial number provided in Tag::CERTIFICATE_SERIAL, or default to 1 if the
+     *   tag is not provided.
+     *
+     * o It must have the subject provided in Tag::CERTIFICATE_SUBJECT, or default to CN="Android
+     *   Keystore Key", if the tag is not provided.
+     *
+     * o It must contain the notBefore and notAfter date-times specified in
+     *   Tag::CERTIFICATE_NOT_BEFORE and Tag::CERTIFICATE_NOT_AFTER, respectively.
+     *
+     * o It must contain a Key Usage extension with:
+     *
+     *    - the digitalSignature bit set iff the attested key has KeyPurpose::SIGN,
+     *    - the dataEncipherment bit set iff the attested key has KeyPurpose::DECRYPT,
+     *    - the keyEncipherment bit set iff the attested key has KeyPurpose::WRAP_KEY,
+     *    - the keyAgreement bit set iff the attested key has KeyPurpose::AGREE_KEY, and
+     *    - the keyCertSignBit set iff the attested key has KeyPurpose::ATTEST_KEY.
+     *
+     * o it must contain a KeyDescription attestation extension with OID 1.3.6.1.4.1.11129.2.1.17.
+     *
+     * The KeyDescription content is defined by the following ASN.1 schema, which is mostly a
+     * straightforward translation of the KeyMint tag/value parameter lists to ASN.1.
+     *
+     * KeyDescription ::= SEQUENCE {
+     *     attestationVersion         INTEGER, # Value 100
+     *     attestationSecurityLevel   SecurityLevel, # See below
+     *     keyMintVersion             INTEGER, # Value 100
+     *     keymintSecurityLevel       SecurityLevel, # See below
+     *     attestationChallenge       OCTET_STRING, # Tag::ATTESTATION_CHALLENGE from attestParams
+     *     uniqueId                   OCTET_STRING, # Empty unless key has Tag::INCLUDE_UNIQUE_ID
+     *     softwareEnforced           AuthorizationList, # See below
+     *     hardwareEnforced           AuthorizationList, # See below
+     * }
+     *
+     * SecurityLevel ::= ENUMERATED {
+     *     Software                   (0),
+     *     TrustedEnvironment         (1),
+     *     StrongBox                  (2),
+     * }
+     *
+     * RootOfTrust ::= SEQUENCE {
+     *     verifiedBootKey            OCTET_STRING,
+     *     deviceLocked               BOOLEAN,
+     *     verifiedBootState          VerifiedBootState,
+     *     # verifiedBootHash must contain 32-byte value that represents the state of all binaries
+     *     # or other components validated by verified boot.  Updating any verified binary or
+     *     # component must cause this value to change.
+     *     verifiedBootHash           OCTET_STRING,
+     * }
+     *
+     * VerifiedBootState ::= ENUMERATED {
+     *     Verified                   (0),
+     *     SelfSigned                 (1),
+     *     Unverified                 (2),
+     *     Failed                     (3),
+     * }
+     *
+     * AuthorizationList ::= SEQUENCE {
+     *     purpose                    [1] EXPLICIT SET OF INTEGER OPTIONAL,
+     *     algorithm                  [2] EXPLICIT INTEGER OPTIONAL,
+     *     keySize                    [3] EXPLICIT INTEGER OPTIONAL,
+     *     blockMode                  [4] EXPLICIT SET OF INTEGER OPTIONAL,
+     *     digest                     [5] EXPLICIT SET OF INTEGER OPTIONAL,
+     *     padding                    [6] EXPLICIT SET OF INTEGER OPTIONAL,
+     *     callerNonce                [7] EXPLICIT NULL OPTIONAL,
+     *     minMacLength               [8] EXPLICIT INTEGER OPTIONAL,
+     *     ecCurve                    [10] EXPLICIT INTEGER OPTIONAL,
+     *     rsaPublicExponent          [200] EXPLICIT INTEGER OPTIONAL,
+     *     rollbackResistance         [303] EXPLICIT NULL OPTIONAL,
+     *     activeDateTime             [400] EXPLICIT INTEGER OPTIONAL,
+     *     originationExpireDateTime  [401] EXPLICIT INTEGER OPTIONAL,
+     *     usageExpireDateTime        [402] EXPLICIT INTEGER OPTIONAL,
+     *     userSecureId               [502] EXPLICIT INTEGER OPTIONAL,
+     *     noAuthRequired             [503] EXPLICIT NULL OPTIONAL,
+     *     userAuthType               [504] EXPLICIT INTEGER OPTIONAL,
+     *     authTimeout                [505] EXPLICIT INTEGER OPTIONAL,
+     *     allowWhileOnBody           [506] EXPLICIT NULL OPTIONAL,
+     *     trustedUserPresenceReq     [507] EXPLICIT NULL OPTIONAL,
+     *     trustedConfirmationReq     [508] EXPLICIT NULL OPTIONAL,
+     *     unlockedDeviceReq          [509] EXPLICIT NULL OPTIONAL,
+     *     creationDateTime           [701] EXPLICIT INTEGER OPTIONAL,
+     *     origin                     [702] EXPLICIT INTEGER OPTIONAL,
+     *     rootOfTrust                [704] EXPLICIT RootOfTrust OPTIONAL,
+     *     osVersion                  [705] EXPLICIT INTEGER OPTIONAL,
+     *     osPatchLevel               [706] EXPLICIT INTEGER OPTIONAL,
+     *     attestationApplicationId   [709] EXPLICIT OCTET_STRING OPTIONAL,
+     *     attestationIdBrand         [710] EXPLICIT OCTET_STRING OPTIONAL,
+     *     attestationIdDevice        [711] EXPLICIT OCTET_STRING OPTIONAL,
+     *     attestationIdProduct       [712] EXPLICIT OCTET_STRING OPTIONAL,
+     *     attestationIdSerial        [713] EXPLICIT OCTET_STRING OPTIONAL,
+     *     attestationIdImei          [714] EXPLICIT OCTET_STRING OPTIONAL,
+     *     attestationIdMeid          [715] EXPLICIT OCTET_STRING OPTIONAL,
+     *     attestationIdManufacturer  [716] EXPLICIT OCTET_STRING OPTIONAL,
+     *     attestationIdModel         [717] EXPLICIT OCTET_STRING OPTIONAL,
+     *     vendorPatchLevel           [718] EXPLICIT INTEGER OPTIONAL,
+     *     bootPatchLevel             [719] EXPLICIT INTEGER OPTIONAL,
+     * }
      */
     Certificate[] certificateChain;
 }
diff --git a/security/keymint/aidl/android/hardware/security/keymint/Tag.aidl b/security/keymint/aidl/android/hardware/security/keymint/Tag.aidl
index cde1fc0..02e7f00 100644
--- a/security/keymint/aidl/android/hardware/security/keymint/Tag.aidl
+++ b/security/keymint/aidl/android/hardware/security/keymint/Tag.aidl
@@ -203,22 +203,7 @@
      */
     RSA_OAEP_MGF_DIGEST = (2 << 28) /* TagType:ENUM_REP */ | 203,
 
-    /**
-     * TODO(seleneh) this tag needs to be deleted from all codes.
-     *
-     * Tag::BLOB_USAGE_REQUIREMENTS specifies the necessary system environment conditions for the
-     * generated key to be used.  Possible values are defined by the KeyBlobUsageRequirements enum.
-     *
-     * This tag is specified by the caller during key generation or import to require that the key
-     * is usable in the specified condition.  If the caller specifies Tag::BLOB_USAGE_REQUIREMENTS
-     * with value KeyBlobUsageRequirements::STANDALONE the IKeyMintDevice must return a key blob
-     * that can be used without file system support.  This is critical for devices with encrypted
-     * disks, where the file system may not be available until after a KeyMint key is used to
-     * decrypt the disk.
-     *
-     * Must be hardware-enforced.
-     */
-    BLOB_USAGE_REQUIREMENTS = (1 << 28) /* TagType:ENUM */ | 301,
+    // Tag 301 reserved
 
     /**
      * Tag::BOOTLOADER_ONLY specifies only the bootloader can use the key.
@@ -935,33 +920,34 @@
     CONFIRMATION_TOKEN = (9 << 28) /* TagType:BYTES */ | 1005,
 
     /**
-     * Tag::CERTIFICATE_SERIAL specifies the serial number to be assigned to the
-     * attestation certificate to be generated for the given key.  This parameter should only
-     * be passed to keyMint in the attestation parameters during generateKey() and importKey().
+     * Tag::CERTIFICATE_SERIAL specifies the serial number to be assigned to the attestation
+     * certificate to be generated for the given key.  This parameter should only be passed to
+     * keyMint in the attestation parameters during generateKey() and importKey().  If not provided,
+     * the serial shall default to 1.
      */
     CERTIFICATE_SERIAL = (8 << 28) /* TagType:BIGNUM */ | 1006,
 
     /**
-     * Tag::CERTIFICATE_SUBJECT the certificate subject. The value is a DER encoded X509 NAME.
-     * This value is used when generating a self signed certificates. This tag may be specified
+     * Tag::CERTIFICATE_SUBJECT the certificate subject.  The value is a DER encoded X509 NAME.
+     * This value is used when generating a self signed certificates.  This tag may be specified
      * during generateKey and importKey. If not provided the subject name shall default to
-     * <TODO default subject here>.
+     * CN="Android Keystore Key".
      */
     CERTIFICATE_SUBJECT = (9 << 28) /* TagType:BYTES */ | 1007,
 
     /**
      * Tag::CERTIFICATE_NOT_BEFORE the beginning of the validity of the certificate in UNIX epoch
-     * time in seconds. This value is used when generating attestation or self signed certificates.
-     * ErrorCode::MISSING_NOT_BEFORE must be returned if this tag is not provided if this tag is
-     * not provided to generateKey or importKey.
+     * time in seconds.  This value is used when generating attestation or self signed certificates.
+     * ErrorCode::MISSING_NOT_BEFORE must be returned if this tag is not provided if this tag is not
+     * provided to generateKey or importKey.
      */
     CERTIFICATE_NOT_BEFORE = (6 << 28) /* TagType:DATE */ | 1008,
 
     /**
-     * Tag::CERTIFICATE_NOT_AFTER the end of the validity of the certificate in UNIX epoch
-     * time in seconds. This value is used when generating attestation or self signed certificates.
-     * ErrorCode::MISSING_NOT_AFTER must be returned if this tag is not provided to generateKey
-     * or importKey.
+     * Tag::CERTIFICATE_NOT_AFTER the end of the validity of the certificate in UNIX epoch time in
+     * seconds.  This value is used when generating attestation or self signed certificates.
+     * ErrorCode::MISSING_NOT_AFTER must be returned if this tag is not provided to generateKey or
+     * importKey.
      */
     CERTIFICATE_NOT_AFTER = (6 << 28) /* TagType:DATE */ | 1009,
 
diff --git a/security/keymint/aidl/vts/functional/KeyMintAidlTestBase.cpp b/security/keymint/aidl/vts/functional/KeyMintAidlTestBase.cpp
index 6202a8b..61f2f77 100644
--- a/security/keymint/aidl/vts/functional/KeyMintAidlTestBase.cpp
+++ b/security/keymint/aidl/vts/functional/KeyMintAidlTestBase.cpp
@@ -119,7 +119,6 @@
 // Attestations don't contain everything in key authorization lists, so we need to filter the key
 // lists to produce the lists that we expect to match the attestations.
 auto kTagsToFilter = {
-        Tag::BLOB_USAGE_REQUIREMENTS,  //
         Tag::CREATION_DATETIME,        //
         Tag::EC_CURVE,
         Tag::HARDWARE_TYPE,
@@ -348,7 +347,7 @@
     SCOPED_TRACE("Begin");
     Status result;
     BeginResult out;
-    result = keymint_->begin(purpose, key_blob, in_params.vector_data(), HardwareAuthToken(), &out);
+    result = keymint_->begin(purpose, key_blob, in_params.vector_data(), std::nullopt, &out);
 
     if (result.isOk()) {
         *out_params = out.params;
@@ -366,7 +365,7 @@
     Status result;
     BeginResult out;
 
-    result = keymint_->begin(purpose, key_blob, in_params.vector_data(), HardwareAuthToken(), &out);
+    result = keymint_->begin(purpose, key_blob, in_params.vector_data(), std::nullopt, &out);
 
     if (result.isOk()) {
         *out_params = out.params;
@@ -942,7 +941,7 @@
     EXPECT_EQ(ErrorCode::OK, error);
     if (error != ErrorCode::OK) return false;
 
-    EXPECT_GE(att_attestation_version, 3U);
+    EXPECT_EQ(att_attestation_version, 100U);
     vector<uint8_t> appId(app_id.begin(), app_id.end());
 
     // check challenge and app id only if we expects a non-fake certificate
@@ -953,7 +952,7 @@
         expected_sw_enforced.push_back(TAG_ATTESTATION_APPLICATION_ID, appId);
     }
 
-    EXPECT_GE(att_keymaster_version, 4U);
+    EXPECT_EQ(att_keymaster_version, 100U);
     EXPECT_EQ(security_level, att_keymaster_security_level);
     EXPECT_EQ(security_level, att_attestation_security_level);
 
diff --git a/security/keymint/aidl/vts/functional/KeyMintTest.cpp b/security/keymint/aidl/vts/functional/KeyMintTest.cpp
index aa008f8..a89cc5b 100644
--- a/security/keymint/aidl/vts/functional/KeyMintTest.cpp
+++ b/security/keymint/aidl/vts/functional/KeyMintTest.cpp
@@ -5372,16 +5372,6 @@
 
 INSTANTIATE_KEYMINT_AIDL_TEST(UnlockedDeviceRequiredTest);
 
-using PerformOperationTest = KeyMintAidlTestBase;
-
-TEST_P(PerformOperationTest, RequireUnimplemented) {
-    vector<uint8_t> response;
-    auto result = keymint_->performOperation({} /* request */, &response);
-    ASSERT_EQ(GetReturnErrorCode(result), ErrorCode::UNIMPLEMENTED);
-}
-
-INSTANTIATE_KEYMINT_AIDL_TEST(PerformOperationTest);
-
 }  // namespace aidl::android::hardware::security::keymint::test
 
 int main(int argc, char** argv) {
diff --git a/security/keymint/aidl/vts/performance/KeyMintBenchmark.cpp b/security/keymint/aidl/vts/performance/KeyMintBenchmark.cpp
index 6c795f5..54b6fdc 100644
--- a/security/keymint/aidl/vts/performance/KeyMintBenchmark.cpp
+++ b/security/keymint/aidl/vts/performance/KeyMintBenchmark.cpp
@@ -228,8 +228,7 @@
                     AuthorizationSet* out_params) {
         Status result;
         BeginResult out;
-        result = keymint_->begin(purpose, key_blob_, in_params.vector_data(), HardwareAuthToken(),
-                                 &out);
+        result = keymint_->begin(purpose, key_blob_, in_params.vector_data(), std::nullopt, &out);
         if (result.isOk()) {
             *out_params = out.params;
             op_ = out.operation;