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 ce12fed..a6be6b1 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
@@ -42,6 +42,7 @@
   USAGE_EXPIRE_DATETIME = 1610613138,
   MIN_SECONDS_BETWEEN_OPS = 805306771,
   MAX_USES_PER_BOOT = 805306772,
+  USAGE_COUNT_LIMIT = 805306773,
   USER_ID = 805306869,
   USER_SECURE_ID = -1610612234,
   NO_AUTH_REQUIRED = 1879048695,
diff --git a/security/keymint/aidl/android/hardware/security/keymint/Tag.aidl b/security/keymint/aidl/android/hardware/security/keymint/Tag.aidl
index f92bf00..bc07235 100644
--- a/security/keymint/aidl/android/hardware/security/keymint/Tag.aidl
+++ b/security/keymint/aidl/android/hardware/security/keymint/Tag.aidl
@@ -333,6 +333,35 @@
     MAX_USES_PER_BOOT = (3 << 28) /* TagType:UINT */ | 404,
 
     /**
+     * Tag::USAGE_COUNT_LIMIT specifies the number of times that a key may be used. This can be
+     * used to limit the use of a key.
+     *
+     * The value is a 32-bit integer representing the current number of attempts left.
+     *
+     * When initializing a limited use key, the value of this tag represents the maximum usage
+     * limit for that key. After the key usage is exhausted, the key blob should be invalidated by
+     * finish() call. Any subsequent attempts to use the key must result in a failure with
+     * ErrorCode::INVALID_KEY_BLOB returned by IKeyMintDevice.
+     *
+     * At this point, if the caller specifies count > 1, it is not expected that any TEE will be
+     * able to enforce this feature in the hardware due to limited resources of secure
+     * storage. In this case, the tag with the value of maximum usage must be added to the key
+     * characteristics with SecurityLevel::SOFTWARE by the IKeyMintDevice.
+     *
+     * On the other hand, if the caller specifies count = 1, some TEEs may have the ability
+     * to enforce this feature in the hardware with its secure storage. If the IKeyMintDevice
+     * implementation can enforce this feature, the tag with value = 1 must be added to the key
+     * characteristics with the SecurityLevel of the IKeyMintDevice. If the IKeyMintDevice can't
+     * enforce this feature even when the count = 1, the tag must be added to the key
+     * characteristics with the SecurityLevel::SOFTWARE.
+     *
+     * When the key is attested, this tag with the same value must also be added to the attestation
+     * record. This tag must have the same SecurityLevel as the tag that is added to the key
+     * characteristics.
+     */
+    USAGE_COUNT_LIMIT = (3 << 28) | 405, /* TagType:UINT */
+
+    /**
      * Tag::USER_ID specifies the ID of the Android user that is permitted to use the key.
      *
      * Must not be hardware-enforced.
diff --git a/security/keymint/aidl/vts/functional/KeyMintTest.cpp b/security/keymint/aidl/vts/functional/KeyMintTest.cpp
index 5989cde..c876440 100644
--- a/security/keymint/aidl/vts/functional/KeyMintTest.cpp
+++ b/security/keymint/aidl/vts/functional/KeyMintTest.cpp
@@ -562,7 +562,7 @@
 }
 
 /*
- * NewKeyGenerationTest.Rsa
+ * NewKeyGenerationTest.RsaWithAttestation
  *
  * Verifies that keymint can generate all required RSA key sizes, and that the resulting keys
  * have correct characteristics.
@@ -607,6 +607,45 @@
 }
 
 /*
+ * NewKeyGenerationTest.LimitedUsageRsa
+ *
+ * Verifies that KeyMint can generate all required RSA key sizes with limited usage, and that the
+ * resulting keys have correct characteristics.
+ */
+TEST_P(NewKeyGenerationTest, LimitedUsageRsa) {
+    for (auto key_size : ValidKeySizes(Algorithm::RSA)) {
+        vector<uint8_t> key_blob;
+        vector<KeyCharacteristics> key_characteristics;
+        ASSERT_EQ(ErrorCode::OK, GenerateKey(AuthorizationSetBuilder()
+                                                     .RsaSigningKey(key_size, 65537)
+                                                     .Digest(Digest::NONE)
+                                                     .Padding(PaddingMode::NONE)
+                                                     .Authorization(TAG_USAGE_COUNT_LIMIT, 1),
+                                             &key_blob, &key_characteristics));
+
+        ASSERT_GT(key_blob.size(), 0U);
+        CheckBaseParams(key_characteristics);
+
+        AuthorizationSet crypto_params = SecLevelAuthorizations(key_characteristics);
+
+        EXPECT_TRUE(crypto_params.Contains(TAG_ALGORITHM, Algorithm::RSA));
+        EXPECT_TRUE(crypto_params.Contains(TAG_KEY_SIZE, key_size))
+                << "Key size " << key_size << "missing";
+        EXPECT_TRUE(crypto_params.Contains(TAG_RSA_PUBLIC_EXPONENT, 65537U));
+
+        // Check the usage count limit tag appears in the authorizations.
+        AuthorizationSet auths;
+        for (auto& entry : key_characteristics) {
+            auths.push_back(AuthorizationSet(entry.authorizations));
+        }
+        EXPECT_TRUE(auths.Contains(TAG_USAGE_COUNT_LIMIT, 1U))
+                << "key usage count limit " << 1U << " missing";
+
+        CheckedDeleteKey(&key_blob);
+    }
+}
+
+/*
  * NewKeyGenerationTest.NoInvalidRsaSizes
  *
  * Verifies that keymint cannot generate any RSA key sizes that are designated as invalid.
@@ -666,6 +705,43 @@
 }
 
 /*
+ * NewKeyGenerationTest.LimitedUsageEcdsa
+ *
+ * Verifies that KeyMint can generate all required EC key sizes with limited usage, and that the
+ * resulting keys have correct characteristics.
+ */
+TEST_P(NewKeyGenerationTest, LimitedUsageEcdsa) {
+    for (auto key_size : ValidKeySizes(Algorithm::EC)) {
+        vector<uint8_t> key_blob;
+        vector<KeyCharacteristics> key_characteristics;
+        ASSERT_EQ(ErrorCode::OK, GenerateKey(AuthorizationSetBuilder()
+                                                     .EcdsaSigningKey(key_size)
+                                                     .Digest(Digest::NONE)
+                                                     .Authorization(TAG_USAGE_COUNT_LIMIT, 1),
+                                             &key_blob, &key_characteristics));
+
+        ASSERT_GT(key_blob.size(), 0U);
+        CheckBaseParams(key_characteristics);
+
+        AuthorizationSet crypto_params = SecLevelAuthorizations(key_characteristics);
+
+        EXPECT_TRUE(crypto_params.Contains(TAG_ALGORITHM, Algorithm::EC));
+        EXPECT_TRUE(crypto_params.Contains(TAG_KEY_SIZE, key_size))
+                << "Key size " << key_size << "missing";
+
+        // Check the usage count limit tag appears in the authorizations.
+        AuthorizationSet auths;
+        for (auto& entry : key_characteristics) {
+            auths.push_back(AuthorizationSet(entry.authorizations));
+        }
+        EXPECT_TRUE(auths.Contains(TAG_USAGE_COUNT_LIMIT, 1U))
+                << "key usage count limit " << 1U << " missing";
+
+        CheckedDeleteKey(&key_blob);
+    }
+}
+
+/*
  * NewKeyGenerationTest.EcdsaDefaultSize
  *
  * Verifies that failing to specify a key size for EC key generation returns
@@ -780,6 +856,44 @@
 }
 
 /*
+ * NewKeyGenerationTest.LimitedUsageHmac
+ *
+ * Verifies that KeyMint supports all required digests with limited usage Hmac, and that the
+ * resulting keys have correct characteristics.
+ */
+TEST_P(NewKeyGenerationTest, LimitedUsageHmac) {
+    for (auto digest : ValidDigests(false /* withNone */, true /* withMD5 */)) {
+        vector<uint8_t> key_blob;
+        vector<KeyCharacteristics> key_characteristics;
+        constexpr size_t key_size = 128;
+        ASSERT_EQ(ErrorCode::OK, GenerateKey(AuthorizationSetBuilder()
+                                                     .HmacKey(key_size)
+                                                     .Digest(digest)
+                                                     .Authorization(TAG_MIN_MAC_LENGTH, 128)
+                                                     .Authorization(TAG_USAGE_COUNT_LIMIT, 1),
+                                             &key_blob, &key_characteristics));
+
+        ASSERT_GT(key_blob.size(), 0U);
+        CheckBaseParams(key_characteristics);
+
+        AuthorizationSet crypto_params = SecLevelAuthorizations(key_characteristics);
+        EXPECT_TRUE(crypto_params.Contains(TAG_ALGORITHM, Algorithm::HMAC));
+        EXPECT_TRUE(crypto_params.Contains(TAG_KEY_SIZE, key_size))
+                << "Key size " << key_size << "missing";
+
+        // Check the usage count limit tag appears in the authorizations.
+        AuthorizationSet auths;
+        for (auto& entry : key_characteristics) {
+            auths.push_back(AuthorizationSet(entry.authorizations));
+        }
+        EXPECT_TRUE(auths.Contains(TAG_USAGE_COUNT_LIMIT, 1U))
+                << "key usage count limit " << 1U << " missing";
+
+        CheckedDeleteKey(&key_blob);
+    }
+}
+
+/*
  * NewKeyGenerationTest.HmacCheckKeySizes
  *
  * Verifies that keymint supports all key sizes, and rejects all invalid key sizes.
@@ -4153,7 +4267,7 @@
 }
 
 /*
- * MaxOperationsTest.TestLimitAes
+ * MaxOperationsTest.TestLimitRsa
  *
  * Verifies that the max uses per boot tag works correctly with RSA keys.
  */
@@ -4180,6 +4294,100 @@
 
 INSTANTIATE_KEYMINT_AIDL_TEST(MaxOperationsTest);
 
+typedef KeyMintAidlTestBase UsageCountLimitTest;
+
+/*
+ * UsageCountLimitTest.TestLimitAes
+ *
+ * Verifies that the usage count limit tag works correctly with AES keys.
+ */
+TEST_P(UsageCountLimitTest, TestLimitAes) {
+    if (SecLevel() == SecurityLevel::STRONGBOX) return;
+
+    ASSERT_EQ(ErrorCode::OK, GenerateKey(AuthorizationSetBuilder()
+                                                 .Authorization(TAG_NO_AUTH_REQUIRED)
+                                                 .AesEncryptionKey(128)
+                                                 .EcbMode()
+                                                 .Padding(PaddingMode::NONE)
+                                                 .Authorization(TAG_USAGE_COUNT_LIMIT, 1)));
+
+    // Check the usage count limit tag appears in the authorizations.
+    AuthorizationSet auths;
+    for (auto& entry : key_characteristics_) {
+        auths.push_back(AuthorizationSet(entry.authorizations));
+    }
+    EXPECT_TRUE(auths.Contains(TAG_USAGE_COUNT_LIMIT, 1U))
+            << "key usage count limit " << 1U << " missing";
+
+    string message = "1234567890123456";
+    auto params = AuthorizationSetBuilder().EcbMode().Padding(PaddingMode::NONE);
+
+    // First usage of AES key should work.
+    EncryptMessage(message, params);
+
+    AuthorizationSet hardware_auths;
+    for (auto& entry : key_characteristics_) {
+        if (entry.securityLevel != SecurityLevel::SOFTWARE) {
+            auths.push_back(AuthorizationSet(entry.authorizations));
+        }
+    }
+    if (hardware_auths.Contains(TAG_USAGE_COUNT_LIMIT, 1U)) {
+        // Usage count limit tag is enforced by hardware. After using the key, the key blob
+        // must be invalidated from secure storage (such as RPMB partition).
+        EXPECT_EQ(ErrorCode::INVALID_KEY_BLOB, Begin(KeyPurpose::ENCRYPT, params));
+    } else {
+        // Usage count limit tag is enforced by software, keymint does nothing.
+        EXPECT_EQ(ErrorCode::OK, Begin(KeyPurpose::ENCRYPT, params));
+    }
+}
+
+/*
+ * UsageCountLimitTest.TestLimitRsa
+ *
+ * Verifies that the usage count limit tag works correctly with RSA keys.
+ */
+TEST_P(UsageCountLimitTest, TestLimitRsa) {
+    if (SecLevel() == SecurityLevel::STRONGBOX) return;
+
+    ASSERT_EQ(ErrorCode::OK, GenerateKey(AuthorizationSetBuilder()
+                                                 .Authorization(TAG_NO_AUTH_REQUIRED)
+                                                 .RsaSigningKey(1024, 65537)
+                                                 .NoDigestOrPadding()
+                                                 .Authorization(TAG_USAGE_COUNT_LIMIT, 1)));
+
+    // Check the usage count limit tag appears in the authorizations.
+    AuthorizationSet auths;
+    for (auto& entry : key_characteristics_) {
+        auths.push_back(AuthorizationSet(entry.authorizations));
+    }
+    EXPECT_TRUE(auths.Contains(TAG_USAGE_COUNT_LIMIT, 1U))
+            << "key usage count limit " << 1U << " missing";
+
+    string message = "1234567890123456";
+    auto params = AuthorizationSetBuilder().NoDigestOrPadding();
+
+    // First usage of RSA key should work.
+    SignMessage(message, params);
+
+    AuthorizationSet hardware_auths;
+    for (auto& entry : key_characteristics_) {
+        if (entry.securityLevel != SecurityLevel::SOFTWARE) {
+            auths.push_back(AuthorizationSet(entry.authorizations));
+        }
+    }
+
+    if (hardware_auths.Contains(TAG_USAGE_COUNT_LIMIT, 1U)) {
+        // Usage count limit tag is enforced by hardware. After using the key, the key blob
+        // must be invalidated from secure storage (such as RPMB partition).
+        EXPECT_EQ(ErrorCode::INVALID_KEY_BLOB, Begin(KeyPurpose::SIGN, params));
+    } else {
+        // Usage count limit tag is enforced by software, keymint does nothing.
+        EXPECT_EQ(ErrorCode::OK, Begin(KeyPurpose::SIGN, params));
+    }
+}
+
+INSTANTIATE_KEYMINT_AIDL_TEST(UsageCountLimitTest);
+
 typedef KeyMintAidlTestBase AddEntropyTest;
 
 /*
diff --git a/security/keymint/support/include/keymint_support/keymint_tags.h b/security/keymint/support/include/keymint_support/keymint_tags.h
index 76aecb7..8d2fe28 100644
--- a/security/keymint/support/include/keymint_support/keymint_tags.h
+++ b/security/keymint/support/include/keymint_support/keymint_tags.h
@@ -119,6 +119,7 @@
 DECLARE_TYPED_TAG(TRUSTED_USER_PRESENCE_REQUIRED);
 DECLARE_TYPED_TAG(UNIQUE_ID);
 DECLARE_TYPED_TAG(UNLOCKED_DEVICE_REQUIRED);
+DECLARE_TYPED_TAG(USAGE_COUNT_LIMIT);
 DECLARE_TYPED_TAG(USAGE_EXPIRE_DATETIME);
 DECLARE_TYPED_TAG(USER_AUTH_TYPE);
 DECLARE_TYPED_TAG(USER_ID);
@@ -135,15 +136,15 @@
         TAG_INVALID_t, TAG_KEY_SIZE_t, TAG_MAC_LENGTH_t, TAG_CALLER_NONCE_t, TAG_MIN_MAC_LENGTH_t,
         TAG_RSA_PUBLIC_EXPONENT_t, TAG_INCLUDE_UNIQUE_ID_t, TAG_ACTIVE_DATETIME_t,
         TAG_ORIGINATION_EXPIRE_DATETIME_t, TAG_USAGE_EXPIRE_DATETIME_t,
-        TAG_MIN_SECONDS_BETWEEN_OPS_t, TAG_MAX_USES_PER_BOOT_t, TAG_USER_ID_t, TAG_USER_SECURE_ID_t,
-        TAG_NO_AUTH_REQUIRED_t, TAG_AUTH_TIMEOUT_t, TAG_ALLOW_WHILE_ON_BODY_t,
-        TAG_UNLOCKED_DEVICE_REQUIRED_t, TAG_APPLICATION_ID_t, TAG_APPLICATION_DATA_t,
-        TAG_CREATION_DATETIME_t, TAG_ROLLBACK_RESISTANCE_t, TAG_HARDWARE_TYPE_t,
-        TAG_ROOT_OF_TRUST_t, TAG_ASSOCIATED_DATA_t, TAG_NONCE_t, TAG_BOOTLOADER_ONLY_t,
-        TAG_OS_VERSION_t, TAG_OS_PATCHLEVEL_t, TAG_UNIQUE_ID_t, TAG_ATTESTATION_CHALLENGE_t,
-        TAG_ATTESTATION_APPLICATION_ID_t, TAG_ATTESTATION_ID_BRAND_t, TAG_ATTESTATION_ID_DEVICE_t,
-        TAG_ATTESTATION_ID_PRODUCT_t, TAG_ATTESTATION_ID_MANUFACTURER_t, TAG_ATTESTATION_ID_MODEL_t,
-        TAG_ATTESTATION_ID_SERIAL_t, TAG_ATTESTATION_ID_IMEI_t, TAG_ATTESTATION_ID_MEID_t,
+        TAG_MIN_SECONDS_BETWEEN_OPS_t, TAG_MAX_USES_PER_BOOT_t, TAG_USAGE_COUNT_LIMIT_t,
+        TAG_USER_ID_t, TAG_USER_SECURE_ID_t, TAG_NO_AUTH_REQUIRED_t, TAG_AUTH_TIMEOUT_t,
+        TAG_ALLOW_WHILE_ON_BODY_t, TAG_UNLOCKED_DEVICE_REQUIRED_t, TAG_APPLICATION_ID_t,
+        TAG_APPLICATION_DATA_t, TAG_CREATION_DATETIME_t, TAG_ROLLBACK_RESISTANCE_t,
+        TAG_HARDWARE_TYPE_t, TAG_ROOT_OF_TRUST_t, TAG_ASSOCIATED_DATA_t, TAG_NONCE_t,
+        TAG_BOOTLOADER_ONLY_t, TAG_OS_VERSION_t, TAG_OS_PATCHLEVEL_t, TAG_UNIQUE_ID_t,
+        TAG_ATTESTATION_CHALLENGE_t, TAG_ATTESTATION_APPLICATION_ID_t, TAG_ATTESTATION_ID_BRAND_t,
+        TAG_ATTESTATION_ID_DEVICE_t, TAG_ATTESTATION_ID_PRODUCT_t,
+        TAG_ATTESTATION_ID_MANUFACTURER_t, TAG_ATTESTATION_ID_MODEL_t,
         TAG_RESET_SINCE_ID_ROTATION_t, TAG_PURPOSE_t, TAG_ALGORITHM_t, TAG_BLOCK_MODE_t,
         TAG_DIGEST_t, TAG_PADDING_t, TAG_ORIGIN_t, TAG_USER_AUTH_TYPE_t, TAG_EC_CURVE_t,
         TAG_BOOT_PATCHLEVEL_t, TAG_VENDOR_PATCHLEVEL_t, TAG_TRUSTED_CONFIRMATION_REQUIRED_t,