diff --git a/keystore2/src/auth_token_handler.rs b/keystore2/src/auth_token_handler.rs
index a1f9399..bedec50 100644
--- a/keystore2/src/auth_token_handler.rs
+++ b/keystore2/src/auth_token_handler.rs
@@ -13,11 +13,15 @@
 // limitations under the License.
 
 //! This module defines the AuthTokenHandler enum and its methods. AuthTokenHandler enum represents
-//! the different states an auth token and an associated verification token can be expressed during
+//! the different states an auth token and an associated timestamp token can be expressed during
 //! the operation life cycle.
 use android_hardware_security_keymint::aidl::android::hardware::security::keymint::{
-    HardwareAuthToken::HardwareAuthToken, VerificationToken::VerificationToken,
+    HardwareAuthToken::HardwareAuthToken,
 };
+use android_hardware_security_secureclock::aidl::android::hardware::security::secureclock::{
+    TimeStampToken::TimeStampToken,
+};
+
 use anyhow::{Context, Result};
 use std::sync::mpsc::Receiver;
 
@@ -32,48 +36,48 @@
     OpAuthRequired,
     /// Used to represent the intermediate state between the time the operation is found to be
     /// using a time_out key with STRONGBOX keymint, and the time a verficiation token is requested
-    /// from the worker thread which obtains verification tokens from the TEE KeyMint.
-    VerificationRequired(HardwareAuthToken),
-    /// Used to represent the intermediate state between the time a verification token is requested
-    /// from the worker thread which obtains verification tokens from the TEE KeyMint and the time
-    /// the verification token is received from the worker thread.
-    Channel(Receiver<(HardwareAuthToken, VerificationToken)>),
+    /// from the worker thread which obtains timestamp tokens from the TEE KeyMint.
+    TimestampRequired(HardwareAuthToken),
+    /// Used to represent the intermediate state between the time a timestamp token is requested
+    /// from the worker thread which obtains timestamp tokens from the TEE KeyMint and the time
+    /// the timestamp token is received from the worker thread.
+    Channel(Receiver<(HardwareAuthToken, TimeStampToken)>),
     /// Used to represent the final state for all operations requiring an auth token for
-    /// authorization, after the matching auth token (and the associated verification token if
+    /// authorization, after the matching auth token (and the associated timestamp token if
     /// required) is found.
-    Token(HardwareAuthToken, Option<VerificationToken>),
+    Token(HardwareAuthToken, Option<TimeStampToken>),
 }
 
 impl AuthTokenHandler {
-    /// If Channel variant, block on it until the verification token is sent by the
-    /// keystore2 worker thread which obtains verification tokens from TEE Keymint and converts the
+    /// If Channel variant, block on it until the timestamp token is sent by the
+    /// keystore2 worker thread which obtains timestamp tokens from TEE Keymint and converts the
     /// object from Channel variant to Token variant.
-    /// Retrieve auth token and verification token from the Token variant of an AuthTokenHandler
+    /// Retrieve auth token and timestamp token from the Token variant of an AuthTokenHandler
     /// instance.
-    pub fn retrieve_auth_and_verification_tokens(
+    pub fn retrieve_auth_and_timestamp_tokens(
         &mut self,
-    ) -> Result<(Option<&HardwareAuthToken>, Option<&VerificationToken>)> {
+    ) -> Result<(Option<&HardwareAuthToken>, Option<&TimeStampToken>)> {
         // Converts to Token variant if Channel variant found, after retrieving the
-        // VerificationToken
+        // TimeStampToken
         if let AuthTokenHandler::Channel(recv) = self {
-            let (auth_token, verification_token) =
-                recv.recv().context("In receive_verification_token: sender disconnected.")?;
-            *self = AuthTokenHandler::Token(auth_token, Some(verification_token));
+            let (auth_token, timestamp_token) =
+                recv.recv().context("In receive_timestamp_token: sender disconnected.")?;
+            *self = AuthTokenHandler::Token(auth_token, Some(timestamp_token));
         }
         // get the tokens from the Token variant
-        if let AuthTokenHandler::Token(auth_token, optional_verification_token) = self {
-            Ok((Some(auth_token), optional_verification_token.as_ref()))
+        if let AuthTokenHandler::Token(auth_token, optional_time_stamp_token) = self {
+            Ok((Some(auth_token), optional_time_stamp_token.as_ref()))
         } else {
             Ok((None, None))
         }
     }
 
-    /// Retrieve auth token from VerificationRequired and Token variants of an
+    /// Retrieve auth token from TimestampRequired and Token variants of an
     /// AuthTokenHandler instance. This method is useful when we only expect an auth token and
-    /// do not expect a verification token.
+    /// do not expect a timestamp token.
     pub fn get_auth_token(&self) -> Option<&HardwareAuthToken> {
         match self {
-            AuthTokenHandler::VerificationRequired(auth_token) => Some(auth_token),
+            AuthTokenHandler::TimestampRequired(auth_token) => Some(auth_token),
             AuthTokenHandler::Token(auth_token, _) => Some(auth_token),
             _ => None,
         }
diff --git a/keystore2/src/authorization.rs b/keystore2/src/authorization.rs
index 08ae07c..409feba 100644
--- a/keystore2/src/authorization.rs
+++ b/keystore2/src/authorization.rs
@@ -20,6 +20,8 @@
 use crate::utils::check_keystore_permission;
 use android_hardware_security_keymint::aidl::android::hardware::security::keymint::{
     HardwareAuthToken::HardwareAuthToken, HardwareAuthenticatorType::HardwareAuthenticatorType,
+};
+use android_hardware_security_secureclock::aidl::android::hardware::security::secureclock::{
     Timestamp::Timestamp,
 };
 use android_security_authorization::binder::{Interface, Result as BinderResult};
diff --git a/keystore2/src/background_task_handler.rs b/keystore2/src/background_task_handler.rs
index fbb6778..b039506 100644
--- a/keystore2/src/background_task_handler.rs
+++ b/keystore2/src/background_task_handler.rs
@@ -16,8 +16,10 @@
 //! the timestamp service (or TEE KeyMint in legacy devices), via a separate thread.
 
 use android_hardware_security_keymint::aidl::android::hardware::security::keymint::{
-    HardwareAuthToken::HardwareAuthToken, IKeyMintDevice::IKeyMintDevice,
-    SecurityLevel::SecurityLevel, VerificationToken::VerificationToken,
+    HardwareAuthToken::HardwareAuthToken,
+};
+use android_hardware_security_secureclock::aidl::android::hardware::security::secureclock::{
+    ISecureClock::ISecureClock, TimeStampToken::TimeStampToken,
 };
 use android_system_keystore2::aidl::android::system::keystore2::OperationChallenge::OperationChallenge;
 use anyhow::Result;
@@ -25,16 +27,20 @@
 use std::sync::mpsc::{Receiver, Sender};
 use std::sync::Mutex;
 use std::thread::{spawn, JoinHandle};
+
+use crate::globals::get_timestamp_service;
+
 /// This is the struct encapsulating the thread which handles background tasks such as
-/// obtaining verification tokens.
+/// obtaining timestamp tokens.
 pub struct BackgroundTaskHandler {
     task_handler: Mutex<Option<JoinHandle<()>>>,
 }
+
 /// This enum defines the two variants of a message that can be passed down to the
 /// BackgroundTaskHandler via the channel.
 pub enum Message {
     ///This variant represents a message sent down the channel when requesting a timestamp token.
-    Inputs((HardwareAuthToken, OperationChallenge, Sender<(HardwareAuthToken, VerificationToken)>)),
+    Inputs((HardwareAuthToken, OperationChallenge, Sender<(HardwareAuthToken, TimeStampToken)>)),
     ///This variant represents a message sent down the channel when signalling the thread to stop.
     Shutdown,
 }
@@ -65,34 +71,32 @@
         // If either a timestamp service or a keymint instance is expected to be found and neither
         // is found, an error is returned.
         // If neither is expected to be found, make timestamp_service field None, and in the thread,
-        // send a default verification token down the channel to the operation.
+        // send a default timestamp token down the channel to the operation.
         // Until timestamp service is available and proper probing of legacy keymaster devices are
         // done, the keymint service is initialized here as it is done in security_level module.
         Ok(spawn(move || {
-            while let Message::Inputs((auth_token, op_challenge, op_sender)) = receiver
-                .recv()
-                .expect(
-                "In background task handler thread. Failed to receive message over the channel.",
-            ) {
-                // TODO: call the timestamp service/old TEE keymaster to get
-                // timestamp/verification tokens and pass it down the sender that is
-                // coupled with a particular operation's receiver.
-                // If none of the services are available, pass the authtoken and a default
-                // verification token down the channel.
-                let km_dev: Box<dyn IKeyMintDevice> =
-                    crate::globals::get_keymint_device(SecurityLevel::TRUSTED_ENVIRONMENT)
-                        .expect("A TEE Keymint must be present.")
-                        .get_interface()
-                        .expect("Fatal: The keymint device does not implement IKeyMintDevice.");
-                let result = km_dev.verifyAuthorization(op_challenge.challenge, &auth_token);
+            while let Message::Inputs((auth_token, op_challenge, op_sender)) =
+                receiver.recv().expect(
+                    "In background task handler thread. Failed to
+                receive message over the channel.",
+                )
+            {
+                let dev: Box<dyn ISecureClock> = get_timestamp_service()
+                    .expect(concat!(
+                        "Secure Clock service must be present ",
+                        "if TimeStampTokens are required."
+                    ))
+                    .get_interface()
+                    .expect("Fatal: Timestamp service does not implement ISecureClock.");
+                let result = dev.generateTimeStamp(op_challenge.challenge);
                 match result {
-                    Ok(verification_token) => {
+                    Ok(timestamp_token) => {
                         // this can fail if the operation is dropped and hence the channel
                         // is hung up.
-                        op_sender.send((auth_token, verification_token)).unwrap_or_else(|e| {
+                        op_sender.send((auth_token, timestamp_token)).unwrap_or_else(|e| {
                             error!(
                                 "In background task handler thread. Failed to send
-                                         verification token to operation {} due to error {:?}.",
+                                         timestamp token to operation {} due to error {:?}.",
                                 op_challenge.challenge, e
                             )
                         });
@@ -101,17 +105,17 @@
                         // log error
                         error!(
                             "In background task handler thread. Failed to receive
-                                     verification token for operation {} due to error {:?}.",
+                                     timestamp token for operation {} due to error {:?}.",
                             op_challenge.challenge, e
                         );
-                        // send default verification token
+                        // send default timestamp token
                         // this can fail if the operation is dropped and the channel is
                         // hung up.
-                        op_sender.send((auth_token, VerificationToken::default())).unwrap_or_else(
+                        op_sender.send((auth_token, TimeStampToken::default())).unwrap_or_else(
                             |e| {
                                 error!(
                                     "In background task handler thread. Failed to send default
-                                         verification token to operation {} due to error {:?}.",
+                                         timestamp token to operation {} due to error {:?}.",
                                     op_challenge.challenge, e
                                 )
                             },
diff --git a/keystore2/src/database.rs b/keystore2/src/database.rs
index ab8b05f..e25fea2 100644
--- a/keystore2/src/database.rs
+++ b/keystore2/src/database.rs
@@ -58,6 +58,8 @@
 use android_hardware_security_keymint::aidl::android::hardware::security::keymint::{
     ErrorCode::ErrorCode as Ec, HardwareAuthToken::HardwareAuthToken,
     HardwareAuthenticatorType::HardwareAuthenticatorType, SecurityLevel::SecurityLevel,
+};
+use android_hardware_security_secureclock::aidl::android::hardware::security::secureclock::{
     Timestamp::Timestamp,
 };
 use android_system_keystore2::aidl::android::system::keystore2::{
@@ -1811,6 +1813,8 @@
     use android_hardware_security_keymint::aidl::android::hardware::security::keymint::{
         HardwareAuthToken::HardwareAuthToken,
         HardwareAuthenticatorType::HardwareAuthenticatorType as kmhw_authenticator_type,
+    };
+    use android_hardware_security_secureclock::aidl::android::hardware::security::secureclock::{
         Timestamp::Timestamp,
     };
     use rusqlite::NO_PARAMS;
diff --git a/keystore2/src/enforcements.rs b/keystore2/src/enforcements.rs
index ae41432..93e077c 100644
--- a/keystore2/src/enforcements.rs
+++ b/keystore2/src/enforcements.rs
@@ -23,8 +23,10 @@
 use android_hardware_security_keymint::aidl::android::hardware::security::keymint::{
     Algorithm::Algorithm, ErrorCode::ErrorCode as Ec, HardwareAuthToken::HardwareAuthToken,
     HardwareAuthenticatorType::HardwareAuthenticatorType, KeyPurpose::KeyPurpose,
-    SecurityLevel::SecurityLevel, Tag::Tag, Timestamp::Timestamp,
-    VerificationToken::VerificationToken,
+    SecurityLevel::SecurityLevel, Tag::Tag,
+};
+use android_hardware_security_secureclock::aidl::android::hardware::security::secureclock::{
+    TimeStampToken::TimeStampToken, Timestamp::Timestamp,
 };
 use android_system_keystore2::aidl::android::system::keystore2::OperationChallenge::OperationChallenge;
 use anyhow::{Context, Result};
@@ -152,8 +154,8 @@
     /// With regard to auth tokens, the following steps are taken:
     /// If the key is time-bound, find a matching auth token from the database.
     /// If the above step is successful, and if the security level is STRONGBOX, return a
-    /// VerificationRequired variant of the AuthTokenHandler with the found auth token to signal
-    /// the operation that it may need to obtain a verification token from TEE KeyMint.
+    /// TimestampRequired variant of the AuthTokenHandler with the found auth token to signal
+    /// the operation that it may need to obtain a timestamp token from TEE KeyMint.
     /// If the security level is not STRONGBOX, return a Token variant of the AuthTokenHandler with
     /// the found auth token to signal the operation that no more authorization required.
     /// If the key is per-op, return an OpAuthRequired variant of the AuthTokenHandler to signal
@@ -346,7 +348,7 @@
                     .context("In authorize_create.")?;
 
                 if security_level == SecurityLevel::STRONGBOX {
-                    return Ok(AuthTokenHandler::VerificationRequired(auth_token));
+                    return Ok(AuthTokenHandler::TimestampRequired(auth_token));
                 } else {
                     return Ok(AuthTokenHandler::Token(auth_token, None));
                 }
@@ -431,18 +433,18 @@
         op_auth_map_guard.insert(op_challenge, None);
     }
 
-    /// Requests a verification token from the background task handler which will retrieve it from
+    /// Requests a timestamp token from the background task handler which will retrieve it from
     /// Timestamp Service or TEE KeyMint.
     /// Once the create_operation receives an operation challenge from KeyMint, if it has
-    /// previously received a VerificationRequired variant of AuthTokenHandler during
-    /// authorize_create_operation, it calls this method to obtain a VerificationToken.
-    pub fn request_verification_token(
+    /// previously received a TimestampRequired variant of AuthTokenHandler during
+    /// authorize_create_operation, it calls this method to obtain a TimeStampToken.
+    pub fn request_timestamp_token(
         &self,
         auth_token: HardwareAuthToken,
         op_challenge: OperationChallenge,
     ) -> Result<AuthTokenHandler> {
         // create a channel for this particular operation
-        let (op_sender, op_receiver) = channel::<(HardwareAuthToken, VerificationToken)>();
+        let (op_sender, op_receiver) = channel::<(HardwareAuthToken, TimeStampToken)>();
         // it is ok to unwrap here because there is no way this mutex gets poisoned.
         let sender_guard = self.sender_to_bth.lock().unwrap();
         if let Some(sender) = &*sender_guard {
@@ -452,7 +454,7 @@
                 .send(Message::Inputs((auth_token, op_challenge, op_sender)))
                 .map_err(|_| KeystoreError::sys())
                 .context(
-                    "In request_verification_token. Sending a request for a verification token
+                    "In request_timestamp_token. Sending a request for a timestamp token
              failed.",
                 )?;
         }
diff --git a/keystore2/src/globals.rs b/keystore2/src/globals.rs
index 035dac1..3c79eed 100644
--- a/keystore2/src/globals.rs
+++ b/keystore2/src/globals.rs
@@ -80,12 +80,12 @@
     pub static ref SUPER_KEY: SuperKeyManager = Default::default();
     /// Map of KeyMint devices.
     static ref KEY_MINT_DEVICES: Mutex<HashMap<SecurityLevel, Asp>> = Default::default();
+    /// Timestamp service.
+    static ref TIME_STAMP_DEVICE: Mutex<Option<Asp>> = Default::default();
     /// A single on-demand worker thread that handles deferred tasks with two different
     /// priorities.
     pub static ref ASYNC_TASK: AsyncTask = Default::default();
     /// Singeleton for enforcements.
-    /// It is safe for this enforcements object to be called by multiple threads because the two
-    /// data structures which maintain its state are protected by mutexes.
     pub static ref ENFORCEMENTS: Enforcements = Enforcements::new();
     /// Background task handler is initialized and exists globally.
     /// The other modules (e.g. enforcements) communicate with it via a channel initialized during
@@ -142,11 +142,58 @@
     if let Some(dev) = devices_map.get(&security_level) {
         Ok(dev.clone())
     } else {
-        let dev = connect_keymint(security_level).map_err(|e| {
-            anyhow::anyhow!(Error::Km(ErrorCode::HARDWARE_TYPE_UNAVAILABLE))
-                .context(format!("In get_keymint_device: {:?}", e))
-        })?;
+        let dev = connect_keymint(security_level).context("In get_keymint_device.")?;
         devices_map.insert(security_level, dev.clone());
         Ok(dev)
     }
 }
+
+static TIME_STAMP_SERVICE_NAME: &str = "android.hardware.security.secureclock.ISecureClock";
+
+/// Make a new connection to a secure clock service.
+/// If no native SecureClock device can be found brings up the compatibility service and attempts
+/// to connect to the legacy wrapper.
+fn connect_secureclock() -> Result<Asp> {
+    let secureclock = map_binder_status_code(binder::get_interface(TIME_STAMP_SERVICE_NAME))
+        .context("In connect_secureclock: Trying to connect to genuine secure clock service.")
+        .or_else(|e| {
+            match e.root_cause().downcast_ref::<Error>() {
+                Some(Error::BinderTransaction(StatusCode::NAME_NOT_FOUND)) => {
+                    // This is a no-op if it was called before.
+                    keystore2_km_compat::add_keymint_device_service();
+
+                    let keystore_compat_service: Box<dyn IKeystoreCompatService> =
+                        map_binder_status_code(binder::get_interface("android.security.compat"))
+                            .context(
+                                "In connect_secureclock: Trying to connect to compat service.",
+                            )?;
+
+                    // Legacy secure clock services were only implemented by TEE.
+                    map_binder_status(keystore_compat_service.getSecureClock())
+                        .map_err(|e| match e {
+                            Error::BinderTransaction(StatusCode::NAME_NOT_FOUND) => {
+                                Error::Km(ErrorCode::HARDWARE_TYPE_UNAVAILABLE)
+                            }
+                            e => e,
+                        })
+                        .context("In connect_secureclock: Trying to get Legacy wrapper.")
+                }
+                _ => Err(e),
+            }
+        })?;
+
+    Ok(Asp::new(secureclock.as_binder()))
+}
+
+/// Get the timestamp service that verifies auth token timeliness towards security levels with
+/// different clocks.
+pub fn get_timestamp_service() -> Result<Asp> {
+    let mut ts_device = TIME_STAMP_DEVICE.lock().unwrap();
+    if let Some(dev) = &*ts_device {
+        Ok(dev.clone())
+    } else {
+        let dev = connect_secureclock().context("In get_timestamp_service.")?;
+        *ts_device = Some(dev.clone());
+        Ok(dev)
+    }
+}
diff --git a/keystore2/src/km_compat/km_compat.cpp b/keystore2/src/km_compat/km_compat.cpp
index ac16666..d965922 100644
--- a/keystore2/src/km_compat/km_compat.cpp
+++ b/keystore2/src/km_compat/km_compat.cpp
@@ -35,7 +35,6 @@
 using ::aidl::android::hardware::security::keymint::Digest;
 using ::aidl::android::hardware::security::keymint::PaddingMode;
 using ::aidl::android::hardware::security::keymint::Tag;
-using ::aidl::android::hardware::security::keymint::VerificationToken;
 using ::aidl::android::system::keystore2::ResponseCode;
 using ::android::hardware::hidl_vec;
 using ::android::hardware::keymaster::V4_0::TagType;
@@ -100,13 +99,13 @@
     return legacyAt;
 }
 
-static V4_0_VerificationToken convertVerificationTokenToLegacy(const VerificationToken& vt) {
+static V4_0_VerificationToken convertTimestampTokenToLegacy(const TimeStampToken& tst) {
     V4_0_VerificationToken legacyVt;
-    legacyVt.challenge = vt.challenge;
-    legacyVt.timestamp = vt.timestamp.milliSeconds;
-    legacyVt.securityLevel =
-        static_cast<::android::hardware::keymaster::V4_0::SecurityLevel>(vt.securityLevel);
-    legacyVt.mac = vt.mac;
+    legacyVt.challenge = tst.challenge;
+    legacyVt.timestamp = tst.timestamp.milliSeconds;
+    // Legacy verification tokens were always minted by TEE.
+    legacyVt.securityLevel = V4_0::SecurityLevel::TRUSTED_ENVIRONMENT;
+    legacyVt.mac = tst.mac;
     return legacyVt;
 }
 
@@ -172,14 +171,6 @@
     return ScopedAStatus::ok();
 }
 
-// We're not implementing this.
-ScopedAStatus KeyMintDevice::verifyAuthorization(int64_t in_challenge ATTRIBUTE_UNUSED,
-                                                 const HardwareAuthToken& in_token ATTRIBUTE_UNUSED,
-                                                 VerificationToken* _aidl_return ATTRIBUTE_UNUSED) {
-    return ScopedAStatus::fromServiceSpecificError(
-        static_cast<int32_t>(V4_0_ErrorCode::UNIMPLEMENTED));
-}
-
 ScopedAStatus KeyMintDevice::addRngEntropy(const std::vector<uint8_t>& in_data) {
     V4_0_ErrorCode errorCode = mDevice->addRngEntropy(in_data);
     return convertErrorCode(errorCode);
@@ -346,13 +337,13 @@
     return convertErrorCode(errorCode);
 }
 
-ScopedAStatus
-KeyMintOperation::update(const std::optional<KeyParameterArray>& in_inParams,
-                         const std::optional<std::vector<uint8_t>>& in_input,
-                         const std::optional<HardwareAuthToken>& in_inAuthToken,
-                         const std::optional<VerificationToken>& in_inVerificationToken,
-                         std::optional<KeyParameterArray>* out_outParams,
-                         std::optional<ByteArray>* out_output, int32_t* _aidl_return) {
+ScopedAStatus KeyMintOperation::update(const std::optional<KeyParameterArray>& in_inParams,
+                                       const std::optional<std::vector<uint8_t>>& in_input,
+                                       const std::optional<HardwareAuthToken>& in_inAuthToken,
+                                       const std::optional<TimeStampToken>& in_inTimeStampToken,
+                                       std::optional<KeyParameterArray>* out_outParams,
+                                       std::optional<ByteArray>* out_output,
+                                       int32_t* _aidl_return) {
     std::vector<V4_0_KeyParameter> legacyParams;
     if (in_inParams.has_value()) {
         legacyParams = convertKeyParametersToLegacy(in_inParams.value().params);
@@ -363,8 +354,8 @@
         authToken = convertAuthTokenToLegacy(in_inAuthToken.value());
     }
     V4_0_VerificationToken verificationToken;
-    if (in_inVerificationToken.has_value()) {
-        verificationToken = convertVerificationTokenToLegacy(in_inVerificationToken.value());
+    if (in_inTimeStampToken.has_value()) {
+        verificationToken = convertTimestampTokenToLegacy(in_inTimeStampToken.value());
     }
     V4_0_ErrorCode errorCode;
     auto result = mDevice->update(
@@ -389,14 +380,13 @@
     return convertErrorCode(errorCode);
 }
 
-ScopedAStatus
-KeyMintOperation::finish(const std::optional<KeyParameterArray>& in_inParams,
-                         const std::optional<std::vector<uint8_t>>& in_input,
-                         const std::optional<std::vector<uint8_t>>& in_inSignature,
-                         const std::optional<HardwareAuthToken>& in_authToken,
-                         const std::optional<VerificationToken>& in_inVerificationToken,
-                         std::optional<KeyParameterArray>* out_outParams,
-                         std::vector<uint8_t>* _aidl_return) {
+ScopedAStatus KeyMintOperation::finish(const std::optional<KeyParameterArray>& in_inParams,
+                                       const std::optional<std::vector<uint8_t>>& in_input,
+                                       const std::optional<std::vector<uint8_t>>& in_inSignature,
+                                       const std::optional<HardwareAuthToken>& in_authToken,
+                                       const std::optional<TimeStampToken>& in_inTimeStampToken,
+                                       std::optional<KeyParameterArray>* out_outParams,
+                                       std::vector<uint8_t>* _aidl_return) {
     V4_0_ErrorCode errorCode;
     std::vector<V4_0_KeyParameter> legacyParams;
     if (in_inParams.has_value()) {
@@ -409,8 +399,8 @@
         authToken = convertAuthTokenToLegacy(in_authToken.value());
     }
     V4_0_VerificationToken verificationToken;
-    if (in_inVerificationToken.has_value()) {
-        verificationToken = convertVerificationTokenToLegacy(in_inVerificationToken.value());
+    if (in_inTimeStampToken.has_value()) {
+        verificationToken = convertTimestampTokenToLegacy(in_inTimeStampToken.value());
     }
     auto result = mDevice->finish(
         mOperationHandle, legacyParams, input, signature, authToken, verificationToken,
@@ -454,9 +444,6 @@
             errorCode = error;
             _aidl_return->challenge = token.challenge;
             _aidl_return->timestamp.milliSeconds = token.timestamp;
-            _aidl_return->securityLevel =
-                static_cast<::aidl::android::hardware::security::keymint::SecurityLevel>(
-                    token.securityLevel);
             _aidl_return->mac = token.mac;
         });
     if (!result.isOk()) {
@@ -679,8 +666,8 @@
             std::optional<KeyParameterArray> outParams;
             std::optional<ByteArray> outByte;
             int32_t status;
-            beginResult.operation->update(std::nullopt, dataVec, HardwareAuthToken(),
-                                          VerificationToken(), &outParams, &outByte, &status);
+            beginResult.operation->update(std::nullopt, dataVec, std::nullopt, std::nullopt,
+                                          &outParams, &outByte, &status);
             if (!status) {
                 return std::vector<uint8_t>();
             }
@@ -920,26 +907,31 @@
 }
 
 sp<Keymaster> getDevice(KeyMintSecurityLevel securityLevel) {
-    auto secLevel = static_cast<SecurityLevel>(securityLevel);
-    auto devices = initializeKeymasters();
-    return devices[secLevel];
+    static std::mutex mutex;
+    static sp<Keymaster> teeDevice;
+    static sp<Keymaster> sbDevice;
+    std::lock_guard<std::mutex> lock(mutex);
+    if (!teeDevice) {
+        auto devices = initializeKeymasters();
+        teeDevice = devices[V4_0::SecurityLevel::TRUSTED_ENVIRONMENT];
+        sbDevice = devices[V4_0::SecurityLevel::STRONGBOX];
+    }
+    switch (securityLevel) {
+    case KeyMintSecurityLevel::TRUSTED_ENVIRONMENT:
+        return teeDevice;
+    case KeyMintSecurityLevel::STRONGBOX:
+        return sbDevice;
+    default:
+        return {};
+    }
 }
 
 std::shared_ptr<KeyMintDevice>
 KeyMintDevice::createKeyMintDevice(KeyMintSecurityLevel securityLevel) {
-    static std::mutex mutex;
-    std::lock_guard<std::mutex> lock(mutex);
-    static std::shared_ptr<KeyMintDevice> device_ptr;
-    if (!device_ptr) {
-        auto secLevel = static_cast<SecurityLevel>(securityLevel);
-        auto devices = initializeKeymasters();
-        auto device = devices[secLevel];
-        if (!device) {
-            return {};
-        }
-        device_ptr = ndk::SharedRefBase::make<KeyMintDevice>(std::move(device), securityLevel);
+    if (auto dev = getDevice(securityLevel)) {
+        return ndk::SharedRefBase::make<KeyMintDevice>(std::move(dev), securityLevel);
     }
-    return device_ptr;
+    return {};
 }
 
 std::shared_ptr<SharedSecret> SharedSecret::createSharedSecret(KeyMintSecurityLevel securityLevel) {
@@ -961,14 +953,16 @@
 ScopedAStatus
 KeystoreCompatService::getKeyMintDevice(KeyMintSecurityLevel in_securityLevel,
                                         std::shared_ptr<IKeyMintDevice>* _aidl_return) {
-    if (mDeviceCache.find(in_securityLevel) == mDeviceCache.end()) {
+    auto i = mDeviceCache.find(in_securityLevel);
+    if (i == mDeviceCache.end()) {
         auto device = KeyMintDevice::createKeyMintDevice(in_securityLevel);
         if (!device) {
             return ScopedAStatus::fromStatus(STATUS_NAME_NOT_FOUND);
         }
-        mDeviceCache[in_securityLevel] = std::move(device);
+        bool inserted = false;
+        std::tie(i, inserted) = mDeviceCache.insert({in_securityLevel, std::move(device)});
     }
-    *_aidl_return = mDeviceCache[in_securityLevel];
+    *_aidl_return = i->second;
     return ScopedAStatus::ok();
 }
 
diff --git a/keystore2/src/km_compat/km_compat.h b/keystore2/src/km_compat/km_compat.h
index 64ad0ba..481481a 100644
--- a/keystore2/src/km_compat/km_compat.h
+++ b/keystore2/src/km_compat/km_compat.h
@@ -38,7 +38,6 @@
 using ::aidl::android::hardware::security::keymint::KeyParameter;
 using ::aidl::android::hardware::security::keymint::KeyParameterArray;
 using ::aidl::android::hardware::security::keymint::KeyPurpose;
-using ::aidl::android::hardware::security::keymint::VerificationToken;
 using KeyMintSecurityLevel = ::aidl::android::hardware::security::keymint::SecurityLevel;
 using V4_0_ErrorCode = ::android::hardware::keymaster::V4_0::ErrorCode;
 using ::aidl::android::hardware::security::keymint::IKeyMintDevice;
@@ -87,8 +86,6 @@
     static std::shared_ptr<KeyMintDevice> createKeyMintDevice(KeyMintSecurityLevel securityLevel);
 
     ScopedAStatus getHardwareInfo(KeyMintHardwareInfo* _aidl_return) override;
-    ScopedAStatus verifyAuthorization(int64_t in_challenge, const HardwareAuthToken& in_token,
-                                      VerificationToken* _aidl_return) override;
     ScopedAStatus addRngEntropy(const std::vector<uint8_t>& in_data) override;
     ScopedAStatus generateKey(const std::vector<KeyParameter>& in_keyParams,
                               KeyCreationResult* out_creationResult) override;
@@ -141,14 +138,14 @@
     ScopedAStatus update(const std::optional<KeyParameterArray>& in_inParams,
                          const std::optional<std::vector<uint8_t>>& in_input,
                          const std::optional<HardwareAuthToken>& in_inAuthToken,
-                         const std::optional<VerificationToken>& in_inVerificationToken,
+                         const std::optional<TimeStampToken>& in_inTimestampToken,
                          std::optional<KeyParameterArray>* out_outParams,
                          std::optional<ByteArray>* out_output, int32_t* _aidl_return);
     ScopedAStatus finish(const std::optional<KeyParameterArray>& in_inParams,
                          const std::optional<std::vector<uint8_t>>& in_input,
                          const std::optional<std::vector<uint8_t>>& in_inSignature,
                          const std::optional<HardwareAuthToken>& in_authToken,
-                         const std::optional<VerificationToken>& in_inVerificationToken,
+                         const std::optional<TimeStampToken>& in_inTimestampToken,
                          std::optional<KeyParameterArray>* out_outParams,
                          std::vector<uint8_t>* _aidl_return);
     ScopedAStatus abort();
diff --git a/keystore2/src/operation.rs b/keystore2/src/operation.rs
index f306df4..8e4f800 100644
--- a/keystore2/src/operation.rs
+++ b/keystore2/src/operation.rs
@@ -134,7 +134,10 @@
     ByteArray::ByteArray, HardwareAuthToken::HardwareAuthToken,
     IKeyMintOperation::IKeyMintOperation, KeyParameter::KeyParameter as KmParam,
     KeyParameterArray::KeyParameterArray, KeyParameterValue::KeyParameterValue as KmParamValue,
-    Tag::Tag, VerificationToken::VerificationToken,
+    Tag::Tag,
+};
+use android_hardware_security_secureclock::aidl::android::hardware::security::secureclock::{
+    TimeStampToken::TimeStampToken,
 };
 use android_system_keystore2::aidl::android::system::keystore2::{
     IKeystoreOperation::BnKeystoreOperation, IKeystoreOperation::IKeystoreOperation,
@@ -356,7 +359,7 @@
                 None,
                 // TODO Get auth token from enforcement module if required.
                 None,
-                // TODO Get verification token from enforcement module if required.
+                // TODO Get timestamp token from enforcement module if required.
                 None,
                 &mut out_params,
                 &mut output,
@@ -369,14 +372,14 @@
 
     /// Based on the authorization information stored in the operation during create_operation(),
     /// and any previous calls to update(), this function returns appropriate auth token and
-    /// verification token to be passed to keymint.
+    /// timestamp token to be passed to keymint.
     /// Note that the call to the global enforcement object happens only during the first call to
     /// update or if finish() is called right after create_opertation.
     fn handle_authorization<'a>(
         auth_token_handler: &'a mut AuthTokenHandler,
         key_params: Option<&Vec<KeyParameter>>,
         op_challenge: Option<&OperationChallenge>,
-    ) -> Result<(Option<&'a HardwareAuthToken>, Option<&'a VerificationToken>)> {
+    ) -> Result<(Option<&'a HardwareAuthToken>, Option<&'a TimeStampToken>)> {
         // keystore performs authorization only if key parameters have been loaded during
         // create_operation()
         if let Some(key_parameters) = key_params {
@@ -395,7 +398,7 @@
                 // this variant is found in every subsequent call to update/finish,
                 // unless the authorization is not required for the key
                 AuthTokenHandler::Token(_, _) => {
-                    auth_token_handler.retrieve_auth_and_verification_tokens()
+                    auth_token_handler.retrieve_auth_and_timestamp_tokens()
                 }
                 _ => Ok((None, None))
             }
@@ -418,7 +421,7 @@
             self.km_op.get_interface().context("In update: Failed to get KeyMintOperation.")?;
 
         let mut auth_handler = self.auth_token_handler.lock().unwrap();
-        let (auth_token_for_km, verification_token_for_km) = Self::handle_authorization(
+        let (auth_token_for_km, timestamp_token_for_km) = Self::handle_authorization(
             &mut auth_handler,
             self.key_params.as_ref(),
             self.op_challenge.as_ref(),
@@ -431,7 +434,7 @@
                 None,
                 Some(input),
                 auth_token_for_km,
-                verification_token_for_km,
+                timestamp_token_for_km,
                 &mut out_params,
                 &mut output,
             )),
@@ -465,7 +468,7 @@
             self.km_op.get_interface().context("In finish: Failed to get KeyMintOperation.")?;
 
         let mut auth_handler = self.auth_token_handler.lock().unwrap();
-        let (auth_token_for_km, verification_token_for_km) = Self::handle_authorization(
+        let (auth_token_for_km, timestamp_token_for_km) = Self::handle_authorization(
             &mut auth_handler,
             self.key_params.as_ref(),
             self.op_challenge.as_ref(),
@@ -480,7 +483,7 @@
                     input,
                     signature,
                     auth_token_for_km,
-                    verification_token_for_km,
+                    timestamp_token_for_km,
                     &mut out_params,
                 )),
             )
diff --git a/keystore2/src/security_level.rs b/keystore2/src/security_level.rs
index 079e92a..7a87e8d 100644
--- a/keystore2/src/security_level.rs
+++ b/keystore2/src/security_level.rs
@@ -281,10 +281,10 @@
                     Some(OperationChallenge { challenge: begin_result.challenge });
                 ENFORCEMENTS.insert_to_op_auth_map(begin_result.challenge);
             }
-            AuthTokenHandler::VerificationRequired(auth_token) => {
-                //request a verification token, given the auth token and the challenge
+            AuthTokenHandler::TimestampRequired(auth_token) => {
+                //request a timestamp token, given the auth token and the challenge
                 auth_token_handler = ENFORCEMENTS
-                    .request_verification_token(
+                    .request_timestamp_token(
                         auth_token,
                         OperationChallenge { challenge: begin_result.challenge },
                     )