diff --git a/security/secretkeeper/aidl/aidl_api/android.hardware.security.secretkeeper/current/android/hardware/security/secretkeeper/ErrorCode.aidl b/security/secretkeeper/aidl/aidl_api/android.hardware.security.secretkeeper/current/android/hardware/security/secretkeeper/ErrorCode.aidl
new file mode 100644
index 0000000..cc07f9b
--- /dev/null
+++ b/security/secretkeeper/aidl/aidl_api/android.hardware.security.secretkeeper/current/android/hardware/security/secretkeeper/ErrorCode.aidl
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+///////////////////////////////////////////////////////////////////////////////
+// THIS FILE IS IMMUTABLE. DO NOT EDIT IN ANY CASE.                          //
+///////////////////////////////////////////////////////////////////////////////
+
+// This file is a snapshot of an AIDL file. Do not edit it manually. There are
+// two cases:
+// 1). this is a frozen version file - do not edit this in any case.
+// 2). this is a 'current' file. If you make a backwards compatible change to
+//     the interface (from the latest frozen version), the build system will
+//     prompt you to update this file with `m <name>-update-api`.
+//
+// You must not make a backward incompatible change to any AIDL file built
+// with the aidl_interface module type with versions property set. The module
+// type is used to build AIDL files in a way that they can be used across
+// independently updatable components of the system. If a device is shipped
+// with such a backward incompatible change, it has a high risk of breaking
+// later when a module using the interface is updated, e.g., Mainline modules.
+
+package android.hardware.security.secretkeeper;
+/* @hide */
+@Backing(type="int") @VintfStability
+enum ErrorCode {
+  OK = 0,
+  UNKNOWN_KEY_ID = 1,
+  INTERNAL_ERROR = 2,
+  REQUEST_MALFORMED = 3,
+}
diff --git a/security/secretkeeper/aidl/android/hardware/security/secretkeeper/ErrorCode.aidl b/security/secretkeeper/aidl/android/hardware/security/secretkeeper/ErrorCode.aidl
new file mode 100644
index 0000000..e9cce09
--- /dev/null
+++ b/security/secretkeeper/aidl/android/hardware/security/secretkeeper/ErrorCode.aidl
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.hardware.security.secretkeeper;
+
+/**
+ * Secretkeeper unencrypted error code, returned via AIDL as service specific errors in
+ * EX_SERVICE_SPECIFIC.
+ * @hide
+ */
+@VintfStability
+@Backing(type="int")
+enum ErrorCode {
+    OK = 0,
+    UNKNOWN_KEY_ID = 1,
+    INTERNAL_ERROR = 2,
+    REQUEST_MALFORMED = 3,
+
+    // TODO(b/291224769): Create a more exhaustive set of error code values.
+}
diff --git a/security/secretkeeper/aidl/android/hardware/security/secretkeeper/ISecretkeeper.aidl b/security/secretkeeper/aidl/android/hardware/security/secretkeeper/ISecretkeeper.aidl
index 1f4768a..cb3e9b9 100644
--- a/security/secretkeeper/aidl/android/hardware/security/secretkeeper/ISecretkeeper.aidl
+++ b/security/secretkeeper/aidl/android/hardware/security/secretkeeper/ISecretkeeper.aidl
@@ -35,7 +35,7 @@
  * Typical operations are (securely) updating the dice policy sealing the Secrets above. These
  * operations are core to AntiRollback protected secrets - ie, ensuring secrets of a pVM are only
  * accessible to same or higher versions of the images.
- * 2. Maintenance api: This is required for removing the Secretkeeper entries for obsolete pvMs.
+ * 2. Maintenance API: This is required for removing the Secretkeeper entries for obsolete pVMs.
  */
 interface ISecretkeeper {
     /**
@@ -60,7 +60,11 @@
      * Virtual Machines). For this, service (& client) must implement a key exchange protocol, which
      * is critical for establishing the secure channel.
      *
+     * If an encrypted response cannot be generated, then a service-specific Binder error using an
+     * error code from ErrorCode.aidl will be returned.
+     *
      * Secretkeeper database should guarantee the following properties:
+     *
      * 1. Confidentiality: No entity (of security privilege lower than Secretkeeper) should
      *    be able to get a client's data in clear.
      *
diff --git a/security/secretkeeper/aidl/android/hardware/security/secretkeeper/SecretManagement.cddl b/security/secretkeeper/aidl/android/hardware/security/secretkeeper/SecretManagement.cddl
index 62a1bd7..66ca8ed 100644
--- a/security/secretkeeper/aidl/android/hardware/security/secretkeeper/SecretManagement.cddl
+++ b/security/secretkeeper/aidl/android/hardware/security/secretkeeper/SecretManagement.cddl
@@ -1,110 +1,73 @@
 ; CDDL for the Secret Management API.
-; Also see processSecretManagementRequest method in ISecretkeeper.aidl
 
-; ProtectedRequestPacket is used by client for accessing Secret Management API
-; in Secretkeeper service. The service returns ProtectedResponsePacket of the corresponding type.
+; The input parameter to the `processSecretManagementRequest` operation in
+; `ISecretkeeper.aidl` is always an encrypted request message, CBOR-encoded as a
+; COSE_Encrypt0 object.  The encryption uses the first of the keys agreed using
+; the associated AuthGraph instance, referred to as `KeySourceToSink`.
+ProtectedRequestPacket = CryptoPayload<RequestPacket, KeySourceToSink>
 
-; ProtectedRequestPacket & ProtectedResponsePacket are encrypted wrappers
-; on RequestPacket & ResponsePacket using symmetric keys agreed between Secretkeeper & clients
-; (these are referred to as KeySourceToSink & KeySinkToSource)
-;
-; The API operation required is encoded using 'Opcode', the arguments using 'Params'
-; and returned values as 'Result'.
-
-ProtectedRequestPacket =
-        ProtectedGetVersionRequest / ProtectedStoreSecretRequest / ProtectedGetSecretRequest
-ProtectedResponsePacket =
-        ProtectedGetVersionResponse / ProtectedStoreSecretResponse / ProtectedGetSecretResponse
-
-ProtectedGetVersionRequest = ProtectedRequestPacket<GetVersionRequestPacket>
-ProtectedGetVersionResponse = ProtectedResponsePacket<GetVersionResponsePacket>
-ProtectedStoreSecretRequest = ProtectedRequestPacket<StoreSecretRequestPacket>
-ProtectedStoreSecretResponse = ProtectedResponsePacket<StoreSecretResponsePacket>
-ProtectedGetSecretRequest = ProtectedRequestPacket<GetSecretRequestPacket>
-ProtectedGetSecretResponse = ProtectedResponsePacket<GetSecretResponsePacket>
-
-GetVersionRequestPacket = RequestPacket<GetVersionOpcode, GetVersionParams>
-GetVersionResponsePacket = ResponsePacket<GetVersionResult>
-StoreSecretRequestPacket = RequestPacket<StoreSecretOpcode, StoreSecretParams>
-StoreSecretResponsePacket = ResponsePacket<StoreSecretResult>
-GetSecretRequestPacket = RequestPacket<GetOpcode, GetSecretParams>
-GetSecretResponsePacket = ResponsePacket<GetSecretResult>
-
-RequestPacket<Opcode, Params> = [
-    Opcode,
-    Params
-]
-ResponsePacket<Result> = ResponsePacketError / ResponsePacketSuccess<Result>
-
-ResponsePacketSuccess = [
-    0,                          ; Indicates successful Response
-    result : Result
-]
-ResponsePacketError = [
-    error_code: ErrorCode,      ; Indicate the error
-    error_message: tstr         ; Additional human-readable context
-]
-
-Opcode = &(
-    GetVersionOpcode: 1,     ; Get version of the SecretManagement API
-    StoreSecretOpcode: 2,          ; Store a secret
-    GetSecretOpcode: 3,            ; Get the secret
-)
-
-GetVersionParams = ()
-GetVersionResult = (version : uint)
-
-StoreSecretParams = (
-    id : bstr .size 64              ; Unique identifier of the secret
-    secret : bstr .size 32,
-    sealing_policy : bstr .cbor DicePolicy,    ; See DicePolicy.cddl for definition of DicePolicy
-)
-StoreSecretResult = ()
-
-GetSecretParams = (
-    id : bstr .size 64              ; Unique identifier of the secret
-    ; Use this to update the sealing policy associated with a secret during GetSecret operation.
-    updated_sealing_policy : bstr .cbor DicePolicy / nil,
-)
-GetSecretResult = (secret : bstr .size 32)
-
-
-ProtectedRequestPacket<Payload, Key> = CryptoPayload<Payload, KeySourceToSink>
-ProtectedResponsePacket<Payload, Key> = ProtectedResponseError
-                                    / ProtectedResponseSuccess<Payload>
-
-ProtectedResponseSuccess<Payload> = [
-    0,                                ; Indicates successful crypto operations. Note: Payload
-                                                    ; may contain Error from functional layer.
-    message: CryptoPayload<Payload, KeySinkToSource>         ; message is the encrypted payload
-]
-
-ProtectedResponseError = [
-    error_code: CryptoErrorCode,           ; Indicates the error. This is in cleartext & will be
-                                           ; visible to Android. These are errors from crypto
-                                           ; layer & indicates the request could not even be read
-    message: tstr                          ; Additional human-readable context
-]
-
-CryptoPayload<Payload, Key> = [         ; COSE_Encrypt0 (untagged), [RFC 9052 s5.2]
+CryptoPayload<Payload, Key> = [ ; COSE_Encrypt0 (untagged), [RFC 9052 s5.2]
     protected: bstr .cbor {
         1 : 3,                  ; Algorithm: AES-GCM mode w/ 256-bit key, 128-bit tag
         4 : bstr                ; key identifier, uniquely identifies the session
                                 ; TODO(b/291228560): Refer to the Key Exchange spec.
     },
     unprotected: {
-        5 : bstr .size 12          ; IV
+        5 : bstr .size 12       ; IV
     },
-    ciphertext : bstr     ; AES-GCM-256(Key, bstr .cbor Payload)
-                          ; AAD for the encryption is CBOR-serialized
-                          ; Enc_structure (RFC 9052 s5.3) with empty external_aad.
+    ciphertext : bstr           ; AES-GCM-256(Key, bstr .cbor Payload)
+                                ; AAD for the encryption is CBOR-serialized
+                                ; Enc_structure (RFC 9052 s5.3) with empty external_aad.
 ]
 
-; TODO(b/291224769): Create a more exhaustive set of CryptoErrorCode
-CryptoErrorCode = &(
-    CryptoErrorCode_SessionExpired: 1,
+; Once decrypted, the request packet is an encoded CBOR array holding:
+; - An initial integer indicating which request is present.
+; - Subsequent objects holding the parameters for that specific request.
+RequestPacket =
+    [GetVersionOpcode, GetVersionParams] /
+    [StoreSecretOpcode, StoreSecretParams] /
+    [GetSecretOpcode, GetSecretParams]
+
+GetVersionOpcode = 1            ; Get version of the SecretManagement API
+StoreSecretOpcode = 2           ; Store a secret
+GetSecretOpcode = 3             ; Get the secret
+
+GetVersionParams = ()
+
+StoreSecretParams = (
+    id : SecretId,
+    secret : Secret,
+    sealing_policy : bstr .cbor DicePolicy,
 )
 
+; INCLUDE DicePolicy.cddl for: DicePolicy
+
+GetSecretParams = (
+    id : SecretId,
+    ; Retrieving the value of a secret may optionally also update the sealing
+    ; policy associated with a secret.
+    updated_sealing_policy : bstr .cbor DicePolicy / nil,
+)
+
+SecretId = bstr .size 64        ; Unique identifier of the secret.
+Secret = bstr .size 32          ; The secret value.
+
+; The return value from a successful `processSecretManagementRequest` operation is a
+; response message encrypted with the second of the keys agreed using the associated
+; AuthGraph instance, referred to as `KeySinkToSource`.
+ProtectedResponsePacket = CryptoPayload<ResponsePacket, KeySinkToSource>
+
+; Once decrypted, the inner response message is encoded as a CBOR array holding:
+; - An initial integer return code value.
+; - Subsequently:
+;    - If the return code is zero: result value(s).
+;    - If the return code is non-zero: an error message.
+ResponsePacket =
+    [0, Result] /
+    [error_code: ErrorCode, error_message: tstr]
+
+; An error code in the inner response message indicates a failure in
+; secret management processing.
 ; TODO(b/291224769): Create a more exhaustive set of ErrorCodes
 ErrorCode = &(
     ; Use this as if no other error code can be used.
@@ -119,4 +82,16 @@
     ErrorCode_DicePolicyError: 5,
 )
 
-; INCLUDE DicePolicy.cddl for: DicePolicy
\ No newline at end of file
+; The particular result variant present is determined by which request
+; message was originally sent.
+Result = &(
+    GetVersionResult,
+    StoreSecretResult,
+    GetSecretResult,
+)
+
+GetVersionResult = (version : uint)
+
+StoreSecretResult = ()
+
+GetSecretResult = (secret : Secret)
diff --git a/security/secretkeeper/aidl/vts/Android.bp b/security/secretkeeper/aidl/vts/Android.bp
index def5d5d..c130a3a 100644
--- a/security/secretkeeper/aidl/vts/Android.bp
+++ b/security/secretkeeper/aidl/vts/Android.bp
@@ -27,7 +27,9 @@
     ],
     rustlibs: [
         "libsecretkeeper_comm_nostd",
+        "libsecretkeeper_core_nostd",
         "android.hardware.security.secretkeeper-V1-rust",
+        "libauthgraph_boringssl",
         "libauthgraph_core",
         "libcoset",
         "libauthgraph_vts_test",
diff --git a/security/secretkeeper/aidl/vts/secretkeeper_test_client.rs b/security/secretkeeper/aidl/vts/secretkeeper_test_client.rs
index cc606b1..a473bd0 100644
--- a/security/secretkeeper/aidl/vts/secretkeeper_test_client.rs
+++ b/security/secretkeeper/aidl/vts/secretkeeper_test_client.rs
@@ -16,8 +16,9 @@
 
 #[cfg(test)]
 use binder::StatusCode;
-use coset::CborSerializable;
+use coset::{CborSerializable, CoseEncrypt0};
 use log::warn;
+use secretkeeper_core::cipher;
 use secretkeeper_comm::data_types::error::SecretkeeperError;
 use secretkeeper_comm::data_types::request::Request;
 use secretkeeper_comm::data_types::request_response_impl::{
@@ -28,6 +29,7 @@
 use secretkeeper_comm::data_types::packet::{ResponsePacket, ResponseType};
 use android_hardware_security_secretkeeper::aidl::android::hardware::security::secretkeeper::ISecretkeeper::ISecretkeeper;
 use authgraph_vts_test as ag_vts;
+use authgraph_boringssl as boring;
 use authgraph_core::key;
 
 const SECRETKEEPER_IDENTIFIER: &str =
@@ -73,7 +75,50 @@
         }
     }
 }
-fn authgraph_key_exchange(sk: binder::Strong<dyn ISecretkeeper>) -> [key::AesKey; 2] {
+
+/// Secretkeeper client information.
+struct SkClient {
+    sk: binder::Strong<dyn ISecretkeeper>,
+    aes_keys: [key::AesKey; 2],
+    session_id: Vec<u8>,
+}
+
+impl SkClient {
+    fn new() -> Option<Self> {
+        let sk = get_connection()?;
+        let (aes_keys, session_id) = authgraph_key_exchange(sk.clone());
+        Some(Self {
+            sk,
+            aes_keys,
+            session_id,
+        })
+    }
+    /// Wrapper around `ISecretkeeper::processSecretManagementRequest` that handles
+    /// encryption and decryption.
+    fn secret_management_request(&self, req_data: &[u8]) -> Vec<u8> {
+        let aes_gcm = boring::BoringAes;
+        let rng = boring::BoringRng;
+        let request_bytes = cipher::encrypt_message(
+            &aes_gcm,
+            &rng,
+            &self.aes_keys[0],
+            &self.session_id,
+            &req_data,
+        )
+        .unwrap();
+
+        let response_bytes = self
+            .sk
+            .processSecretManagementRequest(&request_bytes)
+            .unwrap();
+
+        let response_encrypt0 = CoseEncrypt0::from_slice(&response_bytes).unwrap();
+        cipher::decrypt_message(&aes_gcm, &self.aes_keys[1], &response_encrypt0).unwrap()
+    }
+}
+
+/// Perform AuthGraph key exchange, returning the session keys and session ID.
+fn authgraph_key_exchange(sk: binder::Strong<dyn ISecretkeeper>) -> ([key::AesKey; 2], Vec<u8>) {
     let sink = sk.getAuthGraphKe().expect("failed to get AuthGraph");
     let mut source = ag_vts::test_ag_participant().expect("failed to create a local source");
     ag_vts::sink::test_mainline(&mut source, sink)
@@ -90,7 +135,7 @@
             return;
         }
     };
-    let _aes_keys = authgraph_key_exchange(sk);
+    let (_aes_keys, _session_id) = authgraph_key_exchange(sk);
 }
 
 /// Test that the AuthGraph instance returned by SecretKeeper correctly rejects
@@ -130,23 +175,19 @@
 
 #[test]
 fn secret_management_get_version() {
-    let secretkeeper = match get_connection() {
+    let sk_client = match SkClient::new() {
         Some(sk) => sk,
         None => {
             warn!("Secretkeeper HAL is unavailable, skipping test");
             return;
         }
     };
+
     let request = GetVersionRequest {};
     let request_packet = request.serialize_to_packet();
     let request_bytes = request_packet.to_vec().unwrap();
 
-    // TODO(b/291224769) The request will need to be encrypted & response need to be decrypted
-    // with key & related artifacts pre-shared via Authgraph Key Exchange HAL.
-
-    let response_bytes = secretkeeper
-        .processSecretManagementRequest(&request_bytes)
-        .unwrap();
+    let response_bytes = sk_client.secret_management_request(&request_bytes);
 
     let response_packet = ResponsePacket::from_slice(&response_bytes).unwrap();
     assert_eq!(
@@ -160,13 +201,14 @@
 
 #[test]
 fn secret_management_malformed_request() {
-    let secretkeeper = match get_connection() {
+    let sk_client = match SkClient::new() {
         Some(sk) => sk,
         None => {
             warn!("Secretkeeper HAL is unavailable, skipping test");
             return;
         }
     };
+
     let request = GetVersionRequest {};
     let request_packet = request.serialize_to_packet();
     let mut request_bytes = request_packet.to_vec().unwrap();
@@ -174,12 +216,7 @@
     // Deform the request
     request_bytes[0] = !request_bytes[0];
 
-    // TODO(b/291224769) The request will need to be encrypted & response need to be decrypted
-    // with key & related artifacts pre-shared via Authgraph Key Exchange HAL.
-
-    let response_bytes = secretkeeper
-        .processSecretManagementRequest(&request_bytes)
-        .unwrap();
+    let response_bytes = sk_client.secret_management_request(&request_bytes);
 
     let response_packet = ResponsePacket::from_slice(&response_bytes).unwrap();
     assert_eq!(
@@ -192,7 +229,7 @@
 
 #[test]
 fn secret_management_store_get_secret_found() {
-    let secretkeeper = match get_connection() {
+    let sk_client = match SkClient::new() {
         Some(sk) => sk,
         None => {
             warn!("Secretkeeper HAL is unavailable, skipping test");
@@ -207,9 +244,8 @@
     };
 
     let store_request = store_request.serialize_to_packet().to_vec().unwrap();
-    let store_response = secretkeeper
-        .processSecretManagementRequest(&store_request)
-        .unwrap();
+
+    let store_response = sk_client.secret_management_request(&store_request);
     let store_response = ResponsePacket::from_slice(&store_response).unwrap();
 
     assert_eq!(
@@ -226,9 +262,7 @@
     };
     let get_request = get_request.serialize_to_packet().to_vec().unwrap();
 
-    let get_response = secretkeeper
-        .processSecretManagementRequest(&get_request)
-        .unwrap();
+    let get_response = sk_client.secret_management_request(&get_request);
     let get_response = ResponsePacket::from_slice(&get_response).unwrap();
     assert_eq!(get_response.response_type().unwrap(), ResponseType::Success);
     let get_response = *GetSecretResponse::deserialize_from_packet(get_response).unwrap();
@@ -237,7 +271,7 @@
 
 #[test]
 fn secret_management_store_get_secret_not_found() {
-    let secretkeeper = match get_connection() {
+    let sk_client = match SkClient::new() {
         Some(sk) => sk,
         None => {
             warn!("Secretkeeper HAL is unavailable, skipping test");
@@ -253,9 +287,7 @@
     };
 
     let store_request = store_request.serialize_to_packet().to_vec().unwrap();
-    let store_response = secretkeeper
-        .processSecretManagementRequest(&store_request)
-        .unwrap();
+    let store_response = sk_client.secret_management_request(&store_request);
     let store_response = ResponsePacket::from_slice(&store_response).unwrap();
 
     assert_eq!(
@@ -269,9 +301,7 @@
         updated_sealing_policy: None,
     };
     let get_request = get_request.serialize_to_packet().to_vec().unwrap();
-    let get_response = secretkeeper
-        .processSecretManagementRequest(&get_request)
-        .unwrap();
+    let get_response = sk_client.secret_management_request(&get_request);
 
     // Check that response is `SecretkeeperError::EntryNotFound`
     let get_response = ResponsePacket::from_slice(&get_response).unwrap();