diff --git a/TEST_MAPPING b/TEST_MAPPING
index 7be81a8..25908ad 100644
--- a/TEST_MAPPING
+++ b/TEST_MAPPING
@@ -17,6 +17,9 @@
     },
     {
       "name": "compsvc_device_tests"
+    },
+    {
+      "name": "compos_key_tests"
     }
   ],
   "postsubmit": [
diff --git a/authfs/fd_server/src/aidl.rs b/authfs/fd_server/src/aidl.rs
index 125b991..f13f249 100644
--- a/authfs/fd_server/src/aidl.rs
+++ b/authfs/fd_server/src/aidl.rs
@@ -290,8 +290,10 @@
                 let new_fd = openat(
                     dir.as_raw_fd(),
                     basename,
-                    // TODO(205172873): handle the case when the file already exist, e.g. truncate
-                    // or fail, and possibly allow the client to specify. For now, always truncate.
+                    // This function is supposed to be only called when FUSE/authfs thinks the file
+                    // does not exist. However, if the file does exist from the view of fd_server
+                    // (where the execution context is considered untrusted), we prefer to honor
+                    // authfs and still allow the create to success. Therefore, always use O_TRUNC.
                     OFlag::O_CREAT | OFlag::O_RDWR | OFlag::O_TRUNC,
                     mode,
                 )
diff --git a/authfs/src/fsverity/verifier.rs b/authfs/src/fsverity/verifier.rs
index 61b8e13..aaf4bf7 100644
--- a/authfs/src/fsverity/verifier.rs
+++ b/authfs/src/fsverity/verifier.rs
@@ -112,8 +112,8 @@
 }
 
 pub struct VerifiedFileReader<F: ReadByChunk, M: ReadByChunk> {
+    pub file_size: u64,
     chunked_file: F,
-    file_size: u64,
     merkle_tree: M,
     root_hash: HashBuffer,
 }
diff --git a/authfs/src/fusefs.rs b/authfs/src/fusefs.rs
index 84129b6..5bc25b0 100644
--- a/authfs/src/fusefs.rs
+++ b/authfs/src/fusefs.rs
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+mod file;
 mod mount;
 
 use anyhow::{anyhow, bail, Result};
@@ -37,12 +38,13 @@
 
 use crate::common::{divide_roundup, ChunkedSizeIter, CHUNK_SIZE};
 use crate::file::{
-    validate_basename, Attr, EagerChunkReader, InMemoryDir, RandomWrite, ReadByChunk,
-    RemoteDirEditor, RemoteFileEditor, RemoteFileReader,
+    validate_basename, Attr, InMemoryDir, RandomWrite, ReadByChunk, RemoteDirEditor,
+    RemoteFileEditor, RemoteFileReader,
 };
 use crate::fsstat::RemoteFsStatsReader;
-use crate::fsverity::{VerifiedFileEditor, VerifiedFileReader};
+use crate::fsverity::VerifiedFileEditor;
 
+pub use self::file::LazyVerifiedReadonlyFile;
 pub use self::mount::mount_and_enter_message_loop;
 use self::mount::MAX_WRITE_BYTES;
 
@@ -61,10 +63,7 @@
     ReadonlyDirectory { dir: InMemoryDir },
     /// A file type that is verified against fs-verity signature (thus read-only). The file is
     /// served from a remote server.
-    VerifiedReadonly {
-        reader: VerifiedFileReader<RemoteFileReader, EagerChunkReader>,
-        file_size: u64,
-    },
+    VerifiedReadonly { reader: LazyVerifiedReadonlyFile },
     /// A file type that is a read-only passthrough from a file on a remote server.
     UnverifiedReadonly { reader: RemoteFileReader, file_size: u64 },
     /// A file type that is initially empty, and the content is stored on a remote server. File
@@ -537,10 +536,12 @@
                     AuthFsEntry::ReadonlyDirectory { dir } => {
                         create_dir_stat(inode, dir.number_of_entries(), AccessMode::ReadOnly)
                     }
-                    AuthFsEntry::UnverifiedReadonly { file_size, .. }
-                    | AuthFsEntry::VerifiedReadonly { file_size, .. } => {
+                    AuthFsEntry::UnverifiedReadonly { file_size, .. } => {
                         create_stat(inode, *file_size, AccessMode::ReadOnly)
                     }
+                    AuthFsEntry::VerifiedReadonly { reader } => {
+                        create_stat(inode, reader.file_size()?, AccessMode::ReadOnly)
+                    }
                     AuthFsEntry::VerifiedNew { editor, attr, .. } => {
                         create_stat(inode, editor.size(), AccessMode::Variable(attr.mode()))
                     }
@@ -608,10 +609,12 @@
                     AuthFsEntry::ReadonlyDirectory { dir } => {
                         create_dir_stat(inode, dir.number_of_entries(), AccessMode::ReadOnly)
                     }
-                    AuthFsEntry::UnverifiedReadonly { file_size, .. }
-                    | AuthFsEntry::VerifiedReadonly { file_size, .. } => {
+                    AuthFsEntry::UnverifiedReadonly { file_size, .. } => {
                         create_stat(inode, *file_size, AccessMode::ReadOnly)
                     }
+                    AuthFsEntry::VerifiedReadonly { reader } => {
+                        create_stat(inode, reader.file_size()?, AccessMode::ReadOnly)
+                    }
                     AuthFsEntry::VerifiedNew { editor, attr, .. } => {
                         create_stat(inode, editor.size(), AccessMode::Variable(attr.mode()))
                     }
@@ -664,7 +667,6 @@
         _flags: u32,
         umask: u32,
     ) -> io::Result<(Entry, Option<Self::Handle>, FuseOpenOptions)> {
-        // TODO(205172873): handle O_TRUNC and O_EXCL properly.
         let new_inode = self.create_new_entry_with_ref_count(
             parent,
             name,
@@ -708,8 +710,8 @@
     ) -> io::Result<usize> {
         self.handle_inode(&inode, |config| {
             match config {
-                AuthFsEntry::VerifiedReadonly { reader, file_size } => {
-                    read_chunks(w, reader, *file_size, offset, size)
+                AuthFsEntry::VerifiedReadonly { reader } => {
+                    read_chunks(w, reader, reader.file_size()?, offset, size)
                 }
                 AuthFsEntry::UnverifiedReadonly { reader, file_size } => {
                     read_chunks(w, reader, *file_size, offset, size)
diff --git a/authfs/src/fusefs/file.rs b/authfs/src/fusefs/file.rs
new file mode 100644
index 0000000..8c02281
--- /dev/null
+++ b/authfs/src/fusefs/file.rs
@@ -0,0 +1,127 @@
+/*
+ * Copyright (C) 2022 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.
+ */
+
+use log::error;
+use std::convert::TryInto;
+use std::io;
+use std::path::PathBuf;
+use std::sync::Mutex;
+
+use crate::file::{
+    ChunkBuffer, EagerChunkReader, ReadByChunk, RemoteFileReader, RemoteMerkleTreeReader,
+    VirtFdService,
+};
+use crate::fsverity::{merkle_tree_size, VerifiedFileReader};
+
+enum FileInfo {
+    ByPathUnderDirFd(i32, PathBuf),
+    ByFd(i32),
+}
+
+type Reader = VerifiedFileReader<RemoteFileReader, EagerChunkReader>;
+
+/// A lazily created read-only file that is verified against the given fs-verity digest.
+///
+/// The main purpose of this struct is to wrap and construct `VerifiedFileReader` lazily.
+pub struct LazyVerifiedReadonlyFile {
+    expected_digest: Vec<u8>,
+
+    service: VirtFdService,
+    file_info: FileInfo,
+
+    /// A lazily instantiated reader.
+    reader: Mutex<Option<Reader>>,
+}
+
+impl LazyVerifiedReadonlyFile {
+    /// Prepare the file by a remote path, related to a remote directory FD.
+    pub fn prepare_by_path(
+        service: VirtFdService,
+        remote_dir_fd: i32,
+        remote_path: PathBuf,
+        expected_digest: Vec<u8>,
+    ) -> Self {
+        LazyVerifiedReadonlyFile {
+            service,
+            file_info: FileInfo::ByPathUnderDirFd(remote_dir_fd, remote_path),
+            expected_digest,
+            reader: Mutex::new(None),
+        }
+    }
+
+    /// Prepare the file by a remote file FD.
+    pub fn prepare_by_fd(service: VirtFdService, remote_fd: i32, expected_digest: Vec<u8>) -> Self {
+        LazyVerifiedReadonlyFile {
+            service,
+            file_info: FileInfo::ByFd(remote_fd),
+            expected_digest,
+            reader: Mutex::new(None),
+        }
+    }
+
+    fn ensure_init_then<F, T>(&self, callback: F) -> io::Result<T>
+    where
+        F: FnOnce(&Reader) -> io::Result<T>,
+    {
+        let mut reader = self.reader.lock().unwrap();
+        if reader.is_none() {
+            let remote_file = match &self.file_info {
+                FileInfo::ByPathUnderDirFd(dir_fd, related_path) => {
+                    RemoteFileReader::new_by_path(self.service.clone(), *dir_fd, related_path)?
+                }
+                FileInfo::ByFd(file_fd) => RemoteFileReader::new(self.service.clone(), *file_fd),
+            };
+            let remote_fd = remote_file.get_remote_fd();
+            let file_size = self
+                .service
+                .getFileSize(remote_fd)
+                .map_err(|e| {
+                    error!("Failed to get file size of remote fd {}: {}", remote_fd, e);
+                    io::Error::from_raw_os_error(libc::EIO)
+                })?
+                .try_into()
+                .map_err(|e| {
+                    error!("Failed convert file size: {}", e);
+                    io::Error::from_raw_os_error(libc::EIO)
+                })?;
+            let instance = VerifiedFileReader::new(
+                remote_file,
+                file_size,
+                &self.expected_digest,
+                EagerChunkReader::new(
+                    RemoteMerkleTreeReader::new(self.service.clone(), remote_fd),
+                    merkle_tree_size(file_size),
+                )?,
+            )
+            .map_err(|e| {
+                error!("Failed instantiate a verified file reader: {}", e);
+                io::Error::from_raw_os_error(libc::EIO)
+            })?;
+            *reader = Some(instance);
+        }
+        callback(reader.as_ref().unwrap())
+    }
+
+    pub fn file_size(&self) -> io::Result<u64> {
+        self.ensure_init_then(|reader| Ok(reader.file_size))
+    }
+}
+
+impl ReadByChunk for LazyVerifiedReadonlyFile {
+    fn read_chunk(&self, chunk_index: u64, buf: &mut ChunkBuffer) -> io::Result<usize> {
+        self.ensure_init_then(|reader| reader.read_chunk(chunk_index, buf))
+    }
+}
diff --git a/authfs/src/main.rs b/authfs/src/main.rs
index f664ca2..bdca5b4 100644
--- a/authfs/src/main.rs
+++ b/authfs/src/main.rs
@@ -47,14 +47,11 @@
 mod fsverity;
 mod fusefs;
 
-use file::{
-    Attr, EagerChunkReader, InMemoryDir, RemoteDirEditor, RemoteFileEditor, RemoteFileReader,
-    RemoteMerkleTreeReader,
-};
+use file::{Attr, InMemoryDir, RemoteDirEditor, RemoteFileEditor, RemoteFileReader};
 use fsstat::RemoteFsStatsReader;
-use fsverity::{merkle_tree_size, VerifiedFileEditor, VerifiedFileReader};
+use fsverity::VerifiedFileEditor;
 use fsverity_digests_proto::fsverity_digests::FSVerityDigests;
-use fusefs::{AuthFs, AuthFsEntry};
+use fusefs::{AuthFs, AuthFsEntry, LazyVerifiedReadonlyFile};
 
 #[derive(StructOpt)]
 struct Args {
@@ -186,19 +183,13 @@
     service: file::VirtFdService,
     remote_fd: i32,
     expected_digest: &str,
-    file_size: u64,
 ) -> Result<AuthFsEntry> {
     Ok(AuthFsEntry::VerifiedReadonly {
-        reader: VerifiedFileReader::new(
-            RemoteFileReader::new(service.clone(), remote_fd),
-            file_size,
-            &from_hex_string(expected_digest)?,
-            EagerChunkReader::new(
-                RemoteMerkleTreeReader::new(service.clone(), remote_fd),
-                merkle_tree_size(file_size),
-            )?,
-        )?,
-        file_size,
+        reader: LazyVerifiedReadonlyFile::prepare_by_fd(
+            service,
+            remote_fd,
+            from_hex_string(expected_digest)?,
+        ),
     })
 }
 
@@ -239,12 +230,7 @@
     for config in &args.remote_ro_file {
         authfs.add_entry_at_root_dir(
             remote_fd_to_path_buf(config.remote_fd),
-            new_remote_verified_file_entry(
-                service.clone(),
-                config.remote_fd,
-                &config.digest,
-                service.getFileSize(config.remote_fd)?.try_into()?,
-            )?,
+            new_remote_verified_file_entry(service.clone(), config.remote_fd, &config.digest)?,
         )?;
     }
 
@@ -294,25 +280,13 @@
                 let remote_path_str = path_str.strip_prefix(&config.prefix).ok_or_else(|| {
                     anyhow!("Expect path {} to match prefix {}", path_str, config.prefix)
                 })?;
-                // TODO(205883847): Not all files will be used. Open the remote file lazily.
-                let remote_file = RemoteFileReader::new_by_path(
-                    service.clone(),
-                    config.remote_dir_fd,
-                    Path::new(remote_path_str),
-                )?;
-                let remote_fd = remote_file.get_remote_fd();
-                let file_size = service.getFileSize(remote_fd)?.try_into()?;
                 AuthFsEntry::VerifiedReadonly {
-                    reader: VerifiedFileReader::new(
-                        remote_file,
-                        file_size,
-                        &digest.digest,
-                        EagerChunkReader::new(
-                            RemoteMerkleTreeReader::new(service.clone(), remote_fd),
-                            merkle_tree_size(file_size),
-                        )?,
-                    )?,
-                    file_size,
+                    reader: LazyVerifiedReadonlyFile::prepare_by_path(
+                        service.clone(),
+                        config.remote_dir_fd,
+                        PathBuf::from(remote_path_str),
+                        digest.digest.clone(),
+                    ),
                 }
             };
             authfs.add_entry_at_ro_dir_by_path(dir_root_inode, Path::new(path_str), file_entry)?;
diff --git a/compos/apex/Android.bp b/compos/apex/Android.bp
index aec3c88..6550b4f 100644
--- a/compos/apex/Android.bp
+++ b/compos/apex/Android.bp
@@ -47,6 +47,7 @@
         "composd_cmd",
 
         // Used in VM
+        "compos_key_helper",
         "compsvc",
     ],
 
diff --git a/compos/compos_key_helper/Android.bp b/compos/compos_key_helper/Android.bp
new file mode 100644
index 0000000..c53d88d
--- /dev/null
+++ b/compos/compos_key_helper/Android.bp
@@ -0,0 +1,47 @@
+package {
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+cc_defaults {
+    name: "compos_key_defaults",
+    apex_available: ["com.android.compos"],
+
+    shared_libs: [
+        "libbase",
+        "libbinder_ndk",
+        "libcrypto",
+    ],
+}
+
+cc_library {
+    name: "libcompos_key",
+    defaults: ["compos_key_defaults"],
+    srcs: ["compos_key.cpp"],
+
+    shared_libs: [
+        "android.hardware.security.dice-V1-ndk",
+        "android.security.dice-ndk",
+    ],
+}
+
+cc_binary {
+    name: "compos_key_helper",
+    defaults: ["compos_key_defaults"],
+    srcs: ["compos_key_main.cpp"],
+
+    static_libs: ["libcompos_key"],
+    shared_libs: [
+        "android.security.dice-ndk",
+    ],
+}
+
+cc_test {
+    name: "compos_key_tests",
+    defaults: ["compos_key_defaults"],
+    test_suites: [
+        "general-tests",
+    ],
+
+    srcs: ["compos_key_test.cpp"],
+    static_libs: ["libcompos_key"],
+}
diff --git a/compos/compos_key_helper/compos_key.cpp b/compos/compos_key_helper/compos_key.cpp
new file mode 100644
index 0000000..84a736d
--- /dev/null
+++ b/compos/compos_key_helper/compos_key.cpp
@@ -0,0 +1,85 @@
+/*
+ * Copyright 2022 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.
+ */
+
+#include "compos_key.h"
+
+#include <aidl/android/security/dice/IDiceNode.h>
+#include <android/binder_auto_utils.h>
+#include <android/binder_manager.h>
+#include <openssl/digest.h>
+#include <openssl/hkdf.h>
+#include <openssl/mem.h>
+#include <unistd.h>
+
+using aidl::android::hardware::security::dice::BccHandover;
+using aidl::android::hardware::security::dice::InputValues;
+using aidl::android::security::dice::IDiceNode;
+using android::base::ErrnoError;
+using android::base::Error;
+using android::base::Result;
+
+// Used to ensure the key we derive is distinct from any other.
+constexpr const char* kSigningKeyInfo = "CompOS signing key";
+
+Result<Ed25519KeyPair> deriveKeyFromSecret(const uint8_t* secret, size_t secret_size) {
+    // Ed25519 private keys are derived from a 32 byte seed:
+    // https://datatracker.ietf.org/doc/html/rfc8032#section-5.1.5
+    std::array<uint8_t, 32> seed;
+
+    // We derive the seed from the secret using HKDF - see
+    // https://datatracker.ietf.org/doc/html/rfc5869#section-2.
+    if (!HKDF(seed.data(), seed.size(), EVP_sha256(), secret, secret_size, /*salt=*/nullptr,
+              /*salt_len=*/0, reinterpret_cast<const uint8_t*>(kSigningKeyInfo),
+              strlen(kSigningKeyInfo))) {
+        return Error() << "HKDF failed";
+    }
+
+    Ed25519KeyPair result;
+    ED25519_keypair_from_seed(result.public_key.data(), result.private_key.data(), seed.data());
+    return result;
+}
+
+Result<Signature> sign(const PrivateKey& private_key, const uint8_t* data, size_t data_size) {
+    Signature result;
+    if (!ED25519_sign(result.data(), data, data_size, private_key.data())) {
+        return Error() << "Failed to sign";
+    }
+    return result;
+}
+
+bool verify(const PublicKey& public_key, const Signature& signature, const uint8_t* data,
+            size_t data_size) {
+    return ED25519_verify(data, data_size, signature.data(), public_key.data()) == 1;
+}
+
+Result<Ed25519KeyPair> deriveKeyFromDice() {
+    ndk::SpAIBinder binder{AServiceManager_getService("android.security.dice.IDiceNode")};
+    auto dice_node = IDiceNode::fromBinder(binder);
+    if (!dice_node) {
+        return Error() << "Unable to connect to IDiceNode";
+    }
+
+    const std::vector<InputValues> empty_input_values;
+    BccHandover bcc;
+    auto status = dice_node->derive(empty_input_values, &bcc);
+    if (!status.isOk()) {
+        return Error() << "Derive failed: " << status.getDescription();
+    }
+
+    // We use the sealing CDI because we want stability - the key needs to be the same
+    // for any instance of the "same" VM.
+    return deriveKeyFromSecret(bcc.cdiSeal.data(), bcc.cdiSeal.size());
+}
diff --git a/compos/compos_key_helper/compos_key.h b/compos/compos_key_helper/compos_key.h
new file mode 100644
index 0000000..520f846
--- /dev/null
+++ b/compos/compos_key_helper/compos_key.h
@@ -0,0 +1,42 @@
+/*
+ * Copyright 2022 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.
+ */
+
+#pragma once
+
+#include <android-base/result.h>
+#include <openssl/curve25519.h>
+
+#include <array>
+
+using PrivateKey = std::array<uint8_t, ED25519_PRIVATE_KEY_LEN>;
+using PublicKey = std::array<uint8_t, ED25519_PUBLIC_KEY_LEN>;
+using Signature = std::array<uint8_t, ED25519_SIGNATURE_LEN>;
+
+struct Ed25519KeyPair {
+    PrivateKey private_key;
+    PublicKey public_key;
+};
+
+android::base::Result<Ed25519KeyPair> deriveKeyFromSecret(const uint8_t* secret,
+                                                          size_t secret_size);
+
+android::base::Result<Ed25519KeyPair> deriveKeyFromDice();
+
+android::base::Result<Signature> sign(const PrivateKey& private_key, const uint8_t* data,
+                                      size_t data_size);
+
+bool verify(const PublicKey& public_key, const Signature& signature, const uint8_t* data,
+            size_t data_size);
diff --git a/compos/compos_key_helper/compos_key_main.cpp b/compos/compos_key_helper/compos_key_main.cpp
new file mode 100644
index 0000000..70f7539
--- /dev/null
+++ b/compos/compos_key_helper/compos_key_main.cpp
@@ -0,0 +1,52 @@
+/*
+ * Copyright 2022 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.
+ */
+
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <unistd.h>
+
+#include <iostream>
+#include <string_view>
+
+#include "compos_key.h"
+
+using android::base::ErrnoError;
+using android::base::WriteFully;
+using namespace std::literals;
+
+int main(int argc, char** argv) {
+    android::base::InitLogging(argv, android::base::LogdLogger(android::base::SYSTEM));
+
+    if (argc == 2) {
+        if (argv[1] == "public_key"sv) {
+            auto key_pair = deriveKeyFromDice();
+            if (!key_pair.ok()) {
+                LOG(ERROR) << key_pair.error();
+                return 1;
+            }
+            if (!WriteFully(STDOUT_FILENO, key_pair->public_key.data(),
+                            key_pair->public_key.size())) {
+                PLOG(ERROR) << "Write failed";
+                return 1;
+            }
+            return 0;
+        }
+    }
+
+    std::cerr << "Usage:\n"
+                 "compos_key_helper public_key   Write current public key to stdout\n";
+    return 1;
+}
diff --git a/compos/compos_key_helper/compos_key_test.cpp b/compos/compos_key_helper/compos_key_test.cpp
new file mode 100644
index 0000000..e5c4768
--- /dev/null
+++ b/compos/compos_key_helper/compos_key_test.cpp
@@ -0,0 +1,90 @@
+/*
+ * Copyright 2022 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.
+ */
+
+#include "compos_key.h"
+
+#include <vector>
+
+#include "gtest/gtest.h"
+
+const std::vector<uint8_t> secret = {1, 2, 3};
+const std::vector<uint8_t> other_secret = {3, 2, 3};
+const std::vector<uint8_t> data = {42, 180, 65, 0};
+
+struct ComposKeyTest : public testing::Test {
+    Ed25519KeyPair key_pair;
+
+    void SetUp() override {
+        auto key_pair = deriveKeyFromSecret(secret.data(), secret.size());
+        ASSERT_TRUE(key_pair.ok()) << key_pair.error();
+        this->key_pair = *key_pair;
+    }
+};
+
+TEST_F(ComposKeyTest, SameSecretSameKey) {
+    auto other_key_pair = deriveKeyFromSecret(secret.data(), secret.size());
+    ASSERT_TRUE(other_key_pair.ok()) << other_key_pair.error();
+
+    ASSERT_EQ(key_pair.private_key, other_key_pair->private_key);
+    ASSERT_EQ(key_pair.public_key, other_key_pair->public_key);
+}
+
+TEST_F(ComposKeyTest, DifferentSecretDifferentKey) {
+    auto other_key_pair = deriveKeyFromSecret(other_secret.data(), other_secret.size());
+    ASSERT_TRUE(other_key_pair.ok()) << other_key_pair.error();
+
+    ASSERT_NE(key_pair.private_key, other_key_pair->private_key);
+    ASSERT_NE(key_pair.public_key, other_key_pair->public_key);
+}
+
+TEST_F(ComposKeyTest, CanVerifyValidSignature) {
+    auto signature = sign(key_pair.private_key, data.data(), data.size());
+    ASSERT_TRUE(signature.ok()) << signature.error();
+
+    bool verified = verify(key_pair.public_key, *signature, data.data(), data.size());
+    ASSERT_TRUE(verified);
+}
+
+TEST_F(ComposKeyTest, WrongSignatureDoesNotVerify) {
+    auto signature = sign(key_pair.private_key, data.data(), data.size());
+    ASSERT_TRUE(signature.ok()) << signature.error();
+
+    (*signature)[0] ^= 1;
+
+    bool verified = verify(key_pair.public_key, *signature, data.data(), data.size());
+    ASSERT_FALSE(verified);
+}
+
+TEST_F(ComposKeyTest, WrongDataDoesNotVerify) {
+    auto signature = sign(key_pair.private_key, data.data(), data.size());
+    ASSERT_TRUE(signature.ok()) << signature.error();
+
+    auto other_data = data;
+    other_data[0] ^= 1;
+
+    bool verified = verify(key_pair.public_key, *signature, other_data.data(), other_data.size());
+    ASSERT_FALSE(verified);
+}
+
+TEST_F(ComposKeyTest, WrongKeyDoesNotVerify) {
+    auto signature = sign(key_pair.private_key, data.data(), data.size());
+
+    auto other_key_pair = deriveKeyFromSecret(other_secret.data(), other_secret.size());
+    ASSERT_TRUE(other_key_pair.ok()) << other_key_pair.error();
+
+    bool verified = verify(other_key_pair->public_key, *signature, data.data(), data.size());
+    ASSERT_FALSE(verified);
+}
diff --git a/compos/compos_key_helper/tests/AndroidTest.xml b/compos/compos_key_helper/tests/AndroidTest.xml
new file mode 100644
index 0000000..3c1c657
--- /dev/null
+++ b/compos/compos_key_helper/tests/AndroidTest.xml
@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright 2022 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.
+-->
+<configuration description="Tests for compos_key">
+    <test class="com.android.tradefed.testtype.GTest" >
+        <option name="module-name" value="compos_key_tests" />
+    </test>
+</configuration>
diff --git a/microdroid/init.rc b/microdroid/init.rc
index ebe2464..5f0001f 100644
--- a/microdroid/init.rc
+++ b/microdroid/init.rc
@@ -196,6 +196,3 @@
 "
     chown logd logd /dev/event-log-tags
     chmod 0644 /dev/event-log-tags
-
-on property:sys.boot_completed=1
-    start logd-auditctl
diff --git a/tests/hostside/java/android/virt/test/MicrodroidTestCase.java b/tests/hostside/java/android/virt/test/MicrodroidTestCase.java
index 25adc40..1e96246 100644
--- a/tests/hostside/java/android/virt/test/MicrodroidTestCase.java
+++ b/tests/hostside/java/android/virt/test/MicrodroidTestCase.java
@@ -18,12 +18,16 @@
 
 import static org.hamcrest.CoreMatchers.is;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
 import com.android.tradefed.device.DeviceNotAvailableException;
+import com.android.tradefed.result.TestDescription;
+import com.android.tradefed.result.TestResult;
 import com.android.tradefed.testtype.DeviceJUnit4ClassRunner;
+import com.android.tradefed.testtype.junit4.DeviceTestRunOptions;
 import com.android.tradefed.util.CommandResult;
 import com.android.tradefed.util.CommandStatus;
 import com.android.tradefed.util.FileUtil;
@@ -35,6 +39,7 @@
 import org.junit.runner.RunWith;
 
 import java.io.File;
+import java.util.Map;
 import java.util.Optional;
 
 @RunWith(DeviceJUnit4ClassRunner.class)
@@ -73,6 +78,27 @@
     }
 
     @Test
+    public void testCreateVmRequiresPermission() throws Exception {
+        // Revoke the MANAGE_VIRTUAL_MACHINE permission for the test app
+        CommandRunner android = new CommandRunner(getDevice());
+        android.run("pm", "revoke", PACKAGE_NAME, "android.permission.MANAGE_VIRTUAL_MACHINE");
+
+        // Run MicrodroidTests#connectToVmService test, which should fail
+        final DeviceTestRunOptions options = new DeviceTestRunOptions(PACKAGE_NAME)
+                .setTestClassName(PACKAGE_NAME + ".MicrodroidTests")
+                .setTestMethodName("connectToVmService")
+                .setCheckResults(false);
+        assertFalse(runDeviceTests(options));
+
+        Map<TestDescription, TestResult> results = getLastDeviceRunResults().getTestResults();
+        assertThat(results.size(), is(1));
+        TestResult result = results.values().toArray(new TestResult[0])[0];
+        assertTrue("The test should fail with a permission error",
+                result.getStackTrace()
+                .contains("android.permission.MANAGE_VIRTUAL_MACHINE permission"));
+    }
+
+    @Test
     public void testMicrodroidBoots() throws Exception {
         final String configPath = "assets/vm_config.json"; // path inside the APK
         final String cid =
@@ -119,6 +145,9 @@
         assertThat(runOnMicrodroid("cat /proc/cpuinfo | grep processor | wc -l"),
                 is(Integer.toString(NUM_VCPUS)));
 
+        // Check that selinux is enabled
+        assertThat(runOnMicrodroid("getenforce"), is("Enforcing"));
+
         // TODO(b/176805428): adb is broken for nested VM
         if (!isCuttlefish()) {
             // Check neverallow rules on microdroid
diff --git a/tests/vsock_test.cc b/tests/vsock_test.cc
index 9550651..c478f64 100644
--- a/tests/vsock_test.cc
+++ b/tests/vsock_test.cc
@@ -49,26 +49,14 @@
 static constexpr const char kVmParams[] = "rdinit=/bin/init bin/vsock_client 2 45678 HelloWorld";
 static constexpr const char kTestMessage[] = "HelloWorld";
 
-/** Returns true if the kernel supports protected VMs. */
-bool isProtectedVmSupported() {
-    return android::sysprop::HypervisorProperties::hypervisor_protected_vm_supported().value_or(
-            false);
-}
-
 /** Returns true if the kernel supports unprotected VMs. */
 bool isUnprotectedVmSupported() {
     return android::sysprop::HypervisorProperties::hypervisor_vm_supported().value_or(false);
 }
 
-void runTest(sp<IVirtualizationService> virtualization_service, bool protected_vm) {
-    if (protected_vm) {
-        if (!isProtectedVmSupported()) {
-            GTEST_SKIP() << "Skipping as protected VMs are not supported on this device.";
-        }
-    } else {
-        if (!isUnprotectedVmSupported()) {
-            GTEST_SKIP() << "Skipping as unprotected VMs are not supported on this device.";
-        }
+TEST_F(VirtualizationTest, TestVsock) {
+    if (!isUnprotectedVmSupported()) {
+        GTEST_SKIP() << "Skipping as unprotected VMs are not supported on this device.";
     }
 
     binder::Status status;
@@ -93,11 +81,11 @@
     raw_config.kernel = ParcelFileDescriptor(unique_fd(open(kVmKernelPath, O_RDONLY | O_CLOEXEC)));
     raw_config.initrd = ParcelFileDescriptor(unique_fd(open(kVmInitrdPath, O_RDONLY | O_CLOEXEC)));
     raw_config.params = kVmParams;
-    raw_config.protectedVm = protected_vm;
+    raw_config.protectedVm = false;
 
     VirtualMachineConfig config(std::move(raw_config));
     sp<IVirtualMachine> vm;
-    status = virtualization_service->createVm(config, std::nullopt, std::nullopt, &vm);
+    status = mVirtualizationService->createVm(config, std::nullopt, std::nullopt, &vm);
     ASSERT_TRUE(status.isOk()) << "Error creating VM: " << status;
 
     int32_t cid;
@@ -124,12 +112,4 @@
     ASSERT_EQ(msg, kTestMessage);
 }
 
-TEST_F(VirtualizationTest, TestVsock) {
-    runTest(mVirtualizationService, false);
-}
-
-TEST_F(VirtualizationTest, TestVsockProtected) {
-    runTest(mVirtualizationService, true);
-}
-
 } // namespace virt
diff --git a/virtualizationservice/src/main.rs b/virtualizationservice/src/main.rs
index 69ae076..43e46a3 100644
--- a/virtualizationservice/src/main.rs
+++ b/virtualizationservice/src/main.rs
@@ -40,7 +40,7 @@
 
 fn main() {
     android_logger::init_once(
-        android_logger::Config::default().with_tag(LOG_TAG).with_min_level(Level::Trace),
+        android_logger::Config::default().with_tag(LOG_TAG).with_min_level(Level::Info),
     );
 
     clear_temporary_files().expect("Failed to delete old temporary files");