diff --git a/keystore/blob.cpp b/keystore/blob.cpp
index b2a4a1b..f9485a4 100644
--- a/keystore/blob.cpp
+++ b/keystore/blob.cpp
@@ -159,7 +159,7 @@
 
 class ArrayStreamBuffer : public std::streambuf {
   public:
-    template <typename T, size_t size> ArrayStreamBuffer(const T (&data)[size]) {
+    template <typename T, size_t size> explicit ArrayStreamBuffer(const T (&data)[size]) {
         static_assert(sizeof(T) == 1, "Array element size too large");
         std::streambuf::char_type* d = const_cast<std::streambuf::char_type*>(
             reinterpret_cast<const std::streambuf::char_type*>(&data[0]));
diff --git a/keystore/blob.h b/keystore/blob.h
index 77b6f38..ce488ec 100644
--- a/keystore/blob.h
+++ b/keystore/blob.h
@@ -117,7 +117,7 @@
 
     Blob& operator=(const Blob& rhs);
     Blob& operator=(Blob&& rhs);
-    operator bool() const { return bool(mBlob); }
+    explicit operator bool() const { return bool(mBlob); }
 
     const uint8_t* getValue() const { return mBlob->value; }
 
@@ -242,6 +242,7 @@
     static std::condition_variable locked_blobs_mutex_cond_var_;
 
     const KeyBlobEntry* entry_;
+    // NOLINTNEXTLINE(google-explicit-constructor)
     LockedKeyBlobEntry(const KeyBlobEntry& entry) : entry_(&entry) {}
 
     static void put(const KeyBlobEntry& entry);
@@ -271,7 +272,7 @@
                                                    State state) const;
     ResponseCode deleteBlobs() const;
 
-    inline operator bool() const { return entry_ != nullptr; }
+    inline explicit operator bool() const { return entry_ != nullptr; }
     inline const KeyBlobEntry& operator*() const { return *entry_; }
     inline const KeyBlobEntry* operator->() const { return entry_; }
 };
diff --git a/keystore/grant_store.h b/keystore/grant_store.h
index f8e4f91..1baf32c 100644
--- a/keystore/grant_store.h
+++ b/keystore/grant_store.h
@@ -48,6 +48,7 @@
 
   uint64_t grant_no_;  ///< numeric grant identifier - randomly assigned
 
+  // NOLINTNEXTLINE(google-explicit-constructor)
   operator const uint64_t&() const { return grant_no_; }
 };
 
diff --git a/keystore/include/keystore/KeyAttestationApplicationId.h b/keystore/include/keystore/KeyAttestationApplicationId.h
index dc914c1..861c2e1 100644
--- a/keystore/include/keystore/KeyAttestationApplicationId.h
+++ b/keystore/include/keystore/KeyAttestationApplicationId.h
@@ -33,8 +33,8 @@
     typedef std::vector<std::unique_ptr<KeyAttestationPackageInfo>> PackageInfoVector;
     KeyAttestationApplicationId();
     // Following c'tors are for initializing instances containing test data.
-    KeyAttestationApplicationId(std::unique_ptr<KeyAttestationPackageInfo> package);
-    KeyAttestationApplicationId(PackageInfoVector packages);
+    explicit KeyAttestationApplicationId(std::unique_ptr<KeyAttestationPackageInfo> package);
+    explicit KeyAttestationApplicationId(PackageInfoVector packages);
 
     status_t writeToParcel(Parcel*) const override;
     status_t readFromParcel(const Parcel* parcel) override;
diff --git a/keystore/include/keystore/KeyCharacteristics.h b/keystore/include/keystore/KeyCharacteristics.h
index 40d495c..9c90b8a 100644
--- a/keystore/include/keystore/KeyCharacteristics.h
+++ b/keystore/include/keystore/KeyCharacteristics.h
@@ -27,7 +27,7 @@
 // Parcelable version of keystore::KeyCharacteristics
 struct KeyCharacteristics : public ::android::Parcelable {
     KeyCharacteristics(){};
-    KeyCharacteristics(::keystore::KeyCharacteristics&& other) {
+    explicit KeyCharacteristics(::keystore::KeyCharacteristics&& other) {
         softwareEnforced = std::move(other.softwareEnforced);
         hardwareEnforced = std::move(other.hardwareEnforced);
     }
diff --git a/keystore/include/keystore/KeymasterArguments.h b/keystore/include/keystore/KeymasterArguments.h
index b453b11..3d22f5f 100644
--- a/keystore/include/keystore/KeymasterArguments.h
+++ b/keystore/include/keystore/KeymasterArguments.h
@@ -26,6 +26,7 @@
 // struct for serializing/deserializing a list of KeyParameters
 struct KeymasterArguments : public Parcelable {
     KeymasterArguments(){};
+    // NOLINTNEXTLINE(google-explicit-constructor)
     KeymasterArguments(hardware::hidl_vec<::keystore::KeyParameter>&& other);
     explicit KeymasterArguments(const hardware::hidl_vec<::keystore::KeyParameter>& other);
 
diff --git a/keystore/include/keystore/KeystoreResponse.h b/keystore/include/keystore/KeystoreResponse.h
index 5ad260d..20f7274 100644
--- a/keystore/include/keystore/KeystoreResponse.h
+++ b/keystore/include/keystore/KeystoreResponse.h
@@ -34,6 +34,7 @@
         : response_code_(response_code), error_msg_(std::make_unique<String16>(error_msg)) {}
     explicit KeystoreResponse(const int response_code)
         : response_code_(response_code), error_msg_() {}
+    // NOLINTNEXTLINE(google-explicit-constructor)
     KeystoreResponse(const ::keystore::KeyStoreServiceReturnCode& rc)
         : response_code_(rc.getErrorCode()), error_msg_() {}
     KeystoreResponse(const KeystoreResponse& other)
diff --git a/keystore/include/keystore/Signature.h b/keystore/include/keystore/Signature.h
index 31ecdef..f39acec 100644
--- a/keystore/include/keystore/Signature.h
+++ b/keystore/include/keystore/Signature.h
@@ -27,7 +27,7 @@
   public:
     Signature() = default;
     // Intended for initializing instances containing test data.
-    Signature(std::vector<uint8_t> signature_data);
+    explicit Signature(std::vector<uint8_t> signature_data);
 
     status_t writeToParcel(Parcel*) const override;
     status_t readFromParcel(const Parcel* parcel) override;
diff --git a/keystore/include/keystore/keystore_concurrency.h b/keystore/include/keystore/keystore_concurrency.h
index b60b7a6..039ca31 100644
--- a/keystore/include/keystore/keystore_concurrency.h
+++ b/keystore/include/keystore/keystore_concurrency.h
@@ -85,9 +85,10 @@
 
   public:
     ProxyLock() : impl_() {}
+    // NOLINTNEXTLINE(google-explicit-constructor)
     template <typename... Args> ProxyLock(Args&&... args) : impl_{std::forward<Args>(args)...} {}
-    ProxyLock(Implementation&& impl) : impl_(std::move(impl)) {}
-    operator bool() const { return impl_.value() != nullptr; }
+    explicit ProxyLock(Implementation&& impl) : impl_(std::move(impl)) {}
+    explicit operator bool() const { return impl_.value() != nullptr; }
 
     template <typename T = typename Implementation::lockedType>
     std::enable_if_t<!std::is_const<typename Implementation::lockedType>::value, T*> operator->() {
diff --git a/keystore/include/keystore/keystore_return_types.h b/keystore/include/keystore/keystore_return_types.h
index e091447..f8cf1cc 100644
--- a/keystore/include/keystore/keystore_return_types.h
+++ b/keystore/include/keystore/keystore_return_types.h
@@ -41,10 +41,13 @@
 class KeyStoreServiceReturnCode {
   public:
     KeyStoreServiceReturnCode() : errorCode_(0) {}
+    // NOLINTNEXTLINE(google-explicit-constructor)
     KeyStoreServiceReturnCode(const ErrorCode& errorCode) : errorCode_(int32_t(errorCode)) {}
+    // NOLINTNEXTLINE(google-explicit-constructor)
     KeyStoreServiceReturnCode(const ResponseCode& errorCode) : errorCode_(int32_t(errorCode)) {}
     KeyStoreServiceReturnCode(const KeyStoreServiceReturnCode& errorCode)
         : errorCode_(errorCode.errorCode_) {}
+    // NOLINTNEXTLINE(google-explicit-constructor)
     KeyStoreServiceReturnCode(const KeyStoreNativeReturnCode& errorCode);
     explicit inline KeyStoreServiceReturnCode(const int32_t& errorCode) : errorCode_(errorCode) {}
     inline KeyStoreServiceReturnCode& operator=(const ErrorCode& errorCode) {
@@ -115,11 +118,14 @@
 class KeyStoreNativeReturnCode {
   public:
     KeyStoreNativeReturnCode() : errorCode_(0) {}
+    // NOLINTNEXTLINE(google-explicit-constructor)
     KeyStoreNativeReturnCode(const ErrorCode& errorCode) : errorCode_(int32_t(errorCode)) {}
+    // NOLINTNEXTLINE(google-explicit-constructor)
     KeyStoreNativeReturnCode(const ResponseCode& errorCode) : errorCode_(int32_t(errorCode)) {}
     KeyStoreNativeReturnCode(const KeyStoreNativeReturnCode& errorCode)
         : errorCode_(errorCode.errorCode_) {}
     explicit inline KeyStoreNativeReturnCode(const int32_t& errorCode) : errorCode_(errorCode) {}
+    // NOLINTNEXTLINE(google-explicit-constructor)
     KeyStoreNativeReturnCode(const KeyStoreServiceReturnCode& errorcode);
     inline KeyStoreNativeReturnCode& operator=(const ErrorCode& errorCode) {
         errorCode_ = int32_t(errorCode);
diff --git a/keystore/include/keystore/utils.h b/keystore/include/keystore/utils.h
index 1d8208a..544dd21 100644
--- a/keystore/include/keystore/utils.h
+++ b/keystore/include/keystore/utils.h
@@ -29,8 +29,12 @@
     typedef std::shared_ptr<CollectionType> CollectionPtr;
 
     SharedNullableIterator() {}
-    SharedNullableIterator(const std::shared_ptr<CollectionType>& coll) : coll_(coll) { init(); }
-    SharedNullableIterator(std::shared_ptr<CollectionType>&& coll) : coll_(coll) { init(); }
+    explicit SharedNullableIterator(const std::shared_ptr<CollectionType>& coll) : coll_(coll) {
+        init();
+    }
+    explicit SharedNullableIterator(std::shared_ptr<CollectionType>&& coll) : coll_(coll) {
+        init();
+    }
 
     SharedNullableIterator(const SharedNullableIterator& other)
         : coll_(other.coll_), cur_(other.cur_) {}
diff --git a/keystore/keymaster_worker.cpp b/keystore/keymaster_worker.cpp
index fd07e86..d2175b8 100644
--- a/keystore/keymaster_worker.cpp
+++ b/keystore/keymaster_worker.cpp
@@ -535,7 +535,7 @@
     std::function<void()> f_;
 
   public:
-    Finalize(std::function<void()> f) : f_(f) {}
+    explicit Finalize(std::function<void()> f) : f_(f) {}
     ~Finalize() {
         if (f_) f_();
     }
diff --git a/keystore/keymaster_worker.h b/keystore/keymaster_worker.h
index 2a35977..c02d389 100644
--- a/keystore/keymaster_worker.h
+++ b/keystore/keymaster_worker.h
@@ -95,6 +95,7 @@
 
       public:
         NonCopyableFunction() = default;
+        // NOLINTNEXTLINE(google-explicit-constructor)
         template <typename F> NonCopyableFunction(F f) {
             f_ = std::make_unique<NonCopyableFunctionTypeEraser<F>>(std::move(f));
         }
diff --git a/keystore/keystore_attestation_id.h b/keystore/keystore_attestation_id.h
index f45d5be..63015ee 100644
--- a/keystore/keystore_attestation_id.h
+++ b/keystore/keystore_attestation_id.h
@@ -33,12 +33,18 @@
 
 template <typename T> class StatusOr {
   public:
+    // NOLINTNEXTLINE(google-explicit-constructor)
     StatusOr(const status_t error) : _status(error), _value() {}
+    // NOLINTNEXTLINE(google-explicit-constructor)
     StatusOr(const T& value) : _status(NO_ERROR), _value(value) {}
+    // NOLINTNEXTLINE(google-explicit-constructor)
     StatusOr(T&& value) : _status(NO_ERROR), _value(value) {}
 
+    // NOLINTNEXTLINE(google-explicit-constructor)
     operator const T&() const { return _value; }
+    // NOLINTNEXTLINE(google-explicit-constructor)
     operator T&() { return _value; }
+    // NOLINTNEXTLINE(google-explicit-constructor)
     operator T &&() && { return std::move(_value); }
 
     bool isOk() const { return NO_ERROR == _status; }
diff --git a/keystore/legacy_keymaster_device_wrapper.cpp b/keystore/legacy_keymaster_device_wrapper.cpp
index 4073b42..86d286e 100644
--- a/keystore/legacy_keymaster_device_wrapper.cpp
+++ b/keystore/legacy_keymaster_device_wrapper.cpp
@@ -66,7 +66,7 @@
 
 class KmParamSet : public keymaster_key_param_set_t {
   public:
-    KmParamSet(const hidl_vec<KeyParameter>& keyParams) {
+    explicit KmParamSet(const hidl_vec<KeyParameter>& keyParams) {
         params = new keymaster_key_param_t[keyParams.size()];
         length = keyParams.size();
         for (size_t i = 0; i < keyParams.size(); ++i) {
diff --git a/keystore/legacy_keymaster_device_wrapper.h b/keystore/legacy_keymaster_device_wrapper.h
index ad26221..cd2e5a7 100644
--- a/keystore/legacy_keymaster_device_wrapper.h
+++ b/keystore/legacy_keymaster_device_wrapper.h
@@ -43,7 +43,7 @@
 
 class LegacyKeymasterDeviceWrapper : public IKeymasterDevice {
   public:
-    LegacyKeymasterDeviceWrapper(keymaster2_device_t* dev);
+    explicit LegacyKeymasterDeviceWrapper(keymaster2_device_t* dev);
     virtual ~LegacyKeymasterDeviceWrapper();
 
     // Methods from ::android::hardware::keymaster::V3_0::IKeymasterDevice follow.