diff --git a/src/crypto/CryptoHash.h b/src/crypto/CryptoHash.h
index eafd7375f..3eec9981f 100644
--- a/src/crypto/CryptoHash.h
+++ b/src/crypto/CryptoHash.h
@@ -30,7 +30,7 @@ public:
         Sha256
     };
 
-    CryptoHash(CryptoHash::Algorithm algo);
+    explicit CryptoHash(CryptoHash::Algorithm algo);
     ~CryptoHash();
     void addData(const QByteArray& data);
     void reset();
@@ -40,7 +40,8 @@ public:
 
 private:
     CryptoHashPrivate* const d_ptr;
-    Q_DECLARE_PRIVATE(CryptoHash);
+
+    Q_DECLARE_PRIVATE(CryptoHash)
 };
 
 #endif // KEEPASSX_CRYPTOHASH_H
diff --git a/src/crypto/SymmetricCipher.h b/src/crypto/SymmetricCipher.h
index 2f744520b..aaf50f69b 100644
--- a/src/crypto/SymmetricCipher.h
+++ b/src/crypto/SymmetricCipher.h
@@ -55,8 +55,9 @@ public:
     int blockSize() const;
 
 private:
-    Q_DISABLE_COPY(SymmetricCipher)
     SymmetricCipherBackend* m_backend;
+
+    Q_DISABLE_COPY(SymmetricCipher)
 };
 
 #endif // KEEPASSX_SYMMETRICCIPHER_H
diff --git a/src/crypto/SymmetricCipherBackend.h b/src/crypto/SymmetricCipherBackend.h
index bca002e22..a4e2b01a8 100644
--- a/src/crypto/SymmetricCipherBackend.h
+++ b/src/crypto/SymmetricCipherBackend.h
@@ -23,7 +23,7 @@
 class SymmetricCipherBackend
 {
 public:
-    virtual ~SymmetricCipherBackend() {};
+    virtual ~SymmetricCipherBackend() {}
     virtual void setAlgorithm(SymmetricCipher::Algorithm algo) = 0;
     virtual void setMode(SymmetricCipher::Mode mode) = 0;
     virtual void setDirection(SymmetricCipher::Direction direction) = 0;
diff --git a/src/format/KeePass2RandomStream.cpp b/src/format/KeePass2RandomStream.cpp
index 0cf4a1f46..46df2d501 100644
--- a/src/format/KeePass2RandomStream.cpp
+++ b/src/format/KeePass2RandomStream.cpp
@@ -20,7 +20,7 @@
 #include "crypto/CryptoHash.h"
 #include "format/KeePass2.h"
 
-KeePass2RandomStream::KeePass2RandomStream(QByteArray key)
+KeePass2RandomStream::KeePass2RandomStream(const QByteArray& key)
     : m_cipher(SymmetricCipher::Salsa20, SymmetricCipher::Stream, SymmetricCipher::Encrypt,
           CryptoHash::hash(key, CryptoHash::Sha256), KeePass2::INNER_STREAM_SALSA20_IV)
     , m_offset(0)
diff --git a/src/format/KeePass2RandomStream.h b/src/format/KeePass2RandomStream.h
index a1aa7944f..9f1969522 100644
--- a/src/format/KeePass2RandomStream.h
+++ b/src/format/KeePass2RandomStream.h
@@ -25,7 +25,7 @@
 class KeePass2RandomStream
 {
 public:
-    KeePass2RandomStream(QByteArray key);
+    explicit KeePass2RandomStream(const QByteArray& key);
     QByteArray randomBytes(int size);
     QByteArray process(const QByteArray& data);
     void processInPlace(QByteArray& data);
diff --git a/src/format/KeePass2Reader.h b/src/format/KeePass2Reader.h
index 86d2337c9..97a71b4c5 100644
--- a/src/format/KeePass2Reader.h
+++ b/src/format/KeePass2Reader.h
@@ -27,7 +27,7 @@ class QIODevice;
 
 class KeePass2Reader
 {
-    Q_DECLARE_TR_FUNCTIONS(KeePass2Reader);
+    Q_DECLARE_TR_FUNCTIONS(KeePass2Reader)
 
 public:
     KeePass2Reader();
diff --git a/src/format/KeePass2XmlReader.h b/src/format/KeePass2XmlReader.h
index 1d03a3a22..4e2cb0872 100644
--- a/src/format/KeePass2XmlReader.h
+++ b/src/format/KeePass2XmlReader.h
@@ -35,7 +35,7 @@ class Metadata;
 
 class KeePass2XmlReader
 {
-    Q_DECLARE_TR_FUNCTIONS(KeePass2XmlReader);
+    Q_DECLARE_TR_FUNCTIONS(KeePass2XmlReader)
 
 public:
     KeePass2XmlReader();
diff --git a/src/gui/DatabaseTabWidget.h b/src/gui/DatabaseTabWidget.h
index bb8473710..faa650b58 100644
--- a/src/gui/DatabaseTabWidget.h
+++ b/src/gui/DatabaseTabWidget.h
@@ -46,7 +46,7 @@ class DatabaseTabWidget : public QTabWidget
     Q_OBJECT
 
 public:
-    DatabaseTabWidget(QWidget* parent);
+    explicit DatabaseTabWidget(QWidget* parent);
     void openDatabase(const QString& fileName);
     DatabaseWidget* currentDatabaseWidget();
 
diff --git a/src/gui/EditGroupWidget.h b/src/gui/EditGroupWidget.h
index 1a014eacb..5d7d0c7b5 100644
--- a/src/gui/EditGroupWidget.h
+++ b/src/gui/EditGroupWidget.h
@@ -32,7 +32,7 @@ class EditGroupWidget : public QWidget
     Q_OBJECT
 
 public:
-    EditGroupWidget(QWidget* parent = 0);
+    explicit EditGroupWidget(QWidget* parent = 0);
     ~EditGroupWidget();
 
     void loadGroup(Group* group, bool create);
diff --git a/src/keys/PasswordKey.h b/src/keys/PasswordKey.h
index 7bdc87f37..df545573b 100644
--- a/src/keys/PasswordKey.h
+++ b/src/keys/PasswordKey.h
@@ -26,7 +26,7 @@ class PasswordKey : public Key
 {
 public:
     PasswordKey();
-    PasswordKey(const QString& password);
+    explicit PasswordKey(const QString& password);
     QByteArray rawKey() const;
     void setPassword(const QString& password);
     PasswordKey* clone() const;