Catch and handle all errors from libgcrypt.

29 files changed, 608 insertions, 180 deletions

diff --git a/src/core/Database.cpp b/src/core/Database.cpp
index 4c888eab9..098cc06af 100644
--- a/src/core/Database.cpp
+++ b/src/core/Database.cpp
@@ -188,32 +188,51 @@ void Database::setCompressionAlgo(Database::CompressionAlgorithm algo)
     m_data.compressionAlgo = algo;
 }
 
-void Database::setTransformRounds(quint64 rounds)
+bool Database::setTransformRounds(quint64 rounds)
 {
     if (m_data.transformRounds != rounds) {
+        quint64 oldRounds = m_data.transformRounds;
+
         m_data.transformRounds = rounds;
 
         if (m_data.hasKey) {
-            setKey(m_data.key);
+            if (!setKey(m_data.key)) {
+                m_data.transformRounds = oldRounds;
+                return false;
+            }
         }
     }
+
+    return true;
 }
 
-void Database::setKey(const CompositeKey& key, const QByteArray& transformSeed, bool updateChangedTime)
+bool Database::setKey(const CompositeKey& key, const QByteArray& transformSeed,
+                      bool updateChangedTime)
 {
+    bool ok;
+    QString errorString;
+
+    QByteArray transformedMasterKey =
+            key.transform(transformSeed, transformRounds(), &ok, &errorString);
+    if (!ok) {
+        return false;
+    }
+
     m_data.key = key;
     m_data.transformSeed = transformSeed;
-    m_data.transformedMasterKey = key.transform(transformSeed, transformRounds());
+    m_data.transformedMasterKey = transformedMasterKey;
     m_data.hasKey = true;
     if (updateChangedTime) {
         m_metadata->setMasterKeyChanged(Tools::currentDateTimeUtc());
     }
     Q_EMIT modifiedImmediate();
+
+    return true;
 }
 
-void Database::setKey(const CompositeKey& key)
+bool Database::setKey(const CompositeKey& key)
 {
-    setKey(key, randomGen()->randomArray(32));
+    return setKey(key, randomGen()->randomArray(32));
 }
 
 bool Database::hasKey() const
diff --git a/src/core/Database.h b/src/core/Database.h
index 3e0c675df..97ccad234 100644
--- a/src/core/Database.h
+++ b/src/core/Database.h
@@ -90,13 +90,14 @@ public:
 
     void setCipher(const Uuid& cipher);
     void setCompressionAlgo(Database::CompressionAlgorithm algo);
-    void setTransformRounds(quint64 rounds);
-    void setKey(const CompositeKey& key, const QByteArray& transformSeed, bool updateChangedTime = true);
+    bool setTransformRounds(quint64 rounds);
+    bool setKey(const CompositeKey& key, const QByteArray& transformSeed,
+                bool updateChangedTime = true);
 
     /**
      * Sets the database key and generates a random transform seed.
      */
-    void setKey(const CompositeKey& key);
+    bool setKey(const CompositeKey& key);
     bool hasKey() const;
     bool verifyKey(const CompositeKey& key) const;
     void recycleEntry(Entry* entry);
diff --git a/src/crypto/Crypto.cpp b/src/crypto/Crypto.cpp
index bf3076e85..d4fc6493e 100644
--- a/src/crypto/Crypto.cpp
+++ b/src/crypto/Crypto.cpp
@@ -143,65 +143,137 @@ bool Crypto::checkAlgorithms()
 
 bool Crypto::selfTest()
 {
+    return testSha256() && testAes256() && testTwofish() && testSalsa20();
+}
+
+void Crypto::raiseError(const QString& str)
+{
+    m_errorStr = str;
+    qWarning("Crypto::selfTest: %s", qPrintable(m_errorStr));
+}
+
+bool Crypto::testSha256()
+{
     QByteArray sha256Test = CryptoHash::hash("abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq",
                                              CryptoHash::Sha256);
 
     if (sha256Test != QByteArray::fromHex("248D6A61D20638B8E5C026930C3E6039A33CE45964FF2167F6ECEDD419DB06C1")) {
-        m_errorStr = "SHA-256 mismatch.";
-        qWarning("Crypto::selfTest: %s", qPrintable(m_errorStr));
+        raiseError("SHA-256 mismatch.");
         return false;
     }
 
+    return true;
+}
+
+bool Crypto::testAes256()
+{
     QByteArray key = QByteArray::fromHex("603deb1015ca71be2b73aef0857d77811f352c073b6108d72d9810a30914dff4");
     QByteArray iv = QByteArray::fromHex("000102030405060708090a0b0c0d0e0f");
     QByteArray plainText = QByteArray::fromHex("6bc1bee22e409f96e93d7e117393172a");
     plainText.append(QByteArray::fromHex("ae2d8a571e03ac9c9eb76fac45af8e51"));
     QByteArray cipherText = QByteArray::fromHex("f58c4c04d6e5f1ba779eabfb5f7bfbd6");
     cipherText.append(QByteArray::fromHex("9cfc4e967edb808d679f777bc6702c7d"));
+    bool ok;
 
-    SymmetricCipher aes256Encrypt(SymmetricCipher::Aes256, SymmetricCipher::Cbc, SymmetricCipher::Encrypt, key, iv);
-    if (aes256Encrypt.process(plainText) != cipherText) {
-        m_errorStr = "AES-256 encryption mismatch.";
-        qWarning("Crypto::selfTest: %s", qPrintable(m_errorStr));
+    SymmetricCipher aes256Encrypt(SymmetricCipher::Aes256, SymmetricCipher::Cbc, SymmetricCipher::Encrypt);
+    if (!aes256Encrypt.init(key, iv)) {
+        raiseError(aes256Encrypt.errorString());
+        return false;
+    }
+    QByteArray encryptedText = aes256Encrypt.process(plainText, &ok);
+    if (!ok) {
+        raiseError(aes256Encrypt.errorString());
+        return false;
+    }
+    if (encryptedText != cipherText) {
+        raiseError("AES-256 encryption mismatch.");
         return false;
     }
 
-    SymmetricCipher aes256Descrypt(SymmetricCipher::Aes256, SymmetricCipher::Cbc, SymmetricCipher::Decrypt, key, iv);
-    if (aes256Descrypt.process(cipherText) != plainText) {
-        m_errorStr = "AES-256 decryption mismatch.";
-        qWarning("Crypto::selfTest: %s", qPrintable(m_errorStr));
+    SymmetricCipher aes256Descrypt(SymmetricCipher::Aes256, SymmetricCipher::Cbc, SymmetricCipher::Decrypt);
+    if (!aes256Descrypt.init(key, iv)) {
+        raiseError(aes256Descrypt.errorString());
+        return false;
+    }
+    QByteArray decryptedText = aes256Descrypt.process(cipherText, &ok);
+    if (!ok) {
+        raiseError(aes256Descrypt.errorString());
+        return false;
+    }
+    if (decryptedText != plainText) {
+        raiseError("AES-256 decryption mismatch.");
         return false;
     }
 
-    // Twofish
-    cipherText = QByteArray::fromHex("e0227c3cc80f3cb1b2ed847cc6f57d3c");
+    return true;
+}
+
+bool Crypto::testTwofish()
+{
+    QByteArray key = QByteArray::fromHex("603deb1015ca71be2b73aef0857d77811f352c073b6108d72d9810a30914dff4");
+    QByteArray iv = QByteArray::fromHex("000102030405060708090a0b0c0d0e0f");
+    QByteArray plainText = QByteArray::fromHex("6bc1bee22e409f96e93d7e117393172a");
+    plainText.append(QByteArray::fromHex("ae2d8a571e03ac9c9eb76fac45af8e51"));
+    QByteArray cipherText = QByteArray::fromHex("e0227c3cc80f3cb1b2ed847cc6f57d3c");
     cipherText.append(QByteArray::fromHex("657b1e7960b30fb7c8d62e72ae37c3a0"));
+    bool ok;
 
-    SymmetricCipher twofishEncrypt(SymmetricCipher::Twofish, SymmetricCipher::Cbc, SymmetricCipher::Encrypt, key, iv);
-    if (twofishEncrypt.process(plainText) != cipherText) {
-        m_errorStr = "Twofish encryption mismatch.";
-        qWarning("Crypto::selfTest: %s", qPrintable(m_errorStr));
+    SymmetricCipher twofishEncrypt(SymmetricCipher::Twofish, SymmetricCipher::Cbc, SymmetricCipher::Encrypt);
+    if (!twofishEncrypt.init(key, iv)) {
+        raiseError(twofishEncrypt.errorString());
+        return false;
+    }
+    QByteArray encryptedText = twofishEncrypt.process(plainText, &ok);
+    if (!ok) {
+        raiseError(twofishEncrypt.errorString());
         return false;
     }
+    if (encryptedText != cipherText) {
+        raiseError("Twofish encryption mismatch.");
+        return false;
+    }
+
 
-    SymmetricCipher twofishDecrypt(SymmetricCipher::Twofish, SymmetricCipher::Cbc, SymmetricCipher::Decrypt, key, iv);
-    if (twofishDecrypt.process(cipherText) != plainText) {
-        m_errorStr = "Twofish decryption mismatch.";
-        qWarning("Crypto::selfTest: %s", qPrintable(m_errorStr));
+    SymmetricCipher twofishDecrypt(SymmetricCipher::Twofish, SymmetricCipher::Cbc, SymmetricCipher::Decrypt);
+    if (!twofishDecrypt.init(key, iv)) {
+        raiseError(twofishEncrypt.errorString());
+        return false;
+    }
+    QByteArray decryptedText = twofishDecrypt.process(cipherText, &ok);
+    if (!ok) {
+        raiseError(twofishDecrypt.errorString());
         return false;
     }
+    if (decryptedText != plainText) {
+        raiseError("Twofish encryption mismatch.");
+        return false;
+    }
+
+    return true;
+}
 
+bool Crypto::testSalsa20()
+{
     QByteArray salsa20Key = QByteArray::fromHex("F3F4F5F6F7F8F9FAFBFCFDFEFF000102030405060708090A0B0C0D0E0F101112");
     QByteArray salsa20iv = QByteArray::fromHex("0000000000000000");
     QByteArray salsa20Plain = QByteArray::fromHex("00000000000000000000000000000000");
     QByteArray salsa20Cipher = QByteArray::fromHex("B4C0AFA503BE7FC29A62058166D56F8F");
+    bool ok;
 
     SymmetricCipher salsa20Stream(SymmetricCipher::Salsa20, SymmetricCipher::Stream,
-                                  SymmetricCipher::Encrypt, salsa20Key, salsa20iv);
+                                  SymmetricCipher::Encrypt);
+    if (!salsa20Stream.init(salsa20Key, salsa20iv)) {
+        raiseError(salsa20Stream.errorString());
+        return false;
+    }
 
-    if (salsa20Stream.process(salsa20Plain) != salsa20Cipher) {
-        m_errorStr = "Salsa20 stream cipher mismatch.";
-        qWarning("Crypto::selfTest: %s", qPrintable(m_errorStr));
+    QByteArray salsaProcessed = salsa20Stream.process(salsa20Plain, &ok);
+    if (!ok) {
+        raiseError(salsa20Stream.errorString());
+        return false;
+    }
+    if (salsaProcessed != salsa20Cipher) {
+        raiseError("Salsa20 stream cipher mismatch.");
         return false;
     }
 
diff --git a/src/crypto/Crypto.h b/src/crypto/Crypto.h
index 9926f14b2..07f6454fe 100644
--- a/src/crypto/Crypto.h
+++ b/src/crypto/Crypto.h
@@ -34,6 +34,11 @@ private:
     Crypto();
     static bool checkAlgorithms();
     static bool selfTest();
+    static void raiseError(const QString& str);
+    static bool testSha256();
+    static bool testAes256();
+    static bool testTwofish();
+    static bool testSalsa20();
 
     static bool m_initalized;
     static QString m_errorStr;
diff --git a/src/crypto/SymmetricCipher.cpp b/src/crypto/SymmetricCipher.cpp
index 5f9222653..454548caa 100644
--- a/src/crypto/SymmetricCipher.cpp
+++ b/src/crypto/SymmetricCipher.cpp
@@ -22,17 +22,39 @@
 #include "crypto/SymmetricCipherSalsa20.h"
 
 SymmetricCipher::SymmetricCipher(SymmetricCipher::Algorithm algo, SymmetricCipher::Mode mode,
-                                 SymmetricCipher::Direction direction, const QByteArray& key, const QByteArray& iv)
+                                 SymmetricCipher::Direction direction)
     : m_backend(createBackend(algo, mode, direction))
+    , m_initialized(false)
 {
-    m_backend->setKey(key);
-    m_backend->setIv(iv);
 }
 
 SymmetricCipher::~SymmetricCipher()
 {
 }
 
+bool SymmetricCipher::init(const QByteArray& key, const QByteArray& iv)
+{
+    if (!m_backend->init()) {
+        return false;
+    }
+
+    if (!m_backend->setKey(key)) {
+        return false;
+    }
+
+    if (!m_backend->setIv(iv)) {
+        return false;
+    }
+
+    m_initialized = true;
+    return true;
+}
+
+bool SymmetricCipher::isInitalized() const
+{
+    return m_initialized;
+}
+
 SymmetricCipherBackend* SymmetricCipher::createBackend(SymmetricCipher::Algorithm algo, SymmetricCipher::Mode mode,
                                                        SymmetricCipher::Direction direction)
 {
@@ -55,12 +77,17 @@ SymmetricCipherBackend* SymmetricCipher::createBackend(SymmetricCipher::Algorith
     }
 }
 
-void SymmetricCipher::reset()
+bool SymmetricCipher::reset()
 {
-    m_backend->reset();
+    return m_backend->reset();
 }
 
 int SymmetricCipher::blockSize() const
 {
     return m_backend->blockSize();
 }
+
+QString SymmetricCipher::errorString() const
+{
+    return m_backend->errorString();
+}
diff --git a/src/crypto/SymmetricCipher.h b/src/crypto/SymmetricCipher.h
index d036e532e..65cab76fa 100644
--- a/src/crypto/SymmetricCipher.h
+++ b/src/crypto/SymmetricCipher.h
@@ -20,6 +20,7 @@
 
 #include <QByteArray>
 #include <QScopedPointer>
+#include <QString>
 
 #include "core/Global.h"
 #include "crypto/SymmetricCipherBackend.h"
@@ -48,30 +49,35 @@ public:
     };
 
     SymmetricCipher(SymmetricCipher::Algorithm algo, SymmetricCipher::Mode mode,
-                    SymmetricCipher::Direction direction, const QByteArray& key, const QByteArray& iv);
+                    SymmetricCipher::Direction direction);
     ~SymmetricCipher();
 
-    inline QByteArray process(const QByteArray& data) {
-        return m_backend->process(data);
+    bool init(const QByteArray& key, const QByteArray& iv);
+    bool isInitalized() const;
+
+    inline QByteArray process(const QByteArray& data, bool* ok) {
+        return m_backend->process(data, ok);
     }
 
-    inline void processInPlace(QByteArray& data) {
-        m_backend->processInPlace(data);
+    inline bool processInPlace(QByteArray& data) {
+        return m_backend->processInPlace(data);
     }
 
-    inline void processInPlace(QByteArray& data, quint64 rounds) {
+    inline bool processInPlace(QByteArray& data, quint64 rounds) {
         Q_ASSERT(rounds > 0);
-        m_backend->processInPlace(data, rounds);
+        return m_backend->processInPlace(data, rounds);
     }
 
-    void reset();
+    bool reset();
     int blockSize() const;
+    QString errorString() const;
 
 private:
     static SymmetricCipherBackend* createBackend(SymmetricCipher::Algorithm algo, SymmetricCipher::Mode mode,
                                                  SymmetricCipher::Direction direction);
 
     const QScopedPointer<SymmetricCipherBackend> m_backend;
+    bool m_initialized;
 
     Q_DISABLE_COPY(SymmetricCipher)
 };
diff --git a/src/crypto/SymmetricCipherBackend.h b/src/crypto/SymmetricCipherBackend.h
index e6110cba5..763ffb40d 100644
--- a/src/crypto/SymmetricCipherBackend.h
+++ b/src/crypto/SymmetricCipherBackend.h
@@ -24,15 +24,18 @@ class SymmetricCipherBackend
 {
 public:
     virtual ~SymmetricCipherBackend() {}
-    virtual void setKey(const QByteArray& key) = 0;
-    virtual void setIv(const QByteArray& iv) = 0;
+    virtual bool init() = 0;
+    virtual bool setKey(const QByteArray& key) = 0;
+    virtual bool setIv(const QByteArray& iv) = 0;
 
-    virtual QByteArray process(const QByteArray& data) = 0;
-    virtual void processInPlace(QByteArray& data) = 0;
-    virtual void processInPlace(QByteArray& data, quint64 rounds) = 0;
+    virtual QByteArray process(const QByteArray& data, bool* ok) = 0;
+    virtual bool processInPlace(QByteArray& data) = 0;
+    virtual bool processInPlace(QByteArray& data, quint64 rounds) = 0;
 
-    virtual void reset() = 0;
+    virtual bool reset() = 0;
     virtual int blockSize() const = 0;
+
+    virtual QString errorString() const = 0;
 };
 
 #endif // KEEPASSX_SYMMETRICCIPHERBACKEND_H
diff --git a/src/crypto/SymmetricCipherGcrypt.cpp b/src/crypto/SymmetricCipherGcrypt.cpp
index cf52bafab..5c4fe6ab3 100644
--- a/src/crypto/SymmetricCipherGcrypt.cpp
+++ b/src/crypto/SymmetricCipherGcrypt.cpp
@@ -22,22 +22,12 @@
 
 SymmetricCipherGcrypt::SymmetricCipherGcrypt(SymmetricCipher::Algorithm algo, SymmetricCipher::Mode mode,
                                              SymmetricCipher::Direction direction)
-    : m_algo(gcryptAlgo(algo))
+    : m_ctx(Q_NULLPTR)
+    , m_algo(gcryptAlgo(algo))
     , m_mode(gcryptMode(mode))
     , m_direction(direction)
     , m_blockSize(-1)
 {
-    Q_ASSERT(Crypto::initalized());
-
-    gcry_error_t error;
-
-    error = gcry_cipher_open(&m_ctx, m_algo, m_mode, 0);
-    Q_ASSERT(error == 0); // TODO: real error checking
-
-    size_t blockSizeT;
-    error = gcry_cipher_algo_info(m_algo, GCRYCTL_GET_BLKLEN, Q_NULLPTR, &blockSizeT);
-    Q_ASSERT(error == 0);
-    m_blockSize = blockSizeT;
 }
 
 SymmetricCipherGcrypt::~SymmetricCipherGcrypt()
@@ -83,21 +73,65 @@ int SymmetricCipherGcrypt::gcryptMode(SymmetricCipher::Mode mode)
     }
 }
 
-void SymmetricCipherGcrypt::setKey(const QByteArray& key)
+void SymmetricCipherGcrypt::setErrorString(gcry_error_t err)
+{
+    const char* gcryptError = gcry_strerror(err);
+    const char* gcryptErrorSource = gcry_strsource(err);
+
+    m_errorString = QString("%1/%2").arg(QString::fromLocal8Bit(gcryptErrorSource),
+                                         QString::fromLocal8Bit(gcryptError));
+}
+
+bool SymmetricCipherGcrypt::init()
+{
+    Q_ASSERT(Crypto::initalized());
+
+    gcry_error_t error;
+
+    error = gcry_cipher_open(&m_ctx, m_algo, m_mode, 0);
+    if (error != 0) {
+        setErrorString(error);
+        return false;
+    }
+
+    size_t blockSizeT;
+    error = gcry_cipher_algo_info(m_algo, GCRYCTL_GET_BLKLEN, Q_NULLPTR, &blockSizeT);
+    if (error != 0) {
+        setErrorString(error);
+        return false;
+    }
+
+    m_blockSize = blockSizeT;
+    return true;
+}
+
+bool SymmetricCipherGcrypt::setKey(const QByteArray& key)
 {
     m_key = key;
     gcry_error_t error = gcry_cipher_setkey(m_ctx, m_key.constData(), m_key.size());
-    Q_ASSERT(error == 0);
+
+    if (error != 0) {
+        setErrorString(error);
+        return false;
+    }
+
+    return true;
 }
 
-void SymmetricCipherGcrypt::setIv(const QByteArray& iv)
+bool SymmetricCipherGcrypt::setIv(const QByteArray& iv)
 {
     m_iv = iv;
     gcry_error_t error = gcry_cipher_setiv(m_ctx, m_iv.constData(), m_iv.size());
-    Q_ASSERT(error == 0);
+
+    if (error != 0) {
+        setErrorString(error);
+        return false;
+    }
+
+    return true;
 }
 
-QByteArray SymmetricCipherGcrypt::process(const QByteArray& data)
+QByteArray SymmetricCipherGcrypt::process(const QByteArray& data, bool* ok)
 {
     // TODO: check block size
 
@@ -113,12 +147,16 @@ QByteArray SymmetricCipherGcrypt::process(const QByteArray& data)
         error = gcry_cipher_encrypt(m_ctx, result.data(), data.size(), data.constData(), data.size());
     }
 
-    Q_ASSERT(error == 0);
+    if (error != 0) {
+        setErrorString(error);
+        *ok = false;
+    }
 
+    *ok = true;
     return result;
 }
 
-void SymmetricCipherGcrypt::processInPlace(QByteArray& data)
+bool SymmetricCipherGcrypt::processInPlace(QByteArray& data)
 {
     // TODO: check block size
 
@@ -131,10 +169,15 @@ void SymmetricCipherGcrypt::processInPlace(QByteArray& data)
         error = gcry_cipher_encrypt(m_ctx, data.data(), data.size(), Q_NULLPTR, 0);
     }
 
-    Q_ASSERT(error == 0);
+    if (error != 0) {
+        setErrorString(error);
+        return false;
+    }
+
+    return true;
 }
 
-void SymmetricCipherGcrypt::processInPlace(QByteArray& data, quint64 rounds)
+bool SymmetricCipherGcrypt::processInPlace(QByteArray& data, quint64 rounds)
 {
     // TODO: check block size
 
@@ -146,28 +189,52 @@ void SymmetricCipherGcrypt::processInPlace(QByteArray& data, quint64 rounds)
     if (m_direction == SymmetricCipher::Decrypt) {
         for (quint64 i = 0; i != rounds; ++i) {
             error = gcry_cipher_decrypt(m_ctx, rawData, size, Q_NULLPTR, 0);
-            Q_ASSERT(error == 0);
+
+            if (error != 0) {
+                setErrorString(error);
+                return false;
+            }
         }
     }
     else {
         for (quint64 i = 0; i != rounds; ++i) {
             error = gcry_cipher_encrypt(m_ctx, rawData, size, Q_NULLPTR, 0);
-            Q_ASSERT(error == 0);
+
+            if (error != 0) {
+                setErrorString(error);
+                return false;
+            }
         }
     }
+
+    return true;
 }
 
-void SymmetricCipherGcrypt::reset()
+bool SymmetricCipherGcrypt::reset()
 {
     gcry_error_t error;
 
     error = gcry_cipher_reset(m_ctx);
-    Q_ASSERT(error == 0);
+    if (error != 0) {
+        setErrorString(error);
+        return false;
+    }
+
     error = gcry_cipher_setiv(m_ctx, m_iv.constData(), m_iv.size());
-    Q_ASSERT(error == 0);
+    if (error != 0) {
+        setErrorString(error);
+        return false;
+    }
+
+    return true;
 }
 
 int SymmetricCipherGcrypt::blockSize() const
 {
     return m_blockSize;
 }
+
+QString SymmetricCipherGcrypt::errorString() const
+{
+    return m_errorString;
+}
diff --git a/src/crypto/SymmetricCipherGcrypt.h b/src/crypto/SymmetricCipherGcrypt.h
index c22059a4e..bc1560097 100644
--- a/src/crypto/SymmetricCipherGcrypt.h
+++ b/src/crypto/SymmetricCipherGcrypt.h
@@ -29,19 +29,24 @@ public:
     SymmetricCipherGcrypt(SymmetricCipher::Algorithm algo, SymmetricCipher::Mode mode,
                           SymmetricCipher::Direction direction);
     ~SymmetricCipherGcrypt();
-    void setKey(const QByteArray& key);
-    void setIv(const QByteArray& iv);
 
-    QByteArray process(const QByteArray& data);
-    void processInPlace(QByteArray& data);
-    void processInPlace(QByteArray& data, quint64 rounds);
+    bool init();
+    bool setKey(const QByteArray& key);
+    bool setIv(const QByteArray& iv);
 
-    void reset();
+    QByteArray process(const QByteArray& data, bool* ok);
+    bool processInPlace(QByteArray& data);
+    bool processInPlace(QByteArray& data, quint64 rounds);
+
+    bool reset();
     int blockSize() const;
 
+    QString errorString() const;
+
 private:
     static int gcryptAlgo(SymmetricCipher::Algorithm algo);
     static int gcryptMode(SymmetricCipher::Mode mode);
+    void setErrorString(gcry_error_t err);
 
     gcry_cipher_hd_t m_ctx;
     const int m_algo;
@@ -50,6 +55,7 @@ private:
     QByteArray m_key;
     QByteArray m_iv;
     int m_blockSize;
+    QString m_errorString;
 };
 
 #endif // KEEPASSX_SYMMETRICCIPHERGCRYPT_H
diff --git a/src/crypto/SymmetricCipherSalsa20.h b/src/crypto/SymmetricCipherSalsa20.h
index e3e4726f8..6a5c24562 100644
--- a/src/crypto/SymmetricCipherSalsa20.h
+++ b/src/crypto/SymmetricCipherSalsa20.h
@@ -28,17 +28,18 @@ public:
     SymmetricCipherSalsa20(SymmetricCipher::Algorithm algo, SymmetricCipher::Mode mode,
                            SymmetricCipher::Direction direction);
     ~SymmetricCipherSalsa20();
+    bool init();
     void setAlgorithm(SymmetricCipher::Algorithm algo);
     void setMode(SymmetricCipher::Mode mode);
     void setDirection(SymmetricCipher::Direction direction);
-    void setKey(const QByteArray& key);
-    void setIv(const QByteArray& iv);
+    bool setKey(const QByteArray& key);
+    bool setIv(const QByteArray& iv);
 
-    QByteArray process(const QByteArray& data);
-    void processInPlace(QByteArray& data);
-    void processInPlace(QByteArray& data, quint64 rounds);
+    QByteArray process(const QByteArray& data, bool* ok);
+    bool processInPlace(QByteArray& data);
+    bool processInPlace(QByteArray& data, quint64 rounds);
 
-    void reset();
+    bool reset();
     int blockSize() const;
 
 private:
diff --git a/src/format/KeePass1Reader.cpp b/src/format/KeePass1Reader.cpp
index d4760b9e7..a15c832b3 100644
--- a/src/format/KeePass1Reader.cpp
+++ b/src/format/KeePass1Reader.cpp
@@ -154,14 +154,16 @@ Database* KeePass1Reader::readDatabase(QIODevice* device, const QString& passwor
         raiseError("Invalid number of transform rounds");
         return Q_NULLPTR;
     }
-    m_db->setTransformRounds(m_transformRounds);
+    if (!m_db->setTransformRounds(m_transformRounds)) {
+        raiseError(tr("Unable to calculate master key"));
+        return Q_NULLPTR;
+    }
 
     qint64 contentPos = m_device->pos();
 
     QScopedPointer<SymmetricCipherStream> cipherStream(testKeys(password, keyfileData, contentPos));
 
     if (!cipherStream) {
-        raiseError("Unable to create cipher stream");
         return Q_NULLPTR;
     }
 
@@ -234,7 +236,10 @@ Database* KeePass1Reader::readDatabase(QIODevice* device, const QString& passwor
         key.addKey(newFileKey);
     }
 
-    db->setKey(key);
+    if (!db->setKey(key)) {
+        raiseError(tr("Unable to calculate master key"));
+        return Q_NULLPTR;
+    }
 
     return db.take();
 }
@@ -326,16 +331,26 @@ SymmetricCipherStream* KeePass1Reader::testKeys(const QString& password, const Q
         }
 
         QByteArray finalKey = key(passwordData, keyfileData);
+        if (finalKey.isEmpty()) {
+            return Q_NULLPTR;
+        }
         if (m_encryptionFlags & KeePass1::Rijndael) {
             cipherStream.reset(new SymmetricCipherStream(m_device, SymmetricCipher::Aes256,
-                    SymmetricCipher::Cbc, SymmetricCipher::Decrypt, finalKey, m_encryptionIV));
+                    SymmetricCipher::Cbc, SymmetricCipher::Decrypt));
         }
         else {
             cipherStream.reset(new SymmetricCipherStream(m_device, SymmetricCipher::Twofish,
-                    SymmetricCipher::Cbc, SymmetricCipher::Decrypt, finalKey, m_encryptionIV));
+                    SymmetricCipher::Cbc, SymmetricCipher::Decrypt));
         }
 
-        cipherStream->open(QIODevice::ReadOnly);
+        if (!cipherStream->init(finalKey, m_encryptionIV)) {
+            raiseError(cipherStream->errorString());
+            return Q_NULLPTR;
+        }
+        if (!cipherStream->open(QIODevice::ReadOnly)) {
+            raiseError(cipherStream->errorString());
+            return Q_NULLPTR;
+        }
 
         bool success = verifyKey(cipherStream.data());
 
@@ -372,9 +387,18 @@ QByteArray KeePass1Reader::key(const QByteArray& password, const QByteArray& key
     key.setPassword(password);
     key.setKeyfileData(keyfileData);
 
+    bool ok;
+    QString errorString;
+    QByteArray transformedKey = key.transform(m_transformSeed, m_transformRounds, &ok, &errorString);
+
+    if (!ok) {
+        raiseError(errorString);
+        return QByteArray();
+    }
+
     CryptoHash hash(CryptoHash::Sha256);
     hash.addData(m_masterSeed);
-    hash.addData(key.transform(m_transformSeed, m_transformRounds));
+    hash.addData(transformedKey);
     return hash.result();
 }
 
diff --git a/src/format/KeePass2RandomStream.cpp b/src/format/KeePass2RandomStream.cpp
index 8b4a7c8e2..1944e5d5b 100644
--- a/src/format/KeePass2RandomStream.cpp
+++ b/src/format/KeePass2RandomStream.cpp
@@ -20,14 +20,19 @@
 #include "crypto/CryptoHash.h"
 #include "format/KeePass2.h"
 
-KeePass2RandomStream::KeePass2RandomStream(const QByteArray& key)
-    : m_cipher(SymmetricCipher::Salsa20, SymmetricCipher::Stream, SymmetricCipher::Encrypt,
-          CryptoHash::hash(key, CryptoHash::Sha256), KeePass2::INNER_STREAM_SALSA20_IV)
+KeePass2RandomStream::KeePass2RandomStream()
+    : m_cipher(SymmetricCipher::Salsa20, SymmetricCipher::Stream, SymmetricCipher::Encrypt)
     , m_offset(0)
 {
 }
 
-QByteArray KeePass2RandomStream::randomBytes(int size)
+bool KeePass2RandomStream::init(const QByteArray& key)
+{
+    return m_cipher.init(CryptoHash::hash(key, CryptoHash::Sha256),
+                         KeePass2::INNER_STREAM_SALSA20_IV);
+}
+
+QByteArray KeePass2RandomStream::randomBytes(int size, bool* ok)
 {
     QByteArray result;
 
@@ -35,7 +40,10 @@ QByteArray KeePass2RandomStream::randomBytes(int size)
 
     while (bytesRemaining > 0) {
         if (m_buffer.size() == m_offset) {
-            loadBlock();
+            if (!loadBlock()) {
+                *ok = false;
+                return QByteArray();
+            }
         }
 
         int bytesToCopy = qMin(bytesRemaining, m_buffer.size() - m_offset);
@@ -44,12 +52,20 @@ QByteArray KeePass2RandomStream::randomBytes(int size)
         bytesRemaining -= bytesToCopy;
     }
 
+    *ok = true;
     return result;
 }
 
-QByteArray KeePass2RandomStream::process(const QByteArray& data)
+QByteArray KeePass2RandomStream::process(const QByteArray& data, bool* ok)
 {
-    QByteArray randomData = randomBytes(data.size());
+    bool randomBytesOk;
+
+    QByteArray randomData = randomBytes(data.size(), &randomBytesOk);
+    if (!randomBytesOk) {
+        *ok = false;
+        return QByteArray();
+    }
+
     QByteArray result;
     result.resize(data.size());
 
@@ -57,23 +73,39 @@ QByteArray KeePass2RandomStream::process(const QByteArray& data)
         result[i] = data[i] ^ randomData[i];
     }
 
+    *ok = true;
     return result;
 }
 
-void KeePass2RandomStream::processInPlace(QByteArray& data)
+bool KeePass2RandomStream::processInPlace(QByteArray& data)
 {
-    QByteArray randomData = randomBytes(data.size());
+    bool ok;
+    QByteArray randomData = randomBytes(data.size(), &ok);
+    if (!ok) {
+        return false;
+    }
 
     for (int i = 0; i < data.size(); i++) {
         data[i] = data[i] ^ randomData[i];
     }
+
+    return true;
+}
+
+QString KeePass2RandomStream::errorString() const
+{
+    return m_cipher.errorString();
 }
 
-void KeePass2RandomStream::loadBlock()
+bool KeePass2RandomStream::loadBlock()
 {
     Q_ASSERT(m_offset == m_buffer.size());
 
     m_buffer.fill('\0', m_cipher.blockSize());
-    m_cipher.processInPlace(m_buffer);
+    if (!m_cipher.processInPlace(m_buffer)) {
+        return false;
+    }
     m_offset = 0;
+
+    return true;
 }
diff --git a/src/format/KeePass2RandomStream.h b/src/format/KeePass2RandomStream.h
index c5bcf8cdb..c951a95ad 100644
--- a/src/format/KeePass2RandomStream.h
+++ b/src/format/KeePass2RandomStream.h
@@ -25,13 +25,15 @@
 class KeePass2RandomStream
 {
 public:
-    explicit KeePass2RandomStream(const QByteArray& key);
-    QByteArray randomBytes(int size);
-    QByteArray process(const QByteArray& data);
-    void processInPlace(QByteArray& data);
+    KeePass2RandomStream();
+    bool init(const QByteArray& key);
+    QByteArray randomBytes(int size, bool* ok);
+    QByteArray process(const QByteArray& data, bool* ok);
+    bool processInPlace(QByteArray& data);
+    QString errorString() const;
 
 private:
-    void loadBlock();
+    bool loadBlock();
 
     SymmetricCipher m_cipher;
     QByteArray m_buffer;
diff --git a/src/format/KeePass2Reader.cpp b/src/format/KeePass2Reader.cpp
index 72b4d8e06..20d20d862 100644
--- a/src/format/KeePass2Reader.cpp
+++ b/src/format/KeePass2Reader.cpp
@@ -96,16 +96,26 @@ Database* KeePass2Reader::readDatabase(QIODevice* device, const CompositeKey& ke
         return Q_NULLPTR;
     }
 
-    m_db->setKey(key, m_transformSeed, false);
+    if (!m_db->setKey(key, m_transformSeed, false)) {
+        raiseError(tr("Unable to calculate master key"));
+        return Q_NULLPTR;
+    }
 
     CryptoHash hash(CryptoHash::Sha256);
     hash.addData(m_masterSeed);
     hash.addData(m_db->transformedMasterKey());
     QByteArray finalKey = hash.result();
 
-    SymmetricCipherStream cipherStream(m_device, SymmetricCipher::Aes256, SymmetricCipher::Cbc,
-                                       SymmetricCipher::Decrypt, finalKey, m_encryptionIV);
-    cipherStream.open(QIODevice::ReadOnly);
+    SymmetricCipherStream cipherStream(m_device, SymmetricCipher::Aes256,
+                                       SymmetricCipher::Cbc, SymmetricCipher::Decrypt);
+    if (!cipherStream.init(finalKey, m_encryptionIV)) {
+        raiseError(cipherStream.errorString());
+        return Q_NULLPTR;
+    }
+    if (!cipherStream.open(QIODevice::ReadOnly)) {
+        raiseError(cipherStream.errorString());
+        return Q_NULLPTR;
+    }
 
     QByteArray realStart = cipherStream.read(32);
 
@@ -115,7 +125,10 @@ Database* KeePass2Reader::readDatabase(QIODevice* device, const CompositeKey& ke
     }
 
     HashedBlockStream hashedStream(&cipherStream);
-    hashedStream.open(QIODevice::ReadOnly);
+    if (!hashedStream.open(QIODevice::ReadOnly)) {
+        raiseError(hashedStream.errorString());
+        return Q_NULLPTR;
+    }
 
     QIODevice* xmlDevice;
     QScopedPointer<QtIOCompressor> ioCompressor;
@@ -126,11 +139,18 @@ Database* KeePass2Reader::readDatabase(QIODevice* device, const CompositeKey& ke
     else {
         ioCompressor.reset(new QtIOCompressor(&hashedStream));
         ioCompressor->setStreamFormat(QtIOCompressor::GzipFormat);
-        ioCompressor->open(QIODevice::ReadOnly);
+        if (!ioCompressor->open(QIODevice::ReadOnly)) {
+            raiseError(ioCompressor->errorString());
+            return Q_NULLPTR;
+        }
         xmlDevice = ioCompressor.data();
     }
 
-    KeePass2RandomStream randomStream(m_protectedStreamKey);
+    KeePass2RandomStream randomStream;
+    if (!randomStream.init(m_protectedStreamKey)) {
+        raiseError(randomStream.errorString());
+        return Q_NULLPTR;
+    }
 
     QScopedPointer<QBuffer> buffer;
 
@@ -340,7 +360,9 @@ void KeePass2Reader::setTansformRounds(const QByteArray& data)
         raiseError("Invalid transform rounds size");
     }
     else {
-        m_db->setTransformRounds(Endian::bytesToUInt64(data, KeePass2::BYTEORDER));
+        if (!m_db->setTransformRounds(Endian::bytesToUInt64(data, KeePass2::BYTEORDER))) {
+            raiseError(tr("Unable to calculate master key"));
+        }
     }
 }
 
diff --git a/src/format/KeePass2Writer.cpp b/src/format/KeePass2Writer.cpp
index 69e24746d..f233ac733 100644
--- a/src/format/KeePass2Writer.cpp
+++ b/src/format/KeePass2Writer.cpp
@@ -88,13 +88,20 @@ void KeePass2Writer::writeDatabase(QIODevice* device, Database* db)
     CHECK_RETURN(writeData(header.data()));
 
     SymmetricCipherStream cipherStream(device, SymmetricCipher::Aes256, SymmetricCipher::Cbc,
-                                       SymmetricCipher::Encrypt, finalKey, encryptionIV);
-    cipherStream.open(QIODevice::WriteOnly);
+                                       SymmetricCipher::Encrypt);
+    cipherStream.init(finalKey, encryptionIV);
+    if (!cipherStream.open(QIODevice::WriteOnly)) {
+        raiseError(cipherStream.errorString());
+        return;
+    }
     m_device = &cipherStream;
     CHECK_RETURN(writeData(startBytes));
 
     HashedBlockStream hashedStream(&cipherStream);
-    hashedStream.open(QIODevice::WriteOnly);
+    if (!hashedStream.open(QIODevice::WriteOnly)) {
+        raiseError(hashedStream.errorString());
+        return;
+    }
 
     QScopedPointer<QtIOCompressor> ioCompressor;
 
@@ -104,14 +111,25 @@ void KeePass2Writer::writeDatabase(QIODevice* device, Database* db)
     else {
         ioCompressor.reset(new QtIOCompressor(&hashedStream));
         ioCompressor->setStreamFormat(QtIOCompressor::GzipFormat);
-        ioCompressor->open(QIODevice::WriteOnly);
+        if (!ioCompressor->open(QIODevice::WriteOnly)) {
+            raiseError(ioCompressor->errorString());
+            return;
+        }
         m_device = ioCompressor.data();
     }
 
-    KeePass2RandomStream randomStream(protectedStreamKey);
+    KeePass2RandomStream randomStream;
+    if (!randomStream.init(protectedStreamKey)) {
+        raiseError(randomStream.errorString());
+        return;
+    }
 
     KeePass2XmlWriter xmlWriter;
     xmlWriter.writeDatabase(m_device, db, &randomStream, headerHash);
+
+    if (xmlWriter.hasError()) {
+        raiseError(xmlWriter.errorString());
+    }
 }
 
 bool KeePass2Writer::writeData(const QByteArray& data)
diff --git a/src/format/KeePass2XmlReader.cpp b/src/format/KeePass2XmlReader.cpp
index a5ceb2186..c38448861 100644
--- a/src/format/KeePass2XmlReader.cpp
+++ b/src/format/KeePass2XmlReader.cpp
@@ -809,7 +809,16 @@ void KeePass2XmlReader::parseEntryString(Entry* entry)
 
             if (isProtected && !value.isEmpty()) {
                 if (m_randomStream) {
-                    value = QString::fromUtf8(m_randomStream->process(QByteArray::fromBase64(value.toLatin1())));
+                    QByteArray ciphertext = QByteArray::fromBase64(value.toLatin1());
+                    bool ok;
+                    QByteArray plaintext = m_randomStream->process(ciphertext, &ok);
+                    if (!ok) {
+                        value.clear();
+                        raiseError(m_randomStream->errorString());
+                    }
+                    else {
+                        value = QString::fromUtf8(plaintext);
+                    }
                 }
                 else {
                     raiseError("Unable to decrypt entry string");
diff --git a/src/format/KeePass2XmlWriter.cpp b/src/format/KeePass2XmlWriter.cpp
index 603649812..dda98011c 100644
--- a/src/format/KeePass2XmlWriter.cpp
+++ b/src/format/KeePass2XmlWriter.cpp
@@ -28,6 +28,7 @@ KeePass2XmlWriter::KeePass2XmlWriter()
     : m_db(Q_NULLPTR)
     , m_meta(Q_NULLPTR)
     , m_randomStream(Q_NULLPTR)
+    , m_error(false)
 {
     m_xml.setAutoFormatting(true);
     m_xml.setAutoFormattingIndent(-1); // 1 tab
@@ -65,6 +66,16 @@ void KeePass2XmlWriter::writeDatabase(const QString& filename, Database* db)
     writeDatabase(&file, db);
 }
 
+bool KeePass2XmlWriter::hasError()
+{
+    return m_error;
+}
+
+QString KeePass2XmlWriter::errorString()
+{
+    return m_errorStr;
+}
+
 void KeePass2XmlWriter::generateIdMap()
 {
     QList<Entry*> allEntries = m_db->rootGroup()->entriesRecursive(true);
@@ -340,7 +351,11 @@ void KeePass2XmlWriter::writeEntry(const Entry* entry)
         if (protect) {
             if (m_randomStream) {
                 m_xml.writeAttribute("Protected", "True");
-                QByteArray rawData = m_randomStream->process(entry->attributes()->value(key).toUtf8());
+                bool ok;
+                QByteArray rawData = m_randomStream->process(entry->attributes()->value(key).toUtf8(), &ok);
+                if (!ok) {
+                    raiseError(m_randomStream->errorString());
+                }
                 value = QString::fromLatin1(rawData.toBase64());
             }
             else {
@@ -527,3 +542,9 @@ QString KeePass2XmlWriter::colorPartToString(int value)
 
     return str;
 }
+
+void KeePass2XmlWriter::raiseError(const QString& errorMessage)
+{
+    m_error = true;
+    m_errorStr = errorMessage;
+}
diff --git a/src/format/KeePass2XmlWriter.h b/src/format/KeePass2XmlWriter.h
index 16812fb9c..ea6212448 100644
--- a/src/format/KeePass2XmlWriter.h
+++ b/src/format/KeePass2XmlWriter.h
@@ -39,7 +39,7 @@ public:
     void writeDatabase(QIODevice* device, Database* db, KeePass2RandomStream* randomStream = Q_NULLPTR,
                        const QByteArray& headerHash = QByteArray());
     void writeDatabase(const QString& filename, Database* db);
-    bool error();
+    bool hasError();
     QString errorString();
 
 private:
@@ -74,12 +74,16 @@ private:
     void writeTriState(const QString& qualifiedName, Group::TriState triState);
     QString colorPartToString(int value);
 
+    void raiseError(const QString& errorMessage);
+
     QXmlStreamWriter m_xml;
     Database* m_db;
     Metadata* m_meta;
     KeePass2RandomStream* m_randomStream;
     QByteArray m_headerHash;
     QHash<QByteArray, int> m_idMap;
+    bool m_error;
+    QString m_errorStr;
 };
 
 #endif // KEEPASSX_KEEPASS2XMLWRITER_H
diff --git a/src/gui/DatabaseWidget.cpp b/src/gui/DatabaseWidget.cpp
index 369c69037..8d79c1a92 100644
--- a/src/gui/DatabaseWidget.cpp
+++ b/src/gui/DatabaseWidget.cpp
@@ -599,8 +599,13 @@ void DatabaseWidget::updateMasterKey(bool accepted)
 {
     if (accepted) {
         QApplication::setOverrideCursor(QCursor(Qt::WaitCursor));
-        m_db->setKey(m_changeMasterKeyWidget->newMasterKey());
+        bool result = m_db->setKey(m_changeMasterKeyWidget->newMasterKey());
         QApplication::restoreOverrideCursor();
+
+        if (!result) {
+            MessageBox::critical(this, tr("Error"), tr("Unable to calculate master key"));
+            return;
+        }
     }
     else if (!m_db->hasKey()) {
         Q_EMIT closeRequest();
diff --git a/src/keys/CompositeKey.cpp b/src/keys/CompositeKey.cpp
index 8f6c5319e..314851867 100644
--- a/src/keys/CompositeKey.cpp
+++ b/src/keys/CompositeKey.cpp
@@ -81,34 +81,62 @@ QByteArray CompositeKey::rawKey() const
     return cryptoHash.result();
 }
 
-QByteArray CompositeKey::transform(const QByteArray& seed, quint64 rounds) const
+QByteArray CompositeKey::transform(const QByteArray& seed, quint64 rounds,
+                                   bool* ok, QString* errorString) const
 {
     Q_ASSERT(seed.size() == 32);
     Q_ASSERT(rounds > 0);
 
+    bool okLeft;
+    QString errorStringLeft;
+    bool okRight;
+    QString errorStringRight;
+
     QByteArray key = rawKey();
 
-    QFuture<QByteArray> future = QtConcurrent::run(transformKeyRaw, key.left(16), seed, rounds);
-    QByteArray result2 = transformKeyRaw(key.right(16), seed, rounds);
+    QFuture<QByteArray> future = QtConcurrent::run(transformKeyRaw, key.left(16), seed, rounds, &okLeft, &errorStringLeft);
+    QByteArray result2 = transformKeyRaw(key.right(16), seed, rounds, &okRight, &errorStringRight);
 
     QByteArray transformed;
     transformed.append(future.result());
     transformed.append(result2);
 
+    *ok = (okLeft && okRight);
+
+    if (!okLeft) {
+        *errorString = errorStringLeft;
+        return QByteArray();
+    }
+
+    if (!okRight) {
+        *errorString = errorStringRight;
+        return QByteArray();
+    }
+
     return CryptoHash::hash(transformed, CryptoHash::Sha256);
 }
 
 QByteArray CompositeKey::transformKeyRaw(const QByteArray& key, const QByteArray& seed,
-                                         quint64 rounds)
+                                         quint64 rounds, bool* ok, QString* errorString)
 {
     QByteArray iv(16, 0);
     SymmetricCipher cipher(SymmetricCipher::Aes256, SymmetricCipher::Ecb,
-                           SymmetricCipher::Encrypt, seed, iv);
+                           SymmetricCipher::Encrypt);
+    if (!cipher.init(seed, iv)) {
+        *ok = false;
+        *errorString = cipher.errorString();
+        return QByteArray();
+    }
 
     QByteArray result = key;
 
-    cipher.processInPlace(result, rounds);
+    if (!cipher.processInPlace(result, rounds)) {
+        *ok = false;
+        *errorString = cipher.errorString();
+        return QByteArray();
+    }
 
+    *ok = true;
     return result;
 }
 
@@ -151,7 +179,8 @@ void TransformKeyBenchmarkThread::run()
     QByteArray iv(16, 0);
 
     SymmetricCipher cipher(SymmetricCipher::Aes256, SymmetricCipher::Ecb,
-                           SymmetricCipher::Encrypt, seed, iv);
+                           SymmetricCipher::Encrypt);
+    cipher.init(seed, iv);
 
     QTime t;
     t.start();
diff --git a/src/keys/CompositeKey.h b/src/keys/CompositeKey.h
index ff738e61a..3290d3671 100644
--- a/src/keys/CompositeKey.h
+++ b/src/keys/CompositeKey.h
@@ -34,14 +34,15 @@ public:
     CompositeKey& operator=(const CompositeKey& key);
 
     QByteArray rawKey() const;
-    QByteArray transform(const QByteArray& seed, quint64 rounds) const;
+    QByteArray transform(const QByteArray& seed, quint64 rounds,
+                         bool* ok, QString* errorString) const;
     void addKey(const Key& key);
 
     static int transformKeyBenchmark(int msec);
 
 private:
     static QByteArray transformKeyRaw(const QByteArray& key, const QByteArray& seed,
-                                      quint64 rounds);
+                                      quint64 rounds, bool* ok, QString* errorString);
 
     QList<Key*> m_keys;
 };
diff --git a/src/streams/LayeredStream.cpp b/src/streams/LayeredStream.cpp
index b71eb228a..9f7783bd3 100644
--- a/src/streams/LayeredStream.cpp
+++ b/src/streams/LayeredStream.cpp
@@ -34,11 +34,6 @@ bool LayeredStream::isSequential() const
     return true;
 }
 
-QString LayeredStream::errorString() const
-{
-    return m_baseDevice->errorString();
-}
-
 bool LayeredStream::open(QIODevice::OpenMode mode)
 {
     if (isOpen()) {
diff --git a/src/streams/LayeredStream.h b/src/streams/LayeredStream.h
index 285c16ddf..b243e55b2 100644
--- a/src/streams/LayeredStream.h
+++ b/src/streams/LayeredStream.h
@@ -31,7 +31,6 @@ public:
     virtual ~LayeredStream();
 
     bool isSequential() const Q_DECL_OVERRIDE;
-    virtual QString errorString() const;
     bool open(QIODevice::OpenMode mode) Q_DECL_OVERRIDE;
 
 protected:
diff --git a/src/streams/StoreDataStream.cpp b/src/streams/StoreDataStream.cpp
index da94b851f..18d7db980 100644
--- a/src/streams/StoreDataStream.cpp
+++ b/src/streams/StoreDataStream.cpp
@@ -41,6 +41,10 @@ QByteArray StoreDataStream::storedData() const
 qint64 StoreDataStream::readData(char* data, qint64 maxSize)
 {
     qint64 bytesRead = LayeredStream::readData(data, maxSize);
+    if (bytesRead == -1) {
+        setErrorString(m_baseDevice->errorString());
+        return -1;
+    }
 
     m_storedData.append(data, bytesRead);
 
diff --git a/src/streams/SymmetricCipherStream.cpp b/src/streams/SymmetricCipherStream.cpp
index a6f5b1f5e..48ceb8f4d 100644
--- a/src/streams/SymmetricCipherStream.cpp
+++ b/src/streams/SymmetricCipherStream.cpp
@@ -18,10 +18,9 @@
 #include "SymmetricCipherStream.h"
 
 SymmetricCipherStream::SymmetricCipherStream(QIODevice* baseDevice, SymmetricCipher::Algorithm algo,
-                                             SymmetricCipher::Mode mode, SymmetricCipher::Direction direction,
-                                             const QByteArray& key, const QByteArray& iv)
+                                             SymmetricCipher::Mode mode, SymmetricCipher::Direction direction)
     : LayeredStream(baseDevice)
-    , m_cipher(new SymmetricCipher(algo, mode, direction, key, iv))
+    , m_cipher(new SymmetricCipher(algo, mode, direction))
     , m_bufferPos(0)
     , m_bufferFilling(false)
     , m_error(false)
@@ -33,6 +32,25 @@ SymmetricCipherStream::~SymmetricCipherStream()
     close();
 }
 
+bool SymmetricCipherStream::init(const QByteArray& key, const QByteArray& iv)
+{
+    m_isInitalized = m_cipher->init(key, iv);
+    if (!m_isInitalized) {
+        setErrorString(m_cipher->errorString());
+    }
+
+    return m_isInitalized;
+}
+
+bool SymmetricCipherStream::open(QIODevice::OpenMode mode)
+{
+    if (!m_isInitalized) {
+        return false;
+    }
+
+    return LayeredStream::open(mode);
+}
+
 bool SymmetricCipherStream::reset()
 {
     if (isWritable()) {
@@ -108,7 +126,11 @@ bool SymmetricCipherStream::readBlock()
         return false;
     }
     else {
-        m_cipher->processInPlace(m_buffer);
+        if (!m_cipher->processInPlace(m_buffer)) {
+            m_error = true;
+            setErrorString(m_cipher->errorString());
+            return false;
+        }
         m_bufferPos = 0;
         m_bufferFilling = false;
 
@@ -187,7 +209,11 @@ bool SymmetricCipherStream::writeBlock(bool lastBlock)
         return true;
     }
 
-    m_cipher->processInPlace(m_buffer);
+    if (!m_cipher->processInPlace(m_buffer)) {
+        m_error = true;
+        setErrorString(m_cipher->errorString());
+        return false;
+    }
 
     if (m_baseDevice->write(m_buffer) != m_buffer.size()) {
         m_error = true;
diff --git a/src/streams/SymmetricCipherStream.h b/src/streams/SymmetricCipherStream.h
index 53e252f24..c1865babc 100644
--- a/src/streams/SymmetricCipherStream.h
+++ b/src/streams/SymmetricCipherStream.h
@@ -29,11 +29,13 @@ class SymmetricCipherStream : public LayeredStream
     Q_OBJECT
 
 public:
-    SymmetricCipherStream(QIODevice* baseDevice, SymmetricCipher::Algorithm algo, SymmetricCipher::Mode mode,
-                          SymmetricCipher::Direction direction, const QByteArray& key, const QByteArray& iv);
+    SymmetricCipherStream(QIODevice* baseDevice, SymmetricCipher::Algorithm algo,
+                          SymmetricCipher::Mode mode, SymmetricCipher::Direction direction);
     ~SymmetricCipherStream();
-    bool reset();
-    void close();
+    bool init(const QByteArray& key, const QByteArray& iv);
+    bool open(QIODevice::OpenMode mode) Q_DECL_OVERRIDE;
+    bool reset() Q_DECL_OVERRIDE;
+    void close() Q_DECL_OVERRIDE;
 
 protected:
     qint64 readData(char* data, qint64 maxSize) Q_DECL_OVERRIDE;
@@ -48,6 +50,7 @@ private:
     int m_bufferPos;
     bool m_bufferFilling;
     bool m_error;
+    bool m_isInitalized;
 };
 
 #endif // KEEPASSX_SYMMETRICCIPHERSTREAM_H
diff --git a/tests/TestKeePass2RandomStream.cpp b/tests/TestKeePass2RandomStream.cpp
index 7963e9af8..b41f1e87b 100644
--- a/tests/TestKeePass2RandomStream.cpp
+++ b/tests/TestKeePass2RandomStream.cpp
@@ -39,8 +39,8 @@ void TestKeePass2RandomStream::test()
     const int Size = 128;
 
 
-    SymmetricCipher cipher(SymmetricCipher::Salsa20, SymmetricCipher::Stream, SymmetricCipher::Encrypt,
-                           CryptoHash::hash(key, CryptoHash::Sha256), KeePass2::INNER_STREAM_SALSA20_IV);
+    SymmetricCipher cipher(SymmetricCipher::Salsa20, SymmetricCipher::Stream, SymmetricCipher::Encrypt);
+    QVERIFY(cipher.init(CryptoHash::hash(key, CryptoHash::Sha256), KeePass2::INNER_STREAM_SALSA20_IV));
 
     const QByteArray data(QByteArray::fromHex("601ec313775789a5b7a7f504bbf3d228f443e3ca4d62b59aca84e990cacaf5c5"
                                               "2b0930daa23de94ce87017ba2d84988ddfc9c58db67aada613c2dd08457941a6"
@@ -59,20 +59,27 @@ void TestKeePass2RandomStream::test()
     }
 
 
-    KeePass2RandomStream randomStream(key);
+    KeePass2RandomStream randomStream;
+    bool ok;
+    QVERIFY(randomStream.init(key));
     QByteArray randomStreamData;
-    randomStreamData.append(randomStream.process(data.mid(0, 7)));
-    randomStreamData.append(randomStream.process(data.mid(7, 1)));
+    randomStreamData.append(randomStream.process(data.mid(0, 7), &ok));
+    QVERIFY(ok);
+    randomStreamData.append(randomStream.process(data.mid(7, 1), &ok));
+    QVERIFY(ok);
     QByteArray tmpData = data.mid(8, 12);
     randomStream.processInPlace(tmpData);
     randomStreamData.append(tmpData);
-    randomStreamData.append(randomStream.process(data.mid(20, 44)));
-    randomStreamData.append(randomStream.process(data.mid(64, 64)));
+    randomStreamData.append(randomStream.process(data.mid(20, 44), &ok));
+    QVERIFY(ok);
+    randomStreamData.append(randomStream.process(data.mid(64, 64), &ok));
+    QVERIFY(ok);
 
 
-    SymmetricCipher cipherEncrypt(SymmetricCipher::Salsa20, SymmetricCipher::Stream, SymmetricCipher::Encrypt,
-                                  CryptoHash::hash(key, CryptoHash::Sha256), KeePass2::INNER_STREAM_SALSA20_IV);
-    QByteArray cipherDataEncrypt = cipherEncrypt.process(data);
+    SymmetricCipher cipherEncrypt(SymmetricCipher::Salsa20, SymmetricCipher::Stream, SymmetricCipher::Encrypt);
+    QVERIFY(cipherEncrypt.init(CryptoHash::hash(key, CryptoHash::Sha256), KeePass2::INNER_STREAM_SALSA20_IV));
+    QByteArray cipherDataEncrypt = cipherEncrypt.process(data, &ok);
+    QVERIFY(ok);
 
 
     QCOMPARE(randomStreamData.size(), Size);
diff --git a/tests/TestKeys.cpp b/tests/TestKeys.cpp
index d6758d655..770af52de 100644
--- a/tests/TestKeys.cpp
+++ b/tests/TestKeys.cpp
@@ -43,6 +43,8 @@ void TestKeys::testComposite()
     CompositeKey* compositeKey1 = new CompositeKey();
     PasswordKey* passwordKey1 = new PasswordKey();
     PasswordKey* passwordKey2 = new PasswordKey("test");
+    bool ok;
+    QString errorString;
 
     // make sure that addKey() creates a copy of the keys
     compositeKey1->addKey(*passwordKey1);
@@ -50,13 +52,15 @@ void TestKeys::testComposite()
     delete passwordKey1;
     delete passwordKey2;
 
-    QByteArray transformed = compositeKey1->transform(QByteArray(32, '\0'), 1);
+    QByteArray transformed = compositeKey1->transform(QByteArray(32, '\0'), 1, &ok, &errorString);
+    QVERIFY(ok);
     QCOMPARE(transformed.size(), 32);
 
     // make sure the subkeys are copied
     CompositeKey* compositeKey2 = compositeKey1->clone();
     delete compositeKey1;
-    QCOMPARE(compositeKey2->transform(QByteArray(32, '\0'), 1), transformed);
+    QCOMPARE(compositeKey2->transform(QByteArray(32, '\0'), 1, &ok, &errorString), transformed);
+    QVERIFY(ok);
     delete compositeKey2;
 
     CompositeKey* compositeKey3 = new CompositeKey();
@@ -130,7 +134,7 @@ void TestKeys::testCreateFileKey()
     compositeKey.addKey(fileKey);
 
     Database* dbOrg = new Database();
-    dbOrg->setKey(compositeKey);
+    QVERIFY(dbOrg->setKey(compositeKey));
     dbOrg->metadata()->setName(dbName);
 
     QBuffer dbBuffer;
@@ -182,7 +186,10 @@ void TestKeys::benchmarkTransformKey()
 
     QByteArray seed(32, '\x4B');
 
+    bool ok;
+    QString errorString;
+
     QBENCHMARK {
-        compositeKey.transform(seed, 1e6);
+        compositeKey.transform(seed, 1e6, &ok, &errorString);
     }
 }
diff --git a/tests/TestSymmetricCipher.cpp b/tests/TestSymmetricCipher.cpp
index 6d4e94f6f..ec9badd90 100644
--- a/tests/TestSymmetricCipher.cpp
+++ b/tests/TestSymmetricCipher.cpp
@@ -42,17 +42,20 @@ void TestSymmetricCipher::testAes256CbcEncryption()
     plainText.append(QByteArray::fromHex("ae2d8a571e03ac9c9eb76fac45af8e51"));
     QByteArray cipherText = QByteArray::fromHex("f58c4c04d6e5f1ba779eabfb5f7bfbd6");
     cipherText.append(QByteArray::fromHex("9cfc4e967edb808d679f777bc6702c7d"));
+    bool ok;
 
-    SymmetricCipher cipher(SymmetricCipher::Aes256, SymmetricCipher::Cbc, SymmetricCipher::Encrypt,
-                           key, iv);
+    SymmetricCipher cipher(SymmetricCipher::Aes256, SymmetricCipher::Cbc, SymmetricCipher::Encrypt);
+    QVERIFY(cipher.init(key, iv));
     QCOMPARE(cipher.blockSize(), 16);
 
-    QCOMPARE(cipher.process(plainText),
+    QCOMPARE(cipher.process(plainText, &ok),
              cipherText);
+    QVERIFY(ok);
 
     QBuffer buffer;
     SymmetricCipherStream stream(&buffer, SymmetricCipher::Aes256, SymmetricCipher::Cbc,
-                                 SymmetricCipher::Encrypt, key, iv);
+                                 SymmetricCipher::Encrypt);
+    QVERIFY(stream.init(key, iv));
     buffer.open(QIODevice::WriteOnly);
     stream.open(QIODevice::WriteOnly);
     QVERIFY(stream.reset());
@@ -86,18 +89,22 @@ void TestSymmetricCipher::testAes256CbcDecryption()
     cipherText.append(QByteArray::fromHex("9cfc4e967edb808d679f777bc6702c7d"));
     QByteArray plainText = QByteArray::fromHex("6bc1bee22e409f96e93d7e117393172a");
     plainText.append(QByteArray::fromHex("ae2d8a571e03ac9c9eb76fac45af8e51"));
+    bool ok;
 
-    SymmetricCipher cipher(SymmetricCipher::Aes256, SymmetricCipher::Cbc, SymmetricCipher::Decrypt, key, iv);
+    SymmetricCipher cipher(SymmetricCipher::Aes256, SymmetricCipher::Cbc, SymmetricCipher::Decrypt);
+    QVERIFY(cipher.init(key, iv));
     QCOMPARE(cipher.blockSize(), 16);
 
-    QCOMPARE(cipher.process(cipherText),
+    QCOMPARE(cipher.process(cipherText, &ok),
              plainText);
+    QVERIFY(ok);
 
     // padded with 16 0x16 bytes
     QByteArray cipherTextPadded = cipherText + QByteArray::fromHex("3a3aa5e0213db1a9901f9036cf5102d2");
     QBuffer buffer(&cipherTextPadded);
     SymmetricCipherStream stream(&buffer, SymmetricCipher::Aes256, SymmetricCipher::Cbc,
-                                 SymmetricCipher::Decrypt, key, iv);
+                                 SymmetricCipher::Decrypt);
+    QVERIFY(stream.init(key, iv));
     buffer.open(QIODevice::ReadOnly);
     stream.open(QIODevice::ReadOnly);
 
@@ -123,16 +130,20 @@ void TestSymmetricCipher::testSalsa20()
 
     QByteArray key = QByteArray::fromHex("F3F4F5F6F7F8F9FAFBFCFDFEFF000102030405060708090A0B0C0D0E0F101112");
     QByteArray iv = QByteArray::fromHex("0000000000000000");
+    bool ok;
 
-    SymmetricCipher cipher(SymmetricCipher::Salsa20, SymmetricCipher::Stream, SymmetricCipher::Encrypt, key, iv);
+    SymmetricCipher cipher(SymmetricCipher::Salsa20, SymmetricCipher::Stream, SymmetricCipher::Encrypt);
+    QVERIFY(cipher.init(key, iv));
 
     QByteArray cipherTextA;
     for (int i = 0; i < 8; i++) {
-        cipherTextA.append(cipher.process(QByteArray(64, '\0')));
+        cipherTextA.append(cipher.process(QByteArray(64, '\0'), &ok));
+        QVERIFY(ok);
     }
     cipher.reset();
 
-    QByteArray cipherTextB = cipher.process(QByteArray(512, '\0'));
+    QByteArray cipherTextB = cipher.process(QByteArray(512, '\0'), &ok);
+    QVERIFY(ok);
     cipher.reset();
 
     QByteArray expectedCipherText1;
@@ -180,7 +191,8 @@ void TestSymmetricCipher::testPadding()
     buffer.open(QIODevice::ReadWrite);
 
     SymmetricCipherStream streamEnc(&buffer, SymmetricCipher::Aes256, SymmetricCipher::Cbc,
-                                    SymmetricCipher::Encrypt, key, iv);
+                                    SymmetricCipher::Encrypt);
+    QVERIFY(streamEnc.init(key, iv));
     streamEnc.open(QIODevice::WriteOnly);
     streamEnc.write(plainText);
     streamEnc.close();
@@ -189,7 +201,8 @@ void TestSymmetricCipher::testPadding()
     QCOMPARE(buffer.buffer().size(), 16);
 
     SymmetricCipherStream streamDec(&buffer, SymmetricCipher::Aes256, SymmetricCipher::Cbc,
-                                    SymmetricCipher::Decrypt, key, iv);
+                                    SymmetricCipher::Decrypt);
+    QVERIFY(streamDec.init(key, iv));
     streamDec.open(QIODevice::ReadOnly);
     QByteArray decrypted = streamDec.readAll();
     QCOMPARE(decrypted, plainText);