diff --git a/src/crypto/SymmetricCipher.h b/src/crypto/SymmetricCipher.h
index c5a6f7ec..c5c67543 100644
--- a/src/crypto/SymmetricCipher.h
+++ b/src/crypto/SymmetricCipher.h
@@ -57,7 +57,7 @@ public:
         m_backend->processInPlace(data);
     }
 
-    inline void processInPlace(QByteArray& data, int rounds) {
+    inline void processInPlace(QByteArray& data, quint64 rounds) {
         Q_ASSERT(rounds > 0);
         m_backend->processInPlace(data, rounds);
     }
diff --git a/src/crypto/SymmetricCipherBackend.h b/src/crypto/SymmetricCipherBackend.h
index 64a54500..7b737839 100644
--- a/src/crypto/SymmetricCipherBackend.h
+++ b/src/crypto/SymmetricCipherBackend.h
@@ -30,7 +30,7 @@ public:
 
     virtual QByteArray process(const QByteArray& data) = 0;
     virtual void processInPlace(QByteArray& data) = 0;
-    virtual void processInPlace(QByteArray& data, int rounds) = 0;
+    virtual void processInPlace(QByteArray& data, quint64 rounds) = 0;
 
     virtual void reset() = 0;
     virtual int blockSize() const = 0;
diff --git a/src/crypto/SymmetricCipherGcrypt.cpp b/src/crypto/SymmetricCipherGcrypt.cpp
index ba5c1455..fabe3c4d 100644
--- a/src/crypto/SymmetricCipherGcrypt.cpp
+++ b/src/crypto/SymmetricCipherGcrypt.cpp
@@ -113,20 +113,20 @@ void SymmetricCipherGcrypt::processInPlace(QByteArray& data)
     Q_ASSERT(error == 0);
 }
 
-void SymmetricCipherGcrypt::processInPlace(QByteArray& data, int rounds)
+void SymmetricCipherGcrypt::processInPlace(QByteArray& data, quint64 rounds)
 {
     // TODO check block size
 
     gcry_error_t error;
 
     if (m_direction == SymmetricCipher::Decrypt) {
-        for (int i = 0; i != rounds; ++i) {
+        for (quint64 i = 0; i != rounds; ++i) {
             error = gcry_cipher_decrypt(m_ctx, data.data(), data.size(), 0, 0);
             Q_ASSERT(error == 0);
         }
     }
     else {
-        for (int i = 0; i != rounds; ++i) {
+        for (quint64 i = 0; i != rounds; ++i) {
             error = gcry_cipher_encrypt(m_ctx, data.data(), data.size(), 0, 0);
             Q_ASSERT(error == 0);
         }
diff --git a/src/crypto/SymmetricCipherGcrypt.h b/src/crypto/SymmetricCipherGcrypt.h
index ccf84ada..3af7c705 100644
--- a/src/crypto/SymmetricCipherGcrypt.h
+++ b/src/crypto/SymmetricCipherGcrypt.h
@@ -35,7 +35,7 @@ public:
 
     QByteArray process(const QByteArray& data);
     void processInPlace(QByteArray& data);
-    void processInPlace(QByteArray& data, int rounds);
+    void processInPlace(QByteArray& data, quint64 rounds);
 
     void reset();
     int blockSize() const;
diff --git a/src/crypto/SymmetricCipherSalsa20.cpp b/src/crypto/SymmetricCipherSalsa20.cpp
index 53aa18ba..d8adb05d 100644
--- a/src/crypto/SymmetricCipherSalsa20.cpp
+++ b/src/crypto/SymmetricCipherSalsa20.cpp
@@ -74,11 +74,11 @@ void SymmetricCipherSalsa20::processInPlace(QByteArray& data)
                          reinterpret_cast<u8*>(data.data()), data.size());
 }
 
-void SymmetricCipherSalsa20::processInPlace(QByteArray& data, int rounds)
+void SymmetricCipherSalsa20::processInPlace(QByteArray& data, quint64 rounds)
 {
     Q_ASSERT((data.size() < blockSize()) || ((data.size() % blockSize()) == 0));
 
-    for (int i = 0; i != rounds; ++i) {
+    for (quint64 i = 0; i != rounds; ++i) {
         ECRYPT_encrypt_bytes(&m_ctx, reinterpret_cast<const u8*>(data.constData()),
                              reinterpret_cast<u8*>(data.data()), data.size());
     }
diff --git a/src/crypto/SymmetricCipherSalsa20.h b/src/crypto/SymmetricCipherSalsa20.h
index d0ba3984..ea91e71e 100644
--- a/src/crypto/SymmetricCipherSalsa20.h
+++ b/src/crypto/SymmetricCipherSalsa20.h
@@ -37,7 +37,7 @@ public:
 
     QByteArray process(const QByteArray& data);
     void processInPlace(QByteArray& data);
-    void processInPlace(QByteArray& data, int rounds);
+    void processInPlace(QByteArray& data, quint64 rounds);
 
     void reset();
     int blockSize() const;
diff --git a/src/keys/CompositeKey.cpp b/src/keys/CompositeKey.cpp
index 0dbcacce..33a638b0 100644
--- a/src/keys/CompositeKey.cpp
+++ b/src/keys/CompositeKey.cpp
@@ -71,7 +71,7 @@ QByteArray CompositeKey::rawKey() const
     return cryptoHash.result();
 }
 
-QByteArray CompositeKey::transform(const QByteArray& seed, int rounds) const
+QByteArray CompositeKey::transform(const QByteArray& seed, quint64 rounds) const
 {
     Q_ASSERT(seed.size() == 32);
     Q_ASSERT(rounds > 0);
@@ -89,7 +89,7 @@ QByteArray CompositeKey::transform(const QByteArray& seed, int rounds) const
 }
 
 QByteArray CompositeKey::transformKeyRaw(const QByteArray& key, const QByteArray& seed,
-                                         int rounds) {
+                                         quint64 rounds) {
     QByteArray iv(16, 0);
     SymmetricCipher cipher(SymmetricCipher::Aes256, SymmetricCipher::Ecb,
                            SymmetricCipher::Encrypt, seed, iv);
diff --git a/src/keys/CompositeKey.h b/src/keys/CompositeKey.h
index e95d521f..c95dcfd8 100644
--- a/src/keys/CompositeKey.h
+++ b/src/keys/CompositeKey.h
@@ -33,14 +33,14 @@ public:
     CompositeKey& operator=(const CompositeKey& key);
 
     QByteArray rawKey() const;
-    QByteArray transform(const QByteArray& seed, int rounds) const;
+    QByteArray transform(const QByteArray& seed, quint64 rounds) const;
     void addKey(const Key& key);
 
     static int transformKeyBenchmark(int msec);
 
 private:
     static QByteArray transformKeyRaw(const QByteArray& key, const QByteArray& seed,
-                                      int rounds);
+                                      quint64 rounds);
 
     QList<Key*> m_keys;
 };