Index: src/OFWindowsRegistryKey.h
==================================================================
--- src/OFWindowsRegistryKey.h
+++ src/OFWindowsRegistryKey.h
@@ -190,10 +190,42 @@
  */
 - (void)setString: (nullable OFString *)string
     forValueNamed: (nullable OFString *)name
 	     type: (DWORD)type;
 
+/**
+ * @brief Returns the DWORD for the specified value at the specified path.
+ *
+ * @param name The name of the value to return
+ * @return The DWORD for the specified value
+ */
+- (uint32_t)DWORDForValueNamed: (nullable OFString *)name;
+
+/**
+ * @brief Sets the DWORD for the specified value.
+ *
+ * @param dword The DWORD to set the value to
+ * @param name The name of the value to set
+ */
+- (void)setDWORD: (uint32_t)dword forValueNamed: (nullable OFString *)name;
+
+/**
+ * @brief Returns the QWORD for the specified value at the specified path.
+ *
+ * @param name The name of the value to return
+ * @return The QWORD for the specified value
+ */
+- (uint64_t)QWORDForValueNamed: (nullable OFString *)name;
+
+/**
+ * @brief Sets the QWORD for the specified value.
+ *
+ * @param qword The QWORD to set the value to
+ * @param name The name of the value to set
+ */
+- (void)setQWORD: (uint64_t)qword forValueNamed: (nullable OFString *)name;
+
 /**
  * @brief Deletes the specified value.
  *
  * @param name The value to delete
  */

Index: src/OFWindowsRegistryKey.m
==================================================================
--- src/OFWindowsRegistryKey.m
+++ src/OFWindowsRegistryKey.m
@@ -29,10 +29,11 @@
 #import "OFInvalidEncodingException.h"
 #import "OFInvalidFormatException.h"
 #import "OFOpenWindowsRegistryKeyFailedException.h"
 #import "OFOutOfRangeException.h"
 #import "OFSetWindowsRegistryValueFailedException.h"
+#import "OFUndefinedKeyException.h"
 
 OF_DIRECT_MEMBERS
 @interface OFWindowsRegistryKey ()
 - (instancetype)of_initWithHKey: (HKEY)hKey close: (bool)close;
 @end
@@ -362,10 +363,77 @@
 
 	[self setData: data forValueNamed: name type: type];
 
 	objc_autoreleasePoolPop(pool);
 }
+
+- (uint32_t)DWORDForValueNamed: (OFString *)name
+{
+	void *pool = objc_autoreleasePoolPush();
+	DWORD type, ret;
+	OFData *data = [self dataForValueNamed: name type: &type];
+
+	if (data == nil)
+		/* TODO: This exception is not ideal. */
+		@throw [OFUndefinedKeyException exceptionWithObject: self
+								key: name
+							      value: nil];
+
+	if (type != REG_DWORD)
+		@throw [OFInvalidEncodingException exception];
+
+	if (data.count != sizeof(ret) || data.itemSize != 1)
+		@throw [OFInvalidFormatException exception];
+
+	memcpy(&ret, data.items, sizeof(ret));
+
+	objc_autoreleasePoolPop(pool);
+
+	return ret;
+}
+
+- (void)setDWORD: (uint32_t)dword forValueNamed: (OFString *)name
+{
+	void *pool = objc_autoreleasePoolPush();
+	OFData *data = [OFData dataWithItems: &dword count: sizeof(dword)];
+	[self setData: data forValueNamed: name type: REG_DWORD];
+	objc_autoreleasePoolPop(pool);
+}
+
+- (uint64_t)QWORDForValueNamed: (OFString *)name
+{
+	void *pool = objc_autoreleasePoolPush();
+	DWORD type;
+	uint64_t ret;
+	OFData *data = [self dataForValueNamed: name type: &type];
+
+	if (data == nil)
+		/* TODO: This exception is not ideal. */
+		@throw [OFUndefinedKeyException exceptionWithObject: self
+								key: name
+							      value: nil];
+
+	if (type != REG_QWORD)
+		@throw [OFInvalidEncodingException exception];
+
+	if (data.count != sizeof(ret) || data.itemSize != 1)
+		@throw [OFInvalidFormatException exception];
+
+	memcpy(&ret, data.items, sizeof(ret));
+
+	objc_autoreleasePoolPop(pool);
+
+	return ret;
+}
+
+- (void)setQWORD: (uint64_t)qword forValueNamed: (OFString *)name
+{
+	void *pool = objc_autoreleasePoolPush();
+	OFData *data = [OFData dataWithItems: &qword count: sizeof(qword)];
+	[self setData: data forValueNamed: name type: REG_QWORD];
+	objc_autoreleasePoolPop(pool);
+}
 
 - (void)deleteValueNamed: (OFString *)name
 {
 	void *pool = objc_autoreleasePoolPush();
 	LSTATUS status;

Index: src/exceptions/OFUndefinedKeyException.h
==================================================================
--- src/exceptions/OFUndefinedKeyException.h
+++ src/exceptions/OFUndefinedKeyException.h
@@ -25,11 +25,11 @@
  *	  Coding).
  */
 @interface OFUndefinedKeyException: OFException
 {
 	id _object;
-	OFString *_key;
+	OFString *_Nullable _key;
 	id _Nullable _value;
 }
 
 /**
  * @brief The object on which the key is undefined.
@@ -37,11 +37,11 @@
 @property (readonly, nonatomic) id object;
 
 /**
  * @brief The key which is undefined.
  */
-@property (readonly, nonatomic) OFString *key;
+@property OF_NULLABLE_PROPERTY (readonly, nonatomic) OFString *key;
 
 /**
  * @brief The value for the undefined key
  */
 @property OF_NULLABLE_PROPERTY (readonly, nonatomic) id value;
@@ -64,11 +64,11 @@
  * @param value The value for the undefined key
  *
  * @return A new, autoreleased undefined key exception
  */
 + (instancetype)exceptionWithObject: (id)object
-				key: (OFString *)key
+				key: (nullable OFString *)key
 			      value: (nullable id)value;
 
 + (instancetype)exception OF_UNAVAILABLE;
 
 /**
@@ -89,12 +89,12 @@
  * @param value The value for the undefined key
  *
  * @return An initialized undefined key exception
  */
 - (instancetype)initWithObject: (id)object
-			   key: (OFString *)key
+			   key: (nullable OFString *)key
 			 value: (nullable id)value OF_DESIGNATED_INITIALIZER;
 
 - (instancetype)init OF_UNAVAILABLE;
 @end
 
 OF_ASSUME_NONNULL_END