Index: src/OFSecureData.h
==================================================================
--- src/OFSecureData.h
+++ src/OFSecureData.h
@@ -30,10 +30,20 @@
  */
 @interface OFSecureData: OFData
 {
 	size_t _mappingSize;
 }
+
+#ifdef OF_HAVE_CLASS_PROPERTIES
+@property (class, readonly, nonatomic, getter=isSecure) bool secure;
+#endif
+
+/*!
+ * @brief Whether OFSecureData is secure, meaning preventing the data from
+ *	  being swapped out is supported.
+ */
++ (bool)isSecure;
 
 /*!
  * @brief Creates a new, autoreleased OFSecureData with count items of item
  *	  size 1, all set to zero.
  *

Index: src/OFSecureData.m
==================================================================
--- src/OFSecureData.m
+++ src/OFSecureData.m
@@ -30,10 +30,19 @@
 #import "OFInvalidArgumentException.h"
 #import "OFOutOfMemoryException.h"
 #import "OFOutOfRangeException.h"
 
 @implementation OFSecureData
++ (bool)isSecure
+{
+#if defined(HAVE_MMAP) && defined(HAVE_MLOCK) && defined(MAP_ANON)
+	return true;
+#else
+	return false;
+#endif
+}
+
 + (instancetype)dataWithCount: (size_t)count
 {
 	return [[[self alloc] initWithCount: count] autorelease];
 }