Index: src/OFMapTable.h
==================================================================
--- src/OFMapTable.h
+++ src/OFMapTable.h
@@ -47,10 +47,11 @@
 @interface OFMapTable: OFObject <OFCopying, OFFastEnumeration>
 {
 	of_map_table_functions_t keyFunctions, valueFunctions;
 	struct of_map_table_bucket **buckets;
 	uint32_t minCapacity, capacity, count;
+	uint8_t rotate;
 	unsigned long mutations;
 }
 
 /*!
  * @brief Creates a new OFMapTable with the specified key and value functions.

Index: src/OFMapTable.m
==================================================================
--- src/OFMapTable.m
+++ src/OFMapTable.m
@@ -150,10 +150,19 @@
 
 		buckets = [self allocMemoryWithSize: sizeof(*buckets)
 					      count: capacity];
 
 		memset(buckets, 0, capacity * sizeof(*buckets));
+
+		if (of_hash_seed != 0)
+#if defined(OF_HAVE_ARC4RANDOM)
+			rotate = arc4random() & 31;
+#elif defined(OF_HAVE_RANDOM)
+			rotate = random() & 31;
+#else
+			rotate = rand() & 31;
+#endif
 	} @catch (id e) {
 		[self release];
 		@throw e;
 	}
 
@@ -205,11 +214,11 @@
 {
 	uint32_t i, hash = 0;
 
 	for (i = 0; i < capacity; i++) {
 		if (buckets[i] != NULL && buckets[i] != &deleted) {
-			hash += buckets[i]->hash;
+			hash += OF_ROR(buckets[i]->hash, rotate);
 			hash += valueFunctions.hash(buckets[i]->value);
 		}
 	}
 
 	return hash;
@@ -227,11 +236,12 @@
 
 		for (i = 0; i < capacity; i++)
 			if (buckets[i] != NULL && buckets[i] != &deleted)
 				[copy OF_setValue: buckets[i]->value
 					   forKey: buckets[i]->key
-					     hash: buckets[i]->hash];
+					     hash: OF_ROR(buckets[i]->hash,
+						       rotate)];
 	} @catch (id e) {
 		[copy release];
 		@throw e;
 	}
 
@@ -252,11 +262,11 @@
 	if (key == NULL)
 		@throw [OFInvalidArgumentException
 		    exceptionWithClass: [self class]
 			      selector: _cmd];
 
-	hash = keyFunctions.hash(key);
+	hash = OF_ROL(keyFunctions.hash(key), rotate);
 	last = capacity;
 
 	for (i = hash & (capacity - 1); i < last && buckets[i] != NULL; i++) {
 		if (buckets[i] == &deleted)
 			continue;
@@ -347,10 +357,11 @@
 	if (key == NULL || value == NULL)
 		@throw [OFInvalidArgumentException
 		    exceptionWithClass: [self class]
 			      selector: _cmd];
 
+	hash = OF_ROL(hash, rotate);
 	last = capacity;
 
 	for (i = hash & (capacity - 1); i < last && buckets[i] != NULL; i++) {
 		if (buckets[i] == &deleted)
 			continue;
@@ -442,11 +453,11 @@
 	if (key == NULL)
 		@throw [OFInvalidArgumentException
 		    exceptionWithClass: [self class]
 			      selector: _cmd];
 
-	hash = keyFunctions.hash(key);
+	hash = OF_ROL(keyFunctions.hash(key), rotate);
 	last = capacity;
 
 	for (i = hash & (capacity - 1); i < last && buckets[i] != NULL; i++) {
 		if (buckets[i] == &deleted)
 			continue;

Index: src/macros.h
==================================================================
--- src/macros.h
+++ src/macros.h
@@ -326,10 +326,13 @@
 #endif
 
 #define OF_ROL(value, bits)						\
 	(((value) << ((bits) % (sizeof(value) * 8))) |			\
 	(value) >> (sizeof(value) * 8 - ((bits) % (sizeof(value) * 8))))
+#define OF_ROR(value, bits)						\
+	(((value) >> ((bits) % (sizeof(value) * 8))) |			\
+	(value) << (sizeof(value) * 8 - ((bits) % (sizeof(value) * 8))))
 
 #define OF_HASH_INIT(hash) hash = of_hash_seed
 #define OF_HASH_ADD(hash, byte)			\
 	{					\
 		hash += (uint8_t)(byte);	\