diff --git a/PINCache/PINDiskCache.m b/PINCache/PINDiskCache.m
index ca93bacf..0ded6757 100644
--- a/PINCache/PINDiskCache.m
+++ b/PINCache/PINDiskCache.m
@@ -143,7 +143,7 @@ - (NSString *)encodedString:(NSString *)string
 {
     if (![string length])
         return @"";
-   return [string stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet characterSetWithCharactersInString:@".:/"]];
+   return [string stringByAddingPercentEncodingWithAllowedCharacters:[[NSCharacterSet characterSetWithCharactersInString:@".:/"] invertedSet]];
 }
 
 - (NSString *)decodedString:(NSString *)string
diff --git a/tests/PINCacheTests/PINCacheTests.m b/tests/PINCacheTests/PINCacheTests.m
index e9672bbf..c9ff7665 100644
--- a/tests/PINCacheTests/PINCacheTests.m
+++ b/tests/PINCacheTests/PINCacheTests.m
@@ -8,6 +8,12 @@
 NSString * const PINCacheTestName = @"PINCacheTest";
 NSTimeInterval PINCacheTestBlockTimeout = 5.0;
 
+@interface PINDiskCache()
+
+- (NSString *)encodedString:(NSString *)string;
+
+@end
+
 @interface PINCacheTests ()
 @property (strong, nonatomic) PINCache *cache;
 @end
@@ -62,6 +68,12 @@ - (dispatch_time_t)timeout
 
 #pragma mark - Tests -
 
+- (void)testDiskCacheStringEncoding
+{
+    NSString *string = [self.cache.diskCache encodedString:@"http://www.test.de-<CoolStuff>"];
+    XCTAssertTrue([string isEqualToString:@"http%3A%2F%2Fwww%2Etest%2Ede-<CoolStuff>"]);
+}
+
 - (void)testCoreProperties
 {
     PINCache *cache = [[PINCache alloc] initWithName:PINCacheTestName];