@@ -27,24 +27,48 @@
 
 @implementation OFASN1BitString
 @synthesize bitStringValue = _bitStringValue;
 @synthesize bitStringLength = _bitStringLength;
 
-- (instancetype)init
++ (instancetype)bitStringWithBitStringValue: (OFData *)bitStringValue
+			    bitStringLength: (size_t)bitStringLength
+{
+	return [[[self alloc]
+	    initWithBitStringValue: bitStringValue
+		   bitStringLength: bitStringLength] autorelease];
+}
+
+- (instancetype)initWithBitStringValue: (OFData *)bitStringValue
+		       bitStringLength: (size_t)bitStringLength
 {
-	OF_INVALID_INIT_METHOD
+	self = [super init];
+
+	@try {
+		if ([bitStringValue count] * [bitStringValue itemSize] !=
+		    bitStringLength / 8)
+			@throw [OFInvalidFormatException exception];
+
+		_bitStringValue = [bitStringValue copy];
+		_bitStringLength = bitStringLength;
+	} @catch (id e) {
+		[self release];
+		@throw e;
+	}
+
+	return self;
 }
 
 - (instancetype)initWithTagClass: (of_asn1_tag_class_t)tagClass
 		       tagNumber: (of_asn1_tag_number_t)tagNumber
 		     constructed: (bool)constructed
 	      DEREncodedContents: (OFData *)DEREncodedContents
 {
-	self = [super init];
+	void *pool = objc_autoreleasePoolPush();
+	OFData *bitStringValue;
+	size_t bitStringLength;
 
 	@try {
-		void *pool = objc_autoreleasePoolPush();
 		unsigned char lastByteBits;
 		size_t count = [DEREncodedContents count];
 
 		if (tagClass != OF_ASN1_TAG_CLASS_UNIVERSAL ||
 		    tagNumber != OF_ASN1_TAG_NUMBER_BIT_STRING || constructed)
@@ -61,22 +85,30 @@
 
 		if (SIZE_MAX / 8 < count - 1 ||
 		    SIZE_MAX - (count - 1) * 8 < lastByteBits)
 			@throw [OFOutOfRangeException exception];
 
-		_bitStringLength = (count - 1) * 8 + lastByteBits;
-		_bitStringValue = [[DEREncodedContents
+		bitStringLength = (count - 1) * 8 + lastByteBits;
+		bitStringValue = [[DEREncodedContents
 		    subdataWithRange: of_range(1, count - 1)] copy];
-
-		objc_autoreleasePoolPop(pool);
 	} @catch (id e) {
 		[self release];
 		@throw e;
 	}
 
+	self = [self initWithBitStringValue: bitStringValue
+			    bitStringLength: bitStringLength];
+
+	objc_autoreleasePoolPop(pool);
+
 	return self;
 }
+
+- (instancetype)init
+{
+	OF_INVALID_INIT_METHOD
+}
 
 - (void)dealloc
 {
 	[_bitStringValue release];