@@ -26,10 +26,15 @@
  * A cryptographic hash implementing this protocol can be copied. The entire
  * state is copied, allowing to calculate a new hash from there. This is
  * especially useful for generating many hashes with a common prefix.
  */
 @protocol OFCryptoHash <OFObject, OFCopying>
+#ifdef OF_HAVE_CLASS_PROPERTIES
+@property (class, readonly, nonatomic) size_t digestSize;
+@property (class, readonly, nonatomic) size_t blockSize;
+#endif
+
 /*!
  * A boolean whether the hash has already been calculated.
  */
 @property (readonly, nonatomic, getter=isCalculated) bool calculated;