@@ -143,12 +143,11 @@
 
 	if (size == 0)
 		return self;
 
 	if (calculated)
-		/* FIXME: Maybe a new exception would be better */
-		@throw [OFInvalidArgumentException newWithClass: isa];
+		@throw [OFHashAlreadyCalculatedException newWithClass: isa];
 
 	/* Update bitcount */
 	t = bits[0];
 	if ((bits[0] = t + ((uint32_t)size << 3)) < t)
 		/* Carry from low to high */
@@ -382,12 +381,11 @@
 {
 	if (size == 0)
 		return self;
 
 	if (calculated)
-		/* FIXME: Maybe a new exception would be better */
-		@throw [OFInvalidArgumentException newWithClass: isa];
+		@throw [OFHashAlreadyCalculatedException newWithClass: isa];
 
 	sha1_update(state, &count, buffer, buf, size);
 
 	return self;
 }