diff --git a/library/aria.c b/library/aria.c
index fdc2137..f5354a9 100644
--- a/library/aria.c
+++ b/library/aria.c
@@ -182,7 +182,7 @@
  * ARIA Affine Transform
  * (a, b, c, d) = state in/out
  *
- * If we denote the first by of input by 0, ..., the last byte by f,
+ * If we denote the first byte of input by 0, ..., the last byte by f,
  * then inputs are: a = 0123, b = 4567, c = 89ab, d = cdef.
  *
  * Reading [1] 2.4 or [2] 2.4.3 in columns and performing simple