diff --git a/crypto.c b/crypto.c
index b3b94a1..1d0dae3 100644
--- a/crypto.c
+++ b/crypto.c
@@ -540,8 +540,8 @@ smc_init3 (uint16_t size1, uint16_t size2, uint16_t size3)
 
 
 /**
- * smc_sums_partial calculates sums up until the current index and stores them
- * in @a out. \f$\forall i \leq len: out_i=\sum_{h=1}^iin_h\f$
+ * smc_sums_partial calculates sums up until and including the current index and
+ * stores them in @a out. \f$\forall i \leq len: out_i=\sum_{h=1}^iin_h\f$
  *
  * @param[out] out Where to store the resulting sums. Points must already be
  * initialized beforehand.