diff --git a/crypto/cryptosoft.c b/crypto/cryptosoft.c
index 6c149cf1b1d..255b0b405ab 100644
--- a/crypto/cryptosoft.c
+++ b/crypto/cryptosoft.c
@@ -31,6 +31,7 @@
 #include <endian.h>
 #include <strings.h>
 #include <nuttx/kmalloc.h>
+#include <nuttx/lib/math32.h>
 #include <crypto/bn.h>
 #include <crypto/cryptodev.h>
 #include <crypto/cryptosoft.h>
@@ -42,10 +43,6 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
-#ifndef howmany
-#  define howmany(x, y)  (((x) + ((y) - 1)) / (y))
-#endif
-
 /****************************************************************************
  * Private Data
  ****************************************************************************/
@@ -275,7 +272,7 @@ int swcr_hash(FAR struct cryptop *crp,
 
 int swcr_authenc(FAR struct cryptop *crp)
 {
-  uint32_t blkbuf[howmany(EALG_MAX_BLOCK_LEN, sizeof(uint32_t))];
+  uint32_t blkbuf[div_round_up(EALG_MAX_BLOCK_LEN, sizeof(uint32_t))];
   FAR u_char *blk = (u_char *)blkbuf;
   u_char aalg[AALG_MAX_RESULT_LEN];
   u_char iv[EALG_MAX_BLOCK_LEN];