diff --git a/library/aria.c b/library/aria.c
index 2c36598..a4d6c50 100644
--- a/library/aria.c
+++ b/library/aria.c
@@ -517,8 +517,10 @@
                            unsigned char *output)
 {
     unsigned char temp[MBEDTLS_ARIA_BLOCKSIZE];
-    ARIA_VALIDATE_RET(mode == MBEDTLS_ARIA_ENCRYPT ||
-                      mode == MBEDTLS_ARIA_DECRYPT);
+
+    if ((mode != MBEDTLS_ARIA_ENCRYPT) && (mode != MBEDTLS_ARIA_DECRYPT)) {
+        return MBEDTLS_ERR_ARIA_BAD_INPUT_DATA;
+    }
 
     if (length % MBEDTLS_ARIA_BLOCKSIZE) {
         return MBEDTLS_ERR_ARIA_INVALID_INPUT_LENGTH;
@@ -568,8 +570,10 @@
 {
     unsigned char c;
     size_t n;
-    ARIA_VALIDATE_RET(mode == MBEDTLS_ARIA_ENCRYPT ||
-                      mode == MBEDTLS_ARIA_DECRYPT);
+
+    if ((mode != MBEDTLS_ARIA_ENCRYPT) && (mode != MBEDTLS_ARIA_DECRYPT)) {
+        return MBEDTLS_ERR_ARIA_BAD_INPUT_DATA;
+    }
 
     n = *iv_off;
 
@@ -625,9 +629,6 @@
     int c, i;
     size_t n;
 
-    ARIA_VALIDATE_RET(length == 0 || input  != NULL);
-    ARIA_VALIDATE_RET(length == 0 || output != NULL);
-
     n = *nc_off;
     /* An overly large value of n can lead to an unlimited
      * buffer overflow. Therefore, guard against this