diff --git a/library/aria.c b/library/aria.c
index ca9e147..aff66d6 100644
--- a/library/aria.c
+++ b/library/aria.c
@@ -55,6 +55,12 @@
 #define inline __inline
 #endif
 
+/* Parameter validation macros */
+#define ARIA_VALIDATE_RET( cond )                                       \
+    MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_ARIA_BAD_INPUT_DATA )
+#define ARIA_VALIDATE( cond )                                           \
+    MBEDTLS_INTERNAL_VALIDATE( cond )
+
 /*
  * 32-bit integer manipulation macros (little endian)
  */
@@ -449,9 +455,11 @@
 
     int i;
     uint32_t w[4][4], *w2;
+    ARIA_VALIDATE_RET( ctx != NULL );
+    ARIA_VALIDATE_RET( key != NULL );
 
     if( keybits != 128 && keybits != 192 && keybits != 256 )
-        return( MBEDTLS_ERR_ARIA_INVALID_KEY_LENGTH );
+        return( MBEDTLS_ERR_ARIA_BAD_INPUT_DATA );
 
     /* Copy key to W0 (and potential remainder to W1) */
     GET_UINT32_LE( w[0][0], key,  0 );
@@ -503,6 +511,8 @@
                              const unsigned char *key, unsigned int keybits )
 {
     int i, j, k, ret;
+    ARIA_VALIDATE_RET( ctx != NULL );
+    ARIA_VALIDATE_RET( key != NULL );
 
     ret = mbedtls_aria_setkey_enc( ctx, key, keybits );
     if( ret != 0 )
@@ -539,6 +549,9 @@
     int i;
 
     uint32_t a, b, c, d;
+    ARIA_VALIDATE_RET( ctx != NULL );
+    ARIA_VALIDATE_RET( input != NULL );
+    ARIA_VALIDATE_RET( output != NULL );
 
     GET_UINT32_LE( a, input,  0 );
     GET_UINT32_LE( b, input,  4 );
@@ -586,6 +599,7 @@
 /* Initialize context */
 void mbedtls_aria_init( mbedtls_aria_context *ctx )
 {
+    ARIA_VALIDATE( ctx != NULL );
     memset( ctx, 0, sizeof( mbedtls_aria_context ) );
 }
 
@@ -612,6 +626,13 @@
     int i;
     unsigned char temp[MBEDTLS_ARIA_BLOCKSIZE];
 
+    ARIA_VALIDATE_RET( ctx != NULL );
+    ARIA_VALIDATE_RET( mode == MBEDTLS_ARIA_ENCRYPT ||
+                       mode == MBEDTLS_ARIA_DECRYPT );
+    ARIA_VALIDATE_RET( length == 0 || input  != NULL );
+    ARIA_VALIDATE_RET( length == 0 || output != NULL );
+    ARIA_VALIDATE_RET( iv != NULL );
+
     if( length % MBEDTLS_ARIA_BLOCKSIZE )
         return( MBEDTLS_ERR_ARIA_INVALID_INPUT_LENGTH );
 
@@ -665,7 +686,23 @@
                                unsigned char *output )
 {
     unsigned char c;
-    size_t n = *iv_off;
+    size_t n;
+
+    ARIA_VALIDATE_RET( ctx != NULL );
+    ARIA_VALIDATE_RET( mode == MBEDTLS_ARIA_ENCRYPT ||
+                       mode == MBEDTLS_ARIA_DECRYPT );
+    ARIA_VALIDATE_RET( length == 0 || input  != NULL );
+    ARIA_VALIDATE_RET( length == 0 || output != NULL );
+    ARIA_VALIDATE_RET( iv != NULL );
+    ARIA_VALIDATE_RET( iv_off != NULL );
+
+    n = *iv_off;
+
+    /* An overly large value of n can lead to an unlimited
+     * buffer overflow. Therefore, guard against this
+     * outside of parameter validation. */
+    if( n >= MBEDTLS_ARIA_BLOCKSIZE )
+        return( MBEDTLS_ERR_ARIA_BAD_INPUT_DATA );
 
     if( mode == MBEDTLS_ARIA_DECRYPT )
     {
@@ -713,7 +750,21 @@
                             unsigned char *output )
 {
     int c, i;
-    size_t n = *nc_off;
+    size_t n;
+
+    ARIA_VALIDATE_RET( ctx != NULL );
+    ARIA_VALIDATE_RET( length == 0 || input  != NULL );
+    ARIA_VALIDATE_RET( length == 0 || output != NULL );
+    ARIA_VALIDATE_RET( nonce_counter != NULL );
+    ARIA_VALIDATE_RET( stream_block  != NULL );
+    ARIA_VALIDATE_RET( nc_off != NULL );
+
+    n = *nc_off;
+    /* An overly large value of n can lead to an unlimited
+     * buffer overflow. Therefore, guard against this
+     * outside of parameter validation. */
+    if( n >= MBEDTLS_ARIA_BLOCKSIZE )
+        return( MBEDTLS_ERR_ARIA_BAD_INPUT_DATA );
 
     while( length-- )
     {