diff --git a/include/mbedtls/aria.h b/include/mbedtls/aria.h
index 0cf06c4c7..153c76a71 100644
--- a/include/mbedtls/aria.h
+++ b/include/mbedtls/aria.h
@@ -124,24 +124,21 @@ int mbedtls_aria_setkey_dec( mbedtls_aria_context *ctx,
  * \brief          This function performs an ARIA single-block encryption or
  *                 decryption operation.
  *
- *                 It performs the operation defined in the \p mode parameter
- *                 (encrypt or decrypt), on the input data buffer defined in
- *                 the \p input parameter.
+ *                 It performs encryption or decryption (depending on whether
+ *                 the key was set for encryption on decryption) on the input
+ *                 data buffer defined in the \p input parameter.
  *
  *                 mbedtls_aria_init(), and either mbedtls_aria_setkey_enc() or
  *                 mbedtls_aria_setkey_dec() must be called before the first
  *                 call to this API with the same context.
  *
  * \param ctx      The ARIA context to use for encryption or decryption.
- * \param mode     The ARIA operation: #MBEDTLS_ARIA_ENCRYPT or
- *                 #MBEDTLS_ARIA_DECRYPT.
  * \param input    The 16-Byte buffer holding the input data.
  * \param output   The 16-Byte buffer holding the output data.
 
  * \return         \c 0 on success.
  */
 int mbedtls_aria_crypt_ecb( mbedtls_aria_context *ctx,
-                            int mode,
                             const unsigned char input[MBEDTLS_ARIA_BLOCKSIZE],
                             unsigned char output[MBEDTLS_ARIA_BLOCKSIZE] );
 
diff --git a/library/aria.c b/library/aria.c
index 498a13264..646978e89 100644
--- a/library/aria.c
+++ b/library/aria.c
@@ -536,7 +536,6 @@ int mbedtls_aria_setkey_dec( mbedtls_aria_context *ctx,
  * Encrypt a block
  */
 int mbedtls_aria_crypt_ecb( mbedtls_aria_context *ctx,
-                            int mode,
                             const unsigned char input[MBEDTLS_ARIA_BLOCKSIZE],
                             unsigned char output[MBEDTLS_ARIA_BLOCKSIZE] )
 {
@@ -544,8 +543,6 @@ int mbedtls_aria_crypt_ecb( mbedtls_aria_context *ctx,
 
     uint32_t a, b, c, d;
 
-    ( (void) mode );
-
     GET_UINT32_LE( a, input,  0 );
     GET_UINT32_LE( b, input,  4 );
     GET_UINT32_LE( c, input,  8 );
@@ -626,7 +623,7 @@ int mbedtls_aria_crypt_cbc( mbedtls_aria_context *ctx,
         while( length > 0 )
         {
             memcpy( temp, input, MBEDTLS_ARIA_BLOCKSIZE );
-            mbedtls_aria_crypt_ecb( ctx, mode, input, output );
+            mbedtls_aria_crypt_ecb( ctx, input, output );
 
             for( i = 0; i < MBEDTLS_ARIA_BLOCKSIZE; i++ )
                 output[i] = (unsigned char)( output[i] ^ iv[i] );
@@ -645,7 +642,7 @@ int mbedtls_aria_crypt_cbc( mbedtls_aria_context *ctx,
             for( i = 0; i < MBEDTLS_ARIA_BLOCKSIZE; i++ )
                 output[i] = (unsigned char)( input[i] ^ iv[i] );
 
-            mbedtls_aria_crypt_ecb( ctx, mode, output, output );
+            mbedtls_aria_crypt_ecb( ctx, output, output );
             memcpy( iv, output, MBEDTLS_ARIA_BLOCKSIZE );
 
             input  += MBEDTLS_ARIA_BLOCKSIZE;
@@ -678,7 +675,7 @@ int mbedtls_aria_crypt_cfb128( mbedtls_aria_context *ctx,
         while( length-- )
         {
             if( n == 0 )
-                mbedtls_aria_crypt_ecb( ctx, MBEDTLS_ARIA_ENCRYPT, iv, iv );
+                mbedtls_aria_crypt_ecb( ctx, iv, iv );
 
             c = *input++;
             *output++ = (unsigned char)( c ^ iv[n] );
@@ -692,7 +689,7 @@ int mbedtls_aria_crypt_cfb128( mbedtls_aria_context *ctx,
         while( length-- )
         {
             if( n == 0 )
-                mbedtls_aria_crypt_ecb( ctx, MBEDTLS_ARIA_ENCRYPT, iv, iv );
+                mbedtls_aria_crypt_ecb( ctx, iv, iv );
 
             iv[n] = *output++ = (unsigned char)( iv[n] ^ *input++ );
 
@@ -724,7 +721,7 @@ int mbedtls_aria_crypt_ctr( mbedtls_aria_context *ctx,
     while( length-- )
     {
         if( n == 0 ) {
-            mbedtls_aria_crypt_ecb( ctx, MBEDTLS_ARIA_ENCRYPT, nonce_counter,
+            mbedtls_aria_crypt_ecb( ctx, nonce_counter,
                                 stream_block );
 
             for( i = MBEDTLS_ARIA_BLOCKSIZE; i > 0; i-- )
@@ -916,8 +913,7 @@ int mbedtls_aria_self_test( int verbose )
         if( verbose )
             printf( "  ARIA-ECB-%d (enc): ", 128 + 64 * i );
         mbedtls_aria_setkey_enc( &ctx, aria_test1_ecb_key, 128 + 64 * i );
-        mbedtls_aria_crypt_ecb( &ctx, MBEDTLS_ARIA_ENCRYPT,
-            aria_test1_ecb_pt, blk );
+        mbedtls_aria_crypt_ecb( &ctx, aria_test1_ecb_pt, blk );
         if( memcmp( blk, aria_test1_ecb_ct[i], MBEDTLS_ARIA_BLOCKSIZE ) != 0 )
             ARIA_SELF_TEST_IF_FAIL;
 
@@ -925,8 +921,7 @@ int mbedtls_aria_self_test( int verbose )
         if( verbose )
             printf( "  ARIA-ECB-%d (dec): ", 128 + 64 * i );
         mbedtls_aria_setkey_dec( &ctx, aria_test1_ecb_key, 128 + 64 * i );
-        mbedtls_aria_crypt_ecb( &ctx, MBEDTLS_ARIA_DECRYPT,
-            aria_test1_ecb_ct[i], blk );
+        mbedtls_aria_crypt_ecb( &ctx, aria_test1_ecb_ct[i], blk );
         if( memcmp( blk, aria_test1_ecb_pt, MBEDTLS_ARIA_BLOCKSIZE ) != 0 )
             ARIA_SELF_TEST_IF_FAIL;
     }
diff --git a/library/cipher_wrap.c b/library/cipher_wrap.c
index 47851e9c0..b1ab8f164 100644
--- a/library/cipher_wrap.c
+++ b/library/cipher_wrap.c
@@ -831,7 +831,8 @@ static const mbedtls_cipher_info_t camellia_256_ccm_info = {
 static int aria_crypt_ecb_wrap( void *ctx, mbedtls_operation_t operation,
         const unsigned char *input, unsigned char *output )
 {
-    return mbedtls_aria_crypt_ecb( (mbedtls_aria_context *) ctx, operation, input,
+    (void) operation;
+    return mbedtls_aria_crypt_ecb( (mbedtls_aria_context *) ctx, input,
                                output );
 }
 
@@ -840,7 +841,8 @@ static int aria_crypt_cbc_wrap( void *ctx, mbedtls_operation_t operation,
         size_t length, unsigned char *iv,
         const unsigned char *input, unsigned char *output )
 {
-    return mbedtls_aria_crypt_cbc( (mbedtls_aria_context *) ctx, operation, length, iv,
+    (void) operation;
+    return mbedtls_aria_crypt_cbc( (mbedtls_aria_context *) ctx, length, iv,
                                input, output );
 }
 #endif /* MBEDTLS_CIPHER_MODE_CBC */