diff --git a/library/aria.c b/library/aria.c
index 320f775..6bfdfbd 100644
--- a/library/aria.c
+++ b/library/aria.c
@@ -212,22 +212,22 @@
                             const uint8_t sa[256], const uint8_t sb[256],
                             const uint8_t sc[256], const uint8_t sd[256] )
 {
-    *a = ( (uint32_t) sa[ *a        & 0xFF]       ) ^
-         (((uint32_t) sb[(*a >>  8) & 0xFF]) <<  8) ^
-         (((uint32_t) sc[(*a >> 16) & 0xFF]) << 16) ^
-         (((uint32_t) sd[ *a >> 24        ]) << 24);
-    *b = ( (uint32_t) sa[ *b        & 0xFF]       ) ^
-         (((uint32_t) sb[(*b >>  8) & 0xFF]) <<  8) ^
-         (((uint32_t) sc[(*b >> 16) & 0xFF]) << 16) ^
-         (((uint32_t) sd[ *b >> 24        ]) << 24);
-    *c = ( (uint32_t) sa[ *c        & 0xFF]       ) ^
-         (((uint32_t) sb[(*c >>  8) & 0xFF]) <<  8) ^
-         (((uint32_t) sc[(*c >> 16) & 0xFF]) << 16) ^
-         (((uint32_t) sd[ *c >> 24        ]) << 24);
-    *d = ( (uint32_t) sa[ *d        & 0xFF]       ) ^
-         (((uint32_t) sb[(*d >>  8) & 0xFF]) <<  8) ^
-         (((uint32_t) sc[(*d >> 16) & 0xFF]) << 16) ^
-         (((uint32_t) sd[ *d >> 24        ]) << 24);
+    *a = ( (uint32_t) sa[ MBEDTLS_BYTE_0( *a ) ]       ) ^
+         (((uint32_t) sb[ MBEDTLS_BYTE_1( *a ) ]) <<  8) ^
+         (((uint32_t) sc[ MBEDTLS_BYTE_2( *a ) ]) << 16) ^
+         (((uint32_t) sd[ *a >> 24             ]) << 24);
+    *b = ( (uint32_t) sa[ MBEDTLS_BYTE_0( *b ) ]       ) ^
+         (((uint32_t) sb[ MBEDTLS_BYTE_1( *b ) ]) <<  8) ^
+         (((uint32_t) sc[ MBEDTLS_BYTE_2( *b ) ]) << 16) ^
+         (((uint32_t) sd[ *b >> 24             ]) << 24);
+    *c = ( (uint32_t) sa[ MBEDTLS_BYTE_0( *c ) ]       ) ^
+         (((uint32_t) sb[ MBEDTLS_BYTE_1( *c ) ]) <<  8) ^
+         (((uint32_t) sc[ MBEDTLS_BYTE_2( *c ) ]) << 16) ^
+         (((uint32_t) sd[ *c >> 24             ]) << 24);
+    *d = ( (uint32_t) sa[ MBEDTLS_BYTE_0( *d ) ]       ) ^
+         (((uint32_t) sb[ MBEDTLS_BYTE_1( *d ) ]) <<  8) ^
+         (((uint32_t) sc[ MBEDTLS_BYTE_2( *d ) ]) << 16) ^
+         (((uint32_t) sd[ *d >> 24             ]) << 24);
 }
 
 /*