diff --git a/library/pkcs12.c b/library/pkcs12.c
index 9823d96..3699dd5 100644
--- a/library/pkcs12.c
+++ b/library/pkcs12.c
@@ -330,8 +330,8 @@
         for( i = v; i > 0; i-- )
         {
             j = salt_block[i - 1] + hash_block[i - 1] + c;
-            c = (unsigned char) (j >> 8);
-            salt_block[i - 1] = j & 0xFF;
+            c = MBEDTLS_BYTE_1( j );
+            salt_block[i - 1] = MBEDTLS_BYTE_0( j );
         }
 
         // pwd_block  += B
@@ -339,8 +339,8 @@
         for( i = v; i > 0; i-- )
         {
             j = pwd_block[i - 1] + hash_block[i - 1] + c;
-            c = (unsigned char) (j >> 8);
-            pwd_block[i - 1] = j & 0xFF;
+            c = MBEDTLS_BYTE_1( j );
+            pwd_block[i - 1] = MBEDTLS_BYTE_0( j );
         }
     }