diff --git a/library/ecjpake.c b/library/ecjpake.c
index d229311..7305dfe 100644
--- a/library/ecjpake.c
+++ b/library/ecjpake.c
@@ -180,10 +180,10 @@
     if( ret != 0 )
         return( ret );
 
-    (*p)[0] = (unsigned char)( ( len >> 24 ) & 0xFF );
-    (*p)[1] = (unsigned char)( ( len >> 16 ) & 0xFF );
-    (*p)[2] = (unsigned char)( ( len >>  8 ) & 0xFF );
-    (*p)[3] = (unsigned char)( ( len       ) & 0xFF );
+    (*p)[0] = MBEDTLS_CHAR_3( len );
+    (*p)[1] = MBEDTLS_CHAR_2( len );
+    (*p)[2] = MBEDTLS_CHAR_1( len );
+    (*p)[3] = MBEDTLS_CHAR_0( len );
 
     *p += 4 + len;
 
@@ -223,10 +223,10 @@
     if( end - p < 4 )
         return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );
 
-    *p++ = (unsigned char)( ( id_len >> 24 ) & 0xFF );
-    *p++ = (unsigned char)( ( id_len >> 16 ) & 0xFF );
-    *p++ = (unsigned char)( ( id_len >>  8 ) & 0xFF );
-    *p++ = (unsigned char)( ( id_len       ) & 0xFF );
+    *p++ = MBEDTLS_CHAR_3( id_len );
+    *p++ = MBEDTLS_CHAR_2( id_len );
+    *p++ = MBEDTLS_CHAR_1( id_len );
+    *p++ = MBEDTLS_CHAR_0( id_len );
 
     if( end < p || (size_t)( end - p ) < id_len )
         return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );
@@ -366,7 +366,7 @@
         goto cleanup;
     }
 
-    *(*p)++ = (unsigned char)( len & 0xFF );
+    *(*p)++ = MBEDTLS_CHAR_0( len );
     MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &h, *p, len ) ); /* r */
     *p += len;