diff --git a/library/ssl_ticket.c b/library/ssl_ticket.c
index 80a0356..7b76218 100644
--- a/library/ssl_ticket.c
+++ b/library/ssl_ticket.c
@@ -33,7 +33,8 @@
 #if defined(MBEDTLS_PLATFORM_C)
 #include "mbedtls/platform.h"
 #else
-#define mbedtls_malloc     malloc
+#include <stdlib.h>
+#define mbedtls_calloc    calloc
 #define mbedtls_free       free
 #endif
 
@@ -243,7 +244,7 @@
         if( p + cert_len > end )
             return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
 
-        session->peer_cert = mbedtls_malloc( sizeof( mbedtls_x509_crt ) );
+        session->peer_cert = mbedtls_calloc( 1, sizeof( mbedtls_x509_crt ) );
 
         if( session->peer_cert == NULL )
             return( MBEDTLS_ERR_SSL_MALLOC_FAILED );