diff --git a/library/ssl_cookie.c b/library/ssl_cookie.c
index b51e91a..ae7a420 100644
--- a/library/ssl_cookie.c
+++ b/library/ssl_cookie.c
@@ -36,6 +36,7 @@
 #include <string.h>
 
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
+#include "md_psa.h"
 #define PSA_TO_MBEDTLS_ERR(status) PSA_TO_MBEDTLS_ERR_LIST(status,   \
                                                            psa_to_ssl_errors,             \
                                                            psa_generic_status_to_mbedtls)