diff --git a/library/x509write_crt.c b/library/x509write_crt.c
index 6c78193..59fd589 100644
--- a/library/x509write_crt.c
+++ b/library/x509write_crt.c
@@ -45,6 +45,7 @@
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
 #include "psa/crypto.h"
 #include "mbedtls/psa_util.h"
+#include "md_psa.h"
 #endif /* MBEDTLS_USE_PSA_CRYPTO */
 
 #define CHECK_OVERFLOW_ADD(a, b) \