diff --git a/library/x509_crt.c b/library/x509_crt.c
index c6209fb..0e28dac 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -133,7 +133,8 @@
     MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA256 ) |
     MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA384 ),
     /* Only ECDSA */
-    MBEDTLS_X509_ID_FLAG( MBEDTLS_PK_ECDSA ),
+    MBEDTLS_X509_ID_FLAG( MBEDTLS_PK_ECDSA ) |
+    MBEDTLS_X509_ID_FLAG( MBEDTLS_PK_ECKEY ),
 #if defined(MBEDTLS_ECP_C)
     /* Only NIST P-256 and P-384 */
     MBEDTLS_X509_ID_FLAG( MBEDTLS_ECP_DP_SECP256R1 ) |