diff --git a/ext/lib/crypto/mbedtls/configs/config-tls1_2.h b/ext/lib/crypto/mbedtls/configs/config-tls1_2.h
new file mode 100644
index 0000000000000..640064b03098a
--- /dev/null
+++ b/ext/lib/crypto/mbedtls/configs/config-tls1_2.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2018 Linaro Limited.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * More complete mbedTLS configuration for TLS 1.2 (RFC 5246) for Zephyr,
+ * extending config-mini-tls1_2.h.
+ */
+
+#ifndef MBEDTLS_CONFIG_TLS1_2_H
+#define MBEDTLS_CONFIG_TLS1_2_H
+
+#if 1
+
+/* DHE config - slow but moderate code size impact (~5K x86) */
+#define MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED
+#define MBEDTLS_DHM_C
+
+#else
+
+/* ECDHE config - faster but higher code size impact (~15K x86) */
+#define MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED
+#define MBEDTLS_ECP_DP_SECP256R1_ENABLED
+#define MBEDTLS_ECDH_C
+#define MBEDTLS_ECP_C
+
+#endif
+
+#include <config-mini-tls1_2.h>
+
+#endif /* MBEDTLS_CONFIG_TLS1_2_H */