tools: Add firmware authenticated encryption tool

Add firmware authenticated encryption tool which utilizes OpenSSL
library to encrypt firmwares using a key provided via cmdline. Currently
this tool supports AES-GCM as an authenticated encryption algorithm.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Change-Id: I60e296af1b98f1912a19d5f91066be7ea85836e4
diff --git a/tools/encrypt_fw/include/encrypt.h b/tools/encrypt_fw/include/encrypt.h
new file mode 100644
index 0000000..25d3011
--- /dev/null
+++ b/tools/encrypt_fw/include/encrypt.h
@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) 2019, Linaro Limited. All rights reserved.
+ * Author: Sumit Garg <sumit.garg@linaro.org>
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef ENCRYPT_H
+#define ENCRYPT_H
+
+/* Supported key algorithms */
+enum {
+	KEY_ALG_GCM		/* AES-GCM (default) */
+};
+
+int encrypt_file(unsigned short fw_enc_status, int enc_alg, char *key_string,
+		 char *nonce_string, const char *ip_name, const char *op_name);
+
+#endif /* ENCRYPT_H */