1 files changed, 12 insertions, 0 deletions
diff --git a/src/basic/hmac.h b/src/basic/hmac.h
new file mode 100644
index 0000000..e58c183
--- /dev/null
+++ b/src/basic/hmac.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "sha256.h"
+
+/* Unoptimized implementation based on FIPS 198. 'res' has to be allocated by
+ * the caller. Prefer external OpenSSL functions, and use this only when
+ * linking to OpenSSL is not desirable (eg: libsystemd.so). */
+void hmac_sha256(const void *key, size_t key_size, const void *input, size_t input_size, uint8_t res[static SHA256_DIGEST_SIZE]);