Squashed 'external/toxcore/c-toxcore/' content from commit 67badf69

git-subtree-dir: external/toxcore/c-toxcore
git-subtree-split: 67badf69416a74e74f6d7eb51dd96f37282b8455

toxcore/timed_auth.h

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+/* SPDX-License-Identifier: GPL-3.0-or-later
+ * Copyright © 2019-2021 The TokTok team.
+ */
+#ifndef C_TOXCORE_TOXCORE_TIMED_AUTH_H
+#define C_TOXCORE_TOXCORE_TIMED_AUTH_H
+
+#include "crypto_core.h"
+#include "mono_time.h"
+
+#define TIMED_AUTH_SIZE CRYPTO_HMAC_SIZE
+
+/**
+ * @brief Write timed authentication code of data to timed_auth.
+ *
+ * @param timed_auth Must be of size TIMED_AUTH_SIZE.
+ */
+
+non_null(1, 3, 6) nullable(4)
+void generate_timed_auth(const Mono_Time *mono_time, uint16_t timeout, const uint8_t *key,
+                         const uint8_t *data, uint16_t length, uint8_t *timed_auth);
+
+/**
+ * @brief Check timed_auth. This succeeds if `timed_auth` was generated by
+ * `generate_timed_auth` at most `timeout` seconds ago, and fails if at least
+ * `2*timeout` seconds ago. More precisely, it succeeds iff
+ * `current_time / timeout` is equal to or one more than
+ * `creation_time / timeout`.
+ *
+ * @param timed_auth Must be of size TIMED_AUTH_SIZE.
+ * @return true on success, false otherwise.
+ */
+non_null(1, 3, 6) nullable(4)
+bool check_timed_auth(const Mono_Time *mono_time, uint16_t timeout, const uint8_t *key,
+                      const uint8_t *data, uint16_t length, const uint8_t *timed_auth);
+#endif