Merge branch 'master' into jgrpp

# Conflicts:
#	.github/workflows/ci-build.yml
#	.github/workflows/release-linux.yml
#	.github/workflows/release-macos.yml
#	.github/workflows/release-source.yml
#	.github/workflows/release.yml
#	CMakeLists.txt
#	COMPILING.md
#	src/ai/ai_core.cpp
#	src/ai/ai_gui.cpp
#	src/bridge_gui.cpp
#	src/company_gui.cpp
#	src/console_cmds.cpp
#	src/core/CMakeLists.txt
#	src/core/smallmap_type.hpp
#	src/disaster_vehicle.h
#	src/effectvehicle_base.h
#	src/fontcache.cpp
#	src/game/game_core.cpp
#	src/game/game_gui.cpp
#	src/gamelog.cpp
#	src/gamelog_internal.h
#	src/group_gui.cpp
#	src/linkgraph/linkgraph.h
#	src/misc.cpp
#	src/network/core/config.h
#	src/network/core/udp.cpp
#	src/network/network_chat_gui.cpp
#	src/network/network_content_gui.cpp
#	src/network/network_gui.cpp
#	src/newgrf.cpp
#	src/newgrf_gui.cpp
#	src/newgrf_profiling.cpp
#	src/newgrf_profiling.h
#	src/object_gui.cpp
#	src/openttd.cpp
#	src/openttd.h
#	src/order_gui.cpp
#	src/os/windows/font_win32.cpp
#	src/rail_gui.cpp
#	src/road.cpp
#	src/road_gui.cpp
#	src/saveload/afterload.cpp
#	src/saveload/saveload.h
#	src/script/api/script_controller.cpp
#	src/script/api/script_roadtypelist.cpp
#	src/script/script_config.cpp
#	src/script/script_config.hpp
#	src/script/script_instance.cpp
#	src/script/script_scanner.cpp
#	src/script/squirrel.cpp
#	src/script/squirrel_helper.hpp
#	src/settings_gui.cpp
#	src/settings_internal.h
#	src/settings_type.h
#	src/table/settings/network_private_settings.ini
#	src/timetable_gui.cpp
#	src/vehicle.cpp
#	src/vehicle_base.h
#	src/window_gui.h

src/misc.cpp

@@ -39,9 +39,11 @@
 #include "cargopacket.h"
 #include "tbtr_template_vehicle_func.h"
 #include "event_logs.h"
+#include "3rdparty/monocypher/monocypher.h"
 
 #include "safeguards.h"
 
+std::string _savegame_id; ///< Unique ID of the current savegame.
 
 extern TileIndex _cur_tileloop_tile;
 extern TileIndex _aux_tileloop_tile;
@@ -66,6 +68,36 @@ void InitializeCheats();
 void InitializeNPF();
 void InitializeOldNames();
 
+/**
+ * Generate a unique ID.
+ */
+std::string GenerateUid(std::string_view subject)
+{
+	extern void NetworkRandomBytesWithFallback(void *buf, size_t n);
+	extern std::string BytesToHexString(const byte *data, uint length);
+
+	uint8 random_bytes[32];
+	NetworkRandomBytesWithFallback(random_bytes, lengthof(random_bytes));
+
+	uint8 digest[16];
+
+	crypto_blake2b_ctx ctx;
+	crypto_blake2b_init  (&ctx, lengthof(digest));
+	crypto_blake2b_update(&ctx, random_bytes, lengthof(random_bytes));
+	crypto_blake2b_update(&ctx, (const byte *)subject.data(), subject.size());
+	crypto_blake2b_final (&ctx, digest);
+
+	return BytesToHexString(digest, lengthof(digest));
+}
+
+/**
+ * Generate a unique savegame ID.
+ */
+void GenerateSavegameId()
+{
+	_savegame_id = GenerateUid("OpenTTD Savegame ID");
+}
+
 void InitializeGame(uint size_x, uint size_y, bool reset_date, bool reset_settings)
 {
 	/* Make sure there isn't any window that can influence anything